From: San Mehat <san@google.com>
Date: Tue, 11 Nov 2008 17:35:36 +0000 (-0800)
Subject: mmc: sd: Add new CONFIG_MMC_PARANOID_SD_INIT for enabling retries during SD detection
X-Git-Tag: firefly_0821_release~9833^2~5^2~303
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=52f2c81de615e6842e66232527c334cdd9f78280;p=firefly-linux-kernel-4.4.55.git

mmc: sd: Add new CONFIG_MMC_PARANOID_SD_INIT for enabling retries during SD detection

Signed-off-by: San Mehat <san@google.com>
---

diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
index bb22ffd76ef8..79e279528f96 100644
--- a/drivers/mmc/core/Kconfig
+++ b/drivers/mmc/core/Kconfig
@@ -16,3 +16,12 @@ config MMC_UNSAFE_RESUME
 
 	  This option sets a default which can be overridden by the
 	  module parameter "removable=0" or "removable=1".
+
+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.
+
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 0f5241085557..072c822d66b7 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -402,6 +402,9 @@ struct device_type sd_type = {
 int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid)
 {
 	int err;
+#ifdef CONFIG_MMC_PARANOID_SD_INIT
+	int retries;
+#endif
 
 	/*
 	 * Since we're changing the OCR value, we seem to
@@ -481,7 +484,26 @@ 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;
 	}