src/northbridge/intel/sandybridge/raminit_common.c

/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2014 Damien Zammit <damien@zamaudio.com>
 * Copyright (C) 2014 Vladimir Serbinenko <phcoder@gmail.com>
 * Copyright (C) 2016 Patrick Rudolph <siro@das-labor.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <console/console.h>
#include <console/usb.h>
#include <string.h>
#include <arch/io.h>
#include <cbmem.h>
#include <arch/cbfs.h>
#include <cbfs.h>
#include <northbridge/intel/sandybridge/chip.h>
#include <device/pci_def.h>
#include <delay.h>
#include <arch/cpu.h>
#include "raminit_native.h"
#include "raminit_common.h"
#include "sandybridge.h"

/* FIXME: no ECC support.  */
/* FIXME: no support for 3-channel chipsets.  */

/*
 * Register description:
 * Intel provides a command queue of depth four.
 * Every command is configured by using multiple registers.
 * On executing the command queue you have to provide the depth used.
 *
 * Known registers:
 * Channel X = [0, 1]
 * Command queue index Y = [0, 1, 2, 3]
 *
 * DEFAULT_MCHBAR + 0x4220 + 0x400 * X + 4 * Y: command io register
 *  Controls the DRAM command signals
 *  Bit 0: !RAS
 *  Bit 1: !CAS
 *  Bit 2: !WE
 *
 * DEFAULT_MCHBAR + 0x4200 + 0x400 * X + 4 * Y: addr bankslot io register
 *  Controls the address, bank address and slotrank signals
 *  Bit 0-15 : Address
 *  Bit 20-22: Bank Address
 *  Bit 24-25: slotrank
 *
 * DEFAULT_MCHBAR + 0x4230 + 0x400 * X + 4 * Y: idle register
 *  Controls the idle time after issuing this DRAM command
 *  Bit 16-32: number of clock-cylces to idle
 *
 * DEFAULT_MCHBAR + 0x4284 + 0x400 * channel: execute command queue
 *  Starts to execute all queued commands
 *  Bit 0    : start DRAM command execution
 *  Bit 18-19 : number of queued commands - 1
 */

#define RUN_QUEUE_4284(x)	((((x) - 1) << 18) | 1)	// 0 <= x < 4

static void sfence(void)
{
	asm volatile ("sfence");
}

static void toggle_io_reset(void) {
	/* toggle IO reset bit */
	u32 r32 = MCHBAR32(0x5030);
	MCHBAR32(0x5030) = r32 | 0x20;
	udelay(1);
	MCHBAR32(0x5030) = r32 & ~0x20;
	udelay(1);
}

static u32 get_XOVER_CLK(u8 rankmap)
{
	return rankmap << 24;
}

static u32 get_XOVER_CMD(u8 rankmap)
{
	u32 reg;

	// enable xover cmd
	reg = 0x4000;

	// enable xover ctl
	if (rankmap & 0x3)
		reg |= 0x20000;

	if (rankmap & 0xc)
		reg |= 0x4000000;

	return reg;
}

/* CAS write latency. To be programmed in MR2.
 * See DDR3 SPEC for MR2 documentation. */
u8 get_CWL(u32 tCK)
{
	/* Get CWL based on tCK using the following rule: */
	switch (tCK) {
	case TCK_1333MHZ:
		return 12;
	case TCK_1200MHZ:
	case TCK_1100MHZ:
		return 11;
	case TCK_1066MHZ:
	case TCK_1000MHZ:
		return 10;
	case TCK_933MHZ:
	case TCK_900MHZ:
		return 9;
	case TCK_800MHZ:
	case TCK_700MHZ:
		return 8;
	case TCK_666MHZ:
		return 7;
	case TCK_533MHZ:
		return 6;
	default:
		return 5;
	}
}

void dram_find_common_params(ramctr_timing *ctrl)
{
	size_t valid_dimms;
	int channel, slot;
	dimm_info *dimms = &ctrl->info;

	ctrl->cas_supported = (1 << (MAX_CAS - MIN_CAS + 1)) - 1;
	valid_dimms = 0;
	FOR_ALL_CHANNELS for (slot = 0; slot < 2; slot++) {
		const dimm_attr *dimm = &dimms->dimm[channel][slot];
		if (dimm->dram_type != SPD_MEMORY_TYPE_SDRAM_DDR3)
			continue;
		valid_dimms++;

		/* Find all possible CAS combinations */
		ctrl->cas_supported &= dimm->cas_supported;

		/* Find the smallest common latencies supported by all DIMMs */
		ctrl->tCK = MAX(ctrl->tCK, dimm->tCK);
		ctrl->tAA = MAX(ctrl->tAA, dimm->tAA);
		ctrl->tWR = MAX(ctrl->tWR, dimm->tWR);
		ctrl->tRCD = MAX(ctrl->tRCD, dimm->tRCD);
		ctrl->tRRD = MAX(ctrl->tRRD, dimm->tRRD);
		ctrl->tRP = MAX(ctrl->tRP, dimm->tRP);
		ctrl->tRAS = MAX(ctrl->tRAS, dimm->tRAS);
		ctrl->tRFC = MAX(ctrl->tRFC, dimm->tRFC);
		ctrl->tWTR = MAX(ctrl->tWTR, dimm->tWTR);
		ctrl->tRTP = MAX(ctrl->tRTP, dimm->tRTP);
		ctrl->tFAW = MAX(ctrl->tFAW, dimm->tFAW);
		ctrl->tCWL = MAX(ctrl->tCWL, dimm->tCWL);
		ctrl->tCMD = MAX(ctrl->tCMD, dimm->tCMD);
	}

	if (!ctrl->cas_supported)
		die("Unsupported DIMM combination. "
		    "DIMMS do not support common CAS latency");
	if (!valid_dimms)
		die("No valid DIMMs found");
}

void dram_xover(ramctr_timing * ctrl)
{
	u32 reg;
	int channel;

	FOR_ALL_CHANNELS {
		// enable xover clk
		reg = get_XOVER_CLK(ctrl->rankmap[channel]);
		printram("XOVER CLK [%x] = %x\n", channel * 0x100 + 0xc14,
			 reg);
		MCHBAR32(channel * 0x100 + 0xc14) = reg;

		// enable xover ctl & xover cmd
		reg = get_XOVER_CMD(ctrl->rankmap[channel]);
		printram("XOVER CMD [%x] = %x\n", 0x100 * channel + 0x320c,
			 reg);
		MCHBAR32(0x100 * channel + 0x320c) = reg;
	}
}

static void dram_odt_stretch(ramctr_timing *ctrl, int channel)
{
	struct cpuid_result cpures;
	u32 cpu, stretch;

	stretch = ctrl->ref_card_offset[channel];
	/* ODT stretch: Delay ODT signal by stretch value.
	 * Useful for multi DIMM setups on the same channel. */
	cpures = cpuid(1);
	cpu = cpures.eax;
	if (IS_SANDY_CPU(cpu) && IS_SANDY_CPU_C(cpu)) {
		if (stretch == 2)
			stretch = 3;
		MCHBAR32_AND_OR(0x401c + 0x400 * channel, 0xffffc3ff,
			(stretch << 12) | (stretch << 10));
		printram("OTHP Workaround [%x] = %x\n", addr, reg);
	} else {
		// OTHP
		MCHBAR32_AND_OR(0x400c + 0x400 * channel, 0xfff0ffff,
			(stretch << 16) | (stretch << 18));
		printram("OTHP [%x] = %x\n", addr, reg);
	}
}

void dram_timing_regs(ramctr_timing *ctrl)
{
	u32 reg, addr, val32;
	int channel;

	FOR_ALL_CHANNELS {
		// DBP
		reg = 0;
		reg |= ctrl->tRCD;
		reg |= (ctrl->tRP << 4);
		reg |= (ctrl->CAS << 8);
		reg |= (ctrl->CWL << 12);
		reg |= (ctrl->tRAS << 16);
		printram("DBP [%x] = %x\n", 0x400 * channel + 0x4000, reg);
		MCHBAR32(0x400 * channel + 0x4000) = reg;

		// RAP
		reg = 0;
		reg |= ctrl->tRRD;
		reg |= (ctrl->tRTP << 4);
		reg |= (ctrl->tCKE << 8);
		reg |= (ctrl->tWTR << 12);
		reg |= (ctrl->tFAW << 16);
		reg |= (ctrl->tWR << 24);
		reg |= (3 << 30);
		printram("RAP [%x] = %x\n", 0x400 * channel + 0x4004, reg);
		MCHBAR32(0x400 * channel + 0x4004) = reg;

		// OTHP
		addr = 0x400 * channel + 0x400c;
		reg = 0;
		reg |= ctrl->tXPDLL;
		reg |= (ctrl->tXP << 5);
		reg |= (ctrl->tAONPD << 8);
		reg |= 0xa0000;
		printram("OTHP [%x] = %x\n", addr, reg);
		MCHBAR32(addr) = reg;

		MCHBAR32(0x400 * channel + 0x4014) = 0;

		MCHBAR32_OR(addr, 0x00020000);

		dram_odt_stretch(ctrl, channel);

		/*
		 * TC-Refresh timing parameters
		 * The tREFIx9 field should be programmed to minimum of
		 * 8.9*tREFI (to allow for possible delays from ZQ or
		 * isoc) and tRASmax (70us) divided by 1024.
		 */
		val32 = MIN((ctrl->tREFI * 89) / 10, (70000 << 8) / ctrl->tCK);

		reg = ((ctrl->tREFI & 0xffff) << 0) |
			((ctrl->tRFC & 0x1ff) << 16) |
			(((val32 / 1024) & 0x7f) << 25);
		printram("REFI [%x] = %x\n", 0x400 * channel + 0x4298, reg);
		MCHBAR32(0x400 * channel + 0x4298) = reg;

		MCHBAR32_OR(0x400 * channel + 0x4294,  0xff);

		// SRFTP
		reg = 0;
		val32 = tDLLK;
		reg = (reg & ~0xfff) | val32;
		val32 = ctrl->tXSOffset;
		reg = (reg & ~0xf000) | (val32 << 12);
		val32 = tDLLK - ctrl->tXSOffset;
		reg = (reg & ~0x3ff0000) | (val32 << 16);
		val32 = ctrl->tMOD - 8;
		reg = (reg & ~0xf0000000) | (val32 << 28);
		printram("SRFTP [%x] = %x\n", 0x400 * channel + 0x42a4,
		       reg);
		MCHBAR32(0x400 * channel + 0x42a4) = reg;
	}
}

void dram_dimm_mapping(ramctr_timing *ctrl)
{
	int channel;
	dimm_info *info = &ctrl->info;

	FOR_ALL_CHANNELS {
		dimm_attr *dimmA, *dimmB;
		u32 reg = 0;

		if (info->dimm[channel][0].size_mb >=
		    info->dimm[channel][1].size_mb) {
			dimmA = &info->dimm[channel][0];
			dimmB = &info->dimm[channel][1];
			reg |= 0 << 16;
		} else {
			dimmA = &info->dimm[channel][1];
			dimmB = &info->dimm[channel][0];
			reg |= 1 << 16;
		}

		if (dimmA && (dimmA->ranks > 0)) {
			reg |= dimmA->size_mb / 256;
			reg |= (dimmA->ranks - 1) << 17;
			reg |= (dimmA->width / 8 - 1) << 19;
		}

		if (dimmB && (dimmB->ranks > 0)) {
			reg |= (dimmB->size_mb / 256) << 8;
			reg |= (dimmB->ranks - 1) << 18;
			reg |= (dimmB->width / 8 - 1) << 20;
		}

		reg |= 1 << 21; /* rank interleave */
		reg |= 1 << 22; /* enhanced interleave */

		if ((dimmA && (dimmA->ranks > 0))
		    || (dimmB && (dimmB->ranks > 0))) {
			ctrl->mad_dimm[channel] = reg;
		} else {
			ctrl->mad_dimm[channel] = 0;
		}
	}
}

void dram_dimm_set_mapping(ramctr_timing * ctrl)
{
	int channel;
	FOR_ALL_CHANNELS {
		MCHBAR32(0x5004 + channel * 4) = ctrl->mad_dimm[channel];
	}
}

void dram_zones(ramctr_timing * ctrl, int training)
{
	u32 reg, ch0size, ch1size;
	u8 val;
	reg = 0;
	val = 0;
	if (training) {
		ch0size = ctrl->channel_size_mb[0] ? 256 : 0;
		ch1size = ctrl->channel_size_mb[1] ? 256 : 0;
	} else {
		ch0size = ctrl->channel_size_mb[0];
		ch1size = ctrl->channel_size_mb[1];
	}

	if (ch0size >= ch1size) {
		reg = MCHBAR32(0x5014);
		val = ch1size / 256;
		reg = (reg & ~0xff000000) | val << 24;
		reg = (reg & ~0xff0000) | (2 * val) << 16;
		MCHBAR32(0x5014) = reg;
		MCHBAR32(0x5000) = 0x24;
	} else {
		reg = MCHBAR32(0x5014);
		val = ch0size / 256;
		reg = (reg & ~0xff000000) | val << 24;
		reg = (reg & ~0xff0000) | (2 * val) << 16;
		MCHBAR32(0x5014) = reg;
		MCHBAR32(0x5000) = 0x21;
	}
}

#define HOST_BRIDGE	PCI_DEVFN(0, 0)
#define DEFAULT_TCK	TCK_800MHZ

unsigned int get_mem_min_tck(void)
{
	u32 reg32;
	u8 rev;
	const struct device *dev;
	const struct northbridge_intel_sandybridge_config *cfg = NULL;

	dev = dev_find_slot(0, HOST_BRIDGE);
	if (dev)
		cfg = dev->chip_info;

	/* If this is zero, it just means devicetree.cb didn't set it */
	if (!cfg || cfg->max_mem_clock_mhz == 0) {
		if (IS_ENABLED(CONFIG_NATIVE_RAMINIT_IGNORE_MAX_MEM_FUSES))
			return TCK_1333MHZ;

		rev = pci_read_config8(PCI_DEV(0, 0, 0), PCI_DEVICE_ID);

		if ((rev & BASE_REV_MASK) == BASE_REV_SNB) {
			/* read Capabilities A Register DMFC bits */
			reg32 = pci_read_config32(PCI_DEV(0, 0, 0), CAPID0_A);
			reg32 &= 0x7;

			switch (reg32) {
			case 7: return TCK_533MHZ;
			case 6: return TCK_666MHZ;
			case 5: return TCK_800MHZ;
			/* reserved: */
			default:
				break;
			}
		} else {
			/* read Capabilities B Register DMFC bits */
			reg32 = pci_read_config32(PCI_DEV(0, 0, 0), CAPID0_B);
			reg32 = (reg32 >> 4) & 0x7;

			switch (reg32) {
			case 7: return TCK_533MHZ;
			case 6: return TCK_666MHZ;
			case 5: return TCK_800MHZ;
			case 4: return TCK_933MHZ;
			case 3: return TCK_1066MHZ;
			case 2: return TCK_1200MHZ;
			case 1: return TCK_1333MHZ;
			/* reserved: */
			default:
				break;
			}
		}
		return DEFAULT_TCK;
	} else {
		if (cfg->max_mem_clock_mhz >= 1066)
			return TCK_1066MHZ;
		else if (cfg->max_mem_clock_mhz >= 933)
			return TCK_933MHZ;
		else if (cfg->max_mem_clock_mhz >= 800)
			return TCK_800MHZ;
		else if (cfg->max_mem_clock_mhz >= 666)
			return TCK_666MHZ;
		else if (cfg->max_mem_clock_mhz >= 533)
			return TCK_533MHZ;
		else
			return TCK_400MHZ;
	}
}

#define DEFAULT_PCI_MMIO_SIZE 2048

static unsigned int get_mmio_size(void)
{
	const struct device *dev;
	const struct northbridge_intel_sandybridge_config *cfg = NULL;

	dev = dev_find_slot(0, HOST_BRIDGE);
	if (dev)
		cfg = dev->chip_info;

	/* If this is zero, it just means devicetree.cb didn't set it */
	if (!cfg || cfg->pci_mmio_size == 0)
		return DEFAULT_PCI_MMIO_SIZE;
	else
		return cfg->pci_mmio_size;
}

void dram_memorymap(ramctr_timing * ctrl, int me_uma_size)
{
	u32 reg, val, reclaim;
	u32 tom, gfxstolen, gttsize;
	size_t tsegsize, mmiosize, toludbase, touudbase, gfxstolenbase, gttbase,
	    tsegbase, mestolenbase;
	size_t tsegbasedelta, remapbase, remaplimit;
	uint16_t ggc;

	mmiosize = get_mmio_size();

	ggc = pci_read_config16(NORTHBRIDGE, GGC);
	if (!(ggc & 2)) {
		gfxstolen = ((ggc >> 3) & 0x1f) * 32;
		gttsize = ((ggc >> 8) & 0x3);
	} else {
		gfxstolen = 0;
		gttsize = 0;
	}

	tsegsize = CONFIG_SMM_TSEG_SIZE >> 20;

	tom = ctrl->channel_size_mb[0] + ctrl->channel_size_mb[1];

	mestolenbase = tom - me_uma_size;

	toludbase = MIN(4096 - mmiosize + gfxstolen + gttsize + tsegsize,
			tom - me_uma_size);
	gfxstolenbase = toludbase - gfxstolen;
	gttbase = gfxstolenbase - gttsize;

	tsegbase = gttbase - tsegsize;

	// Round tsegbase down to nearest address aligned to tsegsize
	tsegbasedelta = tsegbase & (tsegsize - 1);
	tsegbase &= ~(tsegsize - 1);

	gttbase -= tsegbasedelta;
	gfxstolenbase -= tsegbasedelta;
	toludbase -= tsegbasedelta;

	// Test if it is possible to reclaim a hole in the RAM addressing
	if (tom - me_uma_size > toludbase) {
		// Reclaim is possible
		reclaim = 1;
		remapbase = MAX(4096, tom - me_uma_size);
		remaplimit =
		    remapbase + MIN(4096, tom - me_uma_size) - toludbase - 1;
		touudbase = remaplimit + 1;
	} else {
		// Reclaim not possible
		reclaim = 0;
		touudbase = tom - me_uma_size;
	}

	// Update memory map in pci-e configuration space
	printk(BIOS_DEBUG, "Update PCI-E configuration space:\n");

	// TOM (top of memory)
	reg = pci_read_config32(PCI_DEV(0, 0, 0), 0xa0);
	val = tom & 0xfff;
	reg = (reg & ~0xfff00000) | (val << 20);
	printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0xa0, reg);
	pci_write_config32(PCI_DEV(0, 0, 0), 0xa0, reg);

	reg = pci_read_config32(PCI_DEV(0, 0, 0), 0xa4);
	val = tom & 0xfffff000;
	reg = (reg & ~0x000fffff) | (val >> 12);
	printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0xa4, reg);
	pci_write_config32(PCI_DEV(0, 0, 0), 0xa4, reg);

	// TOLUD (top of low used dram)
	reg = pci_read_config32(PCI_DEV(0, 0, 0), 0xbc);
	val = toludbase & 0xfff;
	reg = (reg & ~0xfff00000) | (val << 20);
	printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0xbc, reg);
	pci_write_config32(PCI_DEV(0, 0, 0), 0xbc, reg);

	// TOUUD LSB (top of upper usable dram)
	reg = pci_read_config32(PCI_DEV(0, 0, 0), 0xa8);
	val = touudbase & 0xfff;
	reg = (reg & ~0xfff00000) | (val << 20);
	printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0xa8, reg);
	pci_write_config32(PCI_DEV(0, 0, 0), 0xa8, reg);

	// TOUUD MSB
	reg = pci_read_config32(PCI_DEV(0, 0, 0), 0xac);
	val = touudbase & 0xfffff000;
	reg = (reg & ~0x000fffff) | (val >> 12);
	printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0xac, reg);
	pci_write_config32(PCI_DEV(0, 0, 0), 0xac, reg);

	if (reclaim) {
		// REMAP BASE
		pci_write_config32(PCI_DEV(0, 0, 0), 0x90, remapbase << 20);
		pci_write_config32(PCI_DEV(0, 0, 0), 0x94, remapbase >> 12);

		// REMAP LIMIT
		pci_write_config32(PCI_DEV(0, 0, 0), 0x98, remaplimit << 20);
		pci_write_config32(PCI_DEV(0, 0, 0), 0x9c, remaplimit >> 12);
	}
	// TSEG
	reg = pci_read_config32(PCI_DEV(0, 0, 0), 0xb8);
	val = tsegbase & 0xfff;
	reg = (reg & ~0xfff00000) | (val << 20);
	printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0xb8, reg);
	pci_write_config32(PCI_DEV(0, 0, 0), 0xb8, reg);

	// GFX stolen memory
	reg = pci_read_config32(PCI_DEV(0, 0, 0), 0xb0);
	val = gfxstolenbase & 0xfff;
	reg = (reg & ~0xfff00000) | (val << 20);
	printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0xb0, reg);
	pci_write_config32(PCI_DEV(0, 0, 0), 0xb0, reg);

	// GTT stolen memory
	reg = pci_read_config32(PCI_DEV(0, 0, 0), 0xb4);
	val = gttbase & 0xfff;
	reg = (reg & ~0xfff00000) | (val << 20);
	printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0xb4, reg);
	pci_write_config32(PCI_DEV(0, 0, 0), 0xb4, reg);

	if (me_uma_size) {
		reg = pci_read_config32(PCI_DEV(0, 0, 0), 0x7c);
		val = (0x80000 - me_uma_size) & 0xfffff000;
		reg = (reg & ~0x000fffff) | (val >> 12);
		printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0x7c, reg);
		pci_write_config32(PCI_DEV(0, 0, 0), 0x7c, reg);

		// ME base
		reg = pci_read_config32(PCI_DEV(0, 0, 0), 0x70);
		val = mestolenbase & 0xfff;
		reg = (reg & ~0xfff00000) | (val << 20);
		printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0x70, reg);
		pci_write_config32(PCI_DEV(0, 0, 0), 0x70, reg);

		reg = pci_read_config32(PCI_DEV(0, 0, 0), 0x74);
		val = mestolenbase & 0xfffff000;
		reg = (reg & ~0x000fffff) | (val >> 12);
		printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0x74, reg);
		pci_write_config32(PCI_DEV(0, 0, 0), 0x74, reg);

		// ME mask
		reg = pci_read_config32(PCI_DEV(0, 0, 0), 0x78);
		val = (0x80000 - me_uma_size) & 0xfff;
		reg = (reg & ~0xfff00000) | (val << 20);
		reg = (reg & ~0x400) | (1 << 10);	// set lockbit on ME mem

		reg = (reg & ~0x800) | (1 << 11);	// set ME memory enable
		printk(BIOS_DEBUG, "PCI(0, 0, 0)[%x] = %x\n", 0x78, reg);
		pci_write_config32(PCI_DEV(0, 0, 0), 0x78, reg);
	}
}

static void wait_428c(int channel)
{
	while (1) {
		if (MCHBAR32(0x428c + (channel << 10)) & 0x50)
			return;
	}
}

static void write_reset(ramctr_timing * ctrl)
{
	int channel, slotrank;

	/* choose a populated channel.  */
	channel = (ctrl->rankmap[0]) ? 0 : 1;

	wait_428c(channel);

	/* choose a populated rank.  */
	slotrank = (ctrl->rankmap[channel] & 1) ? 0 : 2;

	/* DRAM command ZQCS */
	MCHBAR32(0x4220 + 0x400 * channel) = 0x0f003;
	MCHBAR32(0x4230 + 0x400 * channel) = 0x80c01;
	MCHBAR32(0x4200 + 0x400 * channel) = (slotrank << 24) | 0x60000;
	MCHBAR32(0x4210 + 0x400 * channel) = 0;

	// execute command queue - why is bit 22 set here?!
	MCHBAR32(0x4284 + 0x400 * channel) = (1 << 22) | RUN_QUEUE_4284(1);

	wait_428c(channel);
}

void dram_jedecreset(ramctr_timing * ctrl)
{
	u32 reg;
	int channel;

	while (!(MCHBAR32(0x5084) & 0x10000));
	do {
		reg = MCHBAR32(0x428c);
	} while ((reg & 0x14) == 0);

	// Set state of memory controller
	reg = 0x112;
	MCHBAR32(0x5030) = reg;
	MCHBAR32(0x4ea0) = 0;
	reg |= 2;		//ddr reset
	MCHBAR32(0x5030) = reg;

	// Assert dimm reset signal
	MCHBAR32_AND(0x5030, ~0x2);

	// Wait 200us
	udelay(200);

	// Deassert dimm reset signal
	MCHBAR32_OR(0x5030, 2);

	// Wait 500us
	udelay(500);

	// Enable DCLK
	MCHBAR32_OR(0x5030, 4);

	// XXX Wait 20ns
	udelay(1);

	FOR_ALL_CHANNELS {
		// Set valid rank CKE
		reg = ctrl->rankmap[channel];
		MCHBAR32(0x42a0 + 0x400 * channel) = reg;

		// Wait 10ns for ranks to settle
		//udelay(0.01);

		reg = (reg & ~0xf0) | (ctrl->rankmap[channel] << 4);
		MCHBAR32(0x42a0 + 0x400 * channel) = reg;

		// Write reset using a NOP
		write_reset(ctrl);
	}
}

static odtmap get_ODT(ramctr_timing *ctrl, u8 rank, int channel)
{
	/* Get ODT based on rankmap: */
	int dimms_per_ch = (ctrl->rankmap[channel] & 1)
					+ ((ctrl->rankmap[channel] >> 2) & 1);

	if (dimms_per_ch == 1) {
		return (const odtmap){60, 60};
	} else {
		return (const odtmap){120, 30};
	}
}

static void write_mrreg(ramctr_timing *ctrl, int channel, int slotrank,
			int reg, u32 val)
{
	wait_428c(channel);

	if (ctrl->rank_mirror[channel][slotrank]) {
		/* DDR3 Rank1 Address mirror
		 * swap the following pins:
		 * A3<->A4, A5<->A6, A7<->A8, BA0<->BA1 */
		reg = ((reg >> 1) & 1) | ((reg << 1) & 2);
		val = (val & ~0x1f8) | ((val >> 1) & 0xa8)
		    | ((val & 0xa8) << 1);
	}

	/* DRAM command MRS */
	MCHBAR32(0x4220 + 0x400 * channel) = 0x0f000;
	MCHBAR32(0x4230 + 0x400 * channel) = 0x41001;
	MCHBAR32(0x4200 + 0x400 * channel) =
		(slotrank << 24) | (reg << 20) | val | 0x60000;
	MCHBAR32(0x4210 + 0x400 * channel) = 0;

	/* DRAM command MRS */
	MCHBAR32(0x4224 + 0x400 * channel) = 0x1f000;
	MCHBAR32(0x4234 + 0x400 * channel) = 0x41001;
	MCHBAR32(0x4204 + 0x400 * channel) =
		(slotrank << 24) | (reg << 20) | val | 0x60000;
	MCHBAR32(0x4214 + 0x400 * channel) = 0;

	/* DRAM command MRS */
	MCHBAR32(0x4228 + 0x400 * channel) = 0x0f000;
	MCHBAR32(0x4238 + 0x400 * channel) = 0x1001 | (ctrl->tMOD << 16);
	MCHBAR32(0x4208 + 0x400 * channel) =
		(slotrank << 24) | (reg << 20) | val | 0x60000;
	MCHBAR32(0x4218 + 0x400 * channel) = 0;

	// execute command queue
	MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(3);
}

static u32 make_mr0(ramctr_timing * ctrl, u8 rank)
{
	u16 mr0reg, mch_cas, mch_wr;
	static const u8 mch_wr_t[12] = { 1, 2, 3, 4, 0, 5, 0, 6, 0, 7, 0, 0 };
	const size_t is_mobile = get_platform_type() == PLATFORM_MOBILE;

	/* DLL Reset - self clearing - set after CLK frequency has been changed */
	mr0reg = 0x100;

	// Convert CAS to MCH register friendly
	if (ctrl->CAS < 12) {
		mch_cas = (u16) ((ctrl->CAS - 4) << 1);
	} else {
		mch_cas = (u16) (ctrl->CAS - 12);
		mch_cas = ((mch_cas << 1) | 0x1);
	}

	// Convert tWR to MCH register friendly
	mch_wr = mch_wr_t[ctrl->tWR - 5];

	mr0reg = (mr0reg & ~0x4) | ((mch_cas & 0x1) << 2);
	mr0reg = (mr0reg & ~0x70) | ((mch_cas & 0xe) << 3);
	mr0reg = (mr0reg & ~0xe00) | (mch_wr << 9);

	// Precharge PD - Fast (desktop) 0x1 or slow (mobile) 0x0 - mostly power-saving feature
	mr0reg = (mr0reg & ~0x1000) | (!is_mobile << 12);
	return mr0reg;
}

static void dram_mr0(ramctr_timing *ctrl, u8 rank, int channel)
{
	write_mrreg(ctrl, channel, rank, 0, make_mr0(ctrl, rank));
}

static u32 encode_odt(u32 odt)
{
	switch (odt) {
	case 30:
		return (1 << 9) | (1 << 2);	// RZQ/8, RZQ/4
	case 60:
		return (1 << 2);	// RZQ/4
	case 120:
		return (1 << 6);	// RZQ/2
	default:
	case 0:
		return 0;
	}
}

static u32 make_mr1(ramctr_timing *ctrl, u8 rank, int channel)
{
	odtmap odt;
	u32 mr1reg;

	odt = get_ODT(ctrl, rank, channel);
	mr1reg = 0x2;

	mr1reg |= encode_odt(odt.rttnom);

	return mr1reg;
}

static void dram_mr1(ramctr_timing *ctrl, u8 rank, int channel)
{
	u16 mr1reg;

	mr1reg = make_mr1(ctrl, rank, channel);

	write_mrreg(ctrl, channel, rank, 1, mr1reg);
}

static void dram_mr2(ramctr_timing *ctrl, u8 rank, int channel)
{
	u16 pasr, cwl, mr2reg;
	odtmap odt;
	int srt;

	pasr = 0;
	cwl = ctrl->CWL - 5;
	odt = get_ODT(ctrl, rank, channel);

	srt = ctrl->extended_temperature_range && !ctrl->auto_self_refresh;

	mr2reg = 0;
	mr2reg = (mr2reg & ~0x7) | pasr;
	mr2reg = (mr2reg & ~0x38) | (cwl << 3);
	mr2reg = (mr2reg & ~0x40) | (ctrl->auto_self_refresh << 6);
	mr2reg = (mr2reg & ~0x80) | (srt << 7);
	mr2reg |= (odt.rttwr / 60) << 9;

	write_mrreg(ctrl, channel, rank, 2, mr2reg);
}

static void dram_mr3(ramctr_timing *ctrl, u8 rank, int channel)
{
	write_mrreg(ctrl, channel, rank, 3, 0);
}

void dram_mrscommands(ramctr_timing * ctrl)
{
	u8 slotrank;
	int channel;

	FOR_ALL_POPULATED_CHANNELS {
		FOR_ALL_POPULATED_RANKS {
			// MR2
			dram_mr2(ctrl, slotrank, channel);

			// MR3
			dram_mr3(ctrl, slotrank, channel);

			// MR1
			dram_mr1(ctrl, slotrank, channel);

			// MR0
			dram_mr0(ctrl, slotrank, channel);
		}
	}

	/* DRAM command NOP */
	MCHBAR32(0x4e20) = 0x7;
	MCHBAR32(0x4e30) = 0xf1001;
	MCHBAR32(0x4e00) = 0x60002;
	MCHBAR32(0x4e10) = 0;

	/* DRAM command ZQCL */
	MCHBAR32(0x4e24) = 0x1f003;
	MCHBAR32(0x4e34) = 0x1901001;
	MCHBAR32(0x4e04) = 0x60400;
	MCHBAR32(0x4e14) = 0x288;

	// execute command queue on all channels? Why isn't bit 0 set here?
	MCHBAR32(0x4e84) = 0x40004;

	// Drain
	FOR_ALL_CHANNELS {
		// Wait for ref drained
		wait_428c(channel);
	}

	// Refresh enable
	MCHBAR32_OR(0x5030, 8);

	FOR_ALL_POPULATED_CHANNELS {
		MCHBAR32_AND(0x4020 + 0x400 * channel, ~0x200000);

		wait_428c(channel);

		slotrank = (ctrl->rankmap[channel] & 1) ? 0 : 2;

		// Drain
		wait_428c(channel);

		/* DRAM command ZQCS */
		MCHBAR32(0x4220 + 0x400 * channel) = 0x0f003;
		MCHBAR32(0x4230 + 0x400 * channel) = 0x659001;
		MCHBAR32(0x4200 + 0x400 * channel) =
			(slotrank << 24) | 0x60000;
		MCHBAR32(0x4210 + 0x400 * channel) = 0x3e0;

		// execute command queue
		MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(1);

		// Drain
		wait_428c(channel);
	}
}

static const u32 lane_registers[] = {
	0x0000, 0x0200, 0x0400, 0x0600,
	0x1000, 0x1200, 0x1400, 0x1600,
	0x0800
};

void program_timings(ramctr_timing * ctrl, int channel)
{
	u32 reg32, reg_4024, reg_c14, reg_c18, reg_4028;
	int lane;
	int slotrank, slot;
	int full_shift = 0;
	u16 slot320c[NUM_SLOTS];

	FOR_ALL_POPULATED_RANKS {
		if (full_shift < -ctrl->timings[channel][slotrank].val_320c)
			full_shift = -ctrl->timings[channel][slotrank].val_320c;
	}

	for (slot = 0; slot < NUM_SLOTS; slot++)
		switch ((ctrl->rankmap[channel] >> (2 * slot)) & 3) {
		case 0:
		default:
			slot320c[slot] = 0x7f;
			break;
		case 1:
			slot320c[slot] =
			    ctrl->timings[channel][2 * slot + 0].val_320c +
			    full_shift;
			break;
		case 2:
			slot320c[slot] =
			    ctrl->timings[channel][2 * slot + 1].val_320c +
			    full_shift;
			break;
		case 3:
			slot320c[slot] =
			    (ctrl->timings[channel][2 * slot].val_320c +
			    ctrl->timings[channel][2 * slot + 1].val_320c) / 2 +
			    full_shift;
			break;
		}

	/* enable CMD XOVER */
	reg32 = get_XOVER_CMD(ctrl->rankmap[channel]);
	reg32 |= ((slot320c[0] & 0x3f) << 6) | ((slot320c[0] & 0x40) << 9);
	reg32 |= (slot320c[1] & 0x7f) << 18;
	reg32 |= (full_shift & 0x3f) | ((full_shift & 0x40) << 6);

	MCHBAR32(0x320c + 0x100 * channel) = reg32;

	/* enable CLK XOVER */
	reg_c14 = get_XOVER_CLK(ctrl->rankmap[channel]);
	reg_c18 = 0;

	FOR_ALL_POPULATED_RANKS {
		int shift =
		    ctrl->timings[channel][slotrank].val_320c + full_shift;
		int offset_val_c14;
		if (shift < 0)
			shift = 0;
		offset_val_c14 = ctrl->reg_c14_offset + shift;
		/* set CLK phase shift */
		reg_c14 |= (offset_val_c14 & 0x3f) << (6 * slotrank);
		reg_c18 |= ((offset_val_c14 >> 6) & 1) << slotrank;
	}

	MCHBAR32(0xc14 + channel * 0x100) = reg_c14;
	MCHBAR32(0xc18 + channel * 0x100) = reg_c18;

	reg_4028 = MCHBAR32(0x4028 + 0x400 * channel);
	reg_4028 &= 0xffff0000;

	reg_4024 = 0;

	FOR_ALL_POPULATED_RANKS {
		int post_timA_min_high = 7, post_timA_max_high = 0;
		int pre_timA_min_high = 7, pre_timA_max_high = 0;
		int shift_402x = 0;
		int shift =
		    ctrl->timings[channel][slotrank].val_320c + full_shift;

		if (shift < 0)
			shift = 0;

		FOR_ALL_LANES {
			post_timA_min_high = MIN(post_timA_min_high,
				(ctrl->timings[channel][slotrank].lanes[lane].
					timA + shift) >> 6);
			pre_timA_min_high = MIN(pre_timA_min_high,
				ctrl->timings[channel][slotrank].lanes[lane].
						timA >> 6);
			post_timA_max_high = MAX(post_timA_max_high,
				(ctrl->timings[channel][slotrank].lanes[lane].
					timA + shift) >> 6);
			pre_timA_max_high = MAX(pre_timA_max_high,
				ctrl->timings[channel][slotrank].lanes[lane].
						timA >> 6);
		}

		if (pre_timA_max_high - pre_timA_min_high <
		    post_timA_max_high - post_timA_min_high)
			shift_402x = +1;
		else if (pre_timA_max_high - pre_timA_min_high >
			 post_timA_max_high - post_timA_min_high)
			shift_402x = -1;

		reg_4028 |=
		    (ctrl->timings[channel][slotrank].val_4028 + shift_402x -
		     post_timA_min_high) << (4 * slotrank);
		reg_4024 |=
		    (ctrl->timings[channel][slotrank].val_4024 +
		     shift_402x) << (8 * slotrank);

		FOR_ALL_LANES {
			MCHBAR32(lane_registers[lane] + 0x10 + 0x100 * channel +
				 4 * slotrank)
			    =
			    (((ctrl->timings[channel][slotrank].lanes[lane].
			       timA + shift) & 0x3f)
			     |
			     ((ctrl->timings[channel][slotrank].lanes[lane].
			       rising + shift) << 8)
			     |
			     (((ctrl->timings[channel][slotrank].lanes[lane].
				timA + shift -
				(post_timA_min_high << 6)) & 0x1c0) << 10)
			     | ((ctrl->timings[channel][slotrank].lanes[lane].
				falling + shift) << 20));

			MCHBAR32(lane_registers[lane] + 0x20 + 0x100 * channel +
				 4 * slotrank)
			    =
			    (((ctrl->timings[channel][slotrank].lanes[lane].
			       timC + shift) & 0x3f)
			     |
			     (((ctrl->timings[channel][slotrank].lanes[lane].
				timB + shift) & 0x3f) << 8)
			     |
			     (((ctrl->timings[channel][slotrank].lanes[lane].
				timB + shift) & 0x1c0) << 9)
			     |
			     (((ctrl->timings[channel][slotrank].lanes[lane].
				timC + shift) & 0x40) << 13));
		}
	}
	MCHBAR32(0x4024 + 0x400 * channel) = reg_4024;
	MCHBAR32(0x4028 + 0x400 * channel) = reg_4028;
}

static void test_timA(ramctr_timing * ctrl, int channel, int slotrank)
{
	wait_428c(channel);

	/* DRAM command MRS
	 * write MR3 MPR enable
	 * in this mode only RD and RDA are allowed
	 * all reads return a predefined pattern */
	MCHBAR32(0x4220 + 0x400 * channel) = 0x1f000;
	MCHBAR32(0x4230 + 0x400 * channel) = (0xc01 | (ctrl->tMOD << 16));
	MCHBAR32(0x4200 + 0x400 * channel) = (slotrank << 24) | 0x360004;
	MCHBAR32(0x4210 + 0x400 * channel) = 0;

	/* DRAM command RD */
	MCHBAR32(0x4224 + 0x400 * channel) = 0x1f105;
	MCHBAR32(0x4234 + 0x400 * channel) = 0x4040c01;
	MCHBAR32(0x4204 + 0x400 * channel) = (slotrank << 24);
	MCHBAR32(0x4214 + 0x400 * channel) = 0;

	/* DRAM command RD */
	MCHBAR32(0x4228 + 0x400 * channel) = 0x1f105;
	MCHBAR32(0x4238 + 0x400 * channel) = 0x100f | ((ctrl->CAS + 36) << 16);
	MCHBAR32(0x4208 + 0x400 * channel) = (slotrank << 24) | 0x60000;
	MCHBAR32(0x4218 + 0x400 * channel) = 0;

	/* DRAM command MRS
	 * write MR3 MPR disable */
	MCHBAR32(0x422c + 0x400 * channel) = 0x1f000;
	MCHBAR32(0x423c + 0x400 * channel) = 0xc01 | (ctrl->tMOD << 16);
	MCHBAR32(0x420c + 0x400 * channel) = (slotrank << 24) | 0x360000;
	MCHBAR32(0x421c + 0x400 * channel) = 0;

	// execute command queue
	MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

	wait_428c(channel);
}

static int does_lane_work(ramctr_timing * ctrl, int channel, int slotrank,
			  int lane)
{
	u32 timA = ctrl->timings[channel][slotrank].lanes[lane].timA;
	return ((MCHBAR32(lane_registers[lane] + channel * 0x100 + 4 +
		  ((timA / 32) & 1) * 4)
		 >> (timA % 32)) & 1);
}

struct run {
	int middle;
	int end;
	int start;
	int all;
	int length;
};

static struct run get_longest_zero_run(int *seq, int sz)
{
	int i, ls;
	int bl = 0, bs = 0;
	struct run ret;

	ls = 0;
	for (i = 0; i < 2 * sz; i++)
		if (seq[i % sz]) {
			if (i - ls > bl) {
				bl = i - ls;
				bs = ls;
			}
			ls = i + 1;
		}
	if (bl == 0) {
		ret.middle = sz / 2;
		ret.start = 0;
		ret.end = sz;
		ret.all = 1;
		return ret;
	}

	ret.start = bs % sz;
	ret.end = (bs + bl - 1) % sz;
	ret.middle = (bs + (bl - 1) / 2) % sz;
	ret.length = bl;
	ret.all = 0;

	return ret;
}

static void discover_timA_coarse(ramctr_timing * ctrl, int channel,
				 int slotrank, int *upperA)
{
	int timA;
	int statistics[NUM_LANES][128];
	int lane;

	for (timA = 0; timA < 128; timA++) {
		FOR_ALL_LANES {
			ctrl->timings[channel][slotrank].lanes[lane].timA = timA;
		}
		program_timings(ctrl, channel);

		test_timA(ctrl, channel, slotrank);

		FOR_ALL_LANES {
			statistics[lane][timA] =
			    !does_lane_work(ctrl, channel, slotrank, lane);
		}
	}
	FOR_ALL_LANES {
		struct run rn = get_longest_zero_run(statistics[lane], 128);
		ctrl->timings[channel][slotrank].lanes[lane].timA = rn.middle;
		upperA[lane] = rn.end;
		if (upperA[lane] < rn.middle)
			upperA[lane] += 128;
		printram("timA: %d, %d, %d: 0x%02x-0x%02x-0x%02x\n",
			 channel, slotrank, lane, rn.start, rn.middle, rn.end);
	}
}

static void discover_timA_fine(ramctr_timing * ctrl, int channel, int slotrank,
			       int *upperA)
{
	int timA_delta;
	int statistics[NUM_LANES][51];
	int lane, i;

	memset(statistics, 0, sizeof(statistics));

	for (timA_delta = -25; timA_delta <= 25; timA_delta++) {
		FOR_ALL_LANES ctrl->timings[channel][slotrank].lanes[lane].
		    timA = upperA[lane] + timA_delta + 0x40;
		program_timings(ctrl, channel);

		for (i = 0; i < 100; i++) {
			test_timA(ctrl, channel, slotrank);
			FOR_ALL_LANES {
				statistics[lane][timA_delta + 25] +=
					does_lane_work(ctrl, channel, slotrank,
						lane);
			}
		}
	}
	FOR_ALL_LANES {
		int last_zero, first_all;

		for (last_zero = -25; last_zero <= 25; last_zero++)
			if (statistics[lane][last_zero + 25])
				break;
		last_zero--;
		for (first_all = -25; first_all <= 25; first_all++)
			if (statistics[lane][first_all + 25] == 100)
				break;

		printram("lane %d: %d, %d\n", lane, last_zero,
		       first_all);

		ctrl->timings[channel][slotrank].lanes[lane].timA =
		    (last_zero + first_all) / 2 + upperA[lane];
		printram("Aval: %d, %d, %d: %x\n", channel, slotrank,
		       lane, ctrl->timings[channel][slotrank].lanes[lane].timA);
	}
}

static int discover_402x(ramctr_timing *ctrl, int channel, int slotrank,
			  int *upperA)
{
	int works[NUM_LANES];
	int lane;
	while (1) {
		int all_works = 1, some_works = 0;
		program_timings(ctrl, channel);
		test_timA(ctrl, channel, slotrank);
		FOR_ALL_LANES {
			works[lane] =
			    !does_lane_work(ctrl, channel, slotrank, lane);
			if (works[lane])
				some_works = 1;
			else
				all_works = 0;
		}
		if (all_works)
			return 0;
		if (!some_works) {
			if (ctrl->timings[channel][slotrank].val_4024 < 2) {
				printk(BIOS_EMERG, "402x discovery failed (1): %d, %d\n",
				       channel, slotrank);
				return MAKE_ERR;
			}
			ctrl->timings[channel][slotrank].val_4024 -= 2;
			printram("4024 -= 2;\n");
			continue;
		}
		ctrl->timings[channel][slotrank].val_4028 += 2;
		printram("4028 += 2;\n");
		if (ctrl->timings[channel][slotrank].val_4028 >= 0x10) {
			printk(BIOS_EMERG, "402x discovery failed (2): %d, %d\n",
			       channel, slotrank);
			return MAKE_ERR;
		}
		FOR_ALL_LANES if (works[lane]) {
			ctrl->timings[channel][slotrank].lanes[lane].timA +=
			    128;
			upperA[lane] += 128;
			printram("increment %d, %d, %d\n", channel,
			       slotrank, lane);
		}
	}
	return 0;
}

struct timA_minmax {
	int timA_min_high, timA_max_high;
};

static void pre_timA_change(ramctr_timing * ctrl, int channel, int slotrank,
			    struct timA_minmax *mnmx)
{
	int lane;
	mnmx->timA_min_high = 7;
	mnmx->timA_max_high = 0;

	FOR_ALL_LANES {
		if (mnmx->timA_min_high >
		    (ctrl->timings[channel][slotrank].lanes[lane].timA >> 6))
			mnmx->timA_min_high =
			    (ctrl->timings[channel][slotrank].lanes[lane].
			     timA >> 6);
		if (mnmx->timA_max_high <
		    (ctrl->timings[channel][slotrank].lanes[lane].timA >> 6))
			mnmx->timA_max_high =
			    (ctrl->timings[channel][slotrank].lanes[lane].
			     timA >> 6);
	}
}

static void post_timA_change(ramctr_timing * ctrl, int channel, int slotrank,
			     struct timA_minmax *mnmx)
{
	struct timA_minmax post;
	int shift_402x = 0;

	/* Get changed maxima.  */
	pre_timA_change(ctrl, channel, slotrank, &post);

	if (mnmx->timA_max_high - mnmx->timA_min_high <
	    post.timA_max_high - post.timA_min_high)
		shift_402x = +1;
	else if (mnmx->timA_max_high - mnmx->timA_min_high >
		 post.timA_max_high - post.timA_min_high)
		shift_402x = -1;
	else
		shift_402x = 0;

	ctrl->timings[channel][slotrank].val_4028 += shift_402x;
	ctrl->timings[channel][slotrank].val_4024 += shift_402x;
	printram("4024 += %d;\n", shift_402x);
	printram("4028 += %d;\n", shift_402x);
}

/* Compensate the skew between DQS and DQs.
 * To ease PCB design a small skew between Data Strobe signals and
 * Data Signals is allowed.
 * The controller has to measure and compensate this skew for every byte-lane.
 * By delaying either all DQs signals or DQS signal, a full phase
 * shift can be introduced.
 * It is assumed that one byte-lane's DQs signals have the same routing delay.
 *
 * To measure the actual skew, the DRAM is placed in "read leveling" mode.
 * In read leveling mode the DRAM-chip outputs an alternating periodic pattern.
 * The memory controller iterates over all possible values to do a full phase shift
 * and issues read commands.
 * With DQS and DQs in phase the data read is expected to alternate on every byte:
 * 0xFF 0x00 0xFF ...
 * Once the controller has detected this pattern a bit in the result register is
 * set for the current phase shift.
 */
int read_training(ramctr_timing * ctrl)
{
	int channel, slotrank, lane;
	int err;

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
		int all_high, some_high;
		int upperA[NUM_LANES];
		struct timA_minmax mnmx;

		wait_428c(channel);

		/* DRAM command PREA */
		MCHBAR32(0x4220 + 0x400 * channel) = 0x1f002;
		MCHBAR32(0x4230 + 0x400 * channel) = 0xc01 | (ctrl->tRP << 16);
		MCHBAR32(0x4200 + 0x400 * channel) = (slotrank << 24) | 0x60400;
		MCHBAR32(0x4210 + 0x400 * channel) = 0;

		// execute command queue
		MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(1);

		MCHBAR32(0x3400) = (slotrank << 2) | 0x8001;

		ctrl->timings[channel][slotrank].val_4028 = 4;
		ctrl->timings[channel][slotrank].val_4024 = 55;
		program_timings(ctrl, channel);

		discover_timA_coarse(ctrl, channel, slotrank, upperA);

		all_high = 1;
		some_high = 0;
		FOR_ALL_LANES {
			if (ctrl->timings[channel][slotrank].lanes[lane].timA >=
			    0x40)
				some_high = 1;
			else
				all_high = 0;
		}

		if (all_high) {
			ctrl->timings[channel][slotrank].val_4028--;
			printram("4028--;\n");
			FOR_ALL_LANES {
				ctrl->timings[channel][slotrank].lanes[lane].
				    timA -= 0x40;
				upperA[lane] -= 0x40;

			}
		} else if (some_high) {
			ctrl->timings[channel][slotrank].val_4024++;
			ctrl->timings[channel][slotrank].val_4028++;
			printram("4024++;\n");
			printram("4028++;\n");
		}

		program_timings(ctrl, channel);

		pre_timA_change(ctrl, channel, slotrank, &mnmx);

		err = discover_402x(ctrl, channel, slotrank, upperA);
		if (err)
			return err;

		post_timA_change(ctrl, channel, slotrank, &mnmx);
		pre_timA_change(ctrl, channel, slotrank, &mnmx);

		discover_timA_fine(ctrl, channel, slotrank, upperA);

		post_timA_change(ctrl, channel, slotrank, &mnmx);
		pre_timA_change(ctrl, channel, slotrank, &mnmx);

		FOR_ALL_LANES {
			ctrl->timings[channel][slotrank].lanes[lane].timA -= mnmx.timA_min_high * 0x40;
		}
		ctrl->timings[channel][slotrank].val_4028 -= mnmx.timA_min_high;
		printram("4028 -= %d;\n", mnmx.timA_min_high);

		post_timA_change(ctrl, channel, slotrank, &mnmx);

		printram("4/8: %d, %d, %x, %x\n", channel, slotrank,
		       ctrl->timings[channel][slotrank].val_4024,
		       ctrl->timings[channel][slotrank].val_4028);

		printram("final results:\n");
		FOR_ALL_LANES
			printram("Aval: %d, %d, %d: %x\n", channel, slotrank,
			    lane,
			    ctrl->timings[channel][slotrank].lanes[lane].timA);

		MCHBAR32(0x3400) = 0;

		toggle_io_reset();
	}

	FOR_ALL_POPULATED_CHANNELS {
		program_timings(ctrl, channel);
	}
	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
		MCHBAR32(0x4080 + 0x400 * channel + 4 * lane) = 0;
	}
	return 0;
}

static void test_timC(ramctr_timing * ctrl, int channel, int slotrank)
{
	int lane;

	FOR_ALL_LANES {
		volatile u32 tmp;
		MCHBAR32(0x4340 + 0x400 * channel + 4 * lane) = 0;
		tmp = MCHBAR32(0x4140 + 0x400 * channel + 4 * lane);
	}

	wait_428c(channel);

	/* DRAM command ACT */
	MCHBAR32(0x4220 + 0x400 * channel) = 0x1f006;
	MCHBAR32(0x4230 + 0x400 * channel) =
		(max((ctrl->tFAW >> 2) + 1, ctrl->tRRD) << 10)
		| 4 | (ctrl->tRCD << 16);
	MCHBAR32(0x4200 + 0x400 * channel) = (slotrank << 24) | (6 << 16);
	MCHBAR32(0x4210 + 0x400 * channel) = 0x244;

	/* DRAM command NOP */
	MCHBAR32(0x4224 + 0x400 * channel) = 0x1f207;
	MCHBAR32(0x4234 + 0x400 * channel) = 0x8041001;
	MCHBAR32(0x4204 + 0x400 * channel) = (slotrank << 24) | 8;
	MCHBAR32(0x4214 + 0x400 * channel) = 0x3e0;

	/* DRAM command WR */
	MCHBAR32(0x4228 + 0x400 * channel) = 0x1f201;
	MCHBAR32(0x4238 + 0x400 * channel) = 0x80411f4;
	MCHBAR32(0x4208 + 0x400 * channel) = slotrank << 24;
	MCHBAR32(0x4218 + 0x400 * channel) = 0x242;

	/* DRAM command NOP */
	MCHBAR32(0x422c + 0x400 * channel) = 0x1f207;
	MCHBAR32(0x423c + 0x400 * channel) =
		0x8000c01 | ((ctrl->CWL + ctrl->tWTR + 5) << 16);
	MCHBAR32(0x420c + 0x400 * channel) = (slotrank << 24) | 8;
	MCHBAR32(0x421c + 0x400 * channel) = 0x3e0;

	// execute command queue
	MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

	wait_428c(channel);

	/* DRAM command PREA */
	MCHBAR32(0x4220 + 0x400 * channel) = 0x1f002;
	MCHBAR32(0x4230 + 0x400 * channel) = 0xc01 | (ctrl->tRP << 16);
	MCHBAR32(0x4200 + 0x400 * channel) = (slotrank << 24) | 0x60400;
	MCHBAR32(0x4210 + 0x400 * channel) = 0x240;

	/* DRAM command ACT */
	MCHBAR32(0x4224 + 0x400 * channel) = 0x1f006;
	MCHBAR32(0x4234 + 0x400 * channel) =
		(max(ctrl->tRRD, (ctrl->tFAW >> 2) + 1) << 10)
		| 8 | (ctrl->CAS << 16);
	MCHBAR32(0x4204 + 0x400 * channel) = (slotrank << 24) | 0x60000;
	MCHBAR32(0x4214 + 0x400 * channel) = 0x244;

	/* DRAM command RD */
	MCHBAR32(0x4228 + 0x400 * channel) = 0x1f105;
	MCHBAR32(0x4238 + 0x400 * channel) =
		0x40011f4 | (max(ctrl->tRTP, 8) << 16);
	MCHBAR32(0x4208 + 0x400 * channel) = (slotrank << 24);
	MCHBAR32(0x4218 + 0x400 * channel) = 0x242;

	/* DRAM command PREA */
	MCHBAR32(0x422c + 0x400 * channel) = 0x1f002;
	MCHBAR32(0x423c + 0x400 * channel) = 0xc01 | (ctrl->tRP << 16);
	MCHBAR32(0x420c + 0x400 * channel) = (slotrank << 24) | 0x60400;
	MCHBAR32(0x421c + 0x400 * channel) = 0x240;

	// execute command queue
	MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

	wait_428c(channel);
}

static int discover_timC(ramctr_timing *ctrl, int channel, int slotrank)
{
	int timC;
	int statistics[NUM_LANES][MAX_TIMC + 1];
	int lane;

	wait_428c(channel);

	/* DRAM command PREA */
	MCHBAR32(0x4220 + 0x400 * channel) = 0x1f002;
	MCHBAR32(0x4230 + 0x400 * channel) = 0xc01 | (ctrl->tRP << 16);
	MCHBAR32(0x4200 + 0x400 * channel) = (slotrank << 24) | 0x60400;
	MCHBAR32(0x4210 + 0x400 * channel) = 0x240;

	// execute command queue
	MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(1);

	for (timC = 0; timC <= MAX_TIMC; timC++) {
		FOR_ALL_LANES ctrl->timings[channel][slotrank].lanes[lane].
		    timC = timC;
		program_timings(ctrl, channel);

		test_timC(ctrl, channel, slotrank);

		FOR_ALL_LANES {
			statistics[lane][timC] =
				MCHBAR32(0x4340 + 4 * lane + 0x400 * channel);
		}
	}
	FOR_ALL_LANES {
		struct run rn =
		    get_longest_zero_run(statistics[lane], MAX_TIMC + 1);
		ctrl->timings[channel][slotrank].lanes[lane].timC = rn.middle;
		if (rn.all) {
			printk(BIOS_EMERG, "timC discovery failed: %d, %d, %d\n",
			       channel, slotrank, lane);
			return MAKE_ERR;
		}
		printram("timC: %d, %d, %d: 0x%02x-0x%02x-0x%02x\n",
			channel, slotrank, lane, rn.start, rn.middle, rn.end);
	}
	return 0;
}

static int get_precedening_channels(ramctr_timing * ctrl, int target_channel)
{
	int channel, ret = 0;
	FOR_ALL_POPULATED_CHANNELS if (channel < target_channel)
		 ret++;
	return ret;
}

static void fill_pattern0(ramctr_timing * ctrl, int channel, u32 a, u32 b)
{
	unsigned j;
	unsigned channel_offset =
	    get_precedening_channels(ctrl, channel) * 0x40;
	for (j = 0; j < 16; j++)
		write32((void *)(0x04000000 + channel_offset + 4 * j), j & 2 ? b : a);
	sfence();
}

static int num_of_channels(const ramctr_timing * ctrl)
{
	int ret = 0;
	int channel;
	FOR_ALL_POPULATED_CHANNELS ret++;
	return ret;
}

static void fill_pattern1(ramctr_timing * ctrl, int channel)
{
	unsigned j;
	unsigned channel_offset =
	    get_precedening_channels(ctrl, channel) * 0x40;
	unsigned channel_step = 0x40 * num_of_channels(ctrl);
	for (j = 0; j < 16; j++)
		write32((void *)(0x04000000 + channel_offset + j * 4), 0xffffffff);
	for (j = 0; j < 16; j++)
		write32((void *)(0x04000000 + channel_offset + channel_step + j * 4), 0);
	sfence();
}

static void precharge(ramctr_timing * ctrl)
{
	int channel, slotrank, lane;

	FOR_ALL_POPULATED_CHANNELS {
		FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
			ctrl->timings[channel][slotrank].lanes[lane].falling =
			    16;
			ctrl->timings[channel][slotrank].lanes[lane].rising =
			    16;
		}

		program_timings(ctrl, channel);

		FOR_ALL_POPULATED_RANKS {
			wait_428c(channel);

			/* DRAM command MRS
			 * write MR3 MPR enable
			 * in this mode only RD and RDA are allowed
			 * all reads return a predefined pattern */
			MCHBAR32(0x4220 + 0x400 * channel) = 0x1f000;
			MCHBAR32(0x4230 + 0x400 * channel) =
				0xc01 | (ctrl->tMOD << 16);
			MCHBAR32(0x4200 + 0x400 * channel) =
				(slotrank << 24) | 0x360004;
			MCHBAR32(0x4210 + 0x400 * channel) = 0;

			/* DRAM command RD */
			MCHBAR32(0x4224 + 0x400 * channel) = 0x1f105;
			MCHBAR32(0x4234 + 0x400 * channel) = 0x4041003;
			MCHBAR32(0x4204 + 0x400 * channel) =
				(slotrank << 24) | 0;
			MCHBAR32(0x4214 + 0x400 * channel) = 0;

			/* DRAM command RD */
			MCHBAR32(0x4228 + 0x400 * channel) = 0x1f105;
			MCHBAR32(0x4238 + 0x400 * channel) =
				0x1001 | ((ctrl->CAS + 8) << 16);
			MCHBAR32(0x4208 + 0x400 * channel) =
				(slotrank << 24) | 0x60000;
			MCHBAR32(0x4218 + 0x400 * channel) = 0;

			/* DRAM command MRS
			 * write MR3 MPR disable */
			MCHBAR32(0x422c + 0x400 * channel) = 0x1f000;
			MCHBAR32(0x423c + 0x400 * channel) =
				0xc01 | (ctrl->tMOD << 16);
			MCHBAR32(0x420c + 0x400 * channel) =
				(slotrank << 24) | 0x360000;
			MCHBAR32(0x421c + 0x400 * channel) = 0;

			// execute command queue
			MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

			wait_428c(channel);
		}

		FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
			ctrl->timings[channel][slotrank].lanes[lane].falling =
			    48;
			ctrl->timings[channel][slotrank].lanes[lane].rising =
			    48;
		}

		program_timings(ctrl, channel);

		FOR_ALL_POPULATED_RANKS {
			wait_428c(channel);
			/* DRAM command MRS
			 * write MR3 MPR enable
			 * in this mode only RD and RDA are allowed
			 * all reads return a predefined pattern */
			MCHBAR32(0x4220 + 0x400 * channel) = 0x1f000;
			MCHBAR32(0x4230 + 0x400 * channel) =
				0xc01 | (ctrl->tMOD << 16);
			MCHBAR32(0x4200 + 0x400 * channel) =
				(slotrank << 24) | 0x360004;
			MCHBAR32(0x4210 + 0x400 * channel) = 0;

			/* DRAM command RD */
			MCHBAR32(0x4224 + 0x400 * channel) = 0x1f105;
			MCHBAR32(0x4234 + 0x400 * channel) = 0x4041003;
			MCHBAR32(0x4204 + 0x400 * channel) =
				(slotrank << 24) | 0;
			MCHBAR32(0x4214 + 0x400 * channel) = 0;

			/* DRAM command RD */
			MCHBAR32(0x4228 + 0x400 * channel) = 0x1f105;
			MCHBAR32(0x4238 + 0x400 * channel) =
				0x1001 | ((ctrl->CAS + 8) << 16);
			MCHBAR32(0x4208 + 0x400 * channel) =
				(slotrank << 24) | 0x60000;
			MCHBAR32(0x4218 + 0x400 * channel) = 0;

			/* DRAM command MRS
			 * write MR3 MPR disable */
			MCHBAR32(0x422c + 0x400 * channel) = 0x1f000;
			MCHBAR32(0x423c + 0x400 * channel) =
				0xc01 | (ctrl->tMOD << 16);
			MCHBAR32(0x420c + 0x400 * channel) =
				(slotrank << 24) | 0x360000;
			MCHBAR32(0x421c + 0x400 * channel) = 0;

			// execute command queue
			MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

			wait_428c(channel);
		}
	}
}

static void test_timB(ramctr_timing * ctrl, int channel, int slotrank)
{
	/* enable DQs on this slotrank */
	write_mrreg(ctrl, channel, slotrank, 1,
		    0x80 | make_mr1(ctrl, slotrank, channel));

	wait_428c(channel);
	/* DRAM command NOP */
	MCHBAR32(0x4220 + 0x400 * channel) = 0x1f207;
	MCHBAR32(0x4230 + 0x400 * channel) =
		0x8000c01 | ((ctrl->CWL + ctrl->tWLO) << 16);
	MCHBAR32(0x4200 + 0x400 * channel) = 8 | (slotrank << 24);
	MCHBAR32(0x4210 + 0x400 * channel) = 0;

	/* DRAM command NOP */
	MCHBAR32(0x4224 + 0x400 * channel) = 0x1f107;
	MCHBAR32(0x4234 + 0x400 * channel) =
		0x4000c01 | ((ctrl->CAS + 38) << 16);
	MCHBAR32(0x4204 + 0x400 * channel) = (slotrank << 24) | 4;
	MCHBAR32(0x4214 + 0x400 * channel) = 0;

	// execute command queue
	MCHBAR32(0x400 * channel + 0x4284) = RUN_QUEUE_4284(2);

	wait_428c(channel);

	/* disable DQs on this slotrank */
	write_mrreg(ctrl, channel, slotrank, 1,
		    0x1080 | make_mr1(ctrl, slotrank, channel));
}

static int discover_timB(ramctr_timing *ctrl, int channel, int slotrank)
{
	int timB;
	int statistics[NUM_LANES][128];
	int lane;

	MCHBAR32(0x3400) = 0x108052 | (slotrank << 2);

	for (timB = 0; timB < 128; timB++) {
		FOR_ALL_LANES {
			ctrl->timings[channel][slotrank].lanes[lane].timB = timB;
		}
		program_timings(ctrl, channel);

		test_timB(ctrl, channel, slotrank);

		FOR_ALL_LANES {
			statistics[lane][timB] =
			    !((MCHBAR32(lane_registers[lane] +
				channel * 0x100 + 4 + ((timB / 32) & 1) * 4)
			       >> (timB % 32)) & 1);
		}
	}
	FOR_ALL_LANES {
		struct run rn = get_longest_zero_run(statistics[lane], 128);
		/* timC is a direct function of timB's 6 LSBs.
		 * Some tests increments the value of timB by a small value,
		 * which might cause the 6bit value to overflow, if it's close
		 * to 0x3F. Increment the value by a small offset if it's likely
		 * to overflow, to make sure it won't overflow while running
		 * tests and bricks the system due to a non matching timC.
		 *
		 * TODO: find out why some tests (edge write discovery)
		 *       increment timB. */
		if ((rn.start & 0x3F) == 0x3E)
			rn.start += 2;
		else if ((rn.start & 0x3F) == 0x3F)
			rn.start += 1;
		ctrl->timings[channel][slotrank].lanes[lane].timB = rn.start;
		if (rn.all) {
			printk(BIOS_EMERG, "timB discovery failed: %d, %d, %d\n",
			       channel, slotrank, lane);
			return MAKE_ERR;
		}
		printram("timB: %d, %d, %d: 0x%02x-0x%02x-0x%02x\n",
				 channel, slotrank, lane, rn.start, rn.middle, rn.end);
	}
	return 0;
}

static int get_timB_high_adjust(u64 val)
{
	int i;

	/* good */
	if (val == 0xffffffffffffffffLL)
		return 0;

	if (val >= 0xf000000000000000LL) {
		/* needs negative adjustment */
		for (i = 0; i < 8; i++)
			if (val << (8 * (7 - i) + 4))
				return -i;
	} else {
		/* needs positive adjustment */
		for (i = 0; i < 8; i++)
			if (val >> (8 * (7 - i) + 4))
				return i;
	}
	return 8;
}

static void adjust_high_timB(ramctr_timing * ctrl)
{
	int channel, slotrank, lane, old;
	MCHBAR32(0x3400) = 0x200;
	FOR_ALL_POPULATED_CHANNELS {
		fill_pattern1(ctrl, channel);
		MCHBAR32(0x4288 + (channel << 10)) = 1;
	}
	FOR_ALL_POPULATED_CHANNELS FOR_ALL_POPULATED_RANKS {

		MCHBAR32(0x4288 + 0x400 * channel) = 0x10001;

		wait_428c(channel);

		/* DRAM command ACT */
		MCHBAR32(0x4220 + 0x400 * channel) = 0x1f006;
		MCHBAR32(0x4230 + 0x400 * channel) = 0xc01 | (ctrl->tRCD << 16);
		MCHBAR32(0x4200 + 0x400 * channel) = (slotrank << 24) | 0x60000;
		MCHBAR32(0x4210 + 0x400 * channel) = 0;

		/* DRAM command NOP */
		MCHBAR32(0x4224 + 0x400 * channel) = 0x1f207;
		MCHBAR32(0x4234 + 0x400 * channel) = 0x8040c01;
		MCHBAR32(0x4204 + 0x400 * channel) = (slotrank << 24) | 0x8;
		MCHBAR32(0x4214 + 0x400 * channel) = 0x3e0;

		/* DRAM command WR */
		MCHBAR32(0x4228 + 0x400 * channel) = 0x1f201;
		MCHBAR32(0x4238 + 0x400 * channel) = 0x8041003;
		MCHBAR32(0x4208 + 0x400 * channel) = (slotrank << 24);
		MCHBAR32(0x4218 + 0x400 * channel) = 0x3e2;

		/* DRAM command NOP */
		MCHBAR32(0x422c + 0x400 * channel) = 0x1f207;
		MCHBAR32(0x423c + 0x400 * channel) =
			0x8000c01 | ((ctrl->CWL + ctrl->tWTR + 5) << 16);
		MCHBAR32(0x420c + 0x400 * channel) = (slotrank << 24) | 0x8;
		MCHBAR32(0x421c + 0x400 * channel) = 0x3e0;

		// execute command queue
		MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

		wait_428c(channel);

		/* DRAM command PREA */
		MCHBAR32(0x4220 + 0x400 * channel) = 0x1f002;
		MCHBAR32(0x4230 + 0x400 * channel) =
			0xc01 | ((ctrl->tRP) << 16);
		MCHBAR32(0x4200 + 0x400 * channel) =
			(slotrank << 24) | 0x60400;
		MCHBAR32(0x4210 + 0x400 * channel) = 0x240;

		/* DRAM command ACT */
		MCHBAR32(0x4224 + 0x400 * channel) = 0x1f006;
		MCHBAR32(0x4234 + 0x400 * channel) =
			0xc01 | ((ctrl->tRCD) << 16);
		MCHBAR32(0x4204 + 0x400 * channel) = (slotrank << 24) | 0x60000;
		MCHBAR32(0x4214 + 0x400 * channel) = 0;

		/* DRAM command RD */
		MCHBAR32(0x4228 + 0x400 * channel) = 0x3f105;
		MCHBAR32(0x4238 + 0x400 * channel) = 0x4000c01 | ((ctrl->tRP +
			  ctrl->timings[channel][slotrank].val_4024 +
			  ctrl->timings[channel][slotrank].val_4028) << 16);
		MCHBAR32(0x4208 + 0x400 * channel) = (slotrank << 24) | 0x60008;
		MCHBAR32(0x4218 + 0x400 * channel) = 0;

		// execute command queue
		MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(3);

		wait_428c(channel);
		FOR_ALL_LANES {
			u64 res = MCHBAR32(lane_registers[lane] +
				0x100 * channel + 4);
			res |= ((u64) MCHBAR32(lane_registers[lane] +
				0x100 * channel + 8)) << 32;
			old = ctrl->timings[channel][slotrank].lanes[lane].timB;
			ctrl->timings[channel][slotrank].lanes[lane].timB +=
				get_timB_high_adjust(res) * 64;

			printram("High adjust %d:%016llx\n", lane, res);
			printram("Bval+: %d, %d, %d, %x -> %x\n", channel,
				slotrank, lane, old,
				ctrl->timings[channel][slotrank].lanes[lane].
				timB);
		}
	}
	MCHBAR32(0x3400) = 0;
}

static void write_op(ramctr_timing * ctrl, int channel)
{
	int slotrank;

	wait_428c(channel);

	/* choose an existing rank.  */
	slotrank = !(ctrl->rankmap[channel] & 1) ? 2 : 0;

	/* DRAM command ACT */
	MCHBAR32(0x4220 + 0x400 * channel) = 0x0f003;
	MCHBAR32(0x4230 + 0x400 * channel) = 0x41001;
	MCHBAR32(0x4200 + 0x400 * channel) = (slotrank << 24) | 0x60000;
	MCHBAR32(0x4210 + 0x400 * channel) = 0x3e0;

	// execute command queue
	MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(1);

	wait_428c(channel);
}

/* Compensate the skew between CMD/ADDR/CLK and DQ/DQS lanes.
 * DDR3 adopted the fly-by topology. The data and strobes signals reach
 * the chips at different times with respect to command, address and
 * clock signals.
 * By delaying either all DQ/DQs or all CMD/ADDR/CLK signals, a full phase
 * shift can be introduced.
 * It is assumed that the CLK/ADDR/CMD signals have the same routing delay.
 *
 * To find the required phase shift the DRAM is placed in "write leveling" mode.
 * In this mode the DRAM-chip samples the CLK on every DQS edge and feeds back the
 * sampled value on the data lanes (DQs).
 */
int write_training(ramctr_timing * ctrl)
{
	int channel, slotrank, lane;
	int err;

	FOR_ALL_POPULATED_CHANNELS
		MCHBAR32_OR(0x4008 + 0x400 * channel, 0x8000000);

	FOR_ALL_POPULATED_CHANNELS {
		write_op(ctrl, channel);
		MCHBAR32_OR(0x4020 + 0x400 * channel, 0x200000);
	}

	/* refresh disable */
	MCHBAR32_AND(0x5030, ~8);
	FOR_ALL_POPULATED_CHANNELS {
		write_op(ctrl, channel);
	}

	/* enable write leveling on all ranks
	 * disable all DQ outputs
	 * only NOP is allowed in this mode */
	FOR_ALL_CHANNELS
		FOR_ALL_POPULATED_RANKS
			write_mrreg(ctrl, channel, slotrank, 1,
				make_mr1(ctrl, slotrank, channel) | 0x1080);

	MCHBAR32(0x3400) = 0x108052;

	toggle_io_reset();

	/* set any valid value for timB, it gets corrected later */
	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
		err = discover_timB(ctrl, channel, slotrank);
		if (err)
			return err;
	}

	/* disable write leveling on all ranks */
	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS
		write_mrreg(ctrl, channel,
			slotrank, 1, make_mr1(ctrl, slotrank, channel));

	MCHBAR32(0x3400) = 0;

	FOR_ALL_POPULATED_CHANNELS
		wait_428c(channel);

	/* refresh enable */
	MCHBAR32_OR(0x5030, 8);

	FOR_ALL_POPULATED_CHANNELS {
		volatile u32 tmp;
		MCHBAR32_AND(0x4020 + 0x400 * channel, ~0x00200000);
		tmp = MCHBAR32(0x428c + 0x400 * channel);
		wait_428c(channel);

		/* DRAM command ZQCS */
		MCHBAR32(0x4220 + 0x400 * channel) = 0x0f003;
		MCHBAR32(0x4230 + 0x400 * channel) = 0x659001;
		MCHBAR32(0x4200 + 0x400 * channel) = 0x60000;
		MCHBAR32(0x4210 + 0x400 * channel) = 0x3e0;

		// execute command queue
		MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(1);

		wait_428c(channel);
	}

	toggle_io_reset();

	printram("CPE\n");
	precharge(ctrl);
	printram("CPF\n");

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
		MCHBAR32_AND(0x4080 + 0x400 * channel + 4 * lane, 0);
	}

	FOR_ALL_POPULATED_CHANNELS {
		fill_pattern0(ctrl, channel, 0xaaaaaaaa, 0x55555555);
		MCHBAR32(0x4288 + (channel << 10)) = 0;
	}

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
		err = discover_timC(ctrl, channel, slotrank);
		if (err)
			return err;
	}

	FOR_ALL_POPULATED_CHANNELS
		program_timings(ctrl, channel);

	/* measure and adjust timB timings */
	adjust_high_timB(ctrl);

	FOR_ALL_POPULATED_CHANNELS
		program_timings(ctrl, channel);

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
		MCHBAR32_AND(0x4080 + 0x400 * channel + 4 * lane, 0);
	}
	return 0;
}

static int test_320c(ramctr_timing * ctrl, int channel, int slotrank)
{
	struct ram_rank_timings saved_rt = ctrl->timings[channel][slotrank];
	int timC_delta;
	int lanes_ok = 0;
	int ctr = 0;
	int lane;

	for (timC_delta = -5; timC_delta <= 5; timC_delta++) {
		FOR_ALL_LANES {
			ctrl->timings[channel][slotrank].lanes[lane].timC =
			    saved_rt.lanes[lane].timC + timC_delta;
		}
		program_timings(ctrl, channel);
		FOR_ALL_LANES {
			MCHBAR32(4 * lane + 0x4f40) = 0;
		}

		MCHBAR32(0x4288 + 0x400 * channel) = 0x1f;

		wait_428c(channel);
		/* DRAM command ACT */
		MCHBAR32(0x4220 + 0x400 * channel) = 0x1f006;
		MCHBAR32(0x4230 + 0x400 * channel) =
			((max(ctrl->tRRD, (ctrl->tFAW >> 2) + 1)) << 10)
			| 8 | (ctrl->tRCD << 16);
		MCHBAR32(0x4200 + 0x400 * channel) =
			(slotrank << 24) | ctr | 0x60000;
		MCHBAR32(0x4210 + 0x400 * channel) = 0x244;

		/* DRAM command WR */
		MCHBAR32(0x4224 + 0x400 * channel) = 0x1f201;
		MCHBAR32(0x4234 + 0x400 * channel) =
			0x8001020 | ((ctrl->CWL + ctrl->tWTR + 8) << 16);
		MCHBAR32(0x4204 + 0x400 * channel) = (slotrank << 24);
		MCHBAR32(0x4244 + 0x400 * channel) = 0x389abcd;
		MCHBAR32(0x4214 + 0x400 * channel) = 0x20e42;

		/* DRAM command RD */
		MCHBAR32(0x4228 + 0x400 * channel) = 0x1f105;
		MCHBAR32(0x4238 + 0x400 * channel) =
			0x4001020 | (max(ctrl->tRTP, 8) << 16);
		MCHBAR32(0x4208 + 0x400 * channel) = (slotrank << 24);
		MCHBAR32(0x4248 + 0x400 * channel) = 0x389abcd;
		MCHBAR32(0x4218 + 0x400 * channel) = 0x20e42;

		/* DRAM command PRE */
		MCHBAR32(0x422c + 0x400 * channel) = 0x1f002;
		MCHBAR32(0x423c + 0x400 * channel) = 0xf1001;
		MCHBAR32(0x420c + 0x400 * channel) = (slotrank << 24) | 0x60400;
		MCHBAR32(0x421c + 0x400 * channel) = 0x240;

		// execute command queue
		MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

		wait_428c(channel);
		FOR_ALL_LANES {
			u32 r32 = MCHBAR32(0x4340 + 4 * lane + 0x400 * channel);

			if (r32 == 0)
				lanes_ok |= 1 << lane;
		}
		ctr++;
		if (lanes_ok == ((1 << NUM_LANES) - 1))
			break;
	}

	ctrl->timings[channel][slotrank] = saved_rt;

	return lanes_ok != ((1 << NUM_LANES) - 1);
}

#include "raminit_patterns.h"

static void fill_pattern5(ramctr_timing * ctrl, int channel, int patno)
{
	unsigned i, j;
	unsigned channel_offset =
	    get_precedening_channels(ctrl, channel) * 0x40;
	unsigned channel_step = 0x40 * num_of_channels(ctrl);

	if (patno) {
		u8 base8 = 0x80 >> ((patno - 1) % 8);
		u32 base = base8 | (base8 << 8) | (base8 << 16) | (base8 << 24);
		for (i = 0; i < 32; i++) {
			for (j = 0; j < 16; j++) {
				u32 val = use_base[patno - 1][i] & (1 << (j / 2)) ? base : 0;
				if (invert[patno - 1][i] & (1 << (j / 2)))
					val = ~val;
				write32((void *)(0x04000000 + channel_offset + i * channel_step +
						 j * 4), val);
			}
		}

	} else {
		for (i = 0; i < sizeof(pattern) / sizeof(pattern[0]); i++) {
			for (j = 0; j < 16; j++)
				write32((void *)(0x04000000 + channel_offset + i * channel_step +
						 j * 4), pattern[i][j]);
		}
		sfence();
	}
}

static void reprogram_320c(ramctr_timing * ctrl)
{
	int channel, slotrank;

	FOR_ALL_POPULATED_CHANNELS {
		wait_428c(channel);

		/* choose an existing rank.  */
		slotrank = !(ctrl->rankmap[channel] & 1) ? 2 : 0;

		/* DRAM command ZQCS */
		MCHBAR32(0x4220 + 0x400 * channel) = 0x0f003;
		MCHBAR32(0x4230 + 0x400 * channel) = 0x41001;
		MCHBAR32(0x4200 + 0x400 * channel) = (slotrank << 24) | 0x60000;
		MCHBAR32(0x4210 + 0x400 * channel) = 0x3e0;

		// execute command queue
		MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(1);

		wait_428c(channel);
		MCHBAR32_OR(0x4020 + 0x400 * channel, 0x200000);
	}

	/* refresh disable */
	MCHBAR32_AND(0x5030, ~8);
	FOR_ALL_POPULATED_CHANNELS {
		wait_428c(channel);

		/* choose an existing rank.  */
		slotrank = !(ctrl->rankmap[channel] & 1) ? 2 : 0;

		/* DRAM command ZQCS */
		MCHBAR32(0x4220 + 0x400 * channel) = 0x0f003;
		MCHBAR32(0x4230 + 0x400 * channel) = 0x41001;
		MCHBAR32(0x4200 + 0x400 * channel) = (slotrank << 24) | 0x60000;
		MCHBAR32(0x4210 + 0x400 * channel) = 0x3e0;

		// execute command queue
		MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(1);

		wait_428c(channel);
	}

	/* jedec reset */
	dram_jedecreset(ctrl);
	/* mrs commands. */
	dram_mrscommands(ctrl);

	toggle_io_reset();
}

#define MIN_C320C_LEN 13

static int try_cmd_stretch(ramctr_timing *ctrl, int channel, int cmd_stretch)
{
	struct ram_rank_timings saved_timings[NUM_CHANNELS][NUM_SLOTRANKS];
	int slotrank;
	int c320c;
	int stat[NUM_SLOTRANKS][256];
	int delta = 0;

	printram("Trying cmd_stretch %d on channel %d\n", cmd_stretch, channel);

	FOR_ALL_POPULATED_RANKS {
		saved_timings[channel][slotrank] =
			ctrl->timings[channel][slotrank];
	}

	ctrl->cmd_stretch[channel] = cmd_stretch;

	MCHBAR32(0x4004 + 0x400 * channel) =
		ctrl->tRRD
		| (ctrl->tRTP << 4)
		| (ctrl->tCKE << 8)
		| (ctrl->tWTR << 12)
		| (ctrl->tFAW << 16)
		| (ctrl->tWR << 24)
		| (ctrl->cmd_stretch[channel] << 30);

	if (ctrl->cmd_stretch[channel] == 2)
		delta = 2;
	else if (ctrl->cmd_stretch[channel] == 0)
		delta = 4;

	FOR_ALL_POPULATED_RANKS {
		ctrl->timings[channel][slotrank].val_4024 -= delta;
	}

	for (c320c = -127; c320c <= 127; c320c++) {
		FOR_ALL_POPULATED_RANKS {
			ctrl->timings[channel][slotrank].val_320c = c320c;
		}
		program_timings(ctrl, channel);
		reprogram_320c(ctrl);
		FOR_ALL_POPULATED_RANKS {
			stat[slotrank][c320c + 127] =
					test_320c(ctrl, channel, slotrank);
		}
	}
	FOR_ALL_POPULATED_RANKS {
		struct run rn =
			get_longest_zero_run(stat[slotrank], 255);
		ctrl->timings[channel][slotrank].val_320c = rn.middle - 127;
		printram("cmd_stretch: %d, %d: 0x%02x-0x%02x-0x%02x\n",
				 channel, slotrank, rn.start, rn.middle, rn.end);
		if (rn.all || rn.length < MIN_C320C_LEN) {
			FOR_ALL_POPULATED_RANKS {
				ctrl->timings[channel][slotrank] =
					saved_timings[channel][slotrank];
			}
			return MAKE_ERR;
		}
	}

	return 0;
}

/* Adjust CMD phase shift and try multiple command rates.
 * A command rate of 2T doubles the time needed for address and
 * command decode. */
int command_training(ramctr_timing *ctrl)
{
	int channel;

	FOR_ALL_POPULATED_CHANNELS {
		fill_pattern5(ctrl, channel, 0);
		MCHBAR32(0x4288 + 0x400 * channel) = 0x1f;
	}

	FOR_ALL_POPULATED_CHANNELS {
		int cmdrate, err;

		/*
		 * Dual DIMM per channel:
		 * Issue:      While c320c discovery seems to succeed raminit
		 *             will fail in write training.
		 * Workaround: Skip 1T in dual DIMM mode, that's only
		 *             supported by a few DIMMs.
		 * Only try 1T mode for XMP DIMMs that request it in dual DIMM
		 * mode.
		 *
		 * Single DIMM per channel:
		 * Try command rate 1T and 2T
		 */
		cmdrate = ((ctrl->rankmap[channel] & 0x5) == 0x5);
		if (ctrl->tCMD)
			/* XMP gives the CMD rate in clock ticks, not ns */
			cmdrate = MIN(DIV_ROUND_UP(ctrl->tCMD, 256) - 1, 1);

		for (; cmdrate < 2; cmdrate++) {
			err = try_cmd_stretch(ctrl, channel, cmdrate << 1);

			if (!err)
				break;
		}

		if (err) {
			printk(BIOS_EMERG, "c320c discovery failed\n");
			return err;
		}

		printram("Using CMD rate %uT on channel %u\n",
			 cmdrate + 1, channel);
	}

	FOR_ALL_POPULATED_CHANNELS
	program_timings(ctrl, channel);

	reprogram_320c(ctrl);
	return 0;
}


static int discover_edges_real(ramctr_timing *ctrl, int channel, int slotrank,
				int *edges)
{
	int edge;
	int statistics[NUM_LANES][MAX_EDGE_TIMING + 1];
	int lane;

	for (edge = 0; edge <= MAX_EDGE_TIMING; edge++) {
		FOR_ALL_LANES {
			ctrl->timings[channel][slotrank].lanes[lane].rising =
			    edge;
			ctrl->timings[channel][slotrank].lanes[lane].falling =
			    edge;
		}
		program_timings(ctrl, channel);

		FOR_ALL_LANES {
			volatile u32 tmp;
			MCHBAR32(0x4340 + 0x400 * channel + 4 * lane) = 0;
			tmp = MCHBAR32(0x400 * channel + 4 * lane + 0x4140);
		}

		wait_428c(channel);
		/* DRAM command MRS
		 * write MR3 MPR enable
		 * in this mode only RD and RDA are allowed
		 * all reads return a predefined pattern */
		MCHBAR32(0x4220 + 0x400 * channel) = 0x1f000;
		MCHBAR32(0x4230 + 0x400 * channel) = 0xc01 | (ctrl->tMOD << 16);
		MCHBAR32(0x4200 + 0x400 * channel) =
			(slotrank << 24) | 0x360004;
		MCHBAR32(0x4210 + 0x400 * channel) = 0;

		/* DRAM command RD */
		MCHBAR32(0x4224 + 0x400 * channel) = 0x1f105;
		MCHBAR32(0x4234 + 0x400 * channel) = 0x40411f4;
		MCHBAR32(0x4204 + 0x400 * channel) = slotrank << 24;
		MCHBAR32(0x4214 + 0x400 * channel) = 0;

		/* DRAM command RD */
		MCHBAR32(0x4228 + 0x400 * channel) = 0x1f105;
		MCHBAR32(0x4238 + 0x400 * channel) =
			0x1001 | ((ctrl->CAS + 8) << 16);
		MCHBAR32(0x4208 + 0x400 * channel) = (slotrank << 24) | 0x60000;
		MCHBAR32(0x4218 + 0x400 * channel) = 0;

		/* DRAM command MRS
		 * MR3 disable MPR */
		MCHBAR32(0x422c + 0x400 * channel) = 0x1f000;
		MCHBAR32(0x423c + 0x400 * channel) = 0xc01 | (ctrl->tMOD << 16);
		MCHBAR32(0x420c + 0x400 * channel) =
			(slotrank << 24) | 0x360000;
		MCHBAR32(0x421c + 0x400 * channel) = 0;

		// execute command queue
		MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

		wait_428c(channel);

		FOR_ALL_LANES {
			statistics[lane][edge] =
				MCHBAR32(0x4340 + 0x400 * channel + lane * 4);
		}
	}
	FOR_ALL_LANES {
		struct run rn =
		    get_longest_zero_run(statistics[lane], MAX_EDGE_TIMING + 1);
		edges[lane] = rn.middle;
		if (rn.all) {
			printk(BIOS_EMERG, "edge discovery failed: %d, %d, %d\n",
			       channel, slotrank, lane);
			return MAKE_ERR;
		}
		printram("eval %d, %d, %d: %02x\n", channel, slotrank,
		       lane, edges[lane]);
	}
	return 0;
}

int discover_edges(ramctr_timing *ctrl)
{
	int falling_edges[NUM_CHANNELS][NUM_SLOTRANKS][NUM_LANES];
	int rising_edges[NUM_CHANNELS][NUM_SLOTRANKS][NUM_LANES];
	int channel, slotrank, lane;
	int err;

	MCHBAR32(0x3400) = 0;

	toggle_io_reset();

	FOR_ALL_POPULATED_CHANNELS FOR_ALL_LANES {
		MCHBAR32(4 * lane + 0x400 * channel + 0x4080) = 0;
	}

	FOR_ALL_POPULATED_CHANNELS {
		fill_pattern0(ctrl, channel, 0, 0);
		MCHBAR32(0x4288 + (channel << 10)) = 0;
		FOR_ALL_LANES {
			volatile u32 tmp;
			tmp = MCHBAR32(0x400 * channel + lane * 4 + 0x4140);
		}

		FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
			ctrl->timings[channel][slotrank].lanes[lane].falling =
			    16;
			ctrl->timings[channel][slotrank].lanes[lane].rising =
			    16;
		}

		program_timings(ctrl, channel);

		FOR_ALL_POPULATED_RANKS {
			wait_428c(channel);

			/* DRAM command MRS
			 * MR3 enable MPR
			 * write MR3 MPR enable
			 * in this mode only RD and RDA are allowed
			 * all reads return a predefined pattern */
			MCHBAR32(0x4220 + 0x400 * channel) = 0x1f000;
			MCHBAR32(0x4230 + 0x400 * channel) =
				0xc01 | (ctrl->tMOD << 16);
			MCHBAR32(0x4200 + 0x400 * channel) =
				(slotrank << 24) | 0x360004;
			MCHBAR32(0x4210 + 0x400 * channel) = 0;

			/* DRAM command RD */
			MCHBAR32(0x4224 + 0x400 * channel) = 0x1f105;
			MCHBAR32(0x4234 + 0x400 * channel) = 0x4041003;
			MCHBAR32(0x4204 + 0x400 * channel) =
				(slotrank << 24) | 0;
			MCHBAR32(0x4214 + 0x400 * channel) = 0;

			/* DRAM command RD */
			MCHBAR32(0x4228 + 0x400 * channel) = 0x1f105;
			MCHBAR32(0x4238 + 0x400 * channel) =
				0x1001 | ((ctrl->CAS + 8) << 16);
			MCHBAR32(0x4208 + 0x400 * channel) =
				(slotrank << 24) | 0x60000;
			MCHBAR32(0x4218 + 0x400 * channel) = 0;

			/* DRAM command MRS
			 * MR3 disable MPR */
			MCHBAR32(0x422c + 0x400 * channel) = 0x1f000;
			MCHBAR32(0x423c + 0x400 * channel) =
				0xc01 | (ctrl->tMOD << 16);
			MCHBAR32(0x420c + 0x400 * channel) =
				(slotrank << 24) | 0x360000;
			MCHBAR32(0x421c + 0x400 * channel) = 0;

			// execute command queue
			MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

			wait_428c(channel);
		}

		/* XXX: check any measured value ? */

		FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
			ctrl->timings[channel][slotrank].lanes[lane].falling =
			    48;
			ctrl->timings[channel][slotrank].lanes[lane].rising =
			    48;
		}

		program_timings(ctrl, channel);

		FOR_ALL_POPULATED_RANKS {
			wait_428c(channel);

			/* DRAM command MRS
			 * MR3 enable MPR
			 * write MR3 MPR enable
			 * in this mode only RD and RDA are allowed
			 * all reads return a predefined pattern */
			MCHBAR32(0x4220 + 0x400 * channel) = 0x1f000;
			MCHBAR32(0x4230 + 0x400 * channel) =
				0xc01 | (ctrl->tMOD << 16);
			MCHBAR32(0x4200 + 0x400 * channel) =
				(slotrank << 24) | 0x360004;
			MCHBAR32(0x4210 + 0x400 * channel) = 0;

			/* DRAM command RD */
			MCHBAR32(0x4224 + 0x400 * channel) = 0x1f105;
			MCHBAR32(0x4234 + 0x400 * channel) = 0x4041003;
			MCHBAR32(0x4204 + 0x400 * channel) =
				(slotrank << 24) | 0;
			MCHBAR32(0x4214 + 0x400 * channel) = 0;

			/* DRAM command RD */
			MCHBAR32(0x4228 + 0x400 * channel) = 0x1f105;
			MCHBAR32(0x4238 + 0x400 * channel) =
				0x1001 | ((ctrl->CAS + 8) << 16);
			MCHBAR32(0x4208 + 0x400 * channel) =
				(slotrank << 24) | 0x60000;
			MCHBAR32(0x4218 + 0x400 * channel) = 0;

			/* DRAM command MRS
			 * MR3 disable MPR */
			MCHBAR32(0x422c + 0x400 * channel) = 0x1f000;
			MCHBAR32(0x423c + 0x400 * channel) =
				0xc01 | (ctrl->tMOD << 16);
			MCHBAR32(0x420c + 0x400 * channel) =
				(slotrank << 24) | 0x360000;
			MCHBAR32(0x421c + 0x400 * channel) = 0;

			// execute command queue
			MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

			wait_428c(channel);
		}

		/* XXX: check any measured value ? */

		FOR_ALL_LANES {
			MCHBAR32(0x4080 + 0x400 * channel + lane * 4) =
				~MCHBAR32(0x4040 + 0x400 * channel + lane * 4)
					& 0xff;
		}

		fill_pattern0(ctrl, channel, 0, 0xffffffff);
		MCHBAR32(0x4288 + (channel << 10)) = 0;
	}

	/* FIXME: under some conditions (older chipsets?) vendor BIOS sets both edges to the same value.  */
	MCHBAR32(0x4eb0) = 0x300;
	printram("discover falling edges:\n[%x] = %x\n", 0x4eb0, 0x300);

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
		err = discover_edges_real(ctrl, channel, slotrank,
			falling_edges[channel][slotrank]);
		if (err)
			return err;
	}

	MCHBAR32(0x4eb0) = 0x200;
	printram("discover rising edges:\n[%x] = %x\n", 0x4eb0, 0x200);

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
		err = discover_edges_real(ctrl, channel, slotrank,
				    rising_edges[channel][slotrank]);
		if (err)
			return err;
	}

	MCHBAR32(0x4eb0) = 0;

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
		ctrl->timings[channel][slotrank].lanes[lane].falling =
		    falling_edges[channel][slotrank][lane];
		ctrl->timings[channel][slotrank].lanes[lane].rising =
		    rising_edges[channel][slotrank][lane];
	}

	FOR_ALL_POPULATED_CHANNELS {
		program_timings(ctrl, channel);
	}

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
		MCHBAR32(0x4080 + 0x400 * channel + 4 * lane) = 0;
	}
	return 0;
}

static int discover_edges_write_real(ramctr_timing *ctrl, int channel,
				      int slotrank, int *edges)
{
	int edge;
	u32 raw_statistics[MAX_EDGE_TIMING + 1];
	int statistics[MAX_EDGE_TIMING + 1];
	const int reg3000b24[] = { 0, 0xc, 0x2c };
	int lane, i;
	int lower[NUM_LANES];
	int upper[NUM_LANES];
	int pat;

	FOR_ALL_LANES {
		lower[lane] = 0;
		upper[lane] = MAX_EDGE_TIMING;
	}

	for (i = 0; i < 3; i++) {
		MCHBAR32(0x3000 + 0x100 * channel) = reg3000b24[i] << 24;
		printram("[%x] = 0x%08x\n",
		       0x3000 + 0x100 * channel, reg3000b24[i] << 24);
		for (pat = 0; pat < NUM_PATTERNS; pat++) {
			fill_pattern5(ctrl, channel, pat);
			MCHBAR32(0x4288 + 0x400 * channel) = 0x1f;
			printram("using pattern %d\n", pat);
			for (edge = 0; edge <= MAX_EDGE_TIMING; edge++) {
				FOR_ALL_LANES {
					ctrl->timings[channel][slotrank].lanes[lane].
						rising = edge;
					ctrl->timings[channel][slotrank].lanes[lane].
						falling = edge;
				}
				program_timings(ctrl, channel);

				FOR_ALL_LANES {
					volatile u32 tmp;
					MCHBAR32(0x4340 + 0x400 * channel +
						4 * lane) = 0;
					tmp = MCHBAR32(0x400 * channel +
						4 * lane + 0x4140);
				}
				wait_428c(channel);

				/* DRAM command ACT */
				MCHBAR32(0x4220 + 0x400 * channel) = 0x1f006;
				MCHBAR32(0x4230 + 0x400 * channel) =
					0x4 | (ctrl->tRCD << 16) |
					(max(ctrl->tRRD, (ctrl->tFAW >> 2) + 1)
					<< 10);
				MCHBAR32(0x4200 + 0x400 * channel) =
					(slotrank << 24) | 0x60000;
				MCHBAR32(0x4210 + 0x400 * channel) = 0x240;

				/* DRAM command WR */
				MCHBAR32(0x4224 + 0x400 * channel) = 0x1f201;
				MCHBAR32(0x4234 + 0x400 * channel) = 0x8005020 |
					((ctrl->tWTR + ctrl->CWL + 8) << 16);
				MCHBAR32(0x4204 + 0x400 * channel) =
					slotrank << 24;
				MCHBAR32(0x4214 + 0x400 * channel) = 0x242;

				/* DRAM command RD */
				MCHBAR32(0x4228 + 0x400 * channel) = 0x1f105;
				MCHBAR32(0x4238 + 0x400 * channel) =
					0x4005020 | (max(ctrl->tRTP, 8) << 16);
				MCHBAR32(0x4208 + 0x400 * channel) =
					slotrank << 24;
				MCHBAR32(0x4218 + 0x400 * channel) = 0x242;

				/* DRAM command PRE */
				MCHBAR32(0x422c + 0x400 * channel) = 0x1f002;
				MCHBAR32(0x423c + 0x400 * channel) =
					0xc01 | (ctrl->tRP << 16);
				MCHBAR32(0x420c + 0x400 * channel) =
					(slotrank << 24) | 0x60400;
				MCHBAR32(0x421c + 0x400 * channel) = 0;

				// execute command queue
				MCHBAR32(0x4284 + 0x400 * channel) =
					RUN_QUEUE_4284(4);

				wait_428c(channel);
				FOR_ALL_LANES {
					volatile u32 tmp;
					tmp = MCHBAR32(0x4340 +
					       0x400 * channel + lane * 4);
				}

				raw_statistics[edge] =
					MCHBAR32(0x436c + 0x400 * channel);
			}
			FOR_ALL_LANES {
				struct run rn;
				for (edge = 0; edge <= MAX_EDGE_TIMING; edge++)
					statistics[edge] =
						! !(raw_statistics[edge] & (1 << lane));
				rn = get_longest_zero_run(statistics,
							  MAX_EDGE_TIMING + 1);
				printram("edges: %d, %d, %d: 0x%02x-0x%02x-0x%02x, 0x%02x-0x%02x\n",
					 channel, slotrank, i, rn.start, rn.middle,
					 rn.end, rn.start + ctrl->edge_offset[i],
					 rn.end - ctrl->edge_offset[i]);
				lower[lane] =
					max(rn.start + ctrl->edge_offset[i], lower[lane]);
				upper[lane] =
					min(rn.end - ctrl->edge_offset[i], upper[lane]);
				edges[lane] = (lower[lane] + upper[lane]) / 2;
				if (rn.all || (lower[lane] > upper[lane])) {
					printk(BIOS_EMERG, "edge write discovery failed: %d, %d, %d\n",
					       channel, slotrank, lane);
					return MAKE_ERR;
				}
			}
		}
	}

	MCHBAR32(0x3000) = 0;
	printram("CPA\n");
	return 0;
}

int discover_edges_write(ramctr_timing *ctrl)
{
	int falling_edges[NUM_CHANNELS][NUM_SLOTRANKS][NUM_LANES];
	int rising_edges[NUM_CHANNELS][NUM_SLOTRANKS][NUM_LANES];
	int channel, slotrank, lane;
	int err;

	/* FIXME: under some conditions (older chipsets?) vendor BIOS sets both edges to the same value.  */
	MCHBAR32(0x4eb0) = 0x300;
	printram("discover falling edges write:\n[%x] = %x\n", 0x4eb0, 0x300);

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
		err = discover_edges_write_real(ctrl, channel, slotrank,
					  falling_edges[channel][slotrank]);
		if (err)
			return err;
	}

	MCHBAR32(0x4eb0) = 0x200;
	printram("discover rising edges write:\n[%x] = %x\n", 0x4eb0, 0x200);

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
		err = discover_edges_write_real(ctrl, channel, slotrank,
					  rising_edges[channel][slotrank]);
		if (err)
			return err;
	}

	MCHBAR32(0x4eb0) = 0;

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
		ctrl->timings[channel][slotrank].lanes[lane].falling =
		    falling_edges[channel][slotrank][lane];
		ctrl->timings[channel][slotrank].lanes[lane].rising =
		    rising_edges[channel][slotrank][lane];
	}

	FOR_ALL_POPULATED_CHANNELS
		program_timings(ctrl, channel);

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
		MCHBAR32(0x4080 + 0x400 * channel + 4 * lane) = 0;
	}
	return 0;
}

static void test_timC_write(ramctr_timing *ctrl, int channel, int slotrank)
{
	wait_428c(channel);
	/* DRAM command ACT */
	MCHBAR32(0x4220 + 0x400 * channel) = 0x1f006;
	MCHBAR32(0x4230 + 0x400 * channel) =
		(max((ctrl->tFAW >> 2) + 1, ctrl->tRRD)
		 << 10) | (ctrl->tRCD << 16) | 4;
	MCHBAR32(0x4200 + 0x400 * channel) =
		(slotrank << 24) | 0x60000;
	MCHBAR32(0x4210 + 0x400 * channel) = 0x244;

	/* DRAM command WR */
	MCHBAR32(0x4224 + 0x400 * channel) = 0x1f201;
	MCHBAR32(0x4234 + 0x400 * channel) =
		0x80011e0 | ((ctrl->tWTR + ctrl->CWL + 8) << 16);
	MCHBAR32(0x4204 + 0x400 * channel) = slotrank << 24;
	MCHBAR32(0x4214 + 0x400 * channel) = 0x242;

	/* DRAM command RD */
	MCHBAR32(0x4228 + 0x400 * channel) = 0x1f105;
	MCHBAR32(0x4238 + 0x400 * channel) =
		0x40011e0 | (max(ctrl->tRTP, 8) << 16);
	MCHBAR32(0x4208 + 0x400 * channel) = slotrank << 24;
	MCHBAR32(0x4218 + 0x400 * channel) = 0x242;

	/* DRAM command PRE */
	MCHBAR32(0x422c + 0x400 * channel) = 0x1f002;
	MCHBAR32(0x423c + 0x400 * channel) = 0x1001 | (ctrl->tRP << 16);
	MCHBAR32(0x420c + 0x400 * channel) = (slotrank << 24) | 0x60400;
	MCHBAR32(0x421c + 0x400 * channel) = 0;

	// execute command queue
	MCHBAR32(0x4284 + 0x400 * channel) = RUN_QUEUE_4284(4);

	wait_428c(channel);
}

int discover_timC_write(ramctr_timing *ctrl)
{
	const u8 rege3c_b24[3] = { 0, 0xf, 0x2f };
	int i, pat;

	int lower[NUM_CHANNELS][NUM_SLOTRANKS][NUM_LANES];
	int upper[NUM_CHANNELS][NUM_SLOTRANKS][NUM_LANES];
	int channel, slotrank, lane;

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
		lower[channel][slotrank][lane] = 0;
		upper[channel][slotrank][lane] = MAX_TIMC;
	}

	MCHBAR32(0x4ea8) = 1;
	printram("discover timC write:\n");

	for (i = 0; i < 3; i++)
		FOR_ALL_POPULATED_CHANNELS {
			MCHBAR32_AND_OR(0xe3c + (channel * 0x100), ~0x3f000000,
				rege3c_b24[i] << 24);
			udelay(2);
			for (pat = 0; pat < NUM_PATTERNS; pat++) {
				FOR_ALL_POPULATED_RANKS {
					int timC;
					u32 raw_statistics[MAX_TIMC + 1];
					int statistics[MAX_TIMC + 1];

					/* Make sure rn.start < rn.end */
					statistics[MAX_TIMC] = 1;

					fill_pattern5(ctrl, channel, pat);
					MCHBAR32(0x4288 + 0x400 * channel) =
						0x1f;
					for (timC = 0; timC < MAX_TIMC; timC++) {
						FOR_ALL_LANES
							ctrl->timings[channel][slotrank].lanes[lane].timC = timC;
						program_timings(ctrl, channel);

						test_timC_write (ctrl, channel, slotrank);

						raw_statistics[timC] =
							MCHBAR32(0x436c + 0x400 * channel);
					}
					FOR_ALL_LANES {
						struct run rn;
						for (timC = 0; timC < MAX_TIMC; timC++)
							statistics[timC] =
								!!(raw_statistics[timC] &
								   (1 << lane));

						rn = get_longest_zero_run(statistics,
									  MAX_TIMC + 1);
						if (rn.all) {
							printk(BIOS_EMERG, "timC write discovery failed: %d, %d, %d\n",
							       channel, slotrank, lane);
							return MAKE_ERR;
						}
						printram("timC: %d, %d, %d: 0x%02x-0x%02x-0x%02x, 0x%02x-0x%02x\n",
							 channel, slotrank, i, rn.start,
							 rn.middle, rn.end,
							 rn.start + ctrl->timC_offset[i],
							 rn.end - ctrl->timC_offset[i]);
						lower[channel][slotrank][lane] =
							max(rn.start + ctrl->timC_offset[i],
							    lower[channel][slotrank][lane]);
						upper[channel][slotrank][lane] =
							min(rn.end - ctrl->timC_offset[i],
							    upper[channel][slotrank][lane]);

					}
				}
			}
		}

	FOR_ALL_CHANNELS {
		MCHBAR32_AND((channel * 0x100) + 0xe3c, ~0x3f000000);
		udelay(2);
	}

	MCHBAR32(0x4ea8) = 0;

	printram("CPB\n");

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
		printram("timC %d, %d, %d: %x\n", channel,
		       slotrank, lane,
		       (lower[channel][slotrank][lane] +
			upper[channel][slotrank][lane]) / 2);
		ctrl->timings[channel][slotrank].lanes[lane].timC =
		    (lower[channel][slotrank][lane] +
		     upper[channel][slotrank][lane]) / 2;
	}
	FOR_ALL_POPULATED_CHANNELS {
		program_timings(ctrl, channel);
	}
	return 0;
}

void normalize_training(ramctr_timing * ctrl)
{
	int channel, slotrank, lane;
	int mat;

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
		int delta;
		mat = 0;
		FOR_ALL_LANES mat =
		    max(ctrl->timings[channel][slotrank].lanes[lane].timA, mat);
		printram("normalize %d, %d, %d: mat %d\n",
		    channel, slotrank, lane, mat);

		delta = (mat >> 6) - ctrl->timings[channel][slotrank].val_4028;
		printram("normalize %d, %d, %d: delta %d\n",
		    channel, slotrank, lane, delta);

		ctrl->timings[channel][slotrank].val_4024 += delta;
		ctrl->timings[channel][slotrank].val_4028 += delta;
	}

	FOR_ALL_POPULATED_CHANNELS {
		program_timings(ctrl, channel);
	}
}

void write_controller_mr(ramctr_timing * ctrl)
{
	int channel, slotrank;

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
		MCHBAR32(0x0004 + (channel << 8) + lane_registers[slotrank]) =
			make_mr0(ctrl, slotrank);
		MCHBAR32(0x0008 + (channel << 8) + lane_registers[slotrank]) =
			make_mr1(ctrl, slotrank, channel);
	}
}

int channel_test(ramctr_timing *ctrl)
{
	int channel, slotrank, lane;

	slotrank = 0;
	FOR_ALL_POPULATED_CHANNELS
		if (MCHBAR32(0x42a0 + (channel << 10)) & 0xa000) {
			printk(BIOS_EMERG, "Mini channel test failed (1): %d\n",
			       channel);
			return MAKE_ERR;
		}
	FOR_ALL_POPULATED_CHANNELS {
		fill_pattern0(ctrl, channel, 0x12345678, 0x98765432);

		MCHBAR32(0x4288 + (channel << 10)) = 0;
	}

	for (slotrank = 0; slotrank < 4; slotrank++)
		FOR_ALL_CHANNELS
			if (ctrl->rankmap[channel] & (1 << slotrank)) {
		FOR_ALL_LANES {
			MCHBAR32(0x4f40 + 4 * lane) = 0;
			MCHBAR32(0x4d40 + 4 * lane) = 0;
		}
		wait_428c(channel);

		/* DRAM command ACT */
		MCHBAR32(0x4220 + (channel << 10)) = 0x0001f006;
		MCHBAR32(0x4230 + (channel << 10)) = 0x0028a004;
		MCHBAR32(0x4200 + (channel << 10)) =
			0x00060000 | (slotrank << 24);
		MCHBAR32(0x4210 + (channel << 10)) = 0x00000244;

		/* DRAM command WR */
		MCHBAR32(0x4224 + (channel << 10)) = 0x0001f201;
		MCHBAR32(0x4234 + (channel << 10)) = 0x08281064;
		MCHBAR32(0x4204 + (channel << 10)) =
			0x00000000 | (slotrank << 24);
		MCHBAR32(0x4214 + (channel << 10)) = 0x00000242;

		/* DRAM command RD */
		MCHBAR32(0x4228 + (channel << 10)) = 0x0001f105;
		MCHBAR32(0x4238 + (channel << 10)) = 0x04281064;
		MCHBAR32(0x4208 + (channel << 10)) =
			0x00000000 | (slotrank << 24);
		MCHBAR32(0x4218 + (channel << 10)) = 0x00000242;

		/* DRAM command PRE */
		MCHBAR32(0x422c + (channel << 10)) = 0x0001f002;
		MCHBAR32(0x423c + (channel << 10)) = 0x00280c01;
		MCHBAR32(0x420c + (channel << 10)) =
			0x00060400 | (slotrank << 24);
		MCHBAR32(0x421c + (channel << 10)) = 0x00000240;

		// execute command queue
		MCHBAR32(0x4284 + (channel << 10)) = RUN_QUEUE_4284(4);

		wait_428c(channel);
		FOR_ALL_LANES
			if (MCHBAR32(0x4340 + (channel << 10) + 4 * lane)) {
				printk(BIOS_EMERG, "Mini channel test failed (2): %d, %d, %d\n",
				       channel, slotrank, lane);
				return MAKE_ERR;
			}
	}
	return 0;
}

void set_scrambling_seed(ramctr_timing * ctrl)
{
	int channel;

	/* FIXME: we hardcode seeds. Do we need to use some PRNG for them?
	   I don't think so.  */
	static u32 seeds[NUM_CHANNELS][3] = {
		{0x00009a36, 0xbafcfdcf, 0x46d1ab68},
		{0x00028bfa, 0x53fe4b49, 0x19ed5483}
	};
	FOR_ALL_POPULATED_CHANNELS {
		MCHBAR32(0x4020 + 0x400 * channel) &= ~0x10000000;
		MCHBAR32(0x4034 + 0x400 * channel) = seeds[channel][0];
		MCHBAR32(0x403c + 0x400 * channel) = seeds[channel][1];
		MCHBAR32(0x4038 + 0x400 * channel) = seeds[channel][2];
	}
}

void set_4f8c(void)
{
	struct cpuid_result cpures;
	u32 cpu;

	cpures = cpuid(1);
	cpu = (cpures.eax);
	if (IS_SANDY_CPU(cpu) && (IS_SANDY_CPU_D0(cpu) || IS_SANDY_CPU_D1(cpu))) {
		MCHBAR32(0x4f8c) = 0x141D1519;
	} else {
		MCHBAR32(0x4f8c) = 0x551D1519;
	}
}

void prepare_training(ramctr_timing * ctrl)
{
	int channel;

	FOR_ALL_POPULATED_CHANNELS {
		// Always drive command bus
		MCHBAR32_OR(0x4004 + 0x400 * channel, 0x20000000);
	}

	udelay(1);

	FOR_ALL_POPULATED_CHANNELS {
		wait_428c(channel);
	}
}

void set_4008c(ramctr_timing * ctrl)
{
	int channel, slotrank;

	FOR_ALL_POPULATED_CHANNELS {
		u32 b20, b4_8_12;
		int min_320c = 10000;
		int max_320c = -10000;

		FOR_ALL_POPULATED_RANKS {
			max_320c = max(ctrl->timings[channel][slotrank].val_320c, max_320c);
			min_320c = min(ctrl->timings[channel][slotrank].val_320c, min_320c);
		}

		if (max_320c - min_320c > 51)
			b20 = 0;
		else
			b20 = ctrl->ref_card_offset[channel];

		if (ctrl->reg_320c_range_threshold < max_320c - min_320c)
			b4_8_12 = 0x3330;
		else
			b4_8_12 = 0x2220;

		dram_odt_stretch(ctrl, channel);

		MCHBAR32(0x4008 + (channel << 10)) =
			0x0a000000 | (b20 << 20) |
			((ctrl->ref_card_offset[channel] + 2) << 16) | b4_8_12;
	}
}

void set_42a0(ramctr_timing * ctrl)
{
	int channel;
	FOR_ALL_POPULATED_CHANNELS {
		MCHBAR32(0x42a0 + 0x400 * channel) =
			0x00001000 | ctrl->rankmap[channel];
		MCHBAR32_AND(0x4004 + 0x400 * channel, ~0x20000000);
	}
}

static int encode_5d10(int ns)
{
  return (ns + 499) / 500;
}

/* FIXME: values in this function should be hardware revision-dependent.  */
void final_registers(ramctr_timing * ctrl)
{
	const size_t is_mobile = get_platform_type() == PLATFORM_MOBILE;

	int channel;
	int t1_cycles = 0, t1_ns = 0, t2_ns;
	int t3_ns;
	u32 r32;

	MCHBAR32(0x4cd4) = 0x00000046;

	FOR_ALL_CHANNELS
		MCHBAR32_AND_OR(0x400c + 0x400 * channel, 0xFFFFCFFF, 0x1000);

	if (is_mobile)
		/* APD - DLL Off, 64 DCLKs until idle, decision per rank */
		MCHBAR32(PM_PDWN_Config) = 0x00000740;
	else
		/* APD - PPD, 64 DCLKs until idle, decision per rank */
		MCHBAR32(PM_PDWN_Config) = 0x00000340;

	FOR_ALL_CHANNELS
		MCHBAR32(0x4380 + 0x400 * channel) = 0x00000aaa;

	MCHBAR32(0x4f88) = 0x5f7003ff;	// OK
	MCHBAR32(0x5064) = 0x00073000 | ctrl->reg_5064b0; // OK

	FOR_ALL_CHANNELS {
		switch (ctrl->rankmap[channel]) {
			/* Unpopulated channel.  */
		case 0:
			MCHBAR32(0x4384 + channel * 0x400) = 0;
			break;
			/* Only single-ranked dimms.  */
		case 1:
		case 4:
		case 5:
			MCHBAR32(0x4384 + channel * 0x400) = 0x373131;
			break;
			/* Dual-ranked dimms present.  */
		default:
			MCHBAR32(0x4384 + channel * 0x400) = 0x9b6ea1;
			break;
		}
	}

	MCHBAR32(0x5880) = 0xca9171e5;
	MCHBAR32_AND_OR(0x5888, ~0xffffff, 0xe4d5d0);
	MCHBAR32_AND(0x58a8, ~0x1f);

	FOR_ALL_CHANNELS
		MCHBAR32_AND_OR(0x4294 + 0x400 * channel, ~0x30000, 1 << 16);

	MCHBAR32_OR(0x5030, 1);
	MCHBAR32_OR(0x5030, 0x80);
	MCHBAR32(0x5f18) = 0xfa;

	/* Find a populated channel.  */
	FOR_ALL_POPULATED_CHANNELS
		break;

	t1_cycles = (MCHBAR32(0x4290 + channel * 0x400) >> 8) & 0xff;
	r32 = MCHBAR32(0x5064);
	if (r32 & 0x20000)
		t1_cycles += (r32 & 0xfff);
	t1_cycles += MCHBAR32(channel * 0x400 + 0x42a4) & 0xfff;
	t1_ns = t1_cycles * ctrl->tCK / 256 + 544;
	if (!(r32 & 0x20000))
		t1_ns += 500;

	t2_ns = 10 * ((MCHBAR32(0x5f10) >> 8) & 0xfff);
	if (MCHBAR32(0x5f00) & 8)
	{
		t3_ns = 10 * ((MCHBAR32(0x5f20) >> 8) & 0xfff);
		t3_ns += 10 * (MCHBAR32(0x5f18) & 0xff);
	}
	else
	{
		t3_ns = 500;
	}
	printk(BIOS_DEBUG, "t123: %d, %d, %d\n",
	       t1_ns, t2_ns, t3_ns);
	MCHBAR32_AND_OR(0x5d10, 0xC0C0C0C0,
		((encode_5d10(t1_ns) + encode_5d10(t2_ns)) << 16) |
		(encode_5d10(t1_ns) << 8) | ((encode_5d10(t3_ns) +
		encode_5d10(t2_ns) + encode_5d10(t1_ns)) << 24) | 0xc);
}

void restore_timings(ramctr_timing * ctrl)
{
	int channel, slotrank, lane;

	FOR_ALL_POPULATED_CHANNELS
	    MCHBAR32(0x4004 + 0x400 * channel) =
		ctrl->tRRD
		| (ctrl->tRTP << 4)
		| (ctrl->tCKE << 8)
		| (ctrl->tWTR << 12)
		| (ctrl->tFAW << 16)
		| (ctrl->tWR << 24)
		| (ctrl->cmd_stretch[channel] << 30);

	udelay(1);

	FOR_ALL_POPULATED_CHANNELS {
		wait_428c(channel);
	}

	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS FOR_ALL_LANES {
		MCHBAR32(0x4080 + 0x400 * channel + 4 * lane) = 0;
	}

	FOR_ALL_POPULATED_CHANNELS
		MCHBAR32_OR(0x4008 + 0x400 * channel, 0x8000000);

	FOR_ALL_POPULATED_CHANNELS {
		udelay (1);
		MCHBAR32_OR(0x4020 + 0x400 * channel, 0x200000);
	}

	printram("CPE\n");

	MCHBAR32(0x3400) = 0;
	MCHBAR32(0x4eb0) = 0;

	printram("CP5b\n");

	FOR_ALL_POPULATED_CHANNELS {
		program_timings(ctrl, channel);
	}

	u32 reg, addr;

	while (!(MCHBAR32(0x5084) & 0x10000));
	do {
		reg = MCHBAR32(0x428c);
	} while ((reg & 0x14) == 0);

	// Set state of memory controller
	MCHBAR32(0x5030) = 0x116;
	MCHBAR32(0x4ea0) = 0;

	// Wait 500us
	udelay(500);

	FOR_ALL_CHANNELS {
		// Set valid rank CKE
		reg = 0;
		reg = (reg & ~0xf) | ctrl->rankmap[channel];
		addr = 0x400 * channel + 0x42a0;
		MCHBAR32(addr) = reg;

		// Wait 10ns for ranks to settle
		//udelay(0.01);

		reg = (reg & ~0xf0) | (ctrl->rankmap[channel] << 4);
		MCHBAR32(addr) = reg;

		// Write reset using a NOP
		write_reset(ctrl);
	}

	/* mrs commands. */
	dram_mrscommands(ctrl);

	printram("CP5c\n");

	MCHBAR32(0x3000) = 0;

	FOR_ALL_CHANNELS {
		MCHBAR32_AND(channel * 0x100 + 0xe3c, ~0x3f000000);
		udelay(2);
	}

	MCHBAR32(0x4ea8) = 0;
}