1 files changed, 47 insertions, 29 deletions

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 76bb621e9aa9..1d8409fcf155 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -534,39 +534,57 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
          */
         if ((card->csd.mmca_vsn >= CSD_SPEC_VER_4) &&
             (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) {
-                        if (ddr)
-                                ext_csd_bit = EXT_CSD_DDR_BUS_WIDTH_8;
-                        else
-                                ext_csd_bit = EXT_CSD_BUS_WIDTH_8;
-                        bus_width = MMC_BUS_WIDTH_8;
-                } else {
-                        if (ddr)
-                                ext_csd_bit = EXT_CSD_DDR_BUS_WIDTH_4;
-                        else
-                                ext_csd_bit = EXT_CSD_BUS_WIDTH_4;
-                        bus_width = MMC_BUS_WIDTH_4;
+                static unsigned ext_csd_bits[][2] = {
+                        { EXT_CSD_BUS_WIDTH_8, EXT_CSD_DDR_BUS_WIDTH_8 },
+                        { EXT_CSD_BUS_WIDTH_4, EXT_CSD_DDR_BUS_WIDTH_4 },
+                        { EXT_CSD_BUS_WIDTH_1, EXT_CSD_BUS_WIDTH_1 },
+                };
+                static unsigned bus_widths[] = {
+                        MMC_BUS_WIDTH_8,
+                        MMC_BUS_WIDTH_4,
+                        MMC_BUS_WIDTH_1
+                };
+                unsigned idx, bus_width = 0;
+
+                if (host->caps & MMC_CAP_8_BIT_DATA)
+                        idx = 0;
+                else
+                        idx = 1;
+                for (; idx < ARRAY_SIZE(bus_widths); idx++) {
+                        bus_width = bus_widths[idx];
+                        if (bus_width == MMC_BUS_WIDTH_1)
+                                ddr = 0; /* no DDR for 1-bit width */
+                        err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+                                         EXT_CSD_BUS_WIDTH,
+                                         ext_csd_bits[idx][0]);
+                        if (!err) {
+                                /*
+                                 * If controller can't handle bus width test,
+                                 * use the highest bus width to maintain
+                                 * compatibility with previous MMC behavior.
+                                 */
+                                if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
+                                        break;
+                                mmc_set_bus_width_ddr(card->host,
+                                                      bus_width, MMC_SDR_MODE);
+                                err = mmc_bus_test(card, bus_width);
+                                if (!err)
+                                        break;
+                        }
                 }
 
-                err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-                                 EXT_CSD_BUS_WIDTH, ext_csd_bit);
-
-                if (err && err != -EBADMSG)
-                        goto free_card;
-
+                if (!err && ddr) {
+                        err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+                                        EXT_CSD_BUS_WIDTH,
+                                        ext_csd_bits[idx][1]);
+                }
                 if (err) {
                         printk(KERN_WARNING "%s: switch to bus width %d ddr %d "
-                               "failed\n", mmc_hostname(card->host),
-                               1 << bus_width, ddr);
-                        err = 0;
-                } else {
-                        if (ddr)
-                                mmc_card_set_ddr_mode(card);
-                        else
-                                ddr = MMC_SDR_MODE;
-
+                                "failed\n", mmc_hostname(card->host),
+                                1 << bus_width, ddr);
+                        goto free_card;
+                } else if (ddr) {
+                        mmc_card_set_ddr_mode(card);
                         mmc_set_bus_width_ddr(card->host, bus_width, ddr);
                 }
         }