Unverified Commit bfda0445 authored Jan 03, 2020 by Xinwei Kong Committed by Mark Brown Jan 06, 2020

spi: dw: use "smp_mb()" to avoid sending spi data error



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>

parent 09b6636c

drivers/spi/spi-dw.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -297,6 +297,9 @@ static int dw_spi_transfer_one(struct spi_controller *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 */

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