[coreboot-gerrit] New patch to review for coreboot: mrc: Add support for separate training cache in recovery mode

[Furquan Shaikh]

Furquan Shaikh ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/17242

-gerrit

commit c4f0d285d922fd9ab633841351386fe4f6d12289
Author: Furquan Shaikh 
Date:   Sat Nov 5 23:57:02 2016 -0700

mrc: Add support for separate training cache in recovery mode

1. Re-factor MRC cache driver to properly select RW_MRC_CACHE or
    RECOVERY_MRC_CACHE based on the boot mode.
     - If normal mode boot, use RW_MRC_CACHE, if available.
     - If recovery mode boot:
        - Retrain memory if RECOVERY_MRC_CACHE not present, or recovery is
        requested explicity with retrain memory request.
        - Use RECOVERY_MRC_CACHE otherwise.
    2. Protect RECOVERY_MRC_CACHE before jumping from RO to RW in recovery
    mode.
    3. Update training data in appropriate cache:
     - Use RW_MRC_CACHE if normal mode.
     - Use RECOVERY_MRC_CACHE if present in recovery mode. Else use
     RW_MRC_CACHE.
    4. Add proper debug logs to indicate which training data cache is used
    at any point.

BUG=chrome-os-partner:59352
    BRANCH=None
    TEST=Verified that correct cache is used in both normal and recovery
    mode on reef.

Change-Id: Ie79737a1450bd1ff71543e44a5a3e16950e70fb3
    Signed-off-by: Furquan Shaikh 
---
 src/drivers/intel/fsp2_0/memory_init.c |  18 -----
 src/soc/intel/common/mrc_cache.c       | 136 ++++++++++++++++++++++-----------
 src/soc/intel/common/mrc_cache.h       |   3 +
 3 files changed, 94 insertions(+), 63 deletions(-)

diff --git a/src/drivers/intel/fsp2_0/memory_init.c b/src/drivers/intel/fsp2_0/memory_init.c
index d0a22ce..798cd87 100644
--- a/src/drivers/intel/fsp2_0/memory_init.c
+++ b/src/drivers/intel/fsp2_0/memory_init.c
@@ -55,13 +55,6 @@ static void save_memory_training_data(bool s3wake, uint32_t fsp_version)
    		printk(BIOS_ERR, "Failed to stash MRC data\n");
 }

-/*
- * On every trip to recovery, newly generated MRC data is stored with this
- * version since it is not expected to be a legit version. This ensures that on
- * next normal boot, memory re-training occurs and new MRC data is stored.
- */
-#define MRC_DEAD_VERSION		(0xdeaddead)
-
 static void do_fsp_post_memory_init(bool s3wake, uint32_t fsp_version)
 {
    struct range_entry fsp_mem;
@@ -89,10 +82,6 @@ static void do_fsp_post_memory_init(bool s3wake, uint32_t fsp_version)
    	(uintptr_t)cbmem_find(CBMEM_ID_FSP_RESERVED_MEMORY))
    	die("Failed to accommodate FSP reserved memory request!\n");

-	/* Now that CBMEM is up, save the list so ramstage can use it */
-	if (vboot_recovery_mode_enabled())
-		fsp_version = MRC_DEAD_VERSION;
-
    save_memory_training_data(s3wake, fsp_version);

/* Create romstage handof information */
@@ -113,14 +102,7 @@ static void fsp_fill_mrc_cache(FSPM_ARCH_UPD *arch_upd, bool s3wake,
    if (!IS_ENABLED(CONFIG_CACHE_MRC_SETTINGS))
    	return;

-	/* Don't use saved training data when recovery mode is enabled. */
-	if (vboot_recovery_mode_enabled()) {
-		printk(BIOS_SPEW, "Recovery mode. Not using MRC cache.\n");
-		return;
-	}
-
    if (mrc_cache_get_current_with_version(&mrc_cache, fsp_version)) {
-		printk(BIOS_SPEW, "MRC cache was not found\n");
    	return;
    }

diff --git a/src/soc/intel/common/mrc_cache.c b/src/soc/intel/common/mrc_cache.c
index c123da9..29721e4 100644
--- a/src/soc/intel/common/mrc_cache.c
+++ b/src/soc/intel/common/mrc_cache.c
@@ -34,13 +34,37 @@ struct mrc_data_region {
    uint32_t size;
 };

+/* Protect RW_MRC_CACHE region with a Protected Range Register */
+static int protect_mrc_cache(const struct mrc_data_region *region,
+			     const char *name)
+{
+#if IS_ENABLED(CONFIG_MRC_SETTINGS_PROTECT)
+	if (nvm_is_write_protected() <= 0) {
+		printk(BIOS_INFO, "MRC: NOT enabling PRR for %s.\n", name);
+		return 1;
+	}
+
+	if (nvm_protect(region->base, region->size) < 0) {
+		printk(BIOS_ERR, "MRC: ERROR setting PRR for %s.\n", name);
+		return -1;
+	}
+
+	printk(BIOS_INFO, "MRC: Enabled Protected Range on %s.\n", name);
+#endif
+	return 0;
+}
+
 /* common code */
-static int mrc_cache_get_region(struct mrc_data_region *region)
+static int mrc_cache_get_region(const char *name,
+				struct mrc_data_region *region)
 {
    bool located_by_fmap = true;
    struct region_device rdev;

-	if (fmap_locate_area_as_rdev("RW_MRC_CACHE", &rdev))
+	region->base = NULL;
+	region->size = 0;
+
+	if (fmap_locate_area_as_rdev(name, &rdev))
    	located_by_fmap =  false;

/* CHROMEOS builds must get their MRC cache from FMAP. */
@@ -61,6 +85,18 @@ static int mrc_cache_get_region(struct mrc_data_region *region)
    return 0;
 }

+/*
+ * Check if RECOVERY_MRC_CACHE exists on this device.
+ * Returns 1 if region exists, 0 otherwise.
+ */
+static int mrc_recovery_cache_exists(void)
+{
+	if (!IS_ENABLED(CONFIG_CHROMEOS))
+		return 0;
+
+	return fmap_region_exists(RECOVERY_MRC_CACHE);
+}
+
 static int mrc_cache_in_region(const struct mrc_data_region *region,
                                const struct mrc_saved_data *cache)
 {
@@ -148,22 +184,43 @@ static int __mrc_cache_get_current(const struct mrc_data_region *region,
    	return -1;

if (verified_cache->version != version) {
-		printk(BIOS_DEBUG, "MRC cache version mismatch: %x vs %x\n",
+		printk(BIOS_DEBUG, "MRC: cache version mismatch: %x vs %x\n",
    		verified_cache->version, version);
    	return -1;
    }

-	printk(BIOS_DEBUG, "MRC cache slot %d @ %p\n", slot-1, verified_cache);
+	printk(BIOS_DEBUG, "MRC: cache slot %d @ %p\n", slot-1, verified_cache);

return 0;
 }

int mrc_cache_get_current_with_version(const struct mrc_saved_data **cache,
-					uint32_t version)
+				       uint32_t version)
 {
    struct mrc_data_region region;
+	const char *region_name = DEFAULT_MRC_CACHE;
+
+	if (vboot_recovery_mode_enabled()) {
+		if (mrc_recovery_cache_exists() &&
+		    !vboot_recovery_mode_memory_retrain())
+			region_name = RECOVERY_MRC_CACHE;
+		else
+			region_name = NULL;
+	} else {
+		if (!mrc_cache_get_region(RECOVERY_MRC_CACHE, &region)) {
+			printk(BIOS_INFO, "MRC: Protecting recovery cache.\n");
+			protect_mrc_cache(&region, RECOVERY_MRC_CACHE);
+		}
+	}

-	if (mrc_cache_get_region(&region) < 0)
+	if (!region_name) {
+		printk(BIOS_ERR, "MRC: Requires memory retraining\n");
+		return -1;
+	}
+
+	printk(BIOS_ERR, "MRC: Using data from %s\n", region_name);
+
+	if (mrc_cache_get_region(region_name, &region) < 0)
    	return -1;

return __mrc_cache_get_current(&region, cache, version);
@@ -196,14 +253,14 @@ int mrc_cache_stash_data_with_version(const void *data, size_t size,
    cache = cbmem_add(CBMEM_ID_MRCDATA, cbmem_size);

if (cache == NULL) {
-		printk(BIOS_ERR, "No space in cbmem for MRC data.\n");
+		printk(BIOS_ERR, "MRC: No space in cbmem for training data.\n");
    	return -1;
    }

/* Clear alignment padding bytes at end of data. */
    memset(&cache->data[size], 0, cbmem_size - size - sizeof(*cache));

-	printk(BIOS_DEBUG, "Relocate MRC DATA from %p to %p (%zu bytes)\n",
+	printk(BIOS_DEBUG, "MRC: Relocate data from %p to %p (%zu bytes)\n",
           data, cache, size);

mrc_cache_fill(cache, data, size, version);
@@ -262,48 +319,35 @@ mrc_cache_next_slot(const struct mrc_data_region *region,
    return next_slot;
 }

-/* Protect RW_MRC_CACHE region with a Protected Range Register */
-static int protect_mrc_cache(const struct mrc_data_region *region)
-{
-#if IS_ENABLED(CONFIG_MRC_SETTINGS_PROTECT)
-	if (nvm_is_write_protected() <= 0) {
-		printk(BIOS_INFO, "NOT enabling PRR for RW_MRC_CACHE region\n");
-		return 1;
-	}
-
-	if (nvm_protect(region->base, region->size) < 0) {
-		printk(BIOS_ERR, "ERROR setting PRR for RW_MRC_CACHE region\n");
-		return -1;
-	}
-
-	printk(BIOS_INFO, "Enabled Protected Range on RW_MRC_CACHE region\n");
-#endif
-	return 0;
-}
-
 static void update_mrc_cache(void *unused)
 {
    const struct mrc_saved_data *current_boot;
    const struct mrc_saved_data *current_saved;
    const struct mrc_saved_data *next_slot;
    struct mrc_data_region region;
+	const char *region_name = DEFAULT_MRC_CACHE;

-	printk(BIOS_DEBUG, "Updating MRC cache data.\n");
+	printk(BIOS_DEBUG, "MRC: Updating cache data.\n");

-	current_boot = cbmem_find(CBMEM_ID_MRCDATA);
-	if (!current_boot) {
-		printk(BIOS_ERR, "No MRC cache in cbmem.\n");
+	if (vboot_recovery_mode_enabled() && mrc_recovery_cache_exists())
+		region_name = RECOVERY_MRC_CACHE;
+
+	printk(BIOS_ERR, "MRC: Cache region selected - %s\n", region_name);
+
+	if (mrc_cache_get_region(region_name, &region)) {
+		printk(BIOS_ERR, "MRC: Could not obtain cache region.\n");
    	return;
    }

-	if (mrc_cache_get_region(&region)) {
-		printk(BIOS_ERR, "Could not obtain MRC cache region.\n");
-		return;
+	current_boot = cbmem_find(CBMEM_ID_MRCDATA);
+	if (!current_boot) {
+		printk(BIOS_ERR, "MRC: No cache in cbmem.\n");
+		goto out;
    }

if (!mrc_cache_valid(&region, current_boot)) {
-		printk(BIOS_ERR, "MRC cache data in cbmem invalid.\n");
-		return;
+		printk(BIOS_ERR, "MRC: Cache data in cbmem invalid.\n");
+		goto out;
    }

current_saved = NULL;
@@ -313,20 +357,20 @@ static void update_mrc_cache(void *unused)
    	if (current_saved->size == current_boot->size &&
    	    !memcmp(&current_saved->data[0], &current_boot->data[0],
    	            current_saved->size)) {
-			printk(BIOS_DEBUG, "MRC cache up to date.\n");
-			protect_mrc_cache(&region);
-			return;
+			printk(BIOS_DEBUG, "MRC: Cache up to date.\n");
+			goto out;
    	}
    }

next_slot = mrc_cache_next_slot(&region, current_saved);

if (!mrc_slot_valid(&region, next_slot, current_boot)) {
-		printk(BIOS_DEBUG, "Slot @ %p is invalid.\n", next_slot);
+		printk(BIOS_DEBUG, "MRC: Slot @ %p is invalid.\n", next_slot);
    	if (!nvm_is_erased(region.base, region.size)) {
    		if (nvm_erase(region.base, region.size) < 0) {
-				printk(BIOS_DEBUG, "Failure erasing region.\n");
-				return;
+				printk(BIOS_DEBUG, "MRC: Failure erasing "
+				       "region %s.\n", region_name);
+				goto out;
    		}
    	}
    	next_slot = region.base;
@@ -334,10 +378,12 @@ static void update_mrc_cache(void *unused)

if (nvm_write((void *)next_slot, current_boot,
                   current_boot->size + sizeof(*current_boot))) {
-		printk(BIOS_DEBUG, "Failure writing MRC cache to %p.\n",
-		       next_slot);
+		printk(BIOS_DEBUG, "MRC: Failure writing cache to %s(%p).\n",
+		       region_name, next_slot);
    }
-	protect_mrc_cache(&region);
+
+out:
+	protect_mrc_cache(&region, region_name);
 }

BOOT_STATE_INIT_ENTRY(BS_WRITE_TABLES, BS_ON_ENTRY, update_mrc_cache, NULL);
diff --git a/src/soc/intel/common/mrc_cache.h b/src/soc/intel/common/mrc_cache.h
index 9b14c1e..09ab306 100644
--- a/src/soc/intel/common/mrc_cache.h
+++ b/src/soc/intel/common/mrc_cache.h
@@ -19,6 +19,9 @@
 #include <stddef.h>
 #include <stdint.h>

+#define DEFAULT_MRC_CACHE	"RW_MRC_CACHE"
+#define RECOVERY_MRC_CACHE	"RECOVERY_MRC_CACHE"
+
 /* Wrapper object to save MRC information. */
 struct mrc_saved_data {
    uint32_t signature;