diff options
| -rw-r--r-- | drivers/mtd/ubi/build.c | 14 | ||||
| -rw-r--r-- | drivers/mtd/ubi/kapi.c | 1 | ||||
| -rw-r--r-- | drivers/mtd/ubi/ubi.h | 3 | ||||
| -rw-r--r-- | include/linux/mtd/ubi.h | 19 |
4 files changed, 37 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c index 5ebe280..f38e8de 100644 --- a/drivers/mtd/ubi/build.c +++ b/drivers/mtd/ubi/build.c @@ -690,11 +690,25 @@ static int io_init(struct ubi_device *ubi) ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size); ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0); + ubi->max_write_size = ubi->mtd->writebufsize; + /* + * Maximum write size has to be greater or equivalent to min. I/O + * size, and be multiple of min. I/O size. + */ + if (ubi->max_write_size < ubi->min_io_size || + ubi->max_write_size % ubi->min_io_size || + !is_power_of_2(ubi->max_write_size)) { + ubi_err("bad write buffer size %d for %d min. I/O unit", + ubi->max_write_size, ubi->min_io_size); + return -EINVAL; + } + /* Calculate default aligned sizes of EC and VID headers */ ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size); ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size); dbg_msg("min_io_size %d", ubi->min_io_size); + dbg_msg("max_write_size %d", ubi->max_write_size); dbg_msg("hdrs_min_io_size %d", ubi->hdrs_min_io_size); dbg_msg("ec_hdr_alsize %d", ubi->ec_hdr_alsize); dbg_msg("vid_hdr_alsize %d", ubi->vid_hdr_alsize); diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c index 69fa4ef0..701df4f 100644 --- a/drivers/mtd/ubi/kapi.c +++ b/drivers/mtd/ubi/kapi.c @@ -41,6 +41,7 @@ void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di) di->ubi_num = ubi->ubi_num; di->leb_size = ubi->leb_size; di->min_io_size = ubi->min_io_size; + di->max_write_size = ubi->max_write_size; di->ro_mode = ubi->ro_mode; di->cdev = ubi->cdev.dev; } diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h index 0b0149c..b789943 100644 --- a/drivers/mtd/ubi/ubi.h +++ b/drivers/mtd/ubi/ubi.h @@ -381,6 +381,8 @@ struct ubi_wl_entry; * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or * not * @nor_flash: non-zero if working on top of NOR flash + * @max_write_size: maximum amount of bytes the underlying flash can write at a + * time (MTD write buffer size) * @mtd: MTD device descriptor * * @peb_buf1: a buffer of PEB size used for different purposes @@ -464,6 +466,7 @@ struct ubi_device { int vid_hdr_shift; unsigned int bad_allowed:1; unsigned int nor_flash:1; + int max_write_size; struct mtd_info *mtd; void *peb_buf1; diff --git a/include/linux/mtd/ubi.h b/include/linux/mtd/ubi.h index b31bd9e..36c7059 100644 --- a/include/linux/mtd/ubi.h +++ b/include/linux/mtd/ubi.h @@ -117,17 +117,36 @@ struct ubi_volume_info { * @ubi_num: ubi device number * @leb_size: logical eraseblock size on this UBI device * @min_io_size: minimal I/O unit size + * @max_write_size: maximum amount of bytes the underlying flash can write at a + * time (MTD write buffer size) * @ro_mode: if this device is in read-only mode * @cdev: UBI character device major and minor numbers * * Note, @leb_size is the logical eraseblock size offered by the UBI device. * Volumes of this UBI device may have smaller logical eraseblock size if their * alignment is not equivalent to %1. + * + * The @max_write_size field describes flash write maximum write unit. For + * example, NOR flash allows for changing individual bytes, so @min_io_size is + * %1. However, it does not mean than NOR flash has to write data byte-by-byte. + * Instead, CFI NOR flashes have a write-buffer of, e.g., 64 bytes, and when + * writing large chunks of data, they write 64-bytes at a time. Obviously, this + * improves write throughput. + * + * Also, the MTD device may have N interleaved (striped) flash chips + * underneath, in which case @min_io_size can be physical min. I/O size of + * single flash chip, while @max_write_size can be N * @min_io_size. + * + * The @max_write_size field is always greater or equivalent to @min_io_size. + * E.g., some NOR flashes may have (@min_io_size = 1, @max_write_size = 64). In + * contrast, NAND flashes usually have @min_io_size = @max_write_size = NAND + * page size. */ struct ubi_device_info { int ubi_num; int leb_size; int min_io_size; + int max_write_size; int ro_mode; dev_t cdev; }; |
