From 3373e9004acc0603242622b4378c64bc01d21b5f Mon Sep 17 00:00:00 2001 From: Amelie Delaunay Date: Mon, 10 Aug 2020 09:12:35 +0200 Subject: spi: stm32: fix fifo threshold level in case of short transfer When transfer is shorter than half of the fifo, set the data packet size up to transfer size instead of up to half of the fifo. Check also that threshold is set at least to 1 data frame. Signed-off-by: Amelie Delaunay Signed-off-by: Alain Volmat Link: https://lore.kernel.org/r/1597043558-29668-3-git-send-email-alain.volmat@st.com Signed-off-by: Mark Brown --- drivers/spi/spi-stm32.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) (limited to 'drivers') diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index 814a3ec3b8ad..e5450233f3f8 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -467,20 +467,27 @@ static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz, /** * stm32h7_spi_prepare_fthlv - Determine FIFO threshold level * @spi: pointer to the spi controller data structure + * @xfer_len: length of the message to be transferred */ -static u32 stm32h7_spi_prepare_fthlv(struct stm32_spi *spi) +static u32 stm32h7_spi_prepare_fthlv(struct stm32_spi *spi, u32 xfer_len) { - u32 fthlv, half_fifo; + u32 fthlv, half_fifo, packet; /* data packet should not exceed 1/2 of fifo space */ half_fifo = (spi->fifo_size / 2); + /* data_packet should not exceed transfer length */ + if (half_fifo > xfer_len) + packet = xfer_len; + else + packet = half_fifo; + if (spi->cur_bpw <= 8) - fthlv = half_fifo; + fthlv = packet; else if (spi->cur_bpw <= 16) - fthlv = half_fifo / 2; + fthlv = packet / 2; else - fthlv = half_fifo / 4; + fthlv = packet / 4; /* align packet size with data registers access */ if (spi->cur_bpw > 8) @@ -488,6 +495,9 @@ static u32 stm32h7_spi_prepare_fthlv(struct stm32_spi *spi) else fthlv -= (fthlv % 4); /* multiple of 4 */ + if (!fthlv) + fthlv = 1; + return fthlv; } @@ -1393,7 +1403,7 @@ static void stm32h7_spi_set_bpw(struct stm32_spi *spi) cfg1_setb |= (bpw << STM32H7_SPI_CFG1_DSIZE_SHIFT) & STM32H7_SPI_CFG1_DSIZE; - spi->cur_fthlv = stm32h7_spi_prepare_fthlv(spi); + spi->cur_fthlv = stm32h7_spi_prepare_fthlv(spi, spi->cur_xferlen); fthlv = spi->cur_fthlv - 1; cfg1_clrb |= STM32H7_SPI_CFG1_FTHLV; @@ -1588,6 +1598,8 @@ static int stm32_spi_transfer_one_setup(struct stm32_spi *spi, spin_lock_irqsave(&spi->lock, flags); + spi->cur_xferlen = transfer->len; + if (spi->cur_bpw != transfer->bits_per_word) { spi->cur_bpw = transfer->bits_per_word; spi->cfg->set_bpw(spi); @@ -1635,8 +1647,6 @@ static int stm32_spi_transfer_one_setup(struct stm32_spi *spi, goto out; } - spi->cur_xferlen = transfer->len; - dev_dbg(spi->dev, "transfer communication mode set to %d\n", spi->cur_comm); dev_dbg(spi->dev, -- cgit v1.2.3