From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: linux-i2c@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
linux-iio@vger.kernel.org, linux-input@vger.kernel.org,
linux-media@vger.kernel.org, Mark Brown <broonie@kernel.org>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: [PATCH v6 1/9] i2c: add a message flag for DMA safe buffers
Date: Sat, 4 Nov 2017 21:20:01 +0100 [thread overview]
Message-ID: <20171104202009.3818-2-wsa+renesas@sang-engineering.com> (raw)
In-Reply-To: <20171104202009.3818-1-wsa+renesas@sang-engineering.com>
I2C has no requirement that the buffer of a message needs to be DMA
safe. In case it is, it can now be flagged, so drivers wishing to
do DMA can use the buffer directly.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
include/uapi/linux/i2c.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h
index 009e27bb9abe19..1c683cb319e4b7 100644
--- a/include/uapi/linux/i2c.h
+++ b/include/uapi/linux/i2c.h
@@ -71,6 +71,9 @@ struct i2c_msg {
#define I2C_M_RD 0x0001 /* read data, from slave to master */
/* I2C_M_RD is guaranteed to be 0x0001! */
#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */
+#define I2C_M_DMA_SAFE 0x0200 /* the buffer of this message is DMA safe */
+ /* makes only sense in kernelspace */
+ /* userspace buffers are copied anyway */
#define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */
#define I2C_M_NO_RD_ACK 0x0800 /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */
--
2.11.0
next prev parent reply other threads:[~2017-11-04 20:20 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-04 20:20 [PATCH v6 0/9] i2c: document DMA handling and add helpers for it Wolfram Sang
2017-11-04 20:20 ` Wolfram Sang
2017-11-04 20:20 ` Wolfram Sang [this message]
2017-11-04 20:20 ` [PATCH v6 2/9] i2c: add helpers to ease DMA handling Wolfram Sang
2017-11-04 20:20 ` Wolfram Sang
2017-11-04 20:20 ` [PATCH v6 3/9] i2c: dev: mark RDWR buffers as DMA_SAFE Wolfram Sang
2017-11-04 20:20 ` Wolfram Sang
2017-11-04 20:20 ` [PATCH v6 4/9] i2c: refactor i2c_master_{send_recv} Wolfram Sang
2017-11-11 0:03 ` Jonathan Cameron
2017-11-11 0:03 ` Jonathan Cameron
2017-11-04 20:20 ` [PATCH v6 5/9] i2c: add i2c_master_{send|recv}_dmasafe Wolfram Sang
2017-11-11 0:08 ` Jonathan Cameron
2017-11-11 0:08 ` Jonathan Cameron
2017-11-04 20:20 ` [PATCH v6 6/9] i2c: smbus: use DMA safe buffers for emulated SMBus transactions Wolfram Sang
2017-11-11 0:13 ` Jonathan Cameron
2017-11-11 0:13 ` Jonathan Cameron
2017-11-04 20:20 ` [PATCH v6 7/9] i2c: add docs to clarify DMA handling Wolfram Sang
2017-11-04 20:20 ` [PATCH v6 8/9] i2c: sh_mobile: use core helper to decide when to use DMA Wolfram Sang
2017-11-04 20:20 ` [PATCH v6 9/9] i2c: rcar: skip DMA if buffer is not safe Wolfram Sang
2017-11-08 22:50 ` [PATCH v6 0/9] i2c: document DMA handling and add helpers for it Mark Brown
2017-11-27 18:51 ` Wolfram Sang
2017-11-28 15:34 ` Mark Brown
2017-12-03 19:43 ` Wolfram Sang
2017-12-04 22:05 ` Mark Brown
2017-12-04 22:05 ` Mark Brown
2017-12-05 11:00 ` Jonathan Cameron
2017-12-05 11:00 ` Jonathan Cameron
2017-12-04 21:25 ` Wolfram Sang
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