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Commit c202ad04 authored by Vincent Whitchurch's avatar Vincent Whitchurch Committed by Greg Kroah-Hartman
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spi: s3c64xx: Fix large transfers with DMA 



[ Upstream commit 1224e29572f655facfcd850cf0f0a4784f36a903 ]

The COUNT_VALUE in the PACKET_CNT register is 16-bit so the maximum
value is 65535.  Asking the driver to transfer a larger size currently
leads to the DMA transfer timing out.  Implement ->max_transfer_size()
and have the core split the transfer as needed.

Fixes: 230d42d4 ("spi: Add s3c64xx SPI Controller driver")
Signed-off-by: default avatarVincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20220927112117.77599-5-vincent.whitchurch@axis.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 60a7496b

drivers/spi/spi-s3c64xx.c

+9 −0
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ 
#define S3C64XX_SPI_ST_TX_FIFORDY		(1<<0)



#define S3C64XX_SPI_PACKET_CNT_EN		(1<<16)

#define S3C64XX_SPI_PACKET_CNT_MASK		GENMASK(15, 0)



#define S3C64XX_SPI_PND_TX_UNDERRUN_CLR		(1<<4)

#define S3C64XX_SPI_PND_TX_OVERRUN_CLR		(1<<3)
@@ -654,6 +655,13 @@ static int s3c64xx_spi_prepare_message(struct spi_master *master, 
	return 0;

}



static size_t s3c64xx_spi_max_transfer_size(struct spi_device *spi)

{

	struct spi_controller *ctlr = spi->controller;



	return ctlr->can_dma ? S3C64XX_SPI_PACKET_CNT_MASK : SIZE_MAX;

}



static int s3c64xx_spi_transfer_one(struct spi_master *master,

				    struct spi_device *spi,

				    struct spi_transfer *xfer)
@@ -1118,6 +1126,7 @@ static int s3c64xx_spi_probe(struct platform_device *pdev) 
	master->prepare_transfer_hardware = s3c64xx_spi_prepare_transfer;

	master->prepare_message = s3c64xx_spi_prepare_message;

	master->transfer_one = s3c64xx_spi_transfer_one;

	master->max_transfer_size = s3c64xx_spi_max_transfer_size;

	master->num_chipselect = sci->num_cs;

	master->dma_alignment = 8;

	master->bits_per_word_mask = SPI_BPW_MASK(32) | SPI_BPW_MASK(16) |