linux-kernel - Re: [PATCH v2 06/18] media: venus: firmware: Leave a clue for homegrown porters

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Date:   Fri, 5 May 2023 18:27:57 +0530
From:   Vikash Garodia <quic_vgarodia@...cinc.com>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>,
        Stanimir Varbanov <stanimir.k.varbanov@...il.com>,
        Andy Gross <agross@...nel.org>,
        "Bjorn Andersson" <andersson@...nel.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Dikshita Agarwal <dikshita@....qualcomm.com>,
        Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Mansur Alisha Shaik <mansur@...eaurora.org>,
        Jonathan Marek <jonathan@...ek.ca>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Dikshita Agarwal <quic_dikshita@...cinc.com>
CC:     Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Stanimir Varbanov <stanimir.varbanov@...aro.org>,
        <linux-media@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        "Marijn Suijten" <marijn.suijten@...ainline.org>
Subject: Re: [PATCH v2 06/18] media: venus: firmware: Leave a clue for
 homegrown porters


On 5/4/2023 1:31 PM, Konrad Dybcio wrote:
> Leave a clue about where the seemingly magic values come from, as it
> is not obvious and requires some digging downstream..
>
> Reviewed-by: Dikshita Agarwal <quic_dikshita@...cinc.com>
> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
Reviewed-by: Vikash Garodia <quic_vgarodia@...cinc.com>
> ---
>   drivers/media/platform/qcom/venus/firmware.c | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/drivers/media/platform/qcom/venus/firmware.c b/drivers/media/platform/qcom/venus/firmware.c
> index cfb11c551167..a4cd919e1dbe 100644
> --- a/drivers/media/platform/qcom/venus/firmware.c
> +++ b/drivers/media/platform/qcom/venus/firmware.c
> @@ -241,6 +241,13 @@ int venus_boot(struct venus_core *core)
>   		return ret;
>   
>   	if (core->use_tz && res->cp_size) {
> +		/*
> +		 * Clues for porting using downstream data:
> +		 * cp_start = 0
> +		 * cp_size = venus_ns/virtual-addr-pool[0] (yes, addr not size)

The field is the start address of ns context bank. Since the cp_start is 
0, the start address for (next) non-secure context bank

is interpreted as size of the (previous) content protection region.

> +		 * cp_nonpixel_start = venus_sec_non_pixel/virtual-addr-pool[0]
> +		 * cp_nonpixel_size = venus_sec_non_pixel/virtual-addr-pool[1]
> +		 */
>   		ret = qcom_scm_mem_protect_video_var(res->cp_start,
>   						     res->cp_size,
>   						     res->cp_nonpixel_start,
>