src/drivers/generic/bayhub/bh720.c

/*
 * Driver for BayHub Technology BH720 PCI to eMMC 5.0 HS200 bridge
 *
 * This file is part of the coreboot project.
 *
 * Copyright 2018 Google LLC.
 *
 * 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 <device/device.h>
#include <device/path.h>
#include <device/pci.h>
#include <device/pci_ids.h>
#include "chip.h"

enum {
	BH720_PROTECT			= 0xd0,
	BH720_PROTECT_LOCK_OFF		= 0,
	BH720_PROTECT_LOCK_ON		= BIT(0),
	BH720_PROTECT_OFF		= 0,
	BH720_PROTECT_ON		= BIT(31),

	BH720_LINK_CTRL			= 0x90,
	BH720_LINK_CTRL_L0_ENABLE	= BIT(0),
	BH720_LINK_CTRL_L1_ENABLE	= BIT(1),
	BH720_LINK_CTRL_CLKREQ		= BIT(8),

	BH720_MISC2			= 0xf0,
	BH720_MISC2_ASPM_DISABLE	= BIT(0),
	BH720_MISC2_APSM_CLKREQ_L1	= BIT(7),
	BH720_MISC2_APSM_PHY_L1		= BIT(10),
	BH720_MISC2_APSM_MORE		= BIT(12),

	BH720_RTD3_L1			= 0x3e0,
	BH720_RTD3_L1_DISABLE_L1	= BIT(28),
};

static void bh720_init(struct device *dev)
{
	struct drivers_generic_bayhub_config *config = dev->chip_info;

	pci_dev_init(dev);

	if (config && config->power_saving) {
		/*
		 * This procedure for enabling power-saving mode is from the
		 * BayHub BIOS Implementation Guideline document.
		 */
		pci_write_config32(dev, BH720_PROTECT,
				   BH720_PROTECT_OFF | BH720_PROTECT_LOCK_OFF);
		pci_or_config32(dev, BH720_RTD3_L1, BH720_RTD3_L1_DISABLE_L1);
		pci_or_config32(dev, BH720_LINK_CTRL,
				BH720_LINK_CTRL_L0_ENABLE |
				BH720_LINK_CTRL_L1_ENABLE);
		pci_or_config32(dev, BH720_LINK_CTRL, BH720_LINK_CTRL_CLKREQ);
		pci_update_config32(dev, BH720_MISC2, ~BH720_MISC2_ASPM_DISABLE,
				    BH720_MISC2_APSM_CLKREQ_L1 |
				    BH720_MISC2_APSM_PHY_L1);
		pci_write_config32(dev, BH720_PROTECT,
				   BH720_PROTECT_ON | BH720_PROTECT_LOCK_ON);

		printk(BIOS_INFO, "BayHub BH720: Power-saving enabled (link_ctrl=%#x)\n",
		       pci_read_config32(dev, BH720_LINK_CTRL));
	}
}

static struct pci_operations pci_ops = {
	.set_subsystem = pci_dev_set_subsystem,
};

static struct device_operations bh720_ops = {
	.read_resources		= pci_dev_read_resources,
	.set_resources		= pci_dev_set_resources,
	.enable_resources	= pci_dev_enable_resources,
	.ops_pci		= &pci_ops,
	.init			= bh720_init,
};

static const unsigned short pci_device_ids[] = {
	PCI_DEVICE_ID_O2_BH720,
	0
};

static const struct pci_driver bayhub_bh720 __pci_driver = {
	.ops		= &bh720_ops,
	.vendor		= PCI_VENDOR_ID_O2,
	.devices	= pci_device_ids,
};

static void bh720_enable(struct device *dev)
{
	dev->ops = &bh720_ops;
}

struct chip_operations bayhub_bh720_ops = {
	CHIP_NAME("BayHub Technology BH720 PCI to eMMC 5.0 HS200 bridge")
	.enable_dev = bh720_enable,
};