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Subject[PATCH AUTOSEL 5.5 01/41] spi: spi-omap2-mcspi: Handle DMA size restriction on AM65x
Date
From: Vignesh Raghavendra <vigneshr@ti.com>

[ Upstream commit e4e8276a4f652be2c7bb783a0155d4adb85f5d7d ]

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: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200204124816.16735-2-vigneshr@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-omap2-mcspi.c | 26 +++++++++++++++++++
include/linux/platform_data/spi-omap2-mcspi.h | 1 +
2 files changed, 27 insertions(+)

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 7e2292c11d120..e9bc9cf984d60 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -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);
diff --git a/include/linux/platform_data/spi-omap2-mcspi.h b/include/linux/platform_data/spi-omap2-mcspi.h
index 0bf9fddb83064..3b400b1919a9b 100644
--- a/include/linux/platform_data/spi-omap2-mcspi.h
+++ b/include/linux/platform_data/spi-omap2-mcspi.h
@@ -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 {
--
2.20.1
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