src/lib/dimm_info_util.c

/* SPDX-License-Identifier: GPL-2.0-only */

#include <device/dram/spd.h>
#include <dimm_info_util.h>
#include <smbios.h>
#include <spd.h>
#include <console/console.h>

uint8_t smbios_bus_width_to_spd_width(uint8_t ddr_type, uint16_t total_width,
				      uint16_t data_width)
{
	uint8_t out;

	/* Lookup table as defined in the JEDEC Standard. */
	switch (data_width) {
	case 64:
		out = MEMORY_BUS_WIDTH_64;
		break;
	case 32:
		out = MEMORY_BUS_WIDTH_32;
		break;
	case 16:
		out = MEMORY_BUS_WIDTH_16;
		break;
	case 8:
		out = MEMORY_BUS_WIDTH_8;
		break;
	default:
		printk(BIOS_NOTICE, "Unknown memory size %hu\n", data_width);
		/*
		 * The SMBIOS spec says we should set 0xFFFF on an unknown
		 * value, but we don't have a way of passing that signal via SPD
		 * encoded values.
		 */
		out = MEMORY_BUS_WIDTH_8;
		break;
	}

	uint16_t extension_bits = total_width - data_width;

	switch (extension_bits) {
	case 8:
		if (ddr_type == MEMORY_TYPE_DDR5 || ddr_type == MEMORY_TYPE_LPDDR5)
			out |= SPD_ECC_8BIT_LP5_DDR5;
		else
			out |= SPD_ECC_8BIT;
		break;
	case 0:
		/* No extension bits */
		break;
	default:
		printk(BIOS_NOTICE, "Unknown number of extension bits %hu\n",
		       extension_bits);
		break;
	}

	return out;
}

uint32_t smbios_memory_size_to_mib(uint16_t memory_size, uint32_t extended_size)
{
	/* Memory size is unknown */
	if (memory_size == 0xFFFF)
		return 0;
	/* (32 GiB - 1 MiB) or greater is expressed in the extended size. */
	else if (memory_size == 0x7FFF)
		return extended_size;
	/* When the MSB is flipped, the value is specified in kilobytes */
	else if (memory_size & 0x8000)
		return (memory_size ^ 0x8000) / KiB;
	/* Value contains MiB */
	else
		return memory_size;
}

uint8_t smbios_form_factor_to_spd_mod_type(smbios_memory_type memory_type,
		smbios_memory_form_factor form_factor)
{
	return convert_form_factor_to_module_type(memory_type, form_factor);
}