Linux-SPI Archive on lore.kernel.org
 help / color / Atom feed
From: Serge Semin <Sergey.Semin@baikalelectronics.ru>
To: Mark Brown <broonie@kernel.org>
Cc: Serge Semin <Sergey.Semin@baikalelectronics.ru>,
	Serge Semin <fancer.lancer@gmail.com>,
	Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
	Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>,
	Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>,
	Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>,
	Peter Ujfalusi <peter.ujfalusi@ti.com>,
	Andy Shevchenko <andy.shevchenko@gmail.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Feng Tang <feng.tang@intel.com>, Vinod Koul <vkoul@kernel.org>,
	<linux-spi@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH 2/8] spi: dw-dma: Fail DMA-based transfer if no Tx-buffer specified
Date: Fri, 31 Jul 2020 10:59:47 +0300
Message-ID: <20200731075953.14416-3-Sergey.Semin@baikalelectronics.ru> (raw)
In-Reply-To: <20200731075953.14416-1-Sergey.Semin@baikalelectronics.ru>

Since commit 46164fde6b78 ("spi: dw: Fix Rx-only DMA transfers") if DMA
interface is enabled, then Tx-buffer must be available in each SPI
transfer. It's required since in order to activate the incoming data
reception either DMA or CPU must be pushing data out to the SPI bus.
But the DW APB SSI DMA driver code is still left in state as if Tx-buffer
might be optional, which is no longer true. Let's fix it so an error would
be returned if no Tx-buffer detected and DMA Tx would be always
enabled.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
---
 drivers/spi/spi-dw-dma.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/spi/spi-dw-dma.c b/drivers/spi/spi-dw-dma.c
index 440679fa0764..ec721af61663 100644
--- a/drivers/spi/spi-dw-dma.c
+++ b/drivers/spi/spi-dw-dma.c
@@ -263,9 +263,6 @@ dw_spi_dma_prepare_tx(struct dw_spi *dws, struct spi_transfer *xfer)
 	struct dma_slave_config txconf;
 	struct dma_async_tx_descriptor *txdesc;
 
-	if (!xfer->tx_buf)
-		return NULL;
-
 	memset(&txconf, 0, sizeof(txconf));
 	txconf.direction = DMA_MEM_TO_DEV;
 	txconf.dst_addr = dws->dma_addr;
@@ -384,17 +381,19 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,
 
 static int dw_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer)
 {
-	u16 imr = 0, dma_ctrl = 0;
+	u16 imr, dma_ctrl;
 
-	if (xfer->tx_buf)
-		dma_ctrl |= SPI_DMA_TDMAE;
+	if (!xfer->tx_buf)
+		return -EINVAL;
+
+	/* Set the DMA handshaking interface */
+	dma_ctrl = SPI_DMA_TDMAE;
 	if (xfer->rx_buf)
 		dma_ctrl |= SPI_DMA_RDMAE;
 	dw_writel(dws, DW_SPI_DMACR, dma_ctrl);
 
 	/* Set the interrupt mask */
-	if (xfer->tx_buf)
-		imr |= SPI_INT_TXOI;
+	imr = SPI_INT_TXOI;
 	if (xfer->rx_buf)
 		imr |= SPI_INT_RXUI | SPI_INT_RXOI;
 	spi_umask_intr(dws, imr);
@@ -413,6 +412,8 @@ static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer)
 
 	/* Prepare the TX dma transfer */
 	txdesc = dw_spi_dma_prepare_tx(dws, xfer);
+	if (!txdesc)
+		return -EINVAL;
 
 	/* Prepare the RX dma transfer */
 	rxdesc = dw_spi_dma_prepare_rx(dws, xfer);
@@ -424,17 +425,15 @@ static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer)
 		dma_async_issue_pending(dws->rxchan);
 	}
 
-	if (txdesc) {
-		set_bit(TX_BUSY, &dws->dma_chan_busy);
-		dmaengine_submit(txdesc);
-		dma_async_issue_pending(dws->txchan);
-	}
+	set_bit(TX_BUSY, &dws->dma_chan_busy);
+	dmaengine_submit(txdesc);
+	dma_async_issue_pending(dws->txchan);
 
 	ret = dw_spi_dma_wait(dws, xfer);
 	if (ret)
 		return ret;
 
-	if (txdesc && dws->master->cur_msg->status == -EINPROGRESS) {
+	if (dws->master->cur_msg->status == -EINPROGRESS) {
 		ret = dw_spi_dma_wait_tx_done(dws, xfer);
 		if (ret)
 			return ret;
-- 
2.27.0


  parent reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31  7:59 [PATCH 0/8] spi: dw-dma: Add max SG entries burst capability support Serge Semin
2020-07-31  7:59 ` [PATCH 1/8] spi: dw-dma: Set DMA Level registers on init Serge Semin
2020-07-31  7:59 ` Serge Semin [this message]
2020-07-31  7:59 ` [PATCH 3/8] spi: dw-dma: Configure the DMA channels in dma_setup Serge Semin
2020-07-31  9:16   ` Andy Shevchenko
2020-07-31 12:32     ` Serge Semin
2020-07-31  7:59 ` [PATCH 4/8] spi: dw-dma: Move DMA transfers submission to the channels prep methods Serge Semin
2020-07-31  9:15   ` Andy Shevchenko
2020-07-31 12:46     ` Serge Semin
2020-07-31  7:59 ` [PATCH 5/8] spi: dw-dma: Detach DMA transfer into a dedicated method Serge Semin
2020-07-31  7:59 ` [PATCH 6/8] spi: dw-dma: Move DMAC register cleanup to DMA transfer method Serge Semin
2020-07-31  7:59 ` [PATCH 7/8] spi: dw-dma: Pass exact data to the DMA submit and wait methods Serge Semin
2020-07-31  7:59 ` [PATCH 8/8] spi: dw-dma: Add one-by-one SG list entries transfer Serge Semin
2020-07-31  9:26 ` [PATCH 0/8] spi: dw-dma: Add max SG entries burst capability support Andy Shevchenko
2020-07-31 12:59   ` Serge Semin
2020-08-04 21:14     ` Mark Brown
2020-08-05 11:31       ` Vinod Koul

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200731075953.14416-3-Sergey.Semin@baikalelectronics.ru \
    --to=sergey.semin@baikalelectronics.ru \
    --cc=Alexey.Malahov@baikalelectronics.ru \
    --cc=Georgy.Vlasov@baikalelectronics.ru \
    --cc=Pavel.Parkhomenko@baikalelectronics.ru \
    --cc=Ramil.Zaripov@baikalelectronics.ru \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=andy.shevchenko@gmail.com \
    --cc=broonie@kernel.org \
    --cc=fancer.lancer@gmail.com \
    --cc=feng.tang@intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-spi@vger.kernel.org \
    --cc=peter.ujfalusi@ti.com \
    --cc=vkoul@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-SPI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-spi/0 linux-spi/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-spi linux-spi/ https://lore.kernel.org/linux-spi \
		linux-spi@vger.kernel.org
	public-inbox-index linux-spi

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-spi


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git