From 12547ecbc8832a27dfdcbe3ec88702ba5cfba6f6 Mon Sep 17 00:00:00 2001 From: Vincent Whitchurch Date: Tue, 27 Sep 2022 13:21:17 +0200 Subject: [PATCH] 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: 230d42d422e7 ("spi: Add s3c64xx SPI Controller driver") Signed-off-by: Vincent Whitchurch Link: https://lore.kernel.org/r/20220927112117.77599-5-vincent.whitchurch@axis.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-s3c64xx.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c index 1a6ec226d6e4..0594e214a636 100644 --- a/drivers/spi/spi-s3c64xx.c +++ b/drivers/spi/spi-s3c64xx.c @@ -94,6 +94,7 @@ #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) @@ -640,6 +641,13 @@ 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) @@ -1067,6 +1075,7 @@ 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) | -- 2.20.1