diff options
Diffstat (limited to 'src/vendorcode/google/chromeos')
| -rw-r--r-- | src/vendorcode/google/chromeos/vbnv_flash.c | 161 |
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 1271777bb8..cf7c002bcd 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; } |