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>

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 6defddd..d7d8a93 100644 (file)
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1047,22 +1047,6 @@ 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.
         */
        max_dtr = (unsigned int)-1;
@@ -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));
@@ -1233,6 +1220,23 @@ 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.
         */