linux-kernel - [PATCH 3/3] venus: firmware: Correct assertion of reset bit on remote processor

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Date:   Wed,  5 Oct 2022 11:37:30 +0300
From:   Stanimir Varbanov <stanimir.varbanov@...aro.org>
To:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org
Cc:     Stanimir Varbanov <stanimir.varbanov@...aro.org>
Subject: [PATCH 3/3] venus: firmware: Correct assertion of reset bit on remote processor

Currently we use read/write_relaxed in combination with mb() to assert
reset. This looks wrong because mb() after write_relaxed() will not
order correctly load-update-store sequence. Correct this by use
readl/writel which include memory barriers.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@...aro.org>
---
 drivers/media/platform/qcom/venus/firmware.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/media/platform/qcom/venus/firmware.c b/drivers/media/platform/qcom/venus/firmware.c
index 71e43611d1cf..142d4c74017c 100644
--- a/drivers/media/platform/qcom/venus/firmware.c
+++ b/drivers/media/platform/qcom/venus/firmware.c
@@ -181,17 +181,15 @@ static int venus_shutdown_no_tz(struct venus_core *core)
 
 	if (IS_V6(core)) {
 		/* Assert the reset to XTSS */
-		reg = readl_relaxed(wrapper_tz_base + WRAPPER_TZ_XTSS_SW_RESET);
+		reg = readl(wrapper_tz_base + WRAPPER_TZ_XTSS_SW_RESET);
 		reg |= WRAPPER_XTSS_SW_RESET_BIT;
-		writel_relaxed(reg, wrapper_tz_base + WRAPPER_TZ_XTSS_SW_RESET);
+		writel(reg, wrapper_tz_base + WRAPPER_TZ_XTSS_SW_RESET);
 	} else {
 		/* Assert the reset to ARM9 */
-		reg = readl_relaxed(wrapper_base + WRAPPER_A9SS_SW_RESET);
+		reg = readl(wrapper_base + WRAPPER_A9SS_SW_RESET);
 		reg |= WRAPPER_A9SS_SW_RESET_BIT;
-		writel_relaxed(reg, wrapper_base + WRAPPER_A9SS_SW_RESET);
+		writel(reg, wrapper_base + WRAPPER_A9SS_SW_RESET);
 	}
-	/* Make sure reset is asserted before the mapping is removed */
-	mb();
 
 	iommu = core->fw.iommu_domain;
 
-- 
2.25.1