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From: Sascha Hauer <s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
To: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Anton Bondarenko
	<anton.bondarenko.sama-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Sascha Hauer <s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Subject: [PATCH 04/12] spi: imx: drop fallback to PIO
Date: Fri, 19 Feb 2016 08:43:04 +0100	[thread overview]
Message-ID: <1455867792-26389-5-git-send-email-s.hauer@pengutronix.de> (raw)
In-Reply-To: <1455867792-26389-1-git-send-email-s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

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-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/spi/spi-imx.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index b277375..5a48d07 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 no_dma;
+			return -EINVAL;
 
 		desc_tx->callback = spi_imx_dma_tx_callback;
 		desc_tx->callback_param = (void *)spi_imx;
@@ -957,7 +957,7 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
 					rx->sgl, rx->nents, DMA_DEV_TO_MEM,
 					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 		if (!desc_rx)
-			goto no_dma;
+			return -EINVAL;
 
 		desc_rx->callback = spi_imx_dma_rx_callback;
 		desc_rx->callback_param = (void *)spi_imx;
@@ -1010,10 +1010,6 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
 		ret = transfer->len;
 
 	return ret;
-
-no_dma:
-	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,
@@ -1040,15 +1036,12 @@ 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

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WARNING: multiple messages have this Message-ID (diff)
From: s.hauer@pengutronix.de (Sascha Hauer)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 04/12] spi: imx: drop fallback to PIO
Date: Fri, 19 Feb 2016 08:43:04 +0100	[thread overview]
Message-ID: <1455867792-26389-5-git-send-email-s.hauer@pengutronix.de> (raw)
In-Reply-To: <1455867792-26389-1-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 | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index b277375..5a48d07 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 no_dma;
+			return -EINVAL;
 
 		desc_tx->callback = spi_imx_dma_tx_callback;
 		desc_tx->callback_param = (void *)spi_imx;
@@ -957,7 +957,7 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
 					rx->sgl, rx->nents, DMA_DEV_TO_MEM,
 					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 		if (!desc_rx)
-			goto no_dma;
+			return -EINVAL;
 
 		desc_rx->callback = spi_imx_dma_rx_callback;
 		desc_rx->callback_param = (void *)spi_imx;
@@ -1010,10 +1010,6 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
 		ret = transfer->len;
 
 	return ret;
-
-no_dma:
-	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,
@@ -1040,15 +1036,12 @@ 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

  parent reply	other threads:[~2016-02-19  7:43 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-19  7:43 [PATCH v2] i.MX SPI DMA cleanup Sascha Hauer
2016-02-19  7:43 ` Sascha Hauer
     [not found] ` <1455867792-26389-1-git-send-email-s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2016-02-19  7:43   ` [PATCH 01/12] spi: imx: allow only WML aligned transfers to use DMA Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer
2016-02-19  7:43   ` [PATCH 02/12] spi: imx: use proper dev_* functions for driver messages Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer
2016-02-19  7:43   ` [PATCH 03/12] spi: imx: replace fixed timeout with calculated Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer
2016-02-19  7:43   ` Sascha Hauer [this message]
2016-02-19  7:43     ` [PATCH 04/12] spi: imx: drop fallback to PIO Sascha Hauer
     [not found]     ` <1455867792-26389-5-git-send-email-s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2016-02-19 15:51       ` Mark Brown
2016-02-19 15:51         ` Mark Brown
2016-02-19  7:43   ` [PATCH 05/12] spi: imx: initialize usedma earlier Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer
     [not found]     ` <1455867792-26389-6-git-send-email-s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2016-02-19  8:08       ` Lothar Waßmann
2016-02-19  8:08         ` Lothar Waßmann
2016-02-19  7:43   ` [PATCH 06/12] spi: imx: drop unnecessary read/modify/write Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer
2016-02-19  7:43   ` [PATCH 07/12] spi: imx: drop unncessary dma_is_inited variable Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer
2016-02-19  7:43   ` [PATCH 08/12] spi: imx: add support for all SPI word width for DMA Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer
2016-02-19  7:43   ` [PATCH 09/12] spi: imx: remove unnecessary bit clearing in mx51_ecspi_config Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer
2016-02-19  7:43   ` [PATCH 10/12] spi: imx: make some register defines simpler Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer
2016-02-19  7:43   ` [PATCH 11/12] spi: imx: set MX51_ECSPI_CTRL_SMC bit in setup function Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer
2016-02-19  7:43   ` [PATCH 12/12] spi: imx: drop bogus tests for rx/tx bufs in DMA transfer Sascha Hauer
2016-02-19  7:43     ` Sascha Hauer

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