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From 66983857a54479d76ce6dbd8399e1276698bd3c5 Mon Sep 17 00:00:00 2001
From: San Mehat <san@google.com>
Date: Tue, 11 Nov 2008 09:35:36 -0800
Subject: [PATCH 094/134] mmc: sd: Add new CONFIG_MMC_PARANOID_SD_INIT for enabling retries during SD detection
Signed-off-by: San Mehat <san@google.com>
---
drivers/mmc/core/Kconfig | 8 ++++++++
drivers/mmc/core/sd.c | 24 ++++++++++++++++++++++--
2 files changed, 30 insertions(+), 2 deletions(-)
--- a/drivers/mmc/core/Kconfig
+++ b/drivers/mmc/core/Kconfig
@@ -14,3 +14,11 @@ config MMC_UNSAFE_RESUME
This option is usually just for embedded systems which use
a MMC/SD card for rootfs. Most people should say N here.
+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.
+
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -336,7 +336,9 @@ static int mmc_sd_init_card(struct mmc_h
int err;
u32 cid[4];
unsigned int max_dtr;
-
+#ifdef CONFIG_MMC_PARANOID_SD_INIT
+ int retries;
+#endif
BUG_ON(!host);
WARN_ON(!host->claimed);
@@ -439,11 +441,29 @@ static int mmc_sd_init_card(struct mmc_h
err = mmc_decode_scr(card);
if (err < 0)
goto free_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)
goto free_card;
}
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