chromeos: Add vbnv wrapper for the different backends

Add a wrapper around the vbnv implementations and call into the different
backend functions from there.  Also move some of the common functions to
the common code and simplify the backend drivers.  This will allow some
of the code to be re-used so the CMOS backend can backup the data into
the flash backend.

One side effect of this is that the cache of VBNV was removed from CMOS
and EC backends and moved into the VBNV wrapper, but the flash backend
also still has a separate cache because it has more state and complexity
in the implementation.  The wrapper cached data is not used for normal
vbnv_read/vbnv_write because some callers need the ability to force a
write if the backend storage is cleared (i.e. CMOS clear).

BUG=chrome-os-partner:47915
BRANCH=glados
TEST=build and boot on chell

Change-Id: I4d2e0e99af7e8a44aec77ad9991507401babcca6
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: c30f60434a64f6c0eb9ede45d48ddafff19dd24f
Original-Change-Id: Ia97f6607c5ad837b9aa10b45211137221ccb93a0
Original-Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/324120
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/13597
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

1 files changed, 3 insertions, 83 deletions

diff --git a/src/vendorcode/google/chromeos/vbnv_ec.c b/src/vendorcode/google/chromeos/vbnv_ec.c
index 6e1b0c5f70..0b7b7b5b68 100644
--- a/src/vendorcode/google/chromeos/vbnv_ec.c
+++ b/src/vendorcode/google/chromeos/vbnv_ec.c
@@ -14,96 +14,16 @@
  */
 
 #include <types.h>
-#include <string.h>
-#include <console/console.h>
-#include <arch/early_variables.h>
 #include <ec/google/chromeec/ec.h>
-#include "chromeos.h"
+#include "vbnv.h"
 #include "vbnv_layout.h"
 
-static int vbnv_initialized CAR_GLOBAL;
-static uint8_t vbnv[VBNV_BLOCK_SIZE] CAR_GLOBAL;
-
-/* Wrappers for accessing the variables marked as CAR_GLOBAL. */
-static inline int is_vbnv_initialized(void)
-{
-	return car_get_var(vbnv_initialized);
-}
-
-static inline uint8_t *vbnv_data_addr(int index)
-{
-	uint8_t *vbnv_arr = car_get_var_ptr(vbnv);
-
-	return &vbnv_arr[index];
-}
-
-static inline uint8_t vbnv_data(int index)
-{
-	return *vbnv_data_addr(index);
-}
-
-/* Return CRC-8 of the data, using x^8 + x^2 + x + 1 polynomial.  A
- * table-based algorithm would be faster, but for only 15 bytes isn't
- * worth the code size.
- */
-
-static uint8_t crc8(const uint8_t * data, int len)
-{
-	unsigned crc = 0;
-	int i, j;
-
-	for (j = len; j; j--, data++) {
-		crc ^= (*data << 8);
-		for (i = 8; i; i--) {
-			if (crc & 0x8000)
-				crc ^= (0x1070 << 3);
-			crc <<= 1;
-		}
-	}
-
-	return (uint8_t) (crc >> 8);
-}
-
-void read_vbnv(uint8_t *vbnv_copy)
+void read_vbnv_ec(uint8_t *vbnv_copy)
 {
 	google_chromeec_vbnv_context(1, vbnv_copy, VBNV_BLOCK_SIZE);
-
-	/* Check data for consistency */
-	if ((HEADER_SIGNATURE != (vbnv_copy[HEADER_OFFSET] & HEADER_MASK))
-	    || (crc8(vbnv_copy, CRC_OFFSET) != vbnv_copy[CRC_OFFSET])) {
-
-		/* Data is inconsistent (bad CRC or header),
-		 * so reset to defaults
-		 */
-		memset(vbnv_copy, 0, VBNV_BLOCK_SIZE);
-		vbnv_copy[HEADER_OFFSET] =
-		    (HEADER_SIGNATURE | HEADER_FIRMWARE_SETTINGS_RESET |
-		     HEADER_KERNEL_SETTINGS_RESET);
-	}
 }
 
-void save_vbnv(const uint8_t *vbnv_copy)
+void save_vbnv_ec(const uint8_t *vbnv_copy)
 {
 	google_chromeec_vbnv_context(0, (uint8_t *)vbnv_copy, VBNV_BLOCK_SIZE);
 }
-
-static void vbnv_setup(void)
-{
-	read_vbnv(vbnv_data_addr(0));
-	car_set_var(vbnv_initialized, 1);
-}
-
-int get_recovery_mode_from_vbnv(void)
-{
-	if (!is_vbnv_initialized())
-		vbnv_setup();
-	return vbnv_data(RECOVERY_OFFSET);
-}
-
-int vboot_wants_oprom(void)
-{
-	if (!is_vbnv_initialized())
-		vbnv_setup();
-
-	return (vbnv_data(BOOT_OFFSET) & BOOT_OPROM_NEEDED) ? 1 : 0;
-}