4.14-stable review patch. If anyone has any objections, please let me know.
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From: Rafał Miłecki rafal@milecki.pl
commit 940ec770c295682993d1cccce3081fd7c74fece8 upstream.
Fixing/optimizing bcm_qspi_bspi_read() performance introduced two changes: 1) It added a loop to read all requested data using multiple BSPI ops. 2) It bumped max size of a single BSPI block request from 256 to 512 B.
The later change resulted in occasional BSPI timeouts causing a regression.
For some unknown reason hardware doesn't always handle reads as expected when using 512 B chunks. In such cases it may happen that BSPI returns amount of requested bytes without the last 1-3 ones. It provides the remaining bytes later but doesn't raise an interrupt until another LR start.
Switching back to 256 B reads fixes that problem and regression.
Fixes: 345309fa7c0c ("spi: bcm-qspi: Fix bcm_qspi_bspi_read() performance") Signed-off-by: Rafał Miłecki rafal@milecki.pl Signed-off-by: Mark Brown broonie@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/spi/spi-bcm-qspi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/spi/spi-bcm-qspi.c +++ b/drivers/spi/spi-bcm-qspi.c @@ -88,7 +88,7 @@ #define BSPI_BPP_MODE_SELECT_MASK BIT(8) #define BSPI_BPP_ADDR_SELECT_MASK BIT(16)
-#define BSPI_READ_LENGTH 512 +#define BSPI_READ_LENGTH 256
/* MSPI register offsets */ #define MSPI_SPCR0_LSB 0x000