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soc/common/smbus: Support reading SPD5 hubs for DDR5

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DDR5 uses a Serial Presence Detect (SPD) with hub function
(SPD5 hub device) to store the SPD data. The SPD5 hub has 1024 bytes of
EEPROM (`CONFIG_DIMM_SPD_SIZE=1024`).

Change-Id: Ic5e6c58f255bef86b68ce90a4f853bf4e7c7ccfe
Co-authored-by: Meera Ravindranath <meera.ravindranath@intel.com>
Signed-off-by: Jeremy Soller <jeremy@system76.com>
Signed-off-by: Tim Crawford <tcrawford@system76.com>
This commit is contained in:
Jeremy Soller 2024-05-31 18:35:37 -06:00 committed by Tim Crawford
parent 277c9abeb7
commit 4380e241cb
No known key found for this signature in database
GPG Key ID: 68E558D2BBD856E3
3 changed files with 95 additions and 14 deletions
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12
src/include/spd_bin.h
View File

@ -36,6 +36,18 @@
#define DDR4_SPD_PART_OFF 329
#define DDR4_SPD_PART_LEN 20
#define DDR4_SPD_SN_OFF 325
#define MAX_SPD_PAGE_SIZE_SPD5 128
#define MAX_SPD_SIZE (SPD_PAGE_LEN * 4)
#define SPD_HUB_MEMREG(addr) ((u8)(0x80 | (addr)))
#define SPD5_MR11 0x0B
#define SPD5_MR0 0x00
#define SPD5_MEMREG_REG(addr) ((u8)((~0x80) & (addr)))
#define SPD5_MR0_SPD5_HUB_DEV 0x51
struct spd_offset_table {
u16 start; /* Offset 0 */
u16 end; /* Offset 2 */
};
struct spd_block {
u8 addr_map[CONFIG_DIMM_MAX]; /* 7 bit I2C addresses */

4
src/lib/spd_cache.c
View File

@ -209,7 +209,9 @@ enum cb_err spd_fill_from_cache(uint8_t *spd_cache, struct spd_block *blk)
dram_type = *(spd_cache + SC_SPD_OFFSET(i) + SPD_DRAM_TYPE);
if (dram_type == SPD_DRAM_DDR4)
if (dram_type == SPD_DRAM_DDR5)
blk->len = CONFIG_DIMM_SPD_SIZE;
else if (dram_type == SPD_DRAM_DDR4)
blk->len = SPD_PAGE_LEN_DDR4;
else
blk->len = SPD_PAGE_LEN;

93
src/soc/intel/common/block/smbus/smbuslib.c
View File

@ -13,8 +13,11 @@ static void update_spd_len(struct spd_block *blk)
if (blk->spd_array[i] != NULL)
j |= blk->spd_array[i][SPD_DRAM_TYPE];
/* If spd used is DDR5, then its length is 1024 byte. */
if (j == SPD_DRAM_DDR5)
blk->len = CONFIG_DIMM_SPD_SIZE;
/* If spd used is DDR4, then its length is 512 byte. */
if (j == SPD_DRAM_DDR4)
else if (j == SPD_DRAM_DDR4)
blk->len = SPD_PAGE_LEN_DDR4;
else
blk->len = SPD_PAGE_LEN;
@ -37,6 +40,61 @@ static void smbus_read_spd(u8 *spd, u8 addr)
}
}
static void switch_page(u8 spd_addr, u8 new_page)
{
u32 offset;
/*
* By default,an SPD5 hub accepts 1 byte addressing pointing
* to the first 128 bytes of memory. MR11[2:0] selects the page
* pointer to address the entire 1024 bytes of non-volatile memory.
*/
offset = SPD5_MEMREG_REG(SPD5_MR11);
smbus_write_byte(spd_addr, offset, new_page);
}
/*
* Read the SPD data over the SMBus, at the specified SPD address,
* starting at the specified starting offset and read the given amount of data.
*/
static void smbus_read_spd5(u8 *spd, u8 spd_addr, u16 size)
{
u8 page = ~0;
u32 max_page_size = MAX_SPD_PAGE_SIZE_SPD5;
if (size > MAX_SPD_SIZE) {
printk(BIOS_ERR, "Maximum SPD size reached\n");
return;
}
for (int i = 0; i < size; i++) {
u8 next_page = (u8) (i / max_page_size);
if (next_page != page) {
switch_page(spd_addr, next_page);
page = next_page;
}
unsigned int byte_addr = SPD_HUB_MEMREG(i % max_page_size);
spd[i] = smbus_read_byte(spd_addr, byte_addr);
}
}
/* Read SPD5 MR0 and check if SPD Byte 0 matches the SPD5 HUB MR0 identifier.*/
static int is_spd5_hub(u8 spd_addr)
{
u8 spd_hub_byte;
spd_hub_byte = smbus_read_byte(spd_addr, SPD5_MEMREG_REG(SPD5_MR0));
return spd_hub_byte == SPD5_MR0_SPD5_HUB_DEV;
}
/*
* Reset the SPD page back to page 0 on an SPD5 Hub device at the
* input SPD SMbus address.
*/
static void reset_page_spd5(u8 spd_addr)
{
/* Set SPD5 MR11[2:0] = 0 (Page 0) */
smbus_write_byte(spd_addr, SPD5_MEMREG_REG(SPD5_MR11), 0);
}
/* return -1 if SMBus errors otherwise return 0 */
static int get_spd(u8 *spd, u8 addr)
{
@ -52,22 +110,31 @@ static int get_spd(u8 *spd, u8 addr)
return -1;
}
if (i2c_eeprom_read(addr, 0, SPD_PAGE_LEN, spd) < 0) {
printk(BIOS_INFO, "do_i2c_eeprom_read failed, using fallback\n");
smbus_read_spd(spd, addr);
}
if (is_spd5_hub(addr)) {
smbus_read_spd5(spd, addr, CONFIG_DIMM_SPD_SIZE);
/* Check if module is DDR4, DDR4 spd is 512 byte. */
if (spd[SPD_DRAM_TYPE] == SPD_DRAM_DDR4 && CONFIG_DIMM_SPD_SIZE > SPD_PAGE_LEN) {
/* Switch to page 1 */
smbus_write_byte(SPD_PAGE_1, 0, 0);
/* Reset the page for the next loop iteration */
reset_page_spd5(addr);
} else {
if (i2c_eeprom_read(addr, 0, SPD_PAGE_LEN, spd + SPD_PAGE_LEN) < 0) {
if (i2c_eeprom_read(addr, 0, SPD_PAGE_LEN, spd) < 0) {
printk(BIOS_INFO, "do_i2c_eeprom_read failed, using fallback\n");
smbus_read_spd(spd + SPD_PAGE_LEN, addr);
smbus_read_spd(spd, addr);
}
/* Check if module is DDR4, DDR4 spd is 512 byte. */
if (spd[SPD_DRAM_TYPE] == SPD_DRAM_DDR4 &&
CONFIG_DIMM_SPD_SIZE > SPD_PAGE_LEN) {
/* Switch to page 1 */
smbus_write_byte(SPD_PAGE_1, 0, 0);
if (i2c_eeprom_read(addr, 0, SPD_PAGE_LEN, spd + SPD_PAGE_LEN) < 0) {
printk(BIOS_INFO, "do_i2c_eeprom_read failed, using fallback\n");
smbus_read_spd(spd + SPD_PAGE_LEN, addr);
}
/* Restore to page 0 */
smbus_write_byte(SPD_PAGE_0, 0, 0);
}
/* Restore to page 0 */
smbus_write_byte(SPD_PAGE_0, 0, 0);
}
return 0;
}