[U-Boot] [PATCH][v3] fsl_esdhc: Correcting esdhc timeout counter calculation

[Kumar Gala]

On Mar 2, 2011, at 9:48 PM, Priyanka Jain wrote:

> - Timeout counter value is set as DTOCV bits in SYSCTL register
>  For counter value set as timeout,
>  Timeout period = (2^(timeout + 13)) SD Clock cycles
> 
> - As per 4.6.2.2 section of SD Card specification v2.00, host should
>  cofigure timeout period value to minimum 0.25 sec.
> 
> - Number of SD Clock cycles for 0.25sec should be minimum
> 	(SD Clock/sec * 0.25 sec) SD Clock cycles
> 	= (mmc->tran_speed * 1/4) SD Clock cycles
> 
> - Calculating timeout based on
> 	(2^(timeout + 13)) >=  mmc->tran_speed * 1/4
> 	Taking log2 both the sides and rounding up to next power of 2
> 	=> timeout + 13 = log2(mmc->tran_speed/4) + 1
> 
> Signed-off-by: Priyanka Jain <Priyanka.Jain at freescale.com>
> Signed-off-by: Andy Fleming <afleming at freescale.com>
> Signed-off-by: Kumar Gala <galak at kernel.crashing.org>
> Acked-by: Mingkai Hu <Mingkai.Hu at freescale.com>
> ---
> Changes for v3:
> 	 Including code changes of v1 as suggested by Stefano Babic
> 
> Changes for v2:
> 	Added proper description as suggested by Wolfgang Denk
> 
> drivers/mmc/fsl_esdhc.c |   16 +++++++++++++++-
> 1 files changed, 15 insertions(+), 1 deletions(-)

Stefano,

Got a chance to test on imx?  Would like this fix in v2011.03

- k