mmc: core: when downgrading HS400, callback into drivers earlier

The driver specific downgrade function makes more sense if we run it
before we set the timing to something lower, not after. Otherwise some
non-HS400 communication has already happened.

No need to convert users. There is only one currently which needs this
change in a following patch.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20200901150250.26236-2-wsa+renesas@sang-engineering.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/mmc.c

@@ -1168,13 +1168,13 @@ static int mmc_select_hs400(struct mmc_card *card)
 		return err;
 	}
 
-	/* Set host controller to HS timing */
-	mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
-
 	/* Prepare host to downgrade to HS timing */
 	if (host->ops->hs400_downgrade)
 		host->ops->hs400_downgrade(host);
 
+	/* Set host controller to HS timing */
+	mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
+
 	/* Reduce frequency to HS frequency */
 	max_dtr = card->ext_csd.hs_max_dtr;
 	mmc_set_clock(host, max_dtr);
@@ -1253,6 +1253,9 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
 	if (err)
 		goto out_err;
 
+	if (host->ops->hs400_downgrade)
+		host->ops->hs400_downgrade(host);
+
 	mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
 
 	err = mmc_switch_status(card, true);
@@ -1268,9 +1271,6 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
 
 	mmc_set_timing(host, MMC_TIMING_MMC_HS);
 
-	if (host->ops->hs400_downgrade)
-		host->ops->hs400_downgrade(host);
-
 	err = mmc_switch_status(card, true);
 	if (err)
 		goto out_err;