From: Pratyush Yadav pratyush@kernel.org
cqspi_indirect_read_execute() and cqspi_indirect_write_execute() first set the enable bit on APB region and then start reading/writing to the AHB region. On TI K3 SoCs these regions lie on different endpoints. This means that the order of the two operations is not guaranteed, and they might be reordered at the interconnect level.
It is possible for the AHB write to be executed before the APB write to enable the indirect controller, causing the transaction to be invalid and the write erroring out. Read back the APB region write before accessing the AHB region to make sure the write got flushed and the race condition is eliminated.
Fixes: 140623410536 ("mtd: spi-nor: Add driver for Cadence Quad SPI Flash Controller") CC: stable@vger.kernel.org Reviewed-by: Pratyush Yadav pratyush@kernel.org Signed-off-by: Pratyush Yadav pratyush@kernel.org Signed-off-by: Santhosh Kumar K s-k6@ti.com --- drivers/spi/spi-cadence-quadspi.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c index 9bf823348cd3..eaf9a0f522d5 100644 --- a/drivers/spi/spi-cadence-quadspi.c +++ b/drivers/spi/spi-cadence-quadspi.c @@ -764,6 +764,7 @@ static int cqspi_indirect_read_execute(struct cqspi_flash_pdata *f_pdata, reinit_completion(&cqspi->transfer_complete); writel(CQSPI_REG_INDIRECTRD_START_MASK, reg_base + CQSPI_REG_INDIRECTRD); + readl(reg_base + CQSPI_REG_INDIRECTRD); /* Flush posted write. */
while (remaining > 0) { if (use_irq && @@ -1090,6 +1091,8 @@ static int cqspi_indirect_write_execute(struct cqspi_flash_pdata *f_pdata, reinit_completion(&cqspi->transfer_complete); writel(CQSPI_REG_INDIRECTWR_START_MASK, reg_base + CQSPI_REG_INDIRECTWR); + readl(reg_base + CQSPI_REG_INDIRECTWR); /* Flush posted write. */ + /* * As per 66AK2G02 TRM SPRUHY8F section 11.15.5.3 Indirect Access * Controller programming sequence, couple of cycles of