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spi: spi-cadence: Reverse the order of interleaved write and read operations

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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@amd.com>
Link: https://msgid.link/r/20231218090652.18403-1-amit.kumar-mahapatra@amd.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Amit Kumar Mahapatra 2023-12-18 14:36:52 +05:30 committed by Mark Brown
parent e267a5b3ec
commit 633cd6fe6e
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GPG Key ID: 24D68B725D5487D0
1 changed files with 9 additions and 8 deletions
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17
drivers/spi/spi-cadence.c
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@ -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--;
}
}
}