On Fri, 9 Jun 2023 at 03:58, Chevron Li (WH) <chevron.li@xxxxxxxxxxxxxx> wrote: > > Hi, Ulf, > > Yes, this patch fixes a real problem. > > BR, > Chevron > > > -----Original Message----- > > From: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > Sent: Thursday, June 8, 2023 23:53 > > To: Chevron Li <chevron_li@xxxxxxx> > > Cc: adrian.hunter@xxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; linux- > > kernel@xxxxxxxxxxxxxxx; Shirley Her(SC) <shirley.her@xxxxxxxxxxxxxx>; > > XiaoGuang Yu (WH) <xiaoguang.yu@xxxxxxxxxxxxxx>; Shaper Liu (WH) > > <shaper.liu@xxxxxxxxxxxxxx>; Justin Wang (WH) > > <justin.wang@xxxxxxxxxxxxxx>; Chevron Li (WH) > > <chevron.li@xxxxxxxxxxxxxx> > > Subject: Re: [PATCH V1 1/1] mmc: sdhci: fix DMA configure compatibility issue > > when 64bit DMA mode is used. > > > > On Tue, 23 May 2023 at 13:12, Chevron Li <chevron_li@xxxxxxx> wrote: > > > > > > From: Chevron Li <chevron.li@xxxxxxxxxxxxxx> > > > > > > Bayhub SD host has hardware limitation: > > > 1.The upper 32bit address is inhibited to be written at SD Host Register > > > [03E][13]=0 (32bits addressing) mode, is admitted to be written only at > > > SD Host Register [03E][13]=1 (64bits addressing) mode. > > > 2.Because of above item#1, need to configure SD Host Register [03E][13] to > > > 1(64bits addressing mode) before set 64bit ADMA system address's higher > > > 32bits SD Host Register [05F~05C] if 64 bits addressing mode is used. > > > > > > The hardware limitation is reasonable for below reasons: > > > 1.Normal flow should set DMA working mode first, then do > > > DMA-transfer-related configuration, such as system address. > > > 2.The hardware limitation may avoid the software to configure wrong higher > > > 32bit address at 32bits addressing mode although it is redundant. > > > > > > The change that set 32bits/64bits addressing mode before set ADMA > > address, > > > has no side-effect to other host IPs for below reason: > > > The setting order is reasonable and standard: DMA Mode setting first and > > > then DMA address setting. It meets all DMA setting sequence. > > > > > > Signed-off-by: Chevron Li <chevron.li@xxxxxxxxxxxxxx> > > > > Applied for next, thanks! > > > > Is this material for stable kernels too, as it fixes a real problem, no? > Yes, it fixes a real problem. Okay, I have amended the patch by adding a stable tag to it! [...] Kind regards Uffe
