linux-kernel - Re: [PATCH v3] remoteproc: mediatek: fix side effect of mt8195 sram power on

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <9b9d1cb4c606a051ffc2e926d40a7af33004aaf6.camel@mediatek.com>
Date:   Wed, 16 Mar 2022 09:48:53 +0800
From:   Tinghan Shen <tinghan.shen@...iatek.com>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>
CC:     <linux-remoteproc@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <Project_Global_Chrome_Upstream_Group@...iatek.com>
Subject: Re: [PATCH v3] remoteproc: mediatek: fix side effect of mt8195 sram
 power on

Hi Angelo,

On Mon, 2022-03-14 at 12:31 +0100, AngeloGioacchino Del Regno wrote:
> Il 14/03/22 12:18, Tinghan Shen ha scritto:
> > The definition of L1TCM_SRAM_PDN bits on mt8195 is different to mt8192.
> > 
> > L1TCM_SRAM_PDN bits[3:0] control the power of mt8195 L1TCM SRAM.
> > 
> > L1TCM_SRAM_PDN bits[7:4] control the access path to EMI for SCP.
> > These bits have to be powered on to allow EMI access for SCP.
> > 
> > Bits[7:4] also affect audio DSP because audio DSP and SCP are
> > placed on the same hardware bus. If SCP cannot access EMI, audio DSP is
> > blocked too.
> > 
> > L1TCM_SRAM_PDN bits[31:8] are not used.
> > 
> > This fix removes modification of bits[7:4] when power on/off mt8195 SCP
> > L1TCM. It's because the modification introduces a short period of time
> > blocking audio DSP to access EMI. This was not a problem until we have
> > to load both SCP module and audio DSP module. audio DSP needs to access
> > EMI because it has source/data on DRAM. Audio DSP will have unexpected
> > behavior when it accesses EMI and the SCP driver blocks the EMI path at
> > the same time.
> > 
> > Signed-off-by: Tinghan Shen <tinghan.shen@...iatek.com>
> 
> 
> Hello Tinghan,
> 
> I'm sorry, but in the last review I forgot to mention that you should
> really add a Fixes tag to this commit, since this is.. a fix.
> 
> This is the tag that you should use:
> 
> Fixes: 79111df414fc ("remoteproc: mediatek: Support mt8195 scp")
> 
> After adding that,
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> 

I'll add it at next version.
thank you very much!

Best regards,
TingHan

> > ---
> > v3: fix build error
> > v2: apply comments about macro definition and function calls
> > ---
> >   drivers/remoteproc/mtk_common.h |  2 +
> >   drivers/remoteproc/mtk_scp.c    | 67 +++++++++++++++++++++++++--------
> >   2 files changed, 53 insertions(+), 16 deletions(-)
> >