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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Qii Wang <qii.wang@mediatek.com>,
        Wolfram Sang <wsa@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.9 116/255] i2c: mediatek: move dma reset before i2c reset
Date:   Tue, 17 Nov 2020 14:04:16 +0100
Message-Id: <20201117122144.588804048@linuxfoundation.org>
In-Reply-To: <20201117122138.925150709@linuxfoundation.org>
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From: Qii Wang <qii.wang@mediatek.com>

[ Upstream commit aafced673c06b7c77040c1df42e2e965be5d0376 ]

The i2c driver default do dma reset after i2c reset, but sometimes
i2c reset will trigger dma tx2rx, then apdma write data to dram
which has been i2c_put_dma_safe_msg_buf(kfree). Move dma reset
before i2c reset in mtk_i2c_init_hw to fix it.

Signed-off-by: Qii Wang <qii.wang@mediatek.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-mt65xx.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index 0cbdfbe605b55..33de99b7bc20c 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -475,6 +475,10 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
 {
 	u16 control_reg;
 
+	writel(I2C_DMA_HARD_RST, i2c->pdmabase + OFFSET_RST);
+	udelay(50);
+	writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST);
+
 	mtk_i2c_writew(i2c, I2C_SOFT_RST, OFFSET_SOFTRESET);
 
 	/* Set ioconfig */
@@ -529,10 +533,6 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
 
 	mtk_i2c_writew(i2c, control_reg, OFFSET_CONTROL);
 	mtk_i2c_writew(i2c, I2C_DELAY_LEN, OFFSET_DELAY_LEN);
-
-	writel(I2C_DMA_HARD_RST, i2c->pdmabase + OFFSET_RST);
-	udelay(50);
-	writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST);
 }
 
 static const struct i2c_spec_values *mtk_i2c_get_spec(unsigned int speed)
-- 
2.27.0