6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Amit Kumar Mahapatra <amit.kumar-mahapatra@xxxxxxx>
[ Upstream commit 633cd6fe6e1993ba80e0954c2db127a0b1a3e66f ]
In the existing implementation, when executing interleaved write and read
operations in the ISR for a transfer length greater than the FIFO size,
the TXFIFO write precedes the RXFIFO read. Consequently, the initially
received data in the RXFIFO is pushed out and lost, leading to a failure
in data integrity. To address this issue, reverse the order of interleaved
operations and conduct the RXFIFO read followed by the TXFIFO write.
Fixes: 6afe2ae8dc48 ("spi: spi-cadence: Interleave write of TX and read of RX FIFO")
Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xxxxxxx>
Link: https://msgid.link/r/20231218090652.18403-1-amit.kumar-mahapatra@xxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/spi/spi-cadence.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c
index bd96d8b546cd..5cab7caf4658 100644
--- a/drivers/spi/spi-cadence.c
+++ b/drivers/spi/spi-cadence.c
@@ -317,6 +317,15 @@ static void cdns_spi_process_fifo(struct cdns_spi *xspi, int ntx, int nrx)
xspi->rx_bytes -= nrx;
while (ntx || nrx) {
+ if (nrx) {
+ u8 data = cdns_spi_read(xspi, CDNS_SPI_RXD);
+
+ if (xspi->rxbuf)
+ *xspi->rxbuf++ = data;
+
+ nrx--;
+ }
+
if (ntx) {
if (xspi->txbuf)
cdns_spi_write(xspi, CDNS_SPI_TXD, *xspi->txbuf++);
@@ -326,14 +335,6 @@ static void cdns_spi_process_fifo(struct cdns_spi *xspi, int ntx, int nrx)
ntx--;
}
- if (nrx) {
- u8 data = cdns_spi_read(xspi, CDNS_SPI_RXD);
-
- if (xspi->rxbuf)
- *xspi->rxbuf++ = data;
-
- nrx--;
- }
}
}
--
2.43.0
