Rework Sandybridge MRC cache handling

- Separate Sandybridge from ChromeOS a bit
  The Sandybridge code depends on chromeos features a whole lot.
  As a first step, provide a code path to look up the MRC cache
  without depending on u-boot.

- Move mrc cache handling to separate file
  This enables us to handle the MRC cache from ramstage,
  where we can write the flash safely (eg. to update the
  cache).
  Also teach it to lookup the current MRC cache from CBMEM,
  as the original data block isn't available anymore.

After all the preparations, finally write to the SPI
as necessary. It's a simple round robin wear levelling
that erases the entire MRC cache region when it's full
and starts from the beginning.

Change-Id: I4751385574cf709b03d5c9d153b7481ffc90ce12
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/1001
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

6 files changed, 322 insertions, 114 deletions

diff --git a/src/northbridge/intel/sandybridge/Kconfig b/src/northbridge/intel/sandybridge/Kconfig
index 8cf0a491d6..67b3defb75 100644
--- a/src/northbridge/intel/sandybridge/Kconfig
+++ b/src/northbridge/intel/sandybridge/Kconfig
@@ -37,6 +37,23 @@ config CACHE_MRC_SIZE_KB
 	int
 	default 256
 
+# FIXME: build from rom size
+config MRC_CACHE_BASE
+	hex
+	default 0xff800000
+
+config MRC_CACHE_LOCATION
+	hex
+	default 0x1ec000
+
+config MRC_CACHE_SIZE
+	hex
+	default 0x10000
+
+config MRC_CACHE_ALIGNMENT
+	hex
+	default 0x1000
+
 config DCACHE_RAM_BASE
 	hex
 	default 0xff7f0000
diff --git a/src/northbridge/intel/sandybridge/Makefile.inc b/src/northbridge/intel/sandybridge/Makefile.inc
index 87a0b2efef..824700ea29 100644
--- a/src/northbridge/intel/sandybridge/Makefile.inc
+++ b/src/northbridge/intel/sandybridge/Makefile.inc
@@ -21,9 +21,11 @@ driver-y += northbridge.c
 driver-y += gma.c
 
 ramstage-$(CONFIG_GENERATE_ACPI_TABLES) += acpi.c
+ramstage-y += mrccache.c
 
 romstage-y += udelay.c
 romstage-y += raminit.c
+romstage-y += mrccache.c
 romstage-y += early_init.c
 romstage-y += report_platform.c
 romstage-y += ../../../arch/x86/lib/walkcbfs.S
diff --git a/src/northbridge/intel/sandybridge/mrccache.c b/src/northbridge/intel/sandybridge/mrccache.c
new file mode 100644
index 0000000000..5c4c3825ce
--- /dev/null
+++ b/src/northbridge/intel/sandybridge/mrccache.c
@@ -0,0 +1,265 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2012 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <console/console.h>
+#include <cbfs.h>
+#include <ip_checksum.h>
+#include <device/device.h>
+#include <cbmem.h>
+#include "pei_data.h"
+#include "sandybridge.h"
+#include <spi.h>
+#include <spi_flash.h>
+/* Using the FDT FMAP for finding the MRC cache area requires including FDT
+ * support in coreboot, which we would like to avoid. There are a number of
+ * options:
+ *  - Have each mainboard Kconfig supply a hard-coded offset
+ *  - For ChromeOS devices: implement native FMAP
+ *  - For non-ChromeOS devices: use CBFS
+ * For now let's leave this code in here until the issue is sorted out in
+ * a way that works for everyone.
+ */
+#undef USE_FDT_FMAP_FOR_MRC_CACHE
+#ifdef USE_FDT_FMAP_FOR_MRC_CACHE
+#include <fdt/libfdt.h>
+#endif
+
+struct mrc_data_container *next_mrc_block(struct mrc_data_container *mrc_cache)
+{
+	/* MRC data blocks are aligned within the region */
+	u32 mrc_size = sizeof(*mrc_cache) + mrc_cache->mrc_data_size;
+	if (mrc_size & (MRC_DATA_ALIGN - 1UL)) {
+		mrc_size &= ~(MRC_DATA_ALIGN - 1UL);
+		mrc_size += MRC_DATA_ALIGN;
+	}
+
+	u8 *region_ptr = (u8*)mrc_cache;
+	region_ptr += mrc_size;
+	return (struct mrc_data_container *)region_ptr;
+}
+
+int is_mrc_cache(struct mrc_data_container *mrc_cache)
+{
+	return (!!mrc_cache) && (mrc_cache->mrc_signature == MRC_DATA_SIGNATURE);
+}
+
+u32 get_mrc_cache_region(struct mrc_data_container **mrc_region_ptr)
+{
+	u8 *mrc_region;
+	u32 region_size;
+	u32 *data;
+#ifdef USE_FDT_FMAP_FOR_MRC_CACHE
+	const struct fdt_header *fdt_header;
+	const struct fdt_property *fdtp;
+	int offset, len;
+	const char *compatible = "chromeos,flashmap";
+	const char *subnode = "rw-mrc-cache";
+	const char *property = "reg";
+	u64 flashrom_base = 0;
+
+	fdt_header = cbfs_find_file(CONFIG_FDT_FILE_NAME, CBFS_TYPE_FDT);
+
+	if (!fdt_header) {
+		printk(BIOS_ERR, "%s: no FDT found!\n", __func__);
+		return 0;
+	}
+
+	offset = fdt_node_offset_by_compatible(fdt_header, 0, compatible);
+	if (offset < 0) {
+		printk(BIOS_ERR, "%s: no %s  node found!\n",
+		       __func__, compatible);
+		return 0;
+	}
+
+	if (fdt_get_base_addr(fdt_header, offset, &flashrom_base) < 0) {
+		printk(BIOS_ERR, "%s: no base address in node name!\n",
+		       __func__);
+		return 0;
+	}
+
+	offset = fdt_subnode_offset(fdt_header, offset, subnode);
+	if (offset < 0) {
+		printk(BIOS_ERR, "%s: no %s found!\n", __func__, subnode);
+		return 0;
+	}
+
+	fdtp = fdt_get_property(fdt_header, offset, property, &len);
+	if (!fdtp || (len != 8)) {
+		printk(BIOS_ERR, "%s: property %s at %p, len %d!\n",
+		       __func__, property, fdtp, len);
+		return 0;
+	}
+
+	data = (u32 *)fdtp->data;
+
+	// Calculate actual address of the MRC cache in memory
+	region_size = fdt32_to_cpu(data[1]);
+	mrc_region = (u8*)((unsigned long)flashrom_base + fdt32_to_cpu(data[0]));
+#else
+	data = (u32 *)((void *)(CONFIG_MRC_CACHE_BASE + CONFIG_MRC_CACHE_LOCATION + 12));
+
+	region_size = CONFIG_MRC_CACHE_SIZE;
+	mrc_region = (u8*)(CONFIG_MRC_CACHE_BASE + be32_to_cpu(data[0]));
+#endif
+
+	*mrc_region_ptr = (struct mrc_data_container *)mrc_region;
+
+	return region_size;
+}
+
+/* find the first empty field in the MRC cache area. If there's none, return
+ * the first region. By testing for emptiness caller can detect if flash
+ * needs to be erased.
+ *
+ * FIXME: that interface is crap
+ */
+struct mrc_data_container *find_next_mrc_cache(void)
+{
+	u32 entry_id = 0;
+	struct mrc_data_container *mrc_cache = NULL;
+	u32 region_size = get_mrc_cache_region(&mrc_cache);
+	void *mrc_region = (void*)mrc_cache;
+
+	if (mrc_cache == NULL) {
+		printk(BIOS_ERR, "%s: could not find mrc cache area\n", __func__);
+		return NULL;
+	}
+
+	/* Search for the first empty entry in the region */
+	while (is_mrc_cache(mrc_cache)) {
+		entry_id++;
+		mrc_cache = next_mrc_block(mrc_cache);
+		/* If we exceed the defined area, move to front */
+		if ((void*)mrc_cache >= (void*)(mrc_region + region_size)) {
+			mrc_cache = (struct mrc_data_container *)mrc_region;
+			break;
+		}
+	}
+
+	printk(BIOS_DEBUG, "picked entry %u from cache block when looking for empty block\n", entry_id);
+
+	return mrc_cache;
+}
+
+struct mrc_data_container *find_current_mrc_cache(void)
+{
+	u32 entry_id = 0;
+	struct mrc_data_container *mrc_next, *mrc_cache = NULL;
+	u32 region_size = get_mrc_cache_region(&mrc_cache);
+	void *mrc_region = (void*)mrc_cache;
+	mrc_next = mrc_cache;
+
+	if (mrc_cache == NULL) {
+		printk(BIOS_ERR, "%s: could not find mrc cache area\n", __func__);
+		return NULL;
+	}
+
+	if (mrc_cache->mrc_data_size == -1UL) {
+		printk(BIOS_ERR, "%s: MRC cache not initialized?\n",  __func__);
+		/* return non-initialized cache, so we can discern this
+		 * from having no cache area at all
+		 */
+		return mrc_cache;
+	} else {
+		/* Search for the last filled entry in the region */
+		while (is_mrc_cache(mrc_next)) {
+			entry_id++;
+			mrc_cache = mrc_next;
+			mrc_next = next_mrc_block(mrc_cache);
+			/* Stay in the mrcdata region defined in fdt */
+			if ((void*)mrc_next >= (void*)(mrc_region + region_size))
+				break;
+		}
+		entry_id--;
+	}
+
+	/* Verify checksum */
+	if (mrc_cache->mrc_checksum !=
+	    compute_ip_checksum(mrc_cache->mrc_data,
+				mrc_cache->mrc_data_size)) {
+		printk(BIOS_ERR, "%s: MRC cache checksum mismatch\n", __func__);
+		return NULL;
+	}
+
+	printk(BIOS_DEBUG, "picked entry %u from cache block\n", entry_id);
+
+	return mrc_cache;
+}
+
+/* SPI code needs malloc/free.
+ * Also unknown if writing flash from XIP-flash code is a good idea
+ */
+#if !defined(__PRE_RAM__)
+void update_mrc_cache(void)
+{
+	struct mrc_data_container *current = cbmem_find(CBMEM_ID_MRCDATA);
+	if (!current) {
+		printk(BIOS_ERR, "No MRC cache in cbmem. Can't update flash.\n");
+		return;
+	}
+	if (current->mrc_data_size == -1) {
+		printk(BIOS_ERR, "MRC cache data in cbmem invalid.\n");
+		return;
+	}
+
+	/*
+	 * we need to:
+	 */
+	//  0. compare MRC data to last mrc-cache block (exit if same)
+	struct mrc_data_container *cache;
+	if ((cache = find_current_mrc_cache()) == NULL) {
+		printk(BIOS_DEBUG, "Failure looking for current last block\n");
+		return;
+	}
+
+	if ((cache->mrc_data_size == current->mrc_data_size) && (memcmp(cache, current, cache->mrc_data_size) == 0)) {
+		printk(BIOS_DEBUG, "MRC data in flash is up to date. No update.\n");
+		return;
+	}
+
+	//  1. use spi_flash_probe() to find the flash, then
+	spi_init();
+	struct spi_flash *flash = spi_flash_probe(0, 0, 1000000, SPI_MODE_3);
+	if (!flash) {
+		printk(BIOS_DEBUG, "Could not find SPI device\n");
+		return;
+	}
+
+	//  2. look up the first unused block
+	cache = find_next_mrc_cache();
+	if (!cache) {
+		printk(BIOS_DEBUG, "Could not find MRC cache area\n");
+		return;
+	}
+
+	//  3. if no such place exists, erase entire mrc-cache range & use block 0
+	if (cache->mrc_data_size != -1) {
+		printk(BIOS_DEBUG, "We need to erase the MRC cache region\n");
+		flash->erase(flash, CONFIG_MRC_CACHE_LOCATION, CONFIG_MRC_CACHE_SIZE);
+		/* we know we can start at the beginning again */
+		get_mrc_cache_region(&cache);
+	}
+	//  4. write mrc data with flash->write()
+	printk(BIOS_DEBUG, "Finally: write MRC cache update to flash\n");
+	flash->write(flash, (u32)(((void*)cache)-CONFIG_MRC_CACHE_BASE), current->mrc_data_size + sizeof(*current), current);
+}
+#endif
+
diff --git a/src/northbridge/intel/sandybridge/northbridge.c b/src/northbridge/intel/sandybridge/northbridge.c
index b2baaa3d4e..7d7153e73c 100644
--- a/src/northbridge/intel/sandybridge/northbridge.c
+++ b/src/northbridge/intel/sandybridge/northbridge.c
@@ -77,6 +77,12 @@ int add_northbridge_resources(struct lb_memory *mem)
 	return 0;
 }
 
+void cbmem_post_handling(void);
+void cbmem_post_handling(void)
+{
+	update_mrc_cache();
+}
+
 static int get_pcie_bar(u32 *base, u32 *len)
 {
 	device_t dev;
diff --git a/src/northbridge/intel/sandybridge/raminit.c b/src/northbridge/intel/sandybridge/raminit.c
index 8209980bb1..0df86d6187 100644
--- a/src/northbridge/intel/sandybridge/raminit.c
+++ b/src/northbridge/intel/sandybridge/raminit.c
@@ -36,9 +36,8 @@
 #include "southbridge/intel/bd82x6x/me.h"
 #if CONFIG_CHROMEOS
 #include <vendorcode/google/chromeos/chromeos.h>
-#endif
-#if 0
-#include <fdt/libfdt.h>
+#else
+#define recovery_mode_enabled(x) 0
 #endif
 
 /*
@@ -56,17 +55,6 @@
 #define CMOS_OFFSET_MRC_SEED_CHK 120
 #endif
 
-#define MRC_DATA_ALIGN           0x1000
-#define MRC_DATA_SIGNATURE       (('M'<<0)|('R'<<8)|('C'<<16)|('D'<<24))
-
-struct mrc_data_container {
-	u32	mrc_signature;	// "MRCD"
-	u32	mrc_data_size;	// Actual total size of this structure
-	u32	mrc_checksum;	// IP style checksum
-	u32	reserved;	// For header alignment
-	u8	mrc_data[0];	// Variable size, platform/run time dependent.
-} __attribute__ ((packed));
-
 static void save_mrc_data(struct pei_data *pei_data)
 {
 	u16 c1, c2, checksum;
@@ -119,22 +107,10 @@ static void save_mrc_data(struct pei_data *pei_data)
 	cmos_write((checksum >> 8) & 0xff, CMOS_OFFSET_MRC_SEED_CHK+1);
 }
 
-#if CONFIG_CHROMEOS
 static void prepare_mrc_cache(struct pei_data *pei_data)
 {
-#if 0
-	const struct fdt_header *fdt_header;
-	const struct fdt_property *fdtp;
-	int offset, len;
-	const char *compatible = "chromeos,flashmap";
-	const char *subnode = "rw-mrc-cache";
-	const char *property = "reg";
-	u32 *data;
-	struct mrc_data_container *mrc_cache, *mrc_next;
-	u8 *mrc_region, *region_ptr;
+	struct mrc_data_container *mrc_cache;
 	u16 c1, c2, checksum, seed_checksum;
-	u32 region_size, entry_id = 0;
-	u64 flashrom_base = 0;
 
 	// preset just in case there is an error
 	pei_data->mrc_input = NULL;
@@ -166,96 +142,18 @@ static void prepare_mrc_cache(struct pei_data *pei_data)
 		return;
 	}
 
-	fdt_header = cbfs_find_file(CONFIG_FDT_FILE_NAME, CBFS_TYPE_FDT);
-
-	if (!fdt_header) {
-		printk(BIOS_ERR, "%s: no FDT found!\n", __func__);
-		return;
-	}
-
-	offset = fdt_node_offset_by_compatible(fdt_header, 0, compatible);
-	if (offset < 0) {
-		printk(BIOS_ERR, "%s: no %s  node found!\n",
-		       __func__, compatible);
-		return;
-	}
-
-	if (fdt_get_base_addr(fdt_header, offset, &flashrom_base) < 0) {
-		printk(BIOS_ERR, "%s: no base address in node name!\n",
-		       __func__);
-		return;
-	}
-
-	offset = fdt_subnode_offset(fdt_header, offset, subnode);
-	if (offset < 0) {
-		printk(BIOS_ERR, "%s: no %s found!\n", __func__, subnode);
-		return;
-	}
-
-	fdtp = fdt_get_property(fdt_header, offset, property, &len);
-	if (!fdtp || (len != 8)) {
-		printk(BIOS_ERR, "%s: property %s at %p, len %d!\n",
-		       __func__, property, fdtp, len);
-		return;
-	}
-
-	data = (u32 *)fdtp->data;
-
-	// Calculate actual address of the MRC cache in memory
-	region_size = fdt32_to_cpu(data[1]);
-	mrc_region = region_ptr = (u8*)
-		((unsigned long)flashrom_base + fdt32_to_cpu(data[0]));
-	mrc_cache = mrc_next = (struct mrc_data_container *)mrc_region;
-
-	if (!mrc_cache || mrc_cache->mrc_signature != MRC_DATA_SIGNATURE) {
-		printk(BIOS_ERR, "%s: invalid MRC data\n", __func__);
-		return;
-	}
-
-	if (mrc_cache->mrc_data_size == -1UL) {
-		printk(BIOS_ERR, "%s: MRC cache not initialized?\n",  __func__);
-		return;
-	} else {
-		/* MRC data blocks are aligned within the region */
-		u32 mrc_size = sizeof(*mrc_cache) + mrc_cache->mrc_data_size;
-		if (mrc_size & (MRC_DATA_ALIGN - 1UL)) {
-			mrc_size &= ~(MRC_DATA_ALIGN - 1UL);
-			mrc_size += MRC_DATA_ALIGN;
-		}
-
-		/* Search for the last filled entry in the region */
-		while (mrc_next &&
-		       mrc_next->mrc_signature == MRC_DATA_SIGNATURE) {
-			entry_id++;
-			mrc_cache = mrc_next;
-			/* Stay in the mrcdata region defined in fdt */
-			if ((entry_id * mrc_size) > region_size)
-				break;
-			region_ptr += mrc_size;
-			mrc_next = (struct mrc_data_container *)region_ptr;
-		}
-		entry_id--;
-	}
-
-	/* Verify checksum */
-	if (mrc_cache->mrc_checksum !=
-	    compute_ip_checksum(mrc_cache->mrc_data,
-				mrc_cache->mrc_data_size)) {
-		printk(BIOS_ERR, "%s: MRC cache checksum mismatch\n", __func__);
+	if ((mrc_cache = find_current_mrc_cache()) == NULL) {
+		/* error message printed in find_current_mrc_cache */
 		return;
 	}
 
 	pei_data->mrc_input = mrc_cache->mrc_data;
 	pei_data->mrc_input_len = mrc_cache->mrc_data_size;
 
-	printk(BIOS_DEBUG, "%s: at %p, entry %u size %x checksum %04x\n",
-	       __func__, pei_data->mrc_input, entry_id,
+	printk(BIOS_DEBUG, "%s: at %p, size %x checksum %04x\n",
+	       __func__, pei_data->mrc_input,
 	       pei_data->mrc_input_len, mrc_cache->mrc_checksum);
-#else
-	printk(BIOS_ERR, "MRC cache handling code has to be redone.\n");
-#endif
 }
-#endif
 
 static const char* ecc_decoder[] = {
 	"inactive",
@@ -315,7 +213,6 @@ static void report_memory_config(void)
 void sdram_initialize(struct pei_data *pei_data)
 {
 	struct sys_info sysinfo;
-	const char *target = "mrc.bin";
 	unsigned long entry;
 
 	report_platform_info();
@@ -330,7 +227,6 @@ void sdram_initialize(struct pei_data *pei_data)
 
 	sysinfo.boot_path = pei_data->boot_mode;
 
-#if CONFIG_CHROMEOS
 	/*
 	 * Do not pass MRC data in for recovery mode boot,
 	 * Always pass it in for S3 resume.
@@ -340,20 +236,20 @@ void sdram_initialize(struct pei_data *pei_data)
 
 	/* If MRC data is not found we cannot continue S3 resume. */
 	if (pei_data->boot_mode == 2 && !pei_data->mrc_input) {
+		printk(BIOS_DEBUG, "Giving up in sdram_initialize: No MRC data\n");
 		outb(0x6, 0xcf9);
 		hlt();
 	}
-#endif
 
 	/* Locate and call UEFI System Agent binary. */
-	entry = (unsigned long)cbfs_find_file(target, 0xab);
+	entry = (unsigned long)cbfs_find_file("mrc.bin", 0xab);
 	if (entry) {
 		int rv;
 		asm volatile (
 			      "call *%%ecx\n\t"
 			      :"=a" (rv) : "c" (entry), "a" (pei_data));
 		if (rv) {
-			printk(BIOS_ERR, "MRC returned %d\n", rv);
+			printk(BIOS_ERR, "MRC returned %x\n", rv);
 			die("Nonzero MRC return value\n");
 		}
 	} else {
diff --git a/src/northbridge/intel/sandybridge/sandybridge.h b/src/northbridge/intel/sandybridge/sandybridge.h
index aa62021743..7e12416f46 100644
--- a/src/northbridge/intel/sandybridge/sandybridge.h
+++ b/src/northbridge/intel/sandybridge/sandybridge.h
@@ -221,6 +221,28 @@ void dump_spd_registers(void);
 void dump_mem(unsigned start, unsigned end);
 void report_platform_info(void);
 #endif /* !__SMM__ */
+
+
+#define MRC_DATA_ALIGN           0x1000
+#define MRC_DATA_SIGNATURE       (('M'<<0)|('R'<<8)|('C'<<16)|('D'<<24))
+
+struct mrc_data_container {
+	u32	mrc_signature;	// "MRCD"
+	u32	mrc_data_size;	// Actual total size of this structure
+	u32	mrc_checksum;	// IP style checksum
+	u32	reserved;	// For header alignment
+	u8	mrc_data[0];	// Variable size, platform/run time dependent.
+} __attribute__ ((packed));
+
+struct mrc_data_container *next_mrc_block(struct mrc_data_container *mrc_cache);
+int is_mrc_cache(struct mrc_data_container *mrc_cache);
+u32 get_mrc_cache_region(struct mrc_data_container **mrc_region_ptr);
+struct mrc_data_container *find_next_mrc_cache(void);
+struct mrc_data_container *find_current_mrc_cache(void);
+#if !defined(__PRE_RAM__)
+void update_mrc_cache(void);
+#endif
+
 #endif
 #endif
 #endif