spi: dw: use "smp_mb()" to avoid sending spi data error
[ 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@hisilicon.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
index 5a47e28..6f0f6b9 100644
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -304,6 +304,9 @@
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 */
