[U-Boot] [PATCH RFC]: mmc: Add multi-block support
Lei Wen
adrian.wenl at gmail.com
Sat Oct 16 04:37:41 CEST 2010
Hi Steve,
On Fri, Oct 15, 2010 at 6:12 AM, Steve Sakoman <steve at sakoman.com> wrote:
> From: Alagu Sankar <alagusankar at embwise.com>
>
> This patch adds multi-block read support for generic MMC. It also modifies
> existing multi-block write to limit the maximum number of blocks per transfer.
> A new member is added in the mmc structure for the host controller to specify
> the maximum number of blocks it supports.
>
> Signed-off-by: Alagu Sankar <alagusankar at embwise.com>
> Acked-by: Steve Sakoman <steve.sakoman at linaro.org>
> Tested-by: Steve Sakoman <steve.sakoman at linaro.org>
> ---
>
> This is a re-submission of Alagu's patch, modified only to remove the CONFIG
> option as requested in the earlier discussion of the patch:
>
> http://www.mail-archive.com/u-boot@lists.denx.de/msg32319.html
>
> I tested the patch on OMAP3 and OMAP4 and found no issues. Sadly I did
> not see a performance improvement.
>
> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
> index c543d83..55975bb 100644
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -77,26 +77,16 @@ struct mmc *find_mmc_device(int dev_num)
> return NULL;
> }
>
> -static ulong
> -mmc_bwrite(int dev_num, ulong start, lbaint_t blkcnt, const void*src)
> +static int mmc_write_blocks(struct mmc *mmc, const char *src, uint start,
> + uint blkcnt)
> {
> struct mmc_cmd cmd;
> struct mmc_data data;
> int err;
> - int stoperr = 0;
> - struct mmc *mmc = find_mmc_device(dev_num);
> int blklen;
>
> - if (!mmc)
> - return -1;
> -
> blklen = mmc->write_bl_len;
>
> - if ((start + blkcnt) > mmc->block_dev.lba) {
> - printf("MMC: block number 0x%lx exceeds max(0x%lx)",
> - start + blkcnt, mmc->block_dev.lba);
> - return 0;
> - }
You seems don't want this boudary check, but since it was merged as a
seperated patch
before, you should give your reason for remove this warning.
> err = mmc_set_blocklen(mmc, mmc->write_bl_len);
>
> if (err) {
> @@ -134,18 +124,46 @@ mmc_bwrite(int dev_num, ulong start, lbaint_t blkcnt, const void*src)
> cmd.cmdarg = 0;
> cmd.resp_type = MMC_RSP_R1b;
> cmd.flags = 0;
> - stoperr = mmc_send_cmd(mmc, &cmd, NULL);
> + err = mmc_send_cmd(mmc, &cmd, NULL);
> + }
> +
> + return err;
> +}
> +
> +static ulong
> +mmc_bwrite(int dev_num, ulong start, lbaint_t blkcnt, const void *src)
> +{
> + int err;
> + int i;
> + struct mmc *mmc = find_mmc_device(dev_num);
> + uint b_max = mmc->b_max;
> +
> + if (!mmc)
> + return 0;
> +
> + for (i = blkcnt; i > 0; i -= b_max) {
> + uint blocks = (i > b_max) ? b_max : i;
> +
> + err = mmc_write_blocks(mmc, src, start, blocks);
> + if (err)
> + return blkcnt - i;
> + start += blocks;
> + src += (mmc->write_bl_len * blocks);
> }
>
> return blkcnt;
> }
>
> -int mmc_read_block(struct mmc *mmc, void *dst, uint blocknum)
> +int mmc_read_blocks(struct mmc *mmc, void *dst, uint blocknum, uint blkcnt)
> {
> + int err;
> struct mmc_cmd cmd;
> struct mmc_data data;
>
> - cmd.cmdidx = MMC_CMD_READ_SINGLE_BLOCK;
> + if (blkcnt > 1)
> + cmd.cmdidx = MMC_CMD_READ_MULTIPLE_BLOCK;
> + else
> + cmd.cmdidx = MMC_CMD_READ_SINGLE_BLOCK;
>
> if (mmc->high_capacity)
> cmd.cmdarg = blocknum;
> @@ -156,62 +174,22 @@ int mmc_read_block(struct mmc *mmc, void *dst, uint blocknum)
> cmd.flags = 0;
>
> data.dest = dst;
> - data.blocks = 1;
> + data.blocks = blkcnt;
> data.blocksize = mmc->read_bl_len;
> data.flags = MMC_DATA_READ;
>
> - return mmc_send_cmd(mmc, &cmd, &data);
> -}
> -
> -int mmc_read(struct mmc *mmc, u64 src, uchar *dst, int size)
> -{
> - char *buffer;
> - int i;
> - int blklen = mmc->read_bl_len;
> - int startblock = lldiv(src, mmc->read_bl_len);
> - int endblock = lldiv(src + size - 1, mmc->read_bl_len);
> - int err = 0;
> -
> - /* Make a buffer big enough to hold all the blocks we might read */
> - buffer = malloc(blklen);
> -
> - if (!buffer) {
> - printf("Could not allocate buffer for MMC read!\n");
> - return -1;
> - }
> -
> - /* We always do full block reads from the card */
> - err = mmc_set_blocklen(mmc, mmc->read_bl_len);
> -
> + err = mmc_send_cmd(mmc, &cmd, &data);
> if (err)
> - goto free_buffer;
> -
> - for (i = startblock; i <= endblock; i++) {
> - int segment_size;
> - int offset;
> -
> - err = mmc_read_block(mmc, buffer, i);
> -
> - if (err)
> - goto free_buffer;
> -
> - /*
> - * The first block may not be aligned, so we
> - * copy from the desired point in the block
> - */
> - offset = (src & (blklen - 1));
> - segment_size = MIN(blklen - offset, size);
> -
> - memcpy(dst, buffer + offset, segment_size);
> + return err;
>
> - dst += segment_size;
> - src += segment_size;
> - size -= segment_size;
> + if (blkcnt > 1) {
> + cmd.cmdidx = MMC_CMD_STOP_TRANSMISSION;
> + cmd.cmdarg = 0;
> + cmd.resp_type = MMC_RSP_R1b;
> + cmd.flags = 0;
> + err = mmc_send_cmd(mmc, &cmd, NULL);
> }
>
> -free_buffer:
> - free(buffer);
> -
> return err;
> }
>
> @@ -220,29 +198,26 @@ static ulong mmc_bread(int dev_num, ulong start, lbaint_t blkcnt, void *dst)
> int err;
> int i;
> struct mmc *mmc = find_mmc_device(dev_num);
> + uint b_max = mmc->b_max;
>
> if (!mmc)
> return 0;
>
> - if ((start + blkcnt) > mmc->block_dev.lba) {
> - printf("MMC: block number 0x%lx exceeds max(0x%lx)",
> - start + blkcnt, mmc->block_dev.lba);
> - return 0;
> - }
Same comments as above.
> /* We always do full block reads from the card */
> err = mmc_set_blocklen(mmc, mmc->read_bl_len);
> -
> - if (err) {
> + if (err)
> return 0;
> - }
>
> - for (i = start; i < start + blkcnt; i++, dst += mmc->read_bl_len) {
> - err = mmc_read_block(mmc, dst, i);
> + for (i = blkcnt; i > 0; i -= b_max) {
> + uint blocks = (i > b_max) ? b_max : i;
>
> + err = mmc_read_blocks(mmc, dst, start, blocks);
> if (err) {
> printf("block read failed: %d\n", err);
> - return i - start;
> + return blkcnt - i;
> }
> + start += blocks;
> + dst += (mmc->read_bl_len * blocks);
> }
>
> return blkcnt;
> @@ -872,6 +847,9 @@ int mmc_register(struct mmc *mmc)
> mmc->block_dev.block_read = mmc_bread;
> mmc->block_dev.block_write = mmc_bwrite;
>
> + if (mmc->b_max == 0)
> + mmc->b_max = 1;
> +
> INIT_LIST_HEAD (&mmc->link);
>
> list_add_tail (&mmc->link, &mmc_devices);
> diff --git a/include/mmc.h b/include/mmc.h
> index 9f94f42..245e83a 100644
> --- a/include/mmc.h
> +++ b/include/mmc.h
> @@ -274,6 +274,7 @@ struct mmc {
> struct mmc_cmd *cmd, struct mmc_data *data);
> void (*set_ios)(struct mmc *mmc);
> int (*init)(struct mmc *mmc);
> + uint b_max;
> };
>
> int mmc_register(struct mmc *mmc);
>
Generally, I like the idea to apply multi-read command for reading,
for it really coudl boost the performance
during booting. But considering I have post the silimar patch for only
do the change on the seperating write
command, could you rebase your multi-read patch on mine, and resend it?
Best regards,
Lei
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