From: s.hauer@pengutronix.de (Sascha Hauer)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/9] spi: imx: drop fallback to PIO
Date: Tue, 23 Feb 2016 10:23:50 +0100 [thread overview]
Message-ID: <1456219438-21205-2-git-send-email-s.hauer@pengutronix.de> (raw)
In-Reply-To: <1456219438-21205-1-git-send-email-s.hauer@pengutronix.de>
At the moment the driver decides to fallback to PIO mode the buffers
are already mapped for DMA. It's a bug to access them with the CPU
afterwards, so we cannot just fallback to PIO mode.
It should not be necessary anyway, since we only use DMA when we
verified that it's possible in the fist place, so when prep_slave_sg
fails it's a bug, either in the SDMA driver or in the can_dma
implementation.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
drivers/spi/spi-imx.c | 19 ++++++-------------
1 file changed, 6 insertions(+), 13 deletions(-)
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 6497fc9..a61b1b1 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -945,7 +945,7 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
tx->sgl, tx->nents, DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc_tx)
- goto tx_nodma;
+ return -EINVAL;
desc_tx->callback = spi_imx_dma_tx_callback;
desc_tx->callback_param = (void *)spi_imx;
@@ -956,8 +956,10 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
desc_rx = dmaengine_prep_slave_sg(master->dma_rx,
rx->sgl, rx->nents, DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
- if (!desc_rx)
- goto rx_nodma;
+ if (!desc_rx) {
+ dmaengine_terminate_all(master->dma_tx);
+ return -EINVAL;
+ }
desc_rx->callback = spi_imx_dma_rx_callback;
desc_rx->callback_param = (void *)spi_imx;
@@ -1010,12 +1012,6 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
ret = transfer->len;
return ret;
-
-rx_nodma:
- dmaengine_terminate_all(master->dma_tx);
-tx_nodma:
- dev_warn_once(spi_imx->dev, "DMA not available, falling back to PIO\n");
- return -EAGAIN;
}
static int spi_imx_pio_transfer(struct spi_device *spi,
@@ -1042,15 +1038,12 @@ static int spi_imx_pio_transfer(struct spi_device *spi,
static int spi_imx_transfer(struct spi_device *spi,
struct spi_transfer *transfer)
{
- int ret;
struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
if (spi_imx->bitbang.master->can_dma &&
spi_imx_can_dma(spi_imx->bitbang.master, spi, transfer)) {
spi_imx->usedma = true;
- ret = spi_imx_dma_transfer(spi_imx, transfer);
- if (ret != -EAGAIN)
- return ret;
+ return spi_imx_dma_transfer(spi_imx, transfer);
}
spi_imx->usedma = false;
--
2.7.0
next prev parent reply other threads:[~2016-02-23 9:23 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-23 9:23 [PATCH v3] i.MX SPI DMA cleanup Sascha Hauer
2016-02-23 9:23 ` Sascha Hauer [this message]
2016-02-23 9:23 ` [PATCH 2/9] spi: imx: initialize usedma earlier Sascha Hauer
2016-02-23 10:15 ` Lothar Waßmann
2016-02-23 10:24 ` [PATCH] " Sascha Hauer
2016-02-24 3:19 ` Mark Brown
2016-02-23 9:23 ` [PATCH 3/9] spi: imx: drop unnecessary read/modify/write Sascha Hauer
2016-02-23 9:23 ` [PATCH 4/9] spi: imx: drop unncessary dma_is_inited variable Sascha Hauer
2016-02-23 9:23 ` [PATCH 5/9] spi: imx: add support for all SPI word width for DMA Sascha Hauer
2016-02-23 9:23 ` [PATCH 6/9] spi: imx: remove unnecessary bit clearing in mx51_ecspi_config Sascha Hauer
2016-02-23 9:23 ` [PATCH 7/9] spi: imx: make some register defines simpler Sascha Hauer
2016-02-23 9:23 ` [PATCH 8/9] spi: imx: set MX51_ECSPI_CTRL_SMC bit in setup function Sascha Hauer
2016-02-23 9:23 ` [PATCH 9/9] spi: imx: drop bogus tests for rx/tx bufs in DMA transfer Sascha Hauer
-- strict thread matches above, loose matches on Subject: below --
2016-02-24 8:20 [PATCH v4] i.MX SPI DMA cleanup Sascha Hauer
2016-02-24 8:20 ` [PATCH 1/9] spi: imx: drop fallback to PIO Sascha Hauer
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