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Subject[PATCH v3 04/12] spi: spi-fsl-dspi: Avoid reading more data than written in EOQ mode
Date
From: Vladimir Oltean <vladimir.oltean@nxp.com>

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: d59c90a2400f ("spi: spi-fsl-dspi: Convert TCFQ users to XSPI FIFO mode")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
Changes in v4:
Patch is new.

drivers/spi/spi-fsl-dspi.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 8f2b73cc6ed7..51224b772680 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -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);
--
2.17.1
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