Unverified Commit c6c1e30a authored Mar 18, 2020 by Vladimir Oltean Committed by Mark Brown Mar 18, 2020

spi: spi-fsl-dspi: Avoid reading more data than written in EOQ mode



If dspi->words_in_flight is populated with the hardware FIFO size,
then in dspi_fifo_read it will attempt to read more data at the end of a
buffer that is not a multiple of 16 bytes in length. It will probably
time out attempting to do so.

So limit the num_fifo_entries variable to the actual number of FIFO
entries that is going to be used.

Fixes: d59c90a2 ("spi: spi-fsl-dspi: Convert TCFQ users to XSPI FIFO mode")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-5-olteanv@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>

parent a957499b

drivers/spi/spi-fsl-dspi.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -739,13 +739,16 @@ static void dspi_eoq_fifo_write(struct fsl_dspi *dspi)
		int num_fifo_entries = dspi->devtype_data->fifo_size;
		u16 xfer_cmd = dspi->tx_cmd;

		if (num_fifo_entries * dspi->oper_word_size > dspi->len)
		num_fifo_entries = dspi->len / dspi->oper_word_size;

		dspi->words_in_flight = num_fifo_entries;

		/* Fill TX FIFO with as many transfers as possible */
		while (dspi->len && num_fifo_entries--) {
		while (num_fifo_entries--) {
		dspi->tx_cmd = xfer_cmd;
		/* Request EOQF for last transfer in FIFO */
		if (dspi->len == dspi->oper_word_size \|\| num_fifo_entries == 0)
		if (num_fifo_entries == 0)
		dspi->tx_cmd \|= SPI_PUSHR_CMD_EOQ;
		/* Write combined TX FIFO and CMD FIFO entry */
		dspi_pushr_write(dspi);

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