mmc: sd: Add new CONFIG_MMC_PARANOID_SD_INIT for enabling retries during SD detection
authorSan Mehat <san@google.com>
Tue, 11 Nov 2008 17:35:36 +0000 (09:35 -0800)
committerArve Hjønnevåg <arve@android.com>
Mon, 1 Jul 2013 20:40:22 +0000 (13:40 -0700)
Signed-off-by: San Mehat <san@google.com>
drivers/mmc/core/Kconfig
drivers/mmc/core/sd.c

index 269d072ef55eabc239a4f1ef55980a89918d2186..b2c6616d3b62dbc228a62c02a6e71f3ca91b7d12 100644 (file)
@@ -26,3 +26,11 @@ config MMC_CLKGATE
          support handling this in order for it to be of any use.
 
          If unsure, say N.
+
+config MMC_PARANOID_SD_INIT
+       bool "Enable paranoid SD card initialization (EXPERIMENTAL)"
+       help
+         If you say Y here, the MMC layer will be extra paranoid
+         about re-trying SD init requests. This can be a useful
+         work-around for buggy controllers and hardware. Enable
+         if you are experiencing issues with SD detection.
index 9e645e19cec6c791151c4d6cb7672aa364641dac..232c04fd7cc326cf63386e08fc303238e529a653 100644 (file)
@@ -805,6 +805,9 @@ int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card,
        bool reinit)
 {
        int err;
+#ifdef CONFIG_MMC_PARANOID_SD_INIT
+       int retries;
+#endif
 
        if (!reinit) {
                /*
@@ -831,7 +834,26 @@ int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card,
                /*
                 * Fetch switch information from card.
                 */
+#ifdef CONFIG_MMC_PARANOID_SD_INIT
+               for (retries = 1; retries <= 3; retries++) {
+                       err = mmc_read_switch(card);
+                       if (!err) {
+                               if (retries > 1) {
+                                       printk(KERN_WARNING
+                                              "%s: recovered\n", 
+                                              mmc_hostname(host));
+                               }
+                               break;
+                       } else {
+                               printk(KERN_WARNING
+                                      "%s: read switch failed (attempt %d)\n",
+                                      mmc_hostname(host), retries);
+                       }
+               }
+#else
                err = mmc_read_switch(card);
+#endif
+
                if (err)
                        return err;
        }