This is a note to let you know that I've just added the patch titled
spi: sh-msiof: Fix timeout failures for TX-only DMA transfers
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
spi-sh-msiof-fix-timeout-failures-for-tx-only-dma-transfers.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Apr 9 10:16:32 CEST 2018
From: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Date: Wed, 3 Jan 2018 18:11:14 +0100
Subject: spi: sh-msiof: Fix timeout failures for TX-only DMA transfers
From: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
[ Upstream commit 89434c3c35081439627baa2225622d5bd12242fe ]
When using RX (with or without TX), the DMA interrupt triggers
completion when the RX FIFO has been emptied, i.e. after the full
transfer has finished.
However, when using TX without RX, the DMA interrupt triggers completion
as soon as the DMA engine has filled the TX FIFO, i.e. before the full
transfer has finished. Then sh_msiof_modify_ctr_wait() will spin until
the transfer has really finished and the TFSE bit is cleared, for at
most 1 ms. For slow speeds and/or large transfers, this may cause
timeouts and transfer failures:
spi_sh_msiof e6e10000.spi: failed to shut down hardware
74x164 spi2.0: SPI transfer failed: -110
spi_master spi2: failed to transfer one message from queue
74x164 spi2.0: Failed writing: -110
Fix this by waiting explicitly until the TX FIFO has been emptied.
Based on a patch in the BSP by Hiromitsu Yamasaki.
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/spi/spi-sh-msiof.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
--- a/drivers/spi/spi-sh-msiof.c
+++ b/drivers/spi/spi-sh-msiof.c
@@ -797,11 +797,21 @@ static int sh_msiof_dma_once(struct sh_m
goto stop_dma;
}
- /* wait for tx fifo to be emptied / rx fifo to be filled */
+ /* wait for tx/rx DMA completion */
ret = sh_msiof_wait_for_completion(p);
if (ret)
goto stop_reset;
+ if (!rx) {
+ reinit_completion(&p->done);
+ sh_msiof_write(p, IER, IER_TEOFE);
+
+ /* wait for tx fifo to be emptied */
+ ret = sh_msiof_wait_for_completion(p);
+ if (ret)
+ goto stop_reset;
+ }
+
/* clear status bits */
sh_msiof_reset_str(p);
Patches currently in stable-queue which might be from geert+renesas@xxxxxxxxx are
queue-4.15/acpi-ec-fix-debugfs_create_-usage.patch
queue-4.15/spi-sh-msiof-fix-timeout-failures-for-tx-only-dma-transfers.patch