mmc: Allow host drivers to specify a max block size

Most controllers have an upper limit on the block size. Allow the host
drivers to specify this and make sure we avoid hitting this limit.

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

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index b48c277312de..9bda3fddad17 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -108,6 +108,8 @@ mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
         mrq->cmd->error = 0;
         mrq->cmd->mrq = mrq;
         if (mrq->data) {
+                BUG_ON(mrq->data->blksz > host->max_blk_size);
+
                 mrq->cmd->data = mrq->data;
                 mrq->data->error = 0;
                 mrq->data->mrq = mrq;
@@ -1605,6 +1607,8 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
                 host->max_phys_segs = 1;
                 host->max_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
                 host->max_seg_size = PAGE_CACHE_SIZE;
+
+                host->max_blk_size = 512;
         }
 
         return host;