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>
diff --git a/drivers/mmc/tifm_sd.c b/drivers/mmc/tifm_sd.c
index bdfad15..7e607b7 100644
--- a/drivers/mmc/tifm_sd.c
+++ b/drivers/mmc/tifm_sd.c
@@ -885,10 +885,13 @@
 	mmc->f_max = 24000000;
 	mmc->max_hw_segs = 1;
 	mmc->max_phys_segs = 1;
-	mmc->max_sectors = 127;
-	//2k maximum hw block length
-	mmc->max_seg_size = mmc->max_sectors << 11;
+	// limited by DMA counter - it's safer to stick with
+	// block counter has 11 bits though
+	mmc->max_blk_count = 256;
+	// 2k maximum hw block length
 	mmc->max_blk_size = 2048;
+	mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
+	mmc->max_seg_size = mmc->max_req_size;
 	sock->signal_irq = tifm_sd_signal_irq;
 	rc = tifm_sd_initialize_host(host);