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Commit 1dbe7dad authored by Alexander Stein's avatar Alexander Stein Committed by Dmitry Torokhov
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Input: ads7846 - make transfer buffers DMA safe 



req.sample needs its own cacheline otherwise accessing req.msg fetches
it in again.

Note: This effect doesn't occur if the underlying SPI driver doesn't use
DMA at all.

Signed-off-by: default avatarAlexander Stein <alexander.stein@systec-electronic.com>
Acked-by: default avatarJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent bf283707

drivers/input/touchscreen/ads7846.c

+10 −2
Original line number Original line Diff line number Diff line
@@ -281,17 +281,25 @@ struct ser_req { 
	u8			command;

	u8			command;

	u8			ref_off;

	u8			ref_off;

	u16			scratch;

	u16			scratch;

	__be16			sample;

	struct spi_message	msg;

	struct spi_message	msg;

	struct spi_transfer	xfer[6];

	struct spi_transfer	xfer[6];

	/*

	 * DMA (thus cache coherency maintenance) requires the

	 * transfer buffers to live in their own cache lines.

	 */

	__be16 sample ____cacheline_aligned;

};

};





struct ads7845_ser_req {

struct ads7845_ser_req {

	u8			command[3];

	u8			command[3];

	u8			pwrdown[3];

	u8			pwrdown[3];

	u8			sample[3];

	struct spi_message	msg;

	struct spi_message	msg;

	struct spi_transfer	xfer[2];

	struct spi_transfer	xfer[2];

	/*

	 * DMA (thus cache coherency maintenance) requires the

	 * transfer buffers to live in their own cache lines.

	 */

	u8 sample[3] ____cacheline_aligned;

};

};





static int ads7846_read12_ser(struct device *dev, unsigned command)

static int ads7846_read12_ser(struct device *dev, unsigned command)