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From:   Konrad Dybcio <konrad.dybcio@linaro.org>
Date:   Tue, 30 May 2023 14:30:39 +0200
Subject: [PATCH v4 05/17] media: venus: firmware: Leave a clue about
 obtaining CP VARs
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Message-Id: <20230228-topic-venus-v4-5-feebb2f6e9b8@linaro.org>
References: <20230228-topic-venus-v4-0-feebb2f6e9b8@linaro.org>
In-Reply-To: <20230228-topic-venus-v4-0-feebb2f6e9b8@linaro.org>
To:     Stanimir Varbanov <stanimir.k.varbanov@gmail.com>,
        Vikash Garodia <quic_vgarodia@quicinc.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Dikshita Agarwal <dikshita@qti.qualcomm.com>,
        Bryan O'Donoghue <bryan.odonoghue@linaro.org>,
        Mansur Alisha Shaik <mansur@codeaurora.org>,
        Jonathan Marek <jonathan@marek.ca>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Dikshita Agarwal <quic_dikshita@quicinc.com>
Cc:     Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Stanimir Varbanov <stanimir.varbanov@linaro.org>,
        linux-media@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Marijn Suijten <marijn.suijten@somainline.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Vikash Garodia <quic_vgarodia@quicinc.com>
Precedence: bulk

The qcom_scm_mem_protect_video_var accepts two sets of <addr size>
pairs as arguments. They describe the virtual address ranges of the
CP (Content Protection) and CP_NONPIXEL regions. It is however not
immediately obvious how to obtain these values.

Leave a comment explaining how one can translate the vendor device
tree properties for use with the mainline driver.

Reviewed-by: Dikshita Agarwal <quic_dikshita@quicinc.com>
Reviewed-by: Vikash Garodia <quic_vgarodia@quicinc.com>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/media/platform/qcom/venus/firmware.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/media/platform/qcom/venus/firmware.c b/drivers/media/platform/qcom/venus/firmware.c
index cfb11c551167..572b649c56f3 100644
--- a/drivers/media/platform/qcom/venus/firmware.c
+++ b/drivers/media/platform/qcom/venus/firmware.c
@@ -241,6 +241,16 @@ 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, address and not size!
+		 *   This works, as the non-secure context bank is placed
+		 *   contiguously right after the 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,

-- 
2.40.1