From db2d2dc9a0b58c6faefb6b002fdbed4f0362d1a4 Mon Sep 17 00:00:00 2001 From: Frieder Schrempf Date: Tue, 15 Nov 2022 19:10:00 +0100 Subject: spi: spi-imx: Fix spi_bus_clk if requested clock is higher than input clock In case the requested bus clock is higher than the input clock, the correct dividers (pre = 0, post = 0) are returned from mx51_ecspi_clkdiv(), but *fres is left uninitialized and therefore contains an arbitrary value. This causes trouble for the recently introduced PIO polling feature as the value in spi_imx->spi_bus_clk is used there to calculate for which transfers to enable PIO polling. Fix this by setting *fres even if no clock dividers are in use. This issue was observed on Kontron BL i.MX8MM with an SPI peripheral clock set to 50 MHz by default and a requested SPI bus clock of 80 MHz for the SPI NOR flash. With the fix applied the debug message from mx51_ecspi_clkdiv() now prints the following: spi_imx 30820000.spi: mx51_ecspi_clkdiv: fin: 50000000, fspi: 50000000, post: 0, pre: 0 Fixes: 6fd8b8503a0d ("spi: spi-imx: Fix out-of-order CS/SCLK operation at low speeds") Fixes: 07e759387788 ("spi: spi-imx: add PIO polling support") Cc: Marc Kleine-Budde Cc: David Jander Cc: Fabio Estevam Cc: Mark Brown Cc: Marek Vasut Cc: stable@vger.kernel.org Signed-off-by: Frieder Schrempf Tested-by: Fabio Estevam Acked-by: Marek Vasut Link: https://lore.kernel.org/r/20221115181002.2068270-1-frieder@fris.de Signed-off-by: Mark Brown --- drivers/spi/spi-imx.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/spi/spi-imx.c') diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index 30d82cc7300b..468ce0a2b282 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -444,8 +444,7 @@ static unsigned int mx51_ecspi_clkdiv(struct spi_imx_data *spi_imx, unsigned int pre, post; unsigned int fin = spi_imx->spi_clk; - if (unlikely(fspi > fin)) - return 0; + fspi = min(fspi, fin); post = fls(fin) - fls(fspi); if (fin > fspi << post) -- cgit v1.2.3 From e85e9e0d8cb759013d6474011c227f92e442d746 Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Wed, 16 Nov 2022 17:49:30 +0100 Subject: spi: spi-imx: spi_imx_transfer_one(): check for DMA transfer first The SPI framework checks for each transfer (with the struct spi_controller::can_dma callback) whether the driver wants to use DMA for the transfer. If the driver returns true, the SPI framework will map the transfer's data to the device, start the actual transfer and map the data back. In commit 07e759387788 ("spi: spi-imx: add PIO polling support") the spi-imx driver's spi_imx_transfer_one() function was extended. If the estimated duration of a transfer does not exceed a configurable duration, a polling transfer function is used. This check happens before checking if the driver decided earlier for a DMA transfer. If spi_imx_can_dma() decided to use a DMA transfer, and the user configured a big maximum polling duration, a polling transfer will be used. The DMA unmap after the transfer destroys the transferred data. To fix this problem check in spi_imx_transfer_one() if the driver decided for DMA transfer first, then check the limits for a polling transfer. Fixes: 07e759387788 ("spi: spi-imx: add PIO polling support") Link: https://lore.kernel.org/all/20221111003032.82371-1-festevam@gmail.com Reported-by: Frieder Schrempf Reported-by: Fabio Estevam Tested-by: Fabio Estevam Cc: David Jander Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde Tested-by: Frieder Schrempf Reviewed-by: Frieder Schrempf Link: https://lore.kernel.org/r/20221116164930.855362-1-mkl@pengutronix.de Signed-off-by: Mark Brown --- drivers/spi/spi-imx.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'drivers/spi/spi-imx.c') diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index 468ce0a2b282..d209930069cf 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -1606,6 +1606,13 @@ static int spi_imx_transfer_one(struct spi_controller *controller, if (spi_imx->slave_mode) return spi_imx_pio_transfer_slave(spi, transfer); + /* + * If we decided in spi_imx_can_dma() that we want to do a DMA + * transfer, the SPI transfer has already been mapped, so we + * have to do the DMA transfer here. + */ + if (spi_imx->usedma) + return spi_imx_dma_transfer(spi_imx, transfer); /* * Calculate the estimated time in us the transfer runs. Find * the number of Hz per byte per polling limit. @@ -1617,9 +1624,6 @@ static int spi_imx_transfer_one(struct spi_controller *controller, if (transfer->len < byte_limit) return spi_imx_poll_transfer(spi, transfer); - if (spi_imx->usedma) - return spi_imx_dma_transfer(spi_imx, transfer); - return spi_imx_pio_transfer(spi, transfer); } -- cgit v1.2.3