Change in coreboot[master]: soc/intel/common/blk/memory: Make mixed topo work

[Angel Pons (Code Review)]

Angel Pons has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/60800 )

Change subject: soc/intel/common/blk/memory: Make mixed topo work
......................................................................

soc/intel/common/blk/memory: Make mixed topo work

When using a mixed memory topology with DDR4, it's not possible to boot
when no DIMMs are installed, even though memory-down is available. This
happens because the DIMM SPD length defaults to 256 when no DIMM SPD is
available. Relax the length check when no DIMMs are present to overcome
this problem.

Change-Id: I1cabf64fade1c06a44b6c3892659d54febc7a79a
Signed-off-by: Angel Pons 
---
M src/soc/intel/common/block/memory/meminit.c
1 file changed, 10 insertions(+), 5 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/00/60800/1

diff --git a/src/soc/intel/common/block/memory/meminit.c b/src/soc/intel/common/block/memory/meminit.c
index 50c8b40..78dc2d4 100644
--- a/src/soc/intel/common/block/memory/meminit.c
+++ b/src/soc/intel/common/block/memory/meminit.c
@@ -6,6 +6,7 @@
 #include <commonlib/region.h>
 #include <spd_bin.h>
 #include <string.h>
+#include <types.h>

_Static_assert(CONFIG_MRC_CHANNEL_WIDTH > 0, "MRC channel width must be >0!");
 _Static_assert(CONFIG_DATA_BUS_WIDTH > 0, "Data bus width must be >0!");
@@ -93,7 +94,7 @@

#define CH_DIMM_OFFSET(ch, dimm)	((ch) * CONFIG_DIMMS_PER_CHANNEL + (dimm))

-static void read_spd_dimm(const struct soc_mem_cfg *soc_mem_cfg, const struct mem_spd *info,
+static bool read_spd_dimm(const struct soc_mem_cfg *soc_mem_cfg, const struct mem_spd *info,
    		bool half_populated, struct mem_channel_data *channel_data,
    		size_t *spd_len)
 {
@@ -109,7 +110,7 @@
    uint32_t pop_mask = 0;

if (!(info->topo & MEM_TOPO_DIMM_MODULE))
-		return;
+		return false;

for (ch = 0; ch < num_phys_ch; ch++) {
    	for (dimm = 0; dimm < CONFIG_DIMMS_PER_CHANNEL; dimm++) {
@@ -137,6 +138,8 @@
    }

channel_data->ch_population_flags |= populated_mask_to_flag(pop_mask, num_phys_ch);
+
+	return pop_mask != 0;
 }

void mem_populate_channel_data(const struct soc_mem_cfg *soc_mem_cfg,
@@ -145,11 +148,12 @@
    			struct mem_channel_data *data)
 {
    size_t spd_md_len = 0, spd_dimm_len = 0;
+	bool have_dimms;

memset(data, 0, sizeof(*data));

read_spd_md(soc_mem_cfg, spd_info, half_populated, data, &spd_md_len);
-	read_spd_dimm(soc_mem_cfg, spd_info, half_populated, data, &spd_dimm_len);
+	have_dimms = read_spd_dimm(soc_mem_cfg, spd_info, half_populated, data, &spd_dimm_len);

if (data->ch_population_flags == NO_CHANNEL_POPULATED)
    	die("No channels are populated. Incorrect memory configuration!\n");
@@ -161,11 +165,12 @@
    } else {
    	/*
    	 * SPD lengths must match for CBFS and EEPROM SPD for mixed
-		 * topology.
+		 * topology. Skip this check when no DIMMs are installed.
    	 */
-		if (spd_md_len != spd_dimm_len)
+		if (have_dimms && spd_md_len != spd_dimm_len)
    		die("Length of SPD does not match for mixed topology!\n");

+		/* Use memory-down SPD length in case there are no DIMMs installed */
    	data->spd_len = spd_md_len;
    }
 }