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/* SPDX-License-Identifier: GPL-2.0-only */
#include <assert.h>
#include <console/console.h>
#include <crc_byte.h>
#include <delay.h>
#include <device/pci_ops.h>
#include <device/smbus_host.h>
#include <soc/intel/common/block/smbus/smbuslib.h>
#include <types.h>
#include "eeprom.h"
#define I2C_ADDR_EEPROM 0x57
/*
* Check Signature in EEPROM (M24C32-FMN6TP)
* If signature is there we assume that that the content is valid
*/
int check_signature(const size_t offset, const uint64_t signature)
{
u8 blob[8] = {0};
if (!eeprom_read_buffer(blob, offset, ARRAY_SIZE(blob))) {
/* Check signature */
if (*(uint64_t *)blob == signature) {
printk(BIOS_DEBUG, "CFG EEPROM: Signature valid.\n");
return 1;
}
printk(BIOS_DEBUG, "CFG EEPROM: Signature invalid - skipping option write.\n");
return 0;
}
return 0;
}
/*
* Read board settings from the EEPROM and verify their checksum.
* If checksum is valid, we assume the settings are sane as well.
*/
static bool get_board_settings_from_eeprom(struct eeprom_board_settings *board_cfg)
{
const size_t board_settings_offset = offsetof(struct eeprom_layout, board_settings);
if (eeprom_read_buffer(board_cfg, board_settings_offset, sizeof(*board_cfg))) {
printk(BIOS_ERR, "CFG EEPROM: Failed to read board settings\n");
return false;
}
const uint32_t crc =
CRC(&board_cfg->raw_settings, sizeof(board_cfg->raw_settings), crc32_byte);
if (crc != board_cfg->signature) {
printk(BIOS_ERR, "CFG EEPROM: Board settings have invalid checksum\n");
return false;
}
return true;
}
struct eeprom_board_settings *get_board_settings(void)
{
static struct eeprom_board_settings board_cfg = {0};
/* Tri-state: -1: settings are invalid, 0: uninitialized, 1: settings are valid */
static int checked_valid = 0;
if (checked_valid == 0) {
const bool success = get_board_settings_from_eeprom(&board_cfg);
checked_valid = success ? 1 : -1;
}
return checked_valid > 0 ? &board_cfg : NULL;
}
struct eeprom_bmc_settings *get_bmc_settings(void)
{
const size_t bmc_settings_offset = offsetof(struct eeprom_layout, bmc_settings);
static struct eeprom_bmc_settings bmc_cfg = {0};
/* 0: uninitialized, 1: settings are valid */
static int valid = 0;
if (valid == 0) {
if (eeprom_read_buffer(&bmc_cfg, bmc_settings_offset, sizeof(bmc_cfg))) {
printk(BIOS_ERR, "CFG EEPROM: Failed to read BMC settings\n");
return NULL;
}
valid = 1;
}
return &bmc_cfg;
}
uint8_t get_bmc_hsi(void)
{
uint8_t hsi = 0;
struct eeprom_bmc_settings *s = get_bmc_settings();
if (s)
hsi = s->hsi;
printk(BIOS_DEBUG, "CFG EEPROM: HSI 0x%x\n", hsi);
return hsi;
}
/* Read data from an EEPROM on SMBus and write it to a buffer */
bool eeprom_read_buffer(void *blob, size_t read_offset, size_t size)
{
int ret = 0;
u32 smb_ctrl_reg = pci_read_config32(PCH_DEV_SMBUS, HOSTC);
pci_write_config32(PCH_DEV_SMBUS, HOSTC, smb_ctrl_reg | I2C_EN);
printk(BIOS_SPEW, "%s\tOffset: %04zx\tSize: %02zx\n", __func__,
read_offset, size);
/* We can always read two bytes at a time */
for (size_t i = 0; i < size; i = i + 2) {
u8 tmp[2] = {0};
ret = do_smbus_process_call(SMBUS_IO_BASE, I2C_ADDR_EEPROM, 0,
swab16(read_offset + i), (uint16_t *)&tmp[0]);
if (ret < 0)
break;
/* Write to UPD */
uint8_t *write_ptr = (uint8_t *)blob + i;
write_ptr[0] = tmp[0];
if (size - i > 1)
write_ptr[1] = tmp[1];
}
/* Restore I2C_EN bit */
pci_write_config32(PCH_DEV_SMBUS, HOSTC, smb_ctrl_reg);
return ret;
}
void report_eeprom_error(const size_t off)
{
printk(BIOS_ERR, "MB: Failed to read from EEPROM at addr. 0x%zx\n", off);
}
/*
* Write a single byte into the EEPROM at specified offset.
* Returns true on error, false on success.
*/
static bool eeprom_write_byte(const uint8_t data, const uint16_t write_offset)
{
int ret = 0;
printk(BIOS_SPEW, "CFG EEPROM: Writing %x at %x\n", data, write_offset);
const uint32_t smb_ctrl_reg = pci_read_config32(PCH_DEV_SMBUS, HOSTC);
pci_write_config32(PCH_DEV_SMBUS, HOSTC, smb_ctrl_reg | I2C_EN);
/*
* The EEPROM expects two address bytes.
* Use the first byte of the block data as second address byte.
*/
uint8_t buffer[2] = {
write_offset & 0xff,
data,
};
for (size_t retry = 3; retry > 0; retry--) {
/* The EEPROM NACKs request when busy writing */
ret = do_smbus_block_write(SMBUS_IO_BASE, I2C_ADDR_EEPROM,
(write_offset >> 8) & 0xff,
sizeof(buffer), buffer);
if (ret == sizeof(buffer))
break;
/* Maximum of 5 milliseconds write duration */
mdelay(5);
}
/* Restore I2C_EN bit */
pci_write_config32(PCH_DEV_SMBUS, HOSTC, smb_ctrl_reg);
return ret != sizeof(buffer);
}
/*
* Write board layout if it has changed into EEPROM.
* Return true on error, false on success.
*/
bool write_board_settings(const struct eeprom_board_layout *new_layout)
{
const size_t off = offsetof(struct eeprom_layout, board_layout);
struct eeprom_board_layout old_layout = {0};
bool ret = false;
bool changed = false;
/* Read old settings */
if (eeprom_read_buffer(&old_layout, off, sizeof(old_layout))) {
printk(BIOS_ERR, "CFG EEPROM: Read operation failed\n");
return true;
}
assert(sizeof(old_layout) == sizeof(*new_layout));
const uint8_t *const old = (const uint8_t *)&old_layout;
const uint8_t *const new = (const uint8_t *)new_layout;
/* Compare with new settings and only write changed bytes */
for (size_t i = 0; i < sizeof(old_layout); i++) {
if (old[i] != new[i]) {
changed = true;
if (eeprom_write_byte(new[i], off + i)) {
printk(BIOS_ERR, "CFG EEPROM: Write operation failed\n");
ret = true;
break;
}
}
}
printk(BIOS_DEBUG, "CFG EEPROM: Board Layout up%s\n", changed ? "dated" : " to date");
return ret;
}
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