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authorDaisuke Nojiri <dnojiri@chromium.org>2014-10-29 11:18:11 -0700
committerPatrick Georgi <pgeorgi@google.com>2015-04-02 13:24:29 +0200
commit2b59a838b4b6dd68994ae5883d4f1692c2217b16 (patch)
tree9bf50050f841499d240287adbde16a9acf065ad3 /src/vendorcode
parent2af67c9878bb84e10a6f526cfdeb2aacb76e119c (diff)
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vboot: add vbnv flash driver
this adds a driver for vboot to read and write nvdata in spi flash. it's assumed that flash contents are erased to 1-bits and write operations can only change 1-bits to 0-bits. when all nvram space is used, the driver will erase the whole block and start the next write from the beginning. BUG=chrome-os-partner:32774 BRANCH=ToT TEST=Built for cosmos. Change-Id: I40858f847151aa0770e1101e905476d270550f60 Signed-off-by: Stefan Reinauer <reinauer@chromium.org> Original-Commit-Id: 09713828b7b0cabd13a08de3f34e32bc4dbef4a4 Original-Change-Id: Ia9049f342b21fa4c289cb7b9254ab89ec1ef1699 Original-Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/226525 Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: http://review.coreboot.org/9229 Tested-by: build bot (Jenkins) Reviewed-by: David Hendricks <dhendrix@chromium.org> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Diffstat (limited to 'src/vendorcode')
-rw-r--r--src/vendorcode/google/chromeos/vbnv_flash.c161
1 files changed, 161 insertions, 0 deletions
diff --git a/src/vendorcode/google/chromeos/vbnv_flash.c b/src/vendorcode/google/chromeos/vbnv_flash.c
index 1271777bb..cf7c002bc 100644
--- a/src/vendorcode/google/chromeos/vbnv_flash.c
+++ b/src/vendorcode/google/chromeos/vbnv_flash.c
@@ -17,12 +17,173 @@
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#include <2api.h>
+#include <cbfs.h>
+#include <cbfs_core.h>
+#include <console/console.h>
+#include <spi_flash.h>
+#include <string.h>
+#include <vboot_nvstorage.h>
#include "chromeos.h"
+#if IS_ENABLED(CONFIG_VBOOT_VERIFY_FIRMWARE)
+#define BLOB_SIZE VBNV_BLOCK_SIZE
+#elif IS_ENABLED(CONFIG_VBOOT2_VERIFY_FIRMWARE)
+#define BLOB_SIZE VB2_NVDATA_SIZE
+#else
+#error unable to determine BLOB_SIZE
+#endif
+
+/* FMAP descriptor of the NVRAM area */
+static struct vboot_region nvram_region;
+
+/* offset of the current nvdata in nvram */
+static int blob_offset = -1;
+
+/* cache of the current nvdata */
+static uint8_t cache[BLOB_SIZE];
+
+/* spi_flash struct used when saving data */
+static struct spi_flash *spi_flash = NULL;
+
+/*
+ * This code assumes that flash is erased to 1-bits, and write operations can
+ * only change 1-bits to 0-bits. So if the new contents only change 1-bits to
+ * 0-bits, we can reuse the current blob.
+ */
+static inline uint8_t erase_value(void)
+{
+ return 0xff;
+}
+
+static inline int can_overwrite(uint8_t current, uint8_t new)
+{
+ return (current & new) == new;
+}
+
+static inline int is_initialized(void)
+{
+ return blob_offset >= 0;
+}
+
+static int init_vbnv(void)
+{
+ uint8_t buf[BLOB_SIZE];
+ uint8_t empty_blob[BLOB_SIZE];
+ int offset;
+ int i;
+
+ vboot_locate_region("RW_NVRAM", &nvram_region);
+ if (nvram_region.size < BLOB_SIZE) {
+ printk(BIOS_ERR, "%s: failed to locate NVRAM\n", __func__);
+ return 1;
+ }
+
+ /* Prepare an empty blob to compare against. */
+ for (i = 0; i < BLOB_SIZE; i++)
+ empty_blob[i] = erase_value();
+
+ /*
+ * after the loop, offset is supposed to point the blob right before the
+ * first empty blob, the last blob in the nvram if there is no empty
+ * blob, or 0 if the nvram has never been used.
+ */
+ for (i = 0, offset = 0; i <= nvram_region.size - BLOB_SIZE;
+ i += BLOB_SIZE) {
+ if (vboot_get_region(i, BLOB_SIZE, buf) == NULL) {
+ printk(BIOS_ERR, "failed to read nvdata\n");
+ return 1;
+ }
+ if (!memcmp(buf, empty_blob, BLOB_SIZE))
+ break;
+ offset = i;
+ }
+
+ /* reread the nvdata and write it to the cache */
+ if (vboot_get_region(offset, BLOB_SIZE, cache) == NULL) {
+ printk(BIOS_ERR, "failed to read nvdata\n");
+ return 1;
+ }
+
+ blob_offset = offset;
+
+ return 0;
+}
+
+static int vbnv_flash_probe(void)
+{
+ if (!spi_flash) {
+ spi_flash = spi_flash_probe(CONFIG_BOOT_MEDIA_SPI_BUS, 0);
+ if (!spi_flash) {
+ printk(BIOS_ERR, "failed to probe spi flash\n");
+ return 1;
+ }
+ }
+ return 0;
+}
+
+static int erase_nvram(void)
+{
+ if (vbnv_flash_probe())
+ return 1;
+
+ if (spi_flash->erase(spi_flash, nvram_region.offset_addr,
+ nvram_region.size)) {
+ printk(BIOS_ERR, "failed to erase nvram\n");
+ return 1;
+ }
+
+ printk(BIOS_INFO, "nvram is cleared\n");
+ return 0;
+}
+
void read_vbnv(uint8_t *vbnv_copy)
{
+ if (!is_initialized())
+ if (init_vbnv())
+ return; /* error */
+ memcpy(vbnv_copy, cache, BLOB_SIZE);
}
void save_vbnv(const uint8_t *vbnv_copy)
{
+ int new_offset = blob_offset;
+ int i;
+
+ if (!is_initialized())
+ if (init_vbnv())
+ return; /* error */
+
+ /* Bail out if there have been no changes. */
+ if (!memcmp(vbnv_copy, cache, BLOB_SIZE))
+ return;
+
+ /* See if we can overwrite the current blob with the new one */
+ for (i = 0; i < BLOB_SIZE; i++) {
+ if (!can_overwrite(cache[i], vbnv_copy[i])) {
+ /* unable to overwrite. need to use the next blob */
+ new_offset += BLOB_SIZE;
+ if (new_offset > nvram_region.size - BLOB_SIZE) {
+ if (erase_nvram())
+ return; /* error */
+ new_offset = 0;
+ }
+ break;
+ }
+ }
+
+ if (vbnv_flash_probe())
+ return; /* error */
+
+ if (spi_flash->write(spi_flash, new_offset,
+ BLOB_SIZE, vbnv_copy) != BLOB_SIZE) {
+ printk(BIOS_ERR, "failed to write nvdata\n");
+ return; /* error */
+ }
+
+ /* write was successful. safely move pointer forward */
+ blob_offset = new_offset;
+ memcpy(cache, vbnv_copy, BLOB_SIZE);
+
+ return;
}