[PATCH v2 4/8] spi: stm32h7: ensure message are smaller than max size

From: Alain Volmat
Date: Fri Feb 05 2021 - 14:07:17 EST


Ensure that messages given to transfer_one handler can actually be
handled by it. For that purpose rely on the SPI framework
spi_split_transfers_maxsize function to split messages whenever necessary.

Signed-off-by: Alain Volmat <alain.volmat@xxxxxxxxxxx>
---
v2: reordered within the serie

drivers/spi/spi-stm32.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index a46132e81533..8e4db219b95d 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -1004,6 +1004,20 @@ static int stm32_spi_prepare_msg(struct spi_master *master,
!!(spi_dev->mode & SPI_LSB_FIRST),
!!(spi_dev->mode & SPI_CS_HIGH));

+ /* On STM32H7, messages should not exceed a maximum size setted
+ * afterward via the set_number_of_data function. In order to
+ * ensure that, split large messages into several messages
+ */
+ if (spi->cfg->set_number_of_data) {
+ int ret;
+
+ ret = spi_split_transfers_maxsize(master, msg,
+ STM32H7_SPI_TSIZE_MAX,
+ GFP_KERNEL | GFP_DMA);
+ if (ret)
+ return ret;
+ }
+
spin_lock_irqsave(&spi->lock, flags);

/* CPOL, CPHA and LSB FIRST bits have common register */
--
2.17.1