[MMC] Fix SD timeout calculation

Secure Digital cards use a different algorithm to calculate the timeout
for data transfers. Using the MMC one works often, but not always.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 33525bdf2ab6..c0c7ef2a8b28 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -912,6 +912,7 @@ static void mmc_read_scrs(struct mmc_host *host)
         struct mmc_request mrq;
         struct mmc_command cmd;
         struct mmc_data data;
+        unsigned int timeout_us;
 
         struct scatterlist sg;
 
@@ -947,8 +948,18 @@ static void mmc_read_scrs(struct mmc_host *host)
 
                 memset(&data, 0, sizeof(struct mmc_data));
 
-                data.timeout_ns = card->csd.tacc_ns * 10;
-                data.timeout_clks = card->csd.tacc_clks * 10;
+                data.timeout_ns = card->csd.tacc_ns * 100;
+                data.timeout_clks = card->csd.tacc_clks * 100;
+
+                timeout_us = data.timeout_ns / 1000;
+                timeout_us += data.timeout_clks * 1000 /
+                        (host->ios.clock / 1000);
+
+                if (timeout_us > 100000) {
+                        data.timeout_ns = 100000000;
+                        data.timeout_clks = 0;
+                }
+
                 data.blksz_bits = 3;
                 data.blksz = 1 << 3;
                 data.blocks = 1;