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

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Date:   Tue, 15 Sep 2020 23:07:13 +0530
From:   Sibi Sankar <sibis@...eaurora.org>
To:     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, swboyd@...omium.org,
        Sibi Sankar <sibis@...eaurora.org>
Subject: [PATCH] remoteproc: qcom_q6v5: Assign mpss region to Q6 before MBA cold boot

On secure devices which support warm reset, the modem subsystem requires
access to the mpss region to clear them out. Hence assign the mpss region
to Q6 before MBA cold boot. This will be a nop during a modem SSR.

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

I didn't want to add any new flags for warm reset support because
calling xfer for mpss to q6 shouldn't have any side effects on
platforms that don't support warm resets.

 drivers/remoteproc/qcom_q6v5_mss.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c
index c401bcc263fa5..cc5b7edc02c73 100644
--- a/drivers/remoteproc/qcom_q6v5_mss.c
+++ b/drivers/remoteproc/qcom_q6v5_mss.c
@@ -931,6 +931,18 @@ static int q6v5_mba_load(struct q6v5 *qproc)
 		goto assert_reset;
 	}
 
+	/**
+	 * On secure devices which support warm reboot, the modem subsystem's cold boot is similar
+	 * to an SSR sequence i.e the mba requires access to the modem memory to clear it out during
+	 * Q6 cold boot. For modem SSR it will be a nop.
+	 */
+	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);
-- 
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