git.ipfire.org Git - thirdparty/openwrt.git/blob

   1 From c0b9523ee9a6c3f2cc42529f18b33b0606413abc Mon Sep 17 00:00:00 2001
   2 From: Jonathan Bell <jonathan@raspberrypi.com>
   3 Date: Tue, 4 Jun 2024 13:45:37 +0100
   4 Subject: [PATCH] mmc: sdhci: extend maximum ADMA transfer length to 4MiB
   5
   6 This gains about 8-12% sequential write speed with the fastest SD/eMMC
   7 cards, and Class A1/A2 card sequential performance is only assured with
   8 a 4MiB write length.
   9
  10 Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
  11 ---
  12  drivers/mmc/host/sdhci.c | 15 ++++++++++-----
  13  1 file changed, 10 insertions(+), 5 deletions(-)
  14
  15 --- a/drivers/mmc/host/sdhci.c
  16 +++ b/drivers/mmc/host/sdhci.c
  17 @@ -1081,7 +1081,7 @@ static void sdhci_initialize_data(struct
  18         WARN_ON(host->data);
  19
  20         /* Sanity checks */
  21 -       BUG_ON(data->blksz * data->blocks > 524288);
  22 +       BUG_ON(data->blksz * data->blocks > host->mmc->max_req_size);
  23         BUG_ON(data->blksz > host->mmc->max_blk_size);
  24         BUG_ON(data->blocks > 65535);
  25
  26 @@ -4714,11 +4714,16 @@ int sdhci_setup_host(struct sdhci_host *
  27         spin_lock_init(&host->lock);
  28
  29         /*
  30 -        * Maximum number of sectors in one transfer. Limited by SDMA boundary
  31 -        * size (512KiB). Note some tuning modes impose a 4MiB limit, but this
  32 -        * is less anyway.
  33 +        * Maximum number of sectors in one transfer.
  34 +        * 4MiB is preferred for multi-descriptor DMA as a) card sequential
  35 +        * write speeds are only guaranteed with a 4MiB write length and
  36 +        * b) most tuning modes require a 4MiB limit.
  37 +        * SDMA has a 512KiB boundary size.
  38          */
  39 -       mmc->max_req_size = 524288;
  40 +       if (host->flags & SDHCI_USE_ADMA)
  41 +               mmc->max_req_size = SZ_4M;
  42 +       else
  43 +               mmc->max_req_size = SZ_512K;
  44
  45         /*
  46          * Maximum number of segments. Depends on if the hardware