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soc/intel/common: Add function to protect MRC cache

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Add support for applying write protection to the MRC cache
region in SPI flash.

This is only enabled if there is write protect GPIO that is
set, and the flash status register reports that the flash
chip is currently write protected.

Then it will call out to a SOC specific function that will
enable write protection on the RW_MRC_CACHE region of flash.

The implementation is not quite as clean as I would like because
there is not a common flash protect interface across SOCs so
instead it relies on a new Kconfig variable to be set that will
indicate a SOC implements the function to protect a region of
SPI flash.

BUG=chrome-os-partner:28234
BRANCH=broadwell
TEST=build and boot on samus
1) with either WPSW=0 or SRP0=0 the PRR is not applied
2) with both WPSW=1 and SRP0=1 the PRR is applied

Change-Id: If5907b7ddf3f966c546ae32dc99aa815beb27587
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: a3e0e71dfd7339aab171a26b67aec465a3f332d6
Original-Change-Id: I94e54e4723b1dcdacbb6a05f047d0c0ebc7d8711
Original-Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/241170
Original-Reviewed-by: Shawn N <shawnn@chromium.org>
Reviewed-on: http://review.coreboot.org/9494
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
This commit is contained in:
Duncan Laurie
2015-01-15 15:49:07 -08:00
committed by Patrick Georgi
parent 1006b10206
commit a32b6b9471
4 changed files with 75 additions and 0 deletions
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21
src/soc/intel/common/mrc_cache.c
View File

@ -247,6 +247,25 @@ 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;
@ -279,6 +298,7 @@ static void update_mrc_cache(void *unused)
!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;
}
}
@ -301,6 +321,7 @@ static void update_mrc_cache(void *unused)
printk(BIOS_DEBUG, "Failure writing MRC cache to %p.\n",
next_slot);
}
protect_mrc_cache(&region);
}
BOOT_STATE_INIT_ENTRY(BS_WRITE_TABLES, BS_ON_ENTRY, update_mrc_cache, NULL);