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From:   Loic Poulain <loic.poulain@linaro.org>
Date:   Mon, 21 Feb 2022 11:55:07 +0100
Message-ID: <CAMZdPi__Kf__hy4TGJ1sz=VA_PCZpKk_HPgXX8+AH3sv_8mkmg@mail.gmail.com>
Subject: Re: [PATCH] net: wwan: To support SAHARA port for Qualcomm WWAN module.
To:     =?UTF-8?B?6LCtIOawuOaelw==?= <yonglin.tan@outlook.com>
Cc:     "ryazanov.s.a@gmail.com" <ryazanov.s.a@gmail.com>,
        "johannes@sipsolutions.net" <johannes@sipsolutions.net>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "kuba@kernel.org" <kuba@kernel.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>,
        Manivannan Sadhasivam <mani@kernel.org>
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On Mon, 21 Feb 2022 at 10:27, =E8=B0=AD =E6=B0=B8=E6=9E=97 <yonglin.tan@out=
look.com> wrote:
>
> Dear Loic,
>
> The Qualcomm x24&x55&x6x platform are all using SAHARA port to collect me=
mory dump log. User can use QLOG tool to collect the whole memory dump of d=
evice while the device entered into Dump mode. The firehose protocol is use=
d to download FW from the host, it's different from SAHARA. MHI CH 2&3 are =
used as SAHARA CH but firehose use 34&35 CH.

Ah right, firehose programmer is loaded when entering EDL mode, not SBL.

>
> The bus driver use " MHI_CHANNEL_CONFIG_UL&DL_SBL " to initiate SAHARA CH=
 configs.
>
> The code is Quectel EM1XX channel config.
> MHI_CHANNEL_CONFIG_DL_SBL(3, "SAHARA", 32, 0),
>
> For example,
> - Once the device crashed due to some reasons.
> - The module entered into DUMP mode(SBL Stage), and changed the EE to SBL=
.
> - Then the host should detect the change and re-enumerate the SAHARA port=
.
> - Then users can use QLOG tool to collect the Device Memory LOG by SAHARA=
 Protocol via CH 2&3.

OK, you should add that to the commit message.

Also, instead of exposing the raw sahara protocol, can't this be
integrated with the devcoredump framework
(https://lwn.net/Articles/610887/)?

Regards,
Loic