linux-kernel - [PATCH v2 06/11] spi: dw-dma: Check DMA Tx-desc submission status

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Date:   Sun, 20 Sep 2020 14:23:17 +0300
From:   Serge Semin <Sergey.Semin@...kalelectronics.ru>
To:     Mark Brown <broonie@...nel.org>
CC:     Serge Semin <Sergey.Semin@...kalelectronics.ru>,
        Serge Semin <fancer.lancer@...il.com>,
        Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
        Georgy Vlasov <Georgy.Vlasov@...kalelectronics.ru>,
        Ramil Zaripov <Ramil.Zaripov@...kalelectronics.ru>,
        Pavel Parkhomenko <Pavel.Parkhomenko@...kalelectronics.ru>,
        Peter Ujfalusi <peter.ujfalusi@...com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Feng Tang <feng.tang@...el.com>, Vinod Koul <vkoul@...nel.org>,
        <linux-spi@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 06/11] spi: dw-dma: Check DMA Tx-desc submission status

We suggest to add the dmaengine_submit() return value test for errors.  It
has been unnecessary while the driver was expected to be utilized in pair
with DW DMAC. But since now the driver can be used with any DMA engine, it
might be useful to track the errors on DMA submissions so not miss them
and get into an unpredictable driver behaviour.

Signed-off-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>

---

Changelog v2:
- Replace negative conditional statements with the positive ones.
- Terminate the prepared descriptors on submission errors.
---
 drivers/spi/spi-dw-dma.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-dw-dma.c b/drivers/spi/spi-dw-dma.c
index 769d10ca74b4..aa3900809126 100644
--- a/drivers/spi/spi-dw-dma.c
+++ b/drivers/spi/spi-dw-dma.c
@@ -275,6 +275,8 @@ static struct dma_async_tx_descriptor *
 dw_spi_dma_submit_tx(struct dw_spi *dws, struct spi_transfer *xfer)
 {
 	struct dma_async_tx_descriptor *txdesc;
+	dma_cookie_t cookie;
+	int ret;
 
 	txdesc = dmaengine_prep_slave_sg(dws->txchan,
 				xfer->tx_sg.sgl,
@@ -287,7 +289,13 @@ dw_spi_dma_submit_tx(struct dw_spi *dws, struct spi_transfer *xfer)
 	txdesc->callback = dw_spi_dma_tx_done;
 	txdesc->callback_param = dws;
 
-	dmaengine_submit(txdesc);
+	cookie = dmaengine_submit(txdesc);
+	ret = dma_submit_error(cookie);
+	if (ret) {
+		dmaengine_terminate_sync(dws->txchan);
+		return NULL;
+	}
+
 	set_bit(TX_BUSY, &dws->dma_chan_busy);
 
 	return txdesc;
@@ -371,6 +379,8 @@ static struct dma_async_tx_descriptor *dw_spi_dma_submit_rx(struct dw_spi *dws,
 		struct spi_transfer *xfer)
 {
 	struct dma_async_tx_descriptor *rxdesc;
+	dma_cookie_t cookie;
+	int ret;
 
 	rxdesc = dmaengine_prep_slave_sg(dws->rxchan,
 				xfer->rx_sg.sgl,
@@ -383,7 +393,13 @@ static struct dma_async_tx_descriptor *dw_spi_dma_submit_rx(struct dw_spi *dws,
 	rxdesc->callback = dw_spi_dma_rx_done;
 	rxdesc->callback_param = dws;
 
-	dmaengine_submit(rxdesc);
+	cookie = dmaengine_submit(rxdesc);
+	ret = dma_submit_error(cookie);
+	if (ret) {
+		dmaengine_terminate_sync(dws->rxchan);
+		return NULL;
+	}
+
 	set_bit(RX_BUSY, &dws->dma_chan_busy);
 
 	return rxdesc;
-- 
2.27.0