mmc: dw_mmc: Give a good reset after we give power

We should give dw_mmc a good reset after we apply power.  On some
boards vqmmc may actually be connected to the IP block in the SoC so
it's good to reset after power comes in.

Without this we sometimes see failures enumerating cards on rk3288.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/dw_mmc.c

@@ -1120,13 +1120,23 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 		mci_writel(slot->host, PWREN, regs);
 		break;
 	case MMC_POWER_ON:
-		if (!IS_ERR(mmc->supply.vqmmc) && !slot->host->vqmmc_enabled) {
+		if (!slot->host->vqmmc_enabled) {
+			if (!IS_ERR(mmc->supply.vqmmc)) {
 				ret = regulator_enable(mmc->supply.vqmmc);
 				if (ret < 0)
 					dev_err(slot->host->dev,
-					"failed to enable vqmmc regulator\n");
+						"failed to enable vqmmc\n");
 				else
 					slot->host->vqmmc_enabled = true;
+
+			} else {
+				/* Keep track so we don't reset again */
+				slot->host->vqmmc_enabled = true;
+			}
+
+			/* Reset our state machine after powering on */
+			dw_mci_ctrl_reset(slot->host,
+					  SDMMC_CTRL_ALL_RESET_FLAGS);
 		}
 
 		/* Adjust clock / bus width after power is up */
@@ -1140,10 +1150,9 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 		if (!IS_ERR(mmc->supply.vmmc))
 			mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
 
-		if (!IS_ERR(mmc->supply.vqmmc) && slot->host->vqmmc_enabled) {
+		if (!IS_ERR(mmc->supply.vqmmc) && slot->host->vqmmc_enabled)
 			regulator_disable(mmc->supply.vqmmc);
 		slot->host->vqmmc_enabled = false;
-		}
 
 		regs = mci_readl(slot->host, PWREN);
 		regs &= ~(1 << slot->id);