diff options
| author | Priyanka Jain <Priyanka.Jain@freescale.com> | 2011-03-03 09:18:56 +0530 |
|---|---|---|
| committer | Kumar Gala <galak@kernel.crashing.org> | 2011-03-07 08:49:28 -0600 |
| commit | b71ea33699bb694964929e2cdced80ef794bde69 (patch) | |
| tree | aadaa4c2e5edd0b040c629286fdf16636c736f9d /drivers/net/sh_eth.h | |
| parent | 509e19cab43ba38311749eba5ceebd806116ce38 (diff) | |
| download | olio-uboot-2014.01-b71ea33699bb694964929e2cdced80ef794bde69.tar.xz olio-uboot-2014.01-b71ea33699bb694964929e2cdced80ef794bde69.zip | |
fsl_esdhc: Correcting esdhc timeout counter calculation
- 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@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
Acked-by: Mingkai Hu <Mingkai.Hu@freescale.com>
Tested-by: Stefano Babic <sbabic@denx.de>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Diffstat (limited to 'drivers/net/sh_eth.h')
0 files changed, 0 insertions, 0 deletions