linux-kernel - Re: [PATCH v2] remoteproc: qcom_q6v5: Assign mpss region to Q6 before MBA boot

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Message-ID: <160027666863.4188128.6191735162530147774@swboyd.mtv.corp.google.com>
Date:   Wed, 16 Sep 2020 10:17:48 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Sibi Sankar <sibis@...eaurora.org>, bjorn.andersson@...aro.org
Cc:     agross@...nel.org, linux-arm-msm@...r.kernel.org,
        linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
        ohad@...ery.com, evgreen@...omium.org,
        Sibi Sankar <sibis@...eaurora.org>
Subject: Re: [PATCH v2] remoteproc: qcom_q6v5: Assign mpss region to Q6 before MBA boot

Quoting Sibi Sankar (2020-09-16 07:52:52)
> On secure devices which support warm reset, the MBA firmware requires
> access to the modem region to clear them out. Hence provide Q6 access
> to this region before MBA boot. This will be a nop during a modem SSR.
> 

Does it need a Fixes: tag? Probably.

> Signed-off-by: Sibi Sankar <sibis@...eaurora.org>
> ---
> 

Trivia time!

> 
> diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c
> index c401bcc263fa..f989ca81d374 100644
> --- a/drivers/remoteproc/qcom_q6v5_mss.c
> +++ b/drivers/remoteproc/qcom_q6v5_mss.c
> @@ -931,6 +931,16 @@ static int q6v5_mba_load(struct q6v5 *qproc)
>                 goto assert_reset;
>         }
>  
> +       /* Some versions of the MBA firmware will upon boot wipe the MPSS region as well, so provide

Should have /* on a line by itself.

> +        * the Q6 access to this region.
> +        */
> +       ret = q6v5_xfer_mem_ownership(qproc, &qproc->mpss_perm, false, true,
> +                                     qproc->mpss_phys, qproc->mpss_size);
> +       if (ret) {
> +               dev_err(qproc->dev, "assigning Q6 access to mpss memory failed: %d\n", ret);
> +               goto disable_active_clks;
> +       }
> +
>         /* Assign MBA image access in DDR to q6 */
>         ret = q6v5_xfer_mem_ownership(qproc, &qproc->mba_perm, false, true,
>                                       qproc->mba_phys, qproc->mba_size);
> @@ -1137,8 +1147,7 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
>  
>         /**

Should be /* instead of /**, the latter is for kernel-doc which this is
not.

>          * In case of a modem subsystem restart on secure devices, the modem
> -        * memory can be reclaimed only after MBA is loaded. For modem cold
> -        * boot this will be a nop
> +        * memory can be reclaimed only after MBA is loaded.
>          */
>         q6v5_xfer_mem_ownership(qproc, &qproc->mpss_perm, true, false,
>                                 qproc->mpss_phys, qproc->mpss_size);