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From: Michael Walle <michael@walle.cc>
To: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>,
	Nicolas Ferre <nicolas.ferre@microchip.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Claudiu Beznea <claudiu.beznea@microchip.com>
Cc: linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Michael Walle <michael@walle.cc>
Subject: [PATCH v2] i2c: at91: use dma safe buffers
Date: Thu,  7 Apr 2022 17:08:28 +0200	[thread overview]
Message-ID: <20220407150828.202513-1-michael@walle.cc> (raw)

The supplied buffer might be on the stack and we get the following error
message:
[    3.312058] at91_i2c e0070600.i2c: rejecting DMA map of vmalloc memory

Use i2c_{get,put}_dma_safe_msg_buf() to get a DMA-able memory region if
necessary.

Fixes: 60937b2cdbf9 ("i2c: at91: add dma support")
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
---
changes since v1:
 - remove extra empty line
 - add fixes tag as suggested by Codrin

 drivers/i2c/busses/i2c-at91-master.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
index b0eae94909f4..5eca3b3bb609 100644
--- a/drivers/i2c/busses/i2c-at91-master.c
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -656,6 +656,7 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
 	unsigned int_addr_flag = 0;
 	struct i2c_msg *m_start = msg;
 	bool is_read;
+	u8 *dma_buf;
 
 	dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
 
@@ -703,7 +704,17 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
 	dev->msg = m_start;
 	dev->recv_len_abort = false;
 
+	if (dev->use_dma) {
+		dma_buf = i2c_get_dma_safe_msg_buf(m_start, 1);
+		if (!dma_buf) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		dev->buf = dma_buf;
+	}
+
 	ret = at91_do_twi_transfer(dev);
+	i2c_put_dma_safe_msg_buf(dma_buf, m_start, !ret);
 
 	ret = (ret < 0) ? ret : num;
 out:
-- 
2.30.2


WARNING: multiple messages have this Message-ID (diff)
From: Michael Walle <michael@walle.cc>
To: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>,
	Nicolas Ferre <nicolas.ferre@microchip.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Claudiu Beznea <claudiu.beznea@microchip.com>
Cc: linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Michael Walle <michael@walle.cc>
Subject: [PATCH v2] i2c: at91: use dma safe buffers
Date: Thu,  7 Apr 2022 17:08:28 +0200	[thread overview]
Message-ID: <20220407150828.202513-1-michael@walle.cc> (raw)

The supplied buffer might be on the stack and we get the following error
message:
[    3.312058] at91_i2c e0070600.i2c: rejecting DMA map of vmalloc memory

Use i2c_{get,put}_dma_safe_msg_buf() to get a DMA-able memory region if
necessary.

Fixes: 60937b2cdbf9 ("i2c: at91: add dma support")
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
---
changes since v1:
 - remove extra empty line
 - add fixes tag as suggested by Codrin

 drivers/i2c/busses/i2c-at91-master.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
index b0eae94909f4..5eca3b3bb609 100644
--- a/drivers/i2c/busses/i2c-at91-master.c
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -656,6 +656,7 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
 	unsigned int_addr_flag = 0;
 	struct i2c_msg *m_start = msg;
 	bool is_read;
+	u8 *dma_buf;
 
 	dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
 
@@ -703,7 +704,17 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
 	dev->msg = m_start;
 	dev->recv_len_abort = false;
 
+	if (dev->use_dma) {
+		dma_buf = i2c_get_dma_safe_msg_buf(m_start, 1);
+		if (!dma_buf) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		dev->buf = dma_buf;
+	}
+
 	ret = at91_do_twi_transfer(dev);
+	i2c_put_dma_safe_msg_buf(dma_buf, m_start, !ret);
 
 	ret = (ret < 0) ? ret : num;
 out:
-- 
2.30.2


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             reply	other threads:[~2022-04-07 15:08 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-07 15:08 Michael Walle [this message]
2022-04-07 15:08 ` [PATCH v2] i2c: at91: use dma safe buffers Michael Walle
2022-05-02 21:36 ` Michael Walle
2022-05-02 21:36   ` Michael Walle
2022-05-04 20:23 ` Wolfram Sang
2022-05-04 20:23   ` Wolfram Sang
2022-05-04 20:48   ` Michael Walle
2022-05-04 20:48     ` Michael Walle
2022-05-05 14:51 ` Nathan Chancellor
2022-05-05 14:51   ` Nathan Chancellor
2022-05-05 15:11   ` Michael Walle
2022-05-05 15:11     ` Michael Walle
2022-05-05 15:18     ` Nathan Chancellor
2022-05-05 15:18       ` Nathan Chancellor

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