6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Conor Dooley conor.dooley@microchip.com
commit 91cf42c63f2d8a9c1bcdfe923218e079b32e1a69 upstream.
When the size of a transfer exceeds the size of the FIFO (32 bytes), RX overflows will be generated and receive data will be corrupted and warnings will be produced. For example, here's an error generated by a transfer of 36 bytes:
spi_master spi0: mchp_corespi_interrupt: RX OVERFLOW: rxlen: 4, txlen: 0
The driver is currently split between handling receiving in the interrupt handler, and sending outside of it. Move all handling out of the interrupt handling, and explicitly link the number of bytes read of of the RX FIFO to the number written into the TX one. This both resolves the overflow problems as well as simplifying the flow of the driver.
CC: stable@vger.kernel.org Fixes: 9ac8d17694b6 ("spi: add support for microchip fpga spi controllers") Signed-off-by: Conor Dooley conor.dooley@microchip.com Link: https://patch.msgid.link/20250303-veal-snooper-712c1dfad336@wendy Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/spi/spi-microchip-core.c | 41 +++++++++++++++++---------------------- 1 file changed, 18 insertions(+), 23 deletions(-)
--- a/drivers/spi/spi-microchip-core.c +++ b/drivers/spi/spi-microchip-core.c @@ -70,8 +70,7 @@ #define INT_RX_CHANNEL_OVERFLOW BIT(2) #define INT_TX_CHANNEL_UNDERRUN BIT(3)
-#define INT_ENABLE_MASK (CONTROL_RX_DATA_INT | CONTROL_TX_DATA_INT | \ - CONTROL_RX_OVER_INT | CONTROL_TX_UNDER_INT) +#define INT_ENABLE_MASK (CONTROL_RX_OVER_INT | CONTROL_TX_UNDER_INT)
#define REG_CONTROL (0x00) #define REG_FRAME_SIZE (0x04) @@ -133,10 +132,15 @@ static inline void mchp_corespi_disable( mchp_corespi_write(spi, REG_CONTROL, control); }
-static inline void mchp_corespi_read_fifo(struct mchp_corespi *spi) +static inline void mchp_corespi_read_fifo(struct mchp_corespi *spi, int fifo_max) { - while (spi->rx_len >= spi->n_bytes && !(mchp_corespi_read(spi, REG_STATUS) & STATUS_RXFIFO_EMPTY)) { - u32 data = mchp_corespi_read(spi, REG_RX_DATA); + for (int i = 0; i < fifo_max; i++) { + u32 data; + + while (mchp_corespi_read(spi, REG_STATUS) & STATUS_RXFIFO_EMPTY) + ; + + data = mchp_corespi_read(spi, REG_RX_DATA);
spi->rx_len -= spi->n_bytes;
@@ -211,11 +215,10 @@ static inline void mchp_corespi_set_xfer mchp_corespi_write(spi, REG_FRAMESUP, len); }
-static inline void mchp_corespi_write_fifo(struct mchp_corespi *spi) +static inline void mchp_corespi_write_fifo(struct mchp_corespi *spi, int fifo_max) { - int fifo_max, i = 0; + int i = 0;
- fifo_max = DIV_ROUND_UP(min(spi->tx_len, FIFO_DEPTH), spi->n_bytes); mchp_corespi_set_xfer_size(spi, fifo_max);
while ((i < fifo_max) && !(mchp_corespi_read(spi, REG_STATUS) & STATUS_TXFIFO_FULL)) { @@ -413,19 +416,6 @@ static irqreturn_t mchp_corespi_interrup if (intfield == 0) return IRQ_NONE;
- if (intfield & INT_TXDONE) - mchp_corespi_write(spi, REG_INT_CLEAR, INT_TXDONE); - - if (intfield & INT_RXRDY) { - mchp_corespi_write(spi, REG_INT_CLEAR, INT_RXRDY); - - if (spi->rx_len) - mchp_corespi_read_fifo(spi); - } - - if (!spi->rx_len && !spi->tx_len) - finalise = true; - if (intfield & INT_RX_CHANNEL_OVERFLOW) { mchp_corespi_write(spi, REG_INT_CLEAR, INT_RX_CHANNEL_OVERFLOW); finalise = true; @@ -512,9 +502,14 @@ static int mchp_corespi_transfer_one(str
mchp_corespi_write(spi, REG_SLAVE_SELECT, spi->pending_slave_select);
- while (spi->tx_len) - mchp_corespi_write_fifo(spi); + while (spi->tx_len) { + int fifo_max = DIV_ROUND_UP(min(spi->tx_len, FIFO_DEPTH), spi->n_bytes); + + mchp_corespi_write_fifo(spi, fifo_max); + mchp_corespi_read_fifo(spi, fifo_max); + }
+ spi_finalize_current_transfer(host); return 1; }