From 978c2812b8053d6bee6a20bcbdd59e76cfaafdbf Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 3 Jan 2018 18:11:14 +0100 Subject: [PATCH] spi: sh-msiof: Fix timeout failures for TX-only DMA transfers [ 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 Signed-off-by: Mark Brown Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi-sh-msiof.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c index 092a5fc85b9a4e..2770fbd4ce49ff 100644 --- 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_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);