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authorGeert Uytterhoeven <geert+renesas@glider.be>2018-01-03 18:11:14 +0100
committerMark Brown <broonie@kernel.org>2018-01-03 17:42:42 +0000
commit89434c3c35081439627baa2225622d5bd12242fe (patch)
treefa4398a3ce4f728260105e3995f7f4ac377c9338 /drivers/spi
parent4fbd8d194f06c8a3fd2af1ce560ddb31f7ec8323 (diff)
spi: sh-msiof: Fix timeout failures for TX-only DMA transfers
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@glider.be> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi-sh-msiof.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c
index fcd261f98b9f..06bc4b170c47 100644
--- a/drivers/spi/spi-sh-msiof.c
+++ b/drivers/spi/spi-sh-msiof.c
@@ -784,11 +784,21 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx,
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);

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