mmc: Allow host drivers to specify max block count

Many controllers have an upper limit on the number of blocks that can be
transferred in one request. Allow the host drivers to specify this and make
sure we avoid hitting this limit.

Also change the max_sectors field to avoid confusion. This makes it map
less directly to the block layer limits, but as they didn't apply directly
on MMC cards anyway, this isn't a great loss.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

1 files changed, 9 insertions, 4 deletions

diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
index 155aafe69bf4..99f1db92295b 100644
--- a/drivers/mmc/sdhci.c
+++ b/drivers/mmc/sdhci.c
@@ -1333,15 +1333,15 @@ static int __devinit sdhci_probe_slot(struct pci_dev *pdev, int slot)
 
         /*
          * Maximum number of sectors in one transfer. Limited by DMA boundary
-         * size (512KiB), which means (512 KiB/512=) 1024 entries.
+         * size (512KiB).
          */
-        mmc->max_sectors = 1024;
+        mmc->max_req_size = 524288;
 
         /*
          * Maximum segment size. Could be one segment with the maximum number
-         * of sectors.
+         * of bytes.
          */
-        mmc->max_seg_size = mmc->max_sectors * 512;
+        mmc->max_seg_size = mmc->max_req_size;
 
         /*
          * Maximum block size. This varies from controller to controller and
@@ -1357,6 +1357,11 @@ static int __devinit sdhci_probe_slot(struct pci_dev *pdev, int slot)
         mmc->max_blk_size = 512 << mmc->max_blk_size;
 
         /*
+         * Maximum block count.
+         */
+        mmc->max_blk_count = 65535;
+
+        /*
          * Init tasklets.
          */
         tasklet_init(&host->card_tasklet,