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, 3 insertions, 1 deletions

diff --git a/drivers/mmc/mmc_block.c b/drivers/mmc/mmc_block.c
index 5a4eacac0bbe..19ccfed8a54f 100644
--- a/drivers/mmc/mmc_block.c
+++ b/drivers/mmc/mmc_block.c
@@ -242,10 +242,12 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
                         brq.cmd.arg <<= 9;
                 brq.cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
                 brq.data.blksz = 1 << md->block_bits;
-                brq.data.blocks = req->nr_sectors >> (md->block_bits - 9);
                 brq.stop.opcode = MMC_STOP_TRANSMISSION;
                 brq.stop.arg = 0;
                 brq.stop.flags = MMC_RSP_R1B | MMC_CMD_AC;
+                brq.data.blocks = req->nr_sectors >> (md->block_bits - 9);
+                if (brq.data.blocks > card->host->max_blk_count)
+                        brq.data.blocks = card->host->max_blk_count;
 
                 mmc_set_data_timeout(&brq.data, card, rq_data_dir(req) != READ);