mmc: core: hs200 fixes

This patch fixes following issues when HS200 is enabled:

1. If executing_tuning() host ops is called without mmc_host_clk_hold(),
   card clocks might get turned off (if MMC_CLK_GATING is enabled)
   while execute_tuning() is in progress. So this patch makes sure
   that execute_tuning() is called with mmc_host_clk_hold().

2. If host timing mode is set to HS200 mode, there should not be
   any communication with the card until execute_tuning() is completed.
   But there is a chance that CMD6 might be sent to enable set HPI_EN
   (of HPI_MGMT field in EXT_CSD) before execute_tuning() is called.
   So this patch moves this operation after execute_tuning() is completed.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Reviewed-by: girish.shivananjappa@linaro.org
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/core/mmc.c

@@ -1046,22 +1046,6 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 		}
 	}
 
-	/*
-	 * Enable HPI feature (if supported)
-	 */
-	if (card->ext_csd.hpi) {
-		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-			EXT_CSD_HPI_MGMT, 1, 0);
-		if (err && err != -EBADMSG)
-			goto free_card;
-		if (err) {
-			pr_warning("%s: Enabling HPI failed\n",
-				   mmc_hostname(card->host));
-			err = 0;
-		} else
-			card->ext_csd.hpi_en = 1;
-	}
-
 	/*
 	 * Compute bus speed.
 	 */
@@ -1111,9 +1095,12 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 		 * 4. execute tuning for HS200
 		 */
 		if ((host->caps2 & MMC_CAP2_HS200) &&
-		    card->host->ops->execute_tuning)
+		    card->host->ops->execute_tuning) {
+			mmc_host_clk_hold(card->host);
 			err = card->host->ops->execute_tuning(card->host,
 				MMC_SEND_TUNING_BLOCK_HS200);
+			mmc_host_clk_release(card->host);
+		}
 		if (err) {
 			pr_warning("%s: tuning execution failed\n",
 				   mmc_hostname(card->host));
@@ -1232,6 +1219,23 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 		}
 	}
 
+	/*
+	 * Enable HPI feature (if supported)
+	 */
+	if (card->ext_csd.hpi) {
+		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+				EXT_CSD_HPI_MGMT, 1,
+				card->ext_csd.generic_cmd6_time);
+		if (err && err != -EBADMSG)
+			goto free_card;
+		if (err) {
+			pr_warning("%s: Enabling HPI failed\n",
+				   mmc_hostname(card->host));
+			err = 0;
+		} else
+			card->ext_csd.hpi_en = 1;
+	}
+
 	/*
 	 * If cache size is higher than 0, this indicates
 	 * the existence of cache and it can be turned on.