[U-Boot] [PATCH] fsl_esdhc: Correcting esdhc timeout counter calculation

[Kumar Gala]

From: Priyanka Jain <priyanka.j...@freescale.com>

- Timeout counter value is set as DTOCV bits in SYSCTL register
  For counter value set as x,
  Timeout period = (2^(13+x))/SD_CLOCK

- As per 4.6.2.2 section of SD Card specification v2.00, host should
  cofigure timeout period value to minimum 250 msec.

- SD_CLOCK = mmc->trans_speed

- Calculating x based on
  250 msec = (2^(13+x))/mmc->trans_speed

Signed-off-by: Priyanka Jain <priyanka.j...@freescale.com>
Signed-off-by: Andy Fleming <aflem...@freescale.com>
Signed-off-by: Kumar Gala <ga...@kernel.crashing.org>
---
 drivers/mmc/fsl_esdhc.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
index c6de751..6f8a09d 100644
--- a/drivers/mmc/fsl_esdhc.c
+++ b/drivers/mmc/fsl_esdhc.c
@@ -210,7 +210,10 @@ static int esdhc_setup_data(struct mmc *mmc, struct 
mmc_data *data)
        esdhc_write32(&regs->blkattr, data->blocks << 16 | data->blocksize);
 
        /* Calculate the timeout period for data transactions */
-       timeout = fls(mmc->tran_speed/10) - 1;
+       /* Timeout period = (2^(13+timeout))/mmc->trans_speed
+        * Timeout period should be minimum 250msec as per SD Card spec
+        */
+       timeout = fls(mmc->tran_speed/4);
        timeout -= 13;
 
        if (timeout > 14)
-- 
1.7.2.3

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