From: Alim Akhtar <alim.akhtar@xxxxxxxxxxx> max_blk_count is currently set incorrectly, and the correct value can be determined by looking at the maximum number of bytes which can be transferred and the block size. We use the maximum block size to determine the minimum number of blocks that the controller should support. It could probably do more with a smaller block size but this value should be sufficient for good performance. This improves sequential performance by 82% on write and 6% read on one particular device. TEST= with this patch time dd if=/dev/zero of=/usr/local/100 bs=1M count=100 conv=fdatasync 100+0 records in 100+0 records out 104857600 bytes (105 MB) copied, 2.62541 s, 39.9 MB/s real 0m2.638s user 0m0.000s sys 0m0.645s without this patch: time dd if=/dev/zero of=/usr/local/100 bs=1M count=100 conv=fdatasync 100+0 records in 100+0 records out 104857600 bytes (105 MB) copied, 3.25873 s, 32.2 MB/s real 0m3.265s user 0m0.005s sys 0m0.690s Signed-off-by: Seungwon Jeon <tgih.jun@xxxxxxxxxxx> Signed-off-by: Alim Akhtar <alim.akhtar@xxxxxxxxxxx> Signed-off-by: Sonny Rao <sonnyrao@xxxxxxxxxxxx> Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd@xxxxxxxxxxx> --- drivers/mmc/host/dw_mmc.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 0c56faa..2fc4030 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -2213,10 +2213,24 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id) /* Useful defaults if platform data is unset. */ #ifdef CONFIG_MMC_DW_IDMAC mmc->max_segs = host->ring_size; + + /* the BLKSIZ register is 16-bits wide */ mmc->max_blk_size = 65536; - mmc->max_blk_count = host->ring_size; + + /* + * This value is calculated by taking the size of the + * 32-bit BYTCNT (byte count) register and dividing by the + * BLKSIZ (block size) register. This is the minimum number + * of blocks which could be handled. + */ + mmc->max_blk_count = 0xFFFF; mmc->max_seg_size = 0x1000; - mmc->max_req_size = mmc->max_seg_size * mmc->max_blk_count; + /* + * Maximum request size should be total number of descriptors + * times the maximum amount of data each can reference + */ + + mmc->max_req_size = mmc->max_seg_size * mmc->max_segs; #else mmc->max_segs = 64; mmc->max_blk_size = 65536; /* BLKSIZ is 16 bits */ -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
