cr50: use dedicated region for info1 accesses

The INFO1 flash space is used for various purposes (endorsement key
seed, Board ID and flags, serial number, etc.).

Accessing these spaces in INFO1 is accompanied by managing the flash
region registers, each time opening a window of the appropriate size,
with appropriate permissions, etc,

In fact none of these spaces contain a secret, to simplify things and
preventing situations when concurrent accesses change the flash range
window settings lets dedicate previously unused Region 7 register file
to providing always open read access to INFO1.

Write access will be enabled/disabled as required. In prod images
write accesses will always happen from the vendor command context. In
DBG images CLI commands will also have write access to INFO1.

INFO1 window is accessed by other H1 based devices as well, this is
why it is necessary to enable the window in the common chip code.

BRANCH=cr50, cr50-mp
BUG=b:138256149
TEST=the firmware_Cr50SetBoardId test now passes on Mistral.

Cq-Depend: chrome-internal:1577866, chrome-internal:1581327
Change-Id: Id27348f3b04191f1b3b60fd838d06009f756baa2
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1730147
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Mary Ruthven <mruthven@chromium.org>

1 files changed, 1 insertions, 16 deletions

diff --git a/chip/g/board_id.c b/chip/g/board_id.c
index 1f46bd8226..c863a81fba 100644
--- a/chip/g/board_id.c
+++ b/chip/g/board_id.c
@@ -74,14 +74,6 @@ int read_board_id(struct board_id *id)
 
 	id_p = (uint32_t *)id;
 
-	/* Make sure INFO1 board ID space is readable */
-	if (flash_info_read_enable(INFO_BOARD_ID_OFFSET,
-				   INFO_BOARD_ID_PROTECT_SIZE) !=
-	    EC_SUCCESS) {
-		CPRINTS("%s: failed to enable read access to info", __func__);
-		return EC_ERROR_ACCESS_DENIED;
-	}
-
 	for (i = 0; i < sizeof(*id); i += sizeof(uint32_t)) {
 		int rv;
 
@@ -156,13 +148,7 @@ static int write_board_id(const struct board_id *id, int clear_flags)
 		return EC_ERROR_ACCESS_DENIED;
 	}
 
-	/* Enable write access */
-	if (flash_info_write_enable(INFO_BOARD_ID_OFFSET,
-				    INFO_BOARD_ID_PROTECT_SIZE) !=
-	    EC_SUCCESS) {
-		CPRINTS("%s: failed to enable write access", __func__);
-		return EC_ERROR_ACCESS_DENIED;
-	}
+	flash_info_write_enable();
 
 	/* Write Board ID */
 	rv = flash_info_physical_write(INFO_BOARD_ID_OFFSET +
@@ -171,7 +157,6 @@ static int write_board_id(const struct board_id *id, int clear_flags)
 	if (rv != EC_SUCCESS)
 		CPRINTS("%s: write failed", __func__);
 
-	/* Disable write access */
 	flash_info_write_disable();
 
 	return rv;