Re: [PATCH 1/1] EmbeddedPkg/MmcDxe: Added MaxBlock Transfer Limit 65535 in R/W.

["Pankaj Bansal" <pankaj.bansal@nxp.com>]

+ Meenakshi

> -----Original Message-----
> From: Ard Biesheuvel <ard.biesheuvel@arm.com>
> Sent: Monday, April 6, 2020 7:42 PM
> To: Leif Lindholm <leif@nuviainc.com>; Gaurav Jain <gaurav.jain@nxp.com>
> Cc: devel@edk2.groups.io; Pankaj Bansal <pankaj.bansal@nxp.com>; Haojian
> Zhuang <haojian.zhuang@linaro.org>; Loh, Tien Hock <tien.hock.loh@intel.com>
> Subject: Re: [PATCH 1/1] EmbeddedPkg/MmcDxe: Added MaxBlock Transfer
> Limit 65535 in R/W.
> 
> On 4/6/20 4:08 PM, Leif Lindholm wrote:
> > Hi Gaurav,
> >
> > Haojian, Tien Hock - can you help review/test this change?
> >
> > Best Regards,
> >
> > Leif
> >
> > On Fri, Apr 03, 2020 at 14:54:07 +0530, Gaurav Jain wrote:
> >> Moved BlockCount calculation below BufferSize Validation checks.
> >> First Ensure Buffersize is Not Zero and multiple of Media BlockSize.
> >> then calculate BlockCount and perform Block checks.
> >>
> >> Corrected BlockCount calculation, as BufferSize is multiple of BlockSize,
> >> So adding (BlockSize-1) bytes to BufferSize and
> >> then divide by BlockSize will have no impact on BlockCount.
> >>
> >> Reading Large Images from MMC causes errors.
> >> As per SD Host Controller Spec version 4.20,
> >> Restriction of 16-bit Block Count transfer is 65535.
> >> Max block transfer limit in single cmd is 65535 blocks.
> >> Added Max Block check that can be processed is 0xFFFF.
> >> then Update BlockCount on the basis of MaxBlock.
> >>
> >> Signed-off-by: Gaurav Jain <gaurav.jain@nxp.com>
> 
> 
> Hello Gaurav,
> 
> Could you please elaborate on the underlying need for this change? If
> you are considering using this driver for future NXP platforms, I should
> point out that this legacy driver is only kept around for existing
> users, and new users should use the driver stack in MdeModulePkg, which
> is based on the UEFI spec.
> 
> --
> Ard.
> 
> 
>