From: Kumar Gala <galak@kernel.crashing.org>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] fsl_esdhc: Correcting esdhc timeout counter calculation
Date: Thu, 24 Feb 2011 02:53:34 -0600 [thread overview]
Message-ID: <1298537614-20797-1-git-send-email-galak@kernel.crashing.org> (raw)
From: Priyanka Jain <Priyanka.Jain@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.Jain@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Kumar Gala <galak@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(®s->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
next reply other threads:[~2011-02-24 8:53 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-24 8:53 Kumar Gala [this message]
2011-02-24 9:50 ` [U-Boot] [PATCH] fsl_esdhc: Correcting esdhc timeout counter calculation Wolfgang Denk
2011-02-25 0:14 ` Andy Fleming
2011-02-25 5:35 ` Wolfgang Denk
2011-02-25 9:25 ` Jain Priyanka-B32167
2011-02-25 10:19 ` Wolfgang Denk
2011-02-25 13:45 ` Fleming Andy-AFLEMING
2011-02-25 13:56 ` Wolfgang Denk
2011-02-24 10:37 ` Kumar Gala
2011-02-24 11:11 ` Stefano Babic
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