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Commit a6daa863 authored by Amelie Delaunay's avatar Amelie Delaunay Committed by Greg Kroah-Hartman
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spi: stm32: fix fifo threshold level in case of short transfer 



[ Upstream commit 3373e9004acc0603242622b4378c64bc01d21b5f ]

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: default avatarAmelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: default avatarAlain Volmat <alain.volmat@st.com>
Link: https://lore.kernel.org/r/1597043558-29668-3-git-send-email-alain.volmat@st.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 3c15a3c4

drivers/spi/spi-stm32.c

+18 −8
Original line number Diff line number Diff line
@@ -469,20 +469,27 @@ 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)
@@ -490,6 +497,9 @@ static u32 stm32h7_spi_prepare_fthlv(struct stm32_spi *spi) 
	else

		fthlv -= (fthlv % 4); /* multiple of 4 */



	if (!fthlv)

		fthlv = 1;



	return fthlv;

}
@@ -1396,7 +1406,7 @@ 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;
@@ -1582,6 +1592,8 @@ 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);
@@ -1629,8 +1641,6 @@ 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,