mb, soc: Add the SPD_CACHE_ENABLE

In order to cache the spd data which reads from the memory module, we
add SPD_CACHE_ENABLE option to enable the cache for the spd data. If
this option is enabled, the RW_SPD_CACHE region needs to be added to
the flash layout for caching the data.
Since the user may remove the memory module after the bios caching the
data, we need to add the invalidate flag to invalidate the mrc cache.
Otherwise, the bios will use the mrc cache and can make the device
malfunction.

BUG=b:200243989
BRANCH=firmware-brya-14505.B
TEST=build pass and enable this feature to the brask
     the device could speed up around 150ms with this feature.

Change-Id: If7625a00c865dc268e2a22efd71b34b40c40877b
Signed-off-by: Zhuohao Lee <zhuohao@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62294
Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3 files changed, 58 insertions, 5 deletions

diff --git a/src/soc/intel/common/block/include/intelblocks/meminit.h b/src/soc/intel/common/block/include/intelblocks/meminit.h
index 1fed02f5c6..130249cf71 100644
--- a/src/soc/intel/common/block/include/intelblocks/meminit.h
+++ b/src/soc/intel/common/block/include/intelblocks/meminit.h
@@ -134,11 +134,13 @@ struct mem_channel_data {
  *                 the mainboard.
  * spd_info      : Information about the memory topology.
  * half_populated: Hint from mainboard if channels are half populated.
+ * dimms_changed: True if the dimms is changed after caching the spd data.
  */
 void mem_populate_channel_data(const struct soc_mem_cfg *soc_mem_cfg,
 				const struct mem_spd *spd_info,
 				bool half_populated,
-				struct mem_channel_data *data);
+				struct mem_channel_data *data,
+				bool *dimms_changed);
 
 /*
  * Given a channel number and the maximum number of supported channels, this
diff --git a/src/soc/intel/common/block/memory/Kconfig b/src/soc/intel/common/block/memory/Kconfig
index fdcccbf742..7156be7ff6 100644
--- a/src/soc/intel/common/block/memory/Kconfig
+++ b/src/soc/intel/common/block/memory/Kconfig
@@ -28,4 +28,12 @@ config MRC_CHANNEL_WIDTH
 	  support is expected to set MRC_CHANNEL_WIDTH as per the FSP
 	  MRC expectation.
 
+config SPD_CACHE_ENABLE
+	bool
+	default n
+	help
+	  Enable to cache the spd data to the RW_SPD_CACHE region. If
+	  this option is enabled, please make sure the RW_SPD_CACHE
+	  region is added to the flash layout.
+
 endif
diff --git a/src/soc/intel/common/block/memory/meminit.c b/src/soc/intel/common/block/memory/meminit.c
index 78dc2d443a..89cd4e323e 100644
--- a/src/soc/intel/common/block/memory/meminit.c
+++ b/src/soc/intel/common/block/memory/meminit.c
@@ -5,6 +5,7 @@
 #include <intelblocks/meminit.h>
 #include <commonlib/region.h>
 #include <spd_bin.h>
+#include <spd_cache.h>
 #include <string.h>
 #include <types.h>
 
@@ -96,7 +97,7 @@ static void read_spd_md(const struct soc_mem_cfg *soc_mem_cfg, const struct mem_
 
 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)
+			size_t *spd_len, bool *dimms_changed)
 {
 	size_t ch, dimm;
 	struct spd_block blk = { 0 };
@@ -108,6 +109,7 @@ static bool read_spd_dimm(const struct soc_mem_cfg *soc_mem_cfg, const struct me
 	 * channel is marked as populated.
 	 */
 	uint32_t pop_mask = 0;
+	*dimms_changed = false;
 
 	if (!(info->topo & MEM_TOPO_DIMM_MODULE))
 		return false;
@@ -119,7 +121,46 @@ static bool read_spd_dimm(const struct soc_mem_cfg *soc_mem_cfg, const struct me
 		}
 	}
 
-	get_spd_smbus(&blk);
+	if (CONFIG(SPD_CACHE_ENABLE)) {
+		uint8_t *spd_cache;
+		size_t spd_cache_sz;
+		bool need_update_cache = false;
+		bool dimm_changed = true;
+
+		/* load spd cache from RW_SPD_CACHE */
+		if (load_spd_cache(&spd_cache, &spd_cache_sz) == CB_SUCCESS) {
+			if (!spd_cache_is_valid(spd_cache, spd_cache_sz)) {
+				printk(BIOS_WARNING, "Invalid SPD cache\n");
+			} else {
+				dimm_changed = check_if_dimm_changed(spd_cache, &blk);
+				if (dimm_changed) {
+					/*
+					 * Set flag to indicate that the
+					 * mrc_cache need to be invalidated
+					 */
+					printk(BIOS_INFO,
+					"DIMM change, invalidate cache.\n");
+					*dimms_changed = true;
+				}
+			}
+			need_update_cache = true;
+		}
+
+		if (!dimm_changed) {
+			printk(BIOS_INFO, "Use the SPD cache data\n");
+			spd_fill_from_cache(spd_cache, &blk);
+		} else {
+			/* Access memory info through SMBUS. */
+			get_spd_smbus(&blk);
+
+			if (need_update_cache &&
+				update_spd_cache(&blk) == CB_ERR)
+				printk(BIOS_ERR, "update SPD cache failed\n");
+		}
+	} else {
+		get_spd_smbus(&blk);
+	}
+
 	*spd_len = blk.len;
 
 	for (ch = 0; ch < num_phys_ch; ch++) {
@@ -145,7 +186,8 @@ static bool read_spd_dimm(const struct soc_mem_cfg *soc_mem_cfg, const struct me
 void mem_populate_channel_data(const struct soc_mem_cfg *soc_mem_cfg,
 				const struct mem_spd *spd_info,
 				bool half_populated,
-				struct mem_channel_data *data)
+				struct mem_channel_data *data,
+				bool *dimms_changed)
 {
 	size_t spd_md_len = 0, spd_dimm_len = 0;
 	bool have_dimms;
@@ -153,7 +195,8 @@ void mem_populate_channel_data(const struct soc_mem_cfg *soc_mem_cfg,
 	memset(data, 0, sizeof(*data));
 
 	read_spd_md(soc_mem_cfg, spd_info, half_populated, data, &spd_md_len);
-	have_dimms = 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, dimms_changed);
 
 	if (data->ch_population_flags == NO_CHANNEL_POPULATED)
 		die("No channels are populated. Incorrect memory configuration!\n");