New patch to review for coreboot: chromeos: Add option to backup VBNV CMOS into flash

[Patrick Georgi]

Patrick Georgi ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/13600

-gerrit

commit c6feb09df0e3f30fd99b0613d1442d5dca475f18
Author: Duncan Laurie 
Date:   Tue Jan 26 16:30:36 2016 -0800

chromeos: Add option to backup VBNV CMOS into flash

This adds a new kconfig option that will backup the VBNV data
    from CMOS to flash, and restore it if the CMOS data is invalid
    during boot.

This allows special flags to not get lost when power is lost,
    RTC reset is triggered, or CMOS is corrupted.

BUG=chrome-os-partner:47915
    BRANCH=glados
    TEST=manually tested on chell:
    1-boot and run "enable_dev_usb_boot"
    2-reboot and check that it is enabled with crossystem
    3-run "mosys nvram clear"
    4-reboot and check that it is still enabled

Change-Id: I38103d100117da34471734a6dd31eb7058735c12
    Signed-off-by: Patrick Georgi 
    Original-Commit-Id: 8a356e616c6885d5ae3b776691929675d48a28f9
    Original-Change-Id: I06e7ddff7b272e579c704914a0cf8cc14d6994e8
    Original-Signed-off-by: Duncan Laurie 
    Original-Reviewed-on: https://chromium-review.googlesource.com/324122
    Original-Reviewed-by: Aaron Durbin 
---
 src/vendorcode/google/chromeos/Kconfig      |  8 ++++++++
 src/vendorcode/google/chromeos/Makefile.inc |  5 +++++
 src/vendorcode/google/chromeos/vbnv_cmos.c  | 31 +++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/src/vendorcode/google/chromeos/Kconfig b/src/vendorcode/google/chromeos/Kconfig
index 04a2fad..baa6ca7 100644
--- a/src/vendorcode/google/chromeos/Kconfig
+++ b/src/vendorcode/google/chromeos/Kconfig
@@ -50,6 +50,14 @@ config CHROMEOS_VBNV_CMOS
    help
      VBNV is stored in CMOS

+config CHROMEOS_VBNV_CMOS_BACKUP_TO_FLASH
+	bool "Backup Vboot non-volatile storage from CMOS to flash."
+	default n
+	depends on CHROMEOS_VBNV_CMOS
+	help
+	  Vboot non-volatile storage data will be backed up from CMOS to flash
+	  and restored from flash if the CMOS is invalid due to power loss.
+
 config CHROMEOS_VBNV_EC
    bool "Vboot non-volatile storage in EC."
    default n
diff --git a/src/vendorcode/google/chromeos/Makefile.inc b/src/vendorcode/google/chromeos/Makefile.inc
index 4a65963..d450efb 100644
--- a/src/vendorcode/google/chromeos/Makefile.inc
+++ b/src/vendorcode/google/chromeos/Makefile.inc
@@ -28,6 +28,11 @@ verstage-$(CONFIG_CHROMEOS_VBNV_CMOS) += vbnv_cmos.c
 romstage-$(CONFIG_CHROMEOS_VBNV_CMOS) += vbnv_cmos.c
 ramstage-$(CONFIG_CHROMEOS_VBNV_CMOS) += vbnv_cmos.c

+bootblock-$(CONFIG_CHROMEOS_VBNV_CMOS_BACKUP_TO_FLASH) += vbnv_flash.c
+verstage-$(CONFIG_CHROMEOS_VBNV_CMOS_BACKUP_TO_FLASH) += vbnv_flash.c
+romstage-$(CONFIG_CHROMEOS_VBNV_CMOS_BACKUP_TO_FLASH) += vbnv_flash.c
+ramstage-$(CONFIG_CHROMEOS_VBNV_CMOS_BACKUP_TO_FLASH) += vbnv_flash.c
+
 bootblock-$(CONFIG_CHROMEOS_VBNV_EC) += vbnv_ec.c
 verstage-$(CONFIG_CHROMEOS_VBNV_EC) += vbnv_ec.c
 romstage-$(CONFIG_CHROMEOS_VBNV_EC) += vbnv_ec.c
diff --git a/src/vendorcode/google/chromeos/vbnv_cmos.c b/src/vendorcode/google/chromeos/vbnv_cmos.c
index e0d7ba1..22acefa 100644
--- a/src/vendorcode/google/chromeos/vbnv_cmos.c
+++ b/src/vendorcode/google/chromeos/vbnv_cmos.c
@@ -13,6 +13,8 @@
  * GNU General Public License for more details.
  */

+#include <bootstate.h>
+#include <console/console.h>
 #include <types.h>
 #include <pc80/mc146818rtc.h>
 #include "vbnv.h"
@@ -24,6 +26,21 @@ void read_vbnv_cmos(uint8_t *vbnv_copy)

for (i = 0; i < VBNV_BLOCK_SIZE; i++)
    	vbnv_copy[i] = cmos_read(CONFIG_VBNV_OFFSET + 14 + i);
+
+	if (IS_ENABLED(CONFIG_CHROMEOS_VBNV_CMOS_BACKUP_TO_FLASH)) {
+		if (verify_vbnv(vbnv_copy))
+			return;
+
+		printk(BIOS_INFO, "VBNV: CMOS invalid, restoring from flash\n");
+		read_vbnv_flash(vbnv_copy);
+
+		if (verify_vbnv(vbnv_copy)) {
+			save_vbnv_cmos(vbnv_copy);
+			printk(BIOS_INFO, "VBNV: Flash backup restored\n");
+		} else {
+			printk(BIOS_INFO, "VBNV: Restore from flash failed\n");
+		}
+	}
 }

void save_vbnv_cmos(const uint8_t *vbnv_copy)
@@ -33,3 +50,17 @@ void save_vbnv_cmos(const uint8_t *vbnv_copy)
    for (i = 0; i < VBNV_BLOCK_SIZE; i++)
    	cmos_write(vbnv_copy[i], CONFIG_VBNV_OFFSET + 14 + i);
 }
+
+#if IS_ENABLED(CONFIG_CHROMEOS_VBNV_CMOS_BACKUP_TO_FLASH)
+static void backup_vbnv_cmos(void *unused)
+{
+	uint8_t vbnv_cmos[VBNV_BLOCK_SIZE];
+
+	/* Read current VBNV from CMOS. */
+	read_vbnv_cmos(vbnv_cmos);
+
+	/* Save to flash, will only be saved if different. */
+	save_vbnv_flash(vbnv_cmos);
+}
+BOOT_STATE_INIT_ENTRY(BS_POST_DEVICE, BS_ON_EXIT, backup_vbnv_cmos, NULL);
+#endif