mmc: core: Block CMD23 support for UHS104/SDXC cards.

SD cards operating at UHS104 or better support SET_BLOCK_COUNT.
Signed-off-by: Andrei Warkentin <andreiw@motorola.com>
Reviewed-by: Arindam Nath <arindam.nath@amd.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/card/block.c

@@ -1057,9 +1057,12 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 	blk_queue_logical_block_size(md->queue.queue, 512);
 	set_capacity(md->disk, size);
 
-	if (mmc_host_cmd23(card->host) &&
-	    mmc_card_mmc(card))
-		md->flags |= MMC_BLK_CMD23;
+	if (mmc_host_cmd23(card->host)) {
+		if (mmc_card_mmc(card) ||
+		    (mmc_card_sd(card) &&
+		     card->scr.cmds & SD_SCR_CMD23_SUPPORT))
+			md->flags |= MMC_BLK_CMD23;
+	}
 
 	if (mmc_card_mmc(card) &&
 	    md->flags & MMC_BLK_CMD23 &&

drivers/mmc/core/sd.c

@@ -203,6 +203,8 @@ static int mmc_decode_scr(struct mmc_card *card)
 	else
 		card->erased_byte = 0x0;
 
+	if (scr->sda_spec3)
+		scr->cmds = UNSTUFF_BITS(resp, 32, 2);
 	return 0;
 }
 

include/linux/mmc/card.h

@@ -72,6 +72,9 @@ struct sd_scr {
 	unsigned char		bus_widths;
 #define SD_SCR_BUS_WIDTH_1	(1<<0)
 #define SD_SCR_BUS_WIDTH_4	(1<<2)
+	unsigned char		cmds;
+#define SD_SCR_CMD20_SUPPORT   (1<<0)
+#define SD_SCR_CMD23_SUPPORT   (1<<1)
 };
 
 struct sd_ssr {

include/linux/mmc/sd.h

@@ -66,7 +66,7 @@
 
 #define SCR_SPEC_VER_0		0	/* Implements system specification 1.0 - 1.01 */
 #define SCR_SPEC_VER_1		1	/* Implements system specification 1.10 */
-#define SCR_SPEC_VER_2		2	/* Implements system specification 2.00 */
+#define SCR_SPEC_VER_2		2	/* Implements system specification 2.00-3.0X */
 
 /*
  * SD bus widths