On 03/03/2011 04:48 AM, 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 <[email protected]> > Signed-off-by: Andy Fleming <[email protected]> > Signed-off-by: Kumar Gala <[email protected]> > Acked-by: Mingkai Hu <[email protected]> > ---
Tested on a i.MX51 board. Tested-by: Stefano Babic <[email protected]> Best regards, Stefano Babic -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: [email protected] ===================================================================== _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
