diff options
Diffstat (limited to 'firmware/include/vboot_api.h')
| -rw-r--r-- | firmware/include/vboot_api.h | 46 |
1 files changed, 37 insertions, 9 deletions
diff --git a/firmware/include/vboot_api.h b/firmware/include/vboot_api.h index 81240585..f93df517 100644 --- a/firmware/include/vboot_api.h +++ b/firmware/include/vboot_api.h @@ -555,14 +555,38 @@ VbError_t VbExHashFirmwareBody(VbCommonParams *cparams, * when processing read-only recovery image. */ +/* + * Disks are used in two ways: + * - As a random-access device to read and write the GPT + * - As a streaming device to read the kernel + * These are implemented differently on raw NAND vs eMMC/SATA/USB + * - On eMMC/SATA/USB, both of these refer to the same underlying + * storage, so they have the same size and LBA size. In this case, + * the GPT should not point to the same address as itself. + * - On raw NAND, the GPT is held on a portion of the SPI flash. + * Random access GPT operations refer to the SPI and streaming + * operations refer to NAND. The GPT may therefore point into + * the same offsets as itself. + * These types are distinguished by the following flag and VbDiskInfo + * has separate fields to describe the random-access ("GPT") and + * streaming aspects of the disk. If a disk is random-access (i.e. + * not raw NAND) then these fields are equal. + */ +#define VB_DISK_FLAG_EXTERNAL_GPT 0x00000004 + /* Information on a single disk */ typedef struct VbDiskInfo { /* Disk handle */ VbExDiskHandle_t handle; - /* Size of a LBA sector in bytes */ + /* Size of a random-access LBA sector in bytes */ uint64_t bytes_per_lba; - /* Number of LBA sectors on the device */ + /* Number of random-access LBA sectors on the device. + * If streaming_lba_count is 0, this stands in for the size of the + * randomly accessed portion as well as the streaming portion. + * Otherwise, this is only the randomly-accessed portion. */ uint64_t lba_count; + /* Number of streaming sectors on the device */ + uint64_t streaming_lba_count; /* Flags (see VB_DISK_FLAG_* constants) */ uint32_t flags; /* @@ -604,6 +628,9 @@ VbError_t VbExDiskFreeInfo(VbDiskInfo *infos, * Read lba_count LBA sectors, starting at sector lba_start, from the disk, * into the buffer. * + * This is used for random access to the GPT. It is not for the partition + * contents. The upper limit is lba_count. + * * If the disk handle is invalid (for example, the handle refers to a disk * which as been removed), the function must return error but must not * crash. @@ -615,6 +642,9 @@ VbError_t VbExDiskRead(VbExDiskHandle_t handle, uint64_t lba_start, * Write lba_count LBA sectors, starting at sector lba_start, to the disk, from * the buffer. * + * This is used for random access to the GPT. It does not (necessarily) access + * the streaming portion of the device. + * * If the disk handle is invalid (for example, the handle refers to a disk * which as been removed), the function must return error but must not * crash. @@ -635,10 +665,9 @@ typedef void *VbExStream_t; * * @return Error code, or VBERROR_SUCCESS. * - * lba_start and lba_count are subject to disk type-dependent alignment - * restrictions. An invalid value will lead to an error code. In particular, - * on raw NAND devices, lba_start and lba_count must be page-aligned after - * subtracting the offset of the GPT. + * This is used for access to the contents of the actual partitions on the + * device. It is not used to access the GPT. The size of the content addressed + * is within streaming_lba_count. */ VbError_t VbExStreamOpen(VbExDiskHandle_t handle, uint64_t lba_start, uint64_t lba_count, VbExStream_t *stream_ptr); @@ -653,9 +682,8 @@ VbError_t VbExStreamOpen(VbExDiskHandle_t handle, uint64_t lba_start, * @return Error code, or VBERROR_SUCCESS. Failure to read as much data as * requested is an error. * - * bytes is subject to disk type-dependent alignment restrictions. An invalid - * value will lead to an error code. In particular, on raw NAND devices, bytes - * must be a page multiple. + * This is used for access to the contents of the actual partitions on the + * device. It is not used to access the GPT. */ VbError_t VbExStreamRead(VbExStream_t stream, uint32_t bytes, void *buffer); |