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spi: bcm2835: implement ctlr->max_transfer_size

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The core SPI code will handle splitting transfers if needed as long
as ctlr->max_transfer_size is implemented. It does this in
__spi_pump_transfer_message() immediately before calling
ctlr->prepare_message. So effectively, this change does not
alter the behavior of the driver.

Also, several peripheral drivers make use of spi_max_transfer_size(),
so this should improve compatibility with those drivers.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240126220024.3926403-2-dlechner@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
David Lechner 2024-01-26 16:00:23 -06:00 committed by Mark Brown
parent c8bec3355f
commit 2733092baa
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GPG Key ID: 24D68B725D5487D0
1 changed files with 14 additions and 13 deletions
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27
drivers/spi/spi-bcm2835.c
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@ -1117,19 +1117,6 @@ static int bcm2835_spi_prepare_message(struct spi_controller *ctlr,
struct spi_device *spi = msg->spi;
struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr);
struct bcm2835_spidev *target = spi_get_ctldata(spi);
int ret;
if (ctlr->can_dma) {
/*
* DMA transfers are limited to 16 bit (0 to 65535 bytes) by
* the SPI HW due to DLEN. Split up transfers (32-bit FIFO
* aligned) if the limit is exceeded.
*/
ret = spi_split_transfers_maxsize(ctlr, msg, 65532,
GFP_KERNEL | GFP_DMA);
if (ret)
return ret;
}
/*
* Set up clock polarity before spi_transfer_one_message() asserts
@ -1219,6 +1206,19 @@ static int bcm2835_spi_setup_dma(struct spi_controller *ctlr,
return 0;
}
static size_t bcm2835_spi_max_transfer_size(struct spi_device *spi)
{
/*
* DMA transfers are limited to 16 bit (0 to 65535 bytes) by
* the SPI HW due to DLEN. Split up transfers (32-bit FIFO
* aligned) if the limit is exceeded.
*/
if (spi->controller->can_dma)
return 65532;
return SIZE_MAX;
}
static int bcm2835_spi_setup(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
@ -1348,6 +1348,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
ctlr->mode_bits = BCM2835_SPI_MODE_BITS;
ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
ctlr->num_chipselect = 3;
ctlr->max_transfer_size = bcm2835_spi_max_transfer_size;
ctlr->setup = bcm2835_spi_setup;
ctlr->cleanup = bcm2835_spi_cleanup;
ctlr->transfer_one = bcm2835_spi_transfer_one;