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
next reply other threads:[~2022-04-07 15:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-07 15:08 Michael Walle [this message]
2022-05-02 21:36 ` [PATCH v2] i2c: at91: use dma safe buffers Michael Walle
2022-05-04 20:23 ` Wolfram Sang
2022-05-04 20:48 ` Michael Walle
2022-05-05 14:51 ` Nathan Chancellor
2022-05-05 15:11 ` Michael Walle
2022-05-05 15:18 ` Nathan Chancellor
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