mmc: Add 8-bit bus width support

Signed-off-by: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

drivers/mmc/core/mmc.c

@@ -434,13 +434,24 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 	 * Activate wide bus (if supported).
 	 */
 	if ((card->csd.mmca_vsn >= CSD_SPEC_VER_4) &&
-		(host->caps & MMC_CAP_4_BIT_DATA)) {
+	    (host->caps & (MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA))) {
+		unsigned ext_csd_bit, bus_width;
+
+		if (host->caps & MMC_CAP_8_BIT_DATA) {
+			ext_csd_bit = EXT_CSD_BUS_WIDTH_8;
+			bus_width = MMC_BUS_WIDTH_8;
+		} else {
+			ext_csd_bit = EXT_CSD_BUS_WIDTH_4;
+			bus_width = MMC_BUS_WIDTH_4;
+		}
+
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-			EXT_CSD_BUS_WIDTH, EXT_CSD_BUS_WIDTH_4);
+				 EXT_CSD_BUS_WIDTH, ext_csd_bit);
+
 		if (err)
 			goto free_card;
 
-		mmc_set_bus_width(card->host, MMC_BUS_WIDTH_4);
+		mmc_set_bus_width(card->host, bus_width);
 	}
 
 	if (!oldcard)
@@ -624,4 +635,3 @@ err:
 
 	return err;
 }
-

include/linux/mmc/host.h

@@ -41,6 +41,7 @@ struct mmc_ios {
 
 #define MMC_BUS_WIDTH_1		0
 #define MMC_BUS_WIDTH_4		2
+#define MMC_BUS_WIDTH_8		3
 
 	unsigned char	timing;			/* timing specification used */
 
@@ -116,6 +117,7 @@ struct mmc_host {
 #define MMC_CAP_SDIO_IRQ	(1 << 3)	/* Can signal pending SDIO IRQs */
 #define MMC_CAP_SPI		(1 << 4)	/* Talks only SPI protocols */
 #define MMC_CAP_NEEDS_POLL	(1 << 5)	/* Needs polling for card-detection */
+#define MMC_CAP_8_BIT_DATA	(1 << 6)	/* Can the host do 8 bit transfers */
 
 	/* host specific block data */
 	unsigned int		max_seg_size;	/* see blk_queue_max_segment_size */