Unverified Commit e4e8276a authored by Vignesh Raghavendra's avatar Vignesh Raghavendra Committed by Mark Brown
Browse files

spi: spi-omap2-mcspi: Handle DMA size restriction on AM65x 



On AM654, McSPI can only support 4K - 1 bytes per transfer when DMA is
enabled. Therefore populate master->max_transfer_size callback to
inform client drivers of this restriction when DMA channels are
available.

Signed-off-by: default avatarVignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200204124816.16735-2-vigneshr@ti.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent a5362b84

drivers/spi/spi-omap2-mcspi.c

+26 −0
Original line number Diff line number Diff line
@@ -130,6 +130,7 @@ struct omap2_mcspi { 
	int			fifo_depth;

	bool			slave_aborted;

	unsigned int		pin_dir:1;

	size_t			max_xfer_len;

};



struct omap2_mcspi_cs {
@@ -1305,6 +1306,18 @@ static bool omap2_mcspi_can_dma(struct spi_master *master, 
	return (xfer->len >= DMA_MIN_BYTES);

}



static size_t omap2_mcspi_max_xfer_size(struct spi_device *spi)

{

	struct omap2_mcspi *mcspi = spi_master_get_devdata(spi->master);

	struct omap2_mcspi_dma *mcspi_dma =

		&mcspi->dma_channels[spi->chip_select];



	if (mcspi->max_xfer_len && mcspi_dma->dma_rx)

		return mcspi->max_xfer_len;



	return SIZE_MAX;

}



static int omap2_mcspi_controller_setup(struct omap2_mcspi *mcspi)

{

	struct spi_master	*master = mcspi->master;
@@ -1373,6 +1386,11 @@ static struct omap2_mcspi_platform_config omap4_pdata = { 
	.regs_offset = OMAP4_MCSPI_REG_OFFSET,

};



static struct omap2_mcspi_platform_config am654_pdata = {

	.regs_offset = OMAP4_MCSPI_REG_OFFSET,

	.max_xfer_len = SZ_4K - 1,

};



static const struct of_device_id omap_mcspi_of_match[] = {

	{

		.compatible = "ti,omap2-mcspi",
@@ -1382,6 +1400,10 @@ static const struct of_device_id omap_mcspi_of_match[] = { 
		.compatible = "ti,omap4-mcspi",

		.data = &omap4_pdata,

	},

	{

		.compatible = "ti,am654-mcspi",

		.data = &am654_pdata,

	},

	{ },

};

MODULE_DEVICE_TABLE(of, omap_mcspi_of_match);
@@ -1439,6 +1461,10 @@ static int omap2_mcspi_probe(struct platform_device *pdev) 
		mcspi->pin_dir = pdata->pin_dir;

	}

	regs_offset = pdata->regs_offset;

	if (pdata->max_xfer_len) {

		mcspi->max_xfer_len = pdata->max_xfer_len;

		master->max_transfer_size = omap2_mcspi_max_xfer_size;

	}



	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	mcspi->base = devm_ioremap_resource(&pdev->dev, r);

include/linux/platform_data/spi-omap2-mcspi.h

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ struct omap2_mcspi_platform_config { 
	unsigned short	num_cs;

	unsigned int regs_offset;

	unsigned int pin_dir:1;

	size_t max_xfer_len;

};



struct omap2_mcspi_device_config {

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