From: Dilip Kota eswara.kota@linux.intel.com
[ Upstream commit 661ccf2b3f1360be50242726f7c26ced6a9e7d52 ]
In full duplex mode, rx overflow error is observed. To overcome the error, wait until the complete data got received and proceed further.
Fixes: 17f84b793c01 ("spi: lantiq-ssc: add support for Lantiq SSC SPI controller") Signed-off-by: Dilip Kota eswara.kota@linux.intel.com Link: https://lore.kernel.org/r/efb650b0faa49a00788c4e0ca8ef7196bdba851d.159495701... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-lantiq-ssc.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/spi/spi-lantiq-ssc.c b/drivers/spi/spi-lantiq-ssc.c index 9dfe8b04e6880..55394bdbc5a30 100644 --- a/drivers/spi/spi-lantiq-ssc.c +++ b/drivers/spi/spi-lantiq-ssc.c @@ -184,6 +184,7 @@ struct lantiq_ssc_spi { unsigned int tx_fifo_size; unsigned int rx_fifo_size; unsigned int base_cs; + unsigned int fdx_tx_level; };
static u32 lantiq_ssc_readl(const struct lantiq_ssc_spi *spi, u32 reg) @@ -481,6 +482,7 @@ static void tx_fifo_write(struct lantiq_ssc_spi *spi) u32 data; unsigned int tx_free = tx_fifo_free(spi);
+ spi->fdx_tx_level = 0; while (spi->tx_todo && tx_free) { switch (spi->bits_per_word) { case 2 ... 8: @@ -509,6 +511,7 @@ static void tx_fifo_write(struct lantiq_ssc_spi *spi)
lantiq_ssc_writel(spi, data, LTQ_SPI_TB); tx_free--; + spi->fdx_tx_level++; } }
@@ -520,6 +523,13 @@ static void rx_fifo_read_full_duplex(struct lantiq_ssc_spi *spi) u32 data; unsigned int rx_fill = rx_fifo_level(spi);
+ /* + * Wait until all expected data to be shifted in. + * Otherwise, rx overrun may occur. + */ + while (rx_fill != spi->fdx_tx_level) + rx_fill = rx_fifo_level(spi); + while (rx_fill) { data = lantiq_ssc_readl(spi, LTQ_SPI_RB);