From: Xinwei Kong kong.kongxinwei@hisilicon.com
[ Upstream commit bfda044533b213985bc62bd7ca96f2b984d21b80 ]
Because of out-of-order execution about some CPU architecture, In this debug stage we find Completing spi interrupt enable -> prodrucing TXEI interrupt -> running "interrupt_transfer" function will prior to set "dw->rx and dws->rx_end" data, so this patch add memory barrier to enable dw->rx and dw->rx_end to be visible and solve to send SPI data error. eg: it will fix to this following low possibility error in testing environment which using SPI control to connect TPM Modules
kernel: tpm tpm0: Operation Timed out kernel: tpm tpm0: tpm_relinquish_locality: : error -1
Signed-off-by: fengsheng fengsheng5@huawei.com Signed-off-by: Xinwei Kong kong.kongxinwei@hisilicon.com Link: https://lore.kernel.org/r/1578019930-55858-1-git-send-email-kong.kongxinwei@... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-dw.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c index b461200871f8..cbdad3c4930f 100644 --- a/drivers/spi/spi-dw.c +++ b/drivers/spi/spi-dw.c @@ -305,6 +305,9 @@ static int dw_spi_transfer_one(struct spi_master *master, dws->len = transfer->len; spin_unlock_irqrestore(&dws->buf_lock, flags);
+ /* Ensure dw->rx and dw->rx_end are visible */ + smp_mb(); + spi_enable_chip(dws, 0);
/* Handle per transfer options for bpw and speed */