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soc/intel/common/block/memory: Provide a way to use SPD data from memory

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There can be cases where it is needed to provide the SPD data in a
different way than an EEPROM or CBFS file. This patch adds a third
method where the SPD data can be provided in a memory buffer for
memory-down configurations. Where this memory buffer comes from
and how SPD data is filled in is up to the mainboard code.

To use this new method set 'spd_data.in_mem' to 'true' and provide a
pointer to the SPD data in memory via 'spd_data.ptr' where
'spd_data.len' holds the length of the SPD data in that buffer.

This feature is useful for Siemens mainboards where the SPD data is part
of a larger configuration block called 'HWInfo block'. Though this block
itself do reside in CBFS, the SPD data cannot simply be indexed into
(like with the cbfs_index). Instead, the hwinfo-lib is used to get
dedicated fields from that block, this includes the SPD data, too. With
this patch the SPD data can be retrieved from HWInfo block and passed as
a buffer to the memory initialization code.

Change-Id: I2bd4970967cfe81bba96d8e2b2fd3a0bb85430c4
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88258
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
This commit is contained in:
Werner Zeh 2025-07-01 08:11:55 +02:00 • committed by Matt DeVillier
commit f1d06a5ad4
2 changed files with 26 additions and 8 deletions
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11
src/soc/intel/common/block/include/intelblocks/meminit.h
View file

@ -57,6 +57,17 @@ struct mem_spd {
struct {
uint8_t addr_dimm[CONFIG_DIMMS_PER_CHANNEL];
} smbus[MRC_CHANNELS];
/* If the SPD data is provided in a memory buffer, spd_data.in_mem needs to be
* set to 'true'. In this case spd_data.ptr points to the memory buffer where the
* SPD data is stored in and spd_data.len stores the length of the SPD data
* in that buffer. In this case cbfs_index is ignored.
*/
struct {
bool in_mem;
size_t len;
uintptr_t ptr;
} spd_data;
};
/* Information about memory technology supported by SoC */

23
src/soc/intel/common/block/memory/meminit.c
View file

@ -60,17 +60,24 @@ static void read_spd_md(const struct soc_mem_cfg *soc_mem_cfg, const struct mem_
if (pop_mask == 0)
die("Memory technology does not support the selected configuration!\n");
if (!(info->spd_data.in_mem)) {
printk(BIOS_DEBUG, "SPD index = %zu\n", info->cbfs_index);
printk(BIOS_DEBUG, "SPD index = %zu\n", info->cbfs_index);
/* Memory leak is ok as long as we have memory mapped boot media */
_Static_assert(CONFIG(BOOT_DEVICE_MEMORY_MAPPED),
"Function assumes memory-mapped boot media");
/* Memory leak is ok as long as we have memory mapped boot media */
_Static_assert(CONFIG(BOOT_DEVICE_MEMORY_MAPPED),
"Function assumes memory-mapped boot media");
*spd_len = CONFIG_DIMM_SPD_SIZE;
spd_data = spd_cbfs_map(info->cbfs_index);
if (!spd_data)
die("SPD not found in CBFS or incorrect index!\n");
*spd_len = CONFIG_DIMM_SPD_SIZE;
spd_data = spd_cbfs_map(info->cbfs_index);
if (!spd_data)
die("SPD not found in CBFS or incorrect index!\n");
} else {
*spd_len = info->spd_data.len;
spd_data = info->spd_data.ptr;
if (!spd_data)
die("SPD data in memory expected but no buffer provided!\n");
}
print_spd_info((uint8_t *)spd_data);