From 4a1a06bc8b21c6787a22458142e3ca3c06935517 Mon Sep 17 00:00:00 2001 From: Alagu Sankar Date: Mon, 25 Oct 2010 07:23:56 -0700 Subject: [PATCH] mmc: Add multi-block read support to the generic mmc driver This patch adds multi-block read support for the generic MMC driver. Large reads are broken into chunks of 65535 blocks to ensure that the code works with controllers having a 16 bit block counter. This patch results in a significant performance improvement. Time to read a 45 MB file went from 36 seconds to 9 seconds on Overo Signed-off-by: Steve Sakoman Tested-by: Steve Sakoman Signed-off-by: Sandeep Paulraj --- drivers/mmc/mmc.c | 110 ++++++++++++++++------------------------------ 1 file changed, 39 insertions(+), 71 deletions(-) diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 00fe867c68..6805b33f7a 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -154,110 +154,78 @@ mmc_bwrite(int dev_num, ulong start, lbaint_t blkcnt, const void*src) return blkcnt; } -int mmc_read_block(struct mmc *mmc, void *dst, uint blocknum) +int mmc_read_blocks(struct mmc *mmc, void *dst, ulong start, lbaint_t blkcnt) { 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; + cmd.cmdarg = start; else - cmd.cmdarg = blocknum * mmc->read_bl_len; + cmd.cmdarg = start * mmc->read_bl_len; cmd.resp_type = MMC_RSP_R1; 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); - - 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); + if (mmc_send_cmd(mmc, &cmd, &data)) + return 0; - 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; + if (mmc_send_cmd(mmc, &cmd, NULL)) { + printf("mmc fail to send stop cmd\n"); + return 0; + } } -free_buffer: - free(buffer); - - return err; + return blkcnt; } 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); + lbaint_t cur, blocks_todo = blkcnt; + + if (blkcnt == 0) + return 0; + struct mmc *mmc = find_mmc_device(dev_num); if (!mmc) return 0; if ((start + blkcnt) > mmc->block_dev.lba) { - printf("MMC: block number 0x%lx exceeds max(0x%lx)", + printf("MMC: block number 0x%lx exceeds max(0x%lx)\n", start + blkcnt, mmc->block_dev.lba); return 0; } - /* We always do full block reads from the card */ - err = mmc_set_blocklen(mmc, mmc->read_bl_len); - if (err) { + if (mmc_set_blocklen(mmc, mmc->read_bl_len)) return 0; - } - for (i = start; i < start + blkcnt; i++, dst += mmc->read_bl_len) { - err = mmc_read_block(mmc, dst, i); - - if (err) { - printf("block read failed: %d\n", err); - return i - start; - } - } + do { + /* + * The 65535 constraint comes from some hardware has + * only 16 bit width block number counter + */ + cur = (blocks_todo > 65535) ? 65535 : blocks_todo; + if(mmc_read_blocks(mmc, dst, start, cur) != cur) + return 0; + blocks_todo -= cur; + start += cur; + dst += cur * mmc->read_bl_len; + } while (blocks_todo > 0); return blkcnt; } -- 2.25.1