From: Pratyush Yadav pratyush@kernel.org
[ Upstream commit 1ad55767e77a853c98752ed1e33b68049a243bd7 ]
cqspi_read_setup() and cqspi_write_setup() program the address width as the last step in the setup. This is likely to be immediately followed by a DAC region read/write. On TI K3 SoCs the DAC region is on a different endpoint from the register region. This means that the order of the two operations is not guaranteed, and they might be reordered at the interconnect level. It is possible that the DAC read/write goes through before the address width update goes through. In this situation if the previous command used a different address width the OSPI command is sent with the wrong number of address bytes, resulting in an invalid command and undefined behavior.
Read back the size register to make sure the write gets flushed before accessing the DAC region.
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 Message-ID: 20250905185958.3575037-3-s-k6@ti.com Signed-off-by: Mark Brown broonie@kernel.org [ backported to drivers/mtd/spi-nor ] Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mtd/spi-nor/cadence-quadspi.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c index 7bdc558d85601..85c05973ec4cb 100644 --- a/drivers/mtd/spi-nor/cadence-quadspi.c +++ b/drivers/mtd/spi-nor/cadence-quadspi.c @@ -496,6 +496,7 @@ static int cqspi_read_setup(struct spi_nor *nor) reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK; reg |= (nor->addr_width - 1); writel(reg, reg_base + CQSPI_REG_SIZE); + readl(reg_base + CQSPI_REG_SIZE); /* Flush posted write. */ return 0; }
@@ -608,6 +609,7 @@ static int cqspi_write_setup(struct spi_nor *nor) reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK; reg |= (nor->addr_width - 1); writel(reg, reg_base + CQSPI_REG_SIZE); + readl(reg_base + CQSPI_REG_SIZE); /* Flush posted write. */ return 0; }