linux-kernel - [PATCH 4.0 053/220] spi: imx: read back the RX/TX watermark levels earlier

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Message-Id: <20150502185856.654987385@linuxfoundation.org>
Date:	Sat,  2 May 2015 20:59:28 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Lucas Stach <l.stach@...gutronix.de>,
	Mark Brown <broonie@...nel.org>
Subject: [PATCH 4.0 053/220] spi: imx: read back the RX/TX watermark levels earlier

4.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lucas Stach <l.stach@...gutronix.de>

commit f511ab09dfb0fe7b2335eccac51ff9f001a32e4a upstream.

They are used to decide if the controller can do DMA on a buffer
of a specific length and thus are needed before any transfer is attempted.

This fixes a memory leak where the SPI core uses the drivers can_dma()
callback to determine if a buffer needs to be mapped. As the watermark
levels aren't correct at that point the driver falsely claims to be able to
DMA the buffer when it fact it isn't.
After the transfer has been done the core uses the same callback to
determine if it needs to unmap the buffers. As the driver now correctly
claims to not being able to DMA the buffer the core doesn't attempt to
unmap the buffer which leaves the SGT leaking.

Fixes: f62caccd12c17e4 (spi: spi-imx: add DMA support)
Signed-off-by: Lucas Stach <l.stach@...gutronix.de>
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/spi/spi-imx.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -370,8 +370,6 @@ static int __maybe_unused mx51_ecspi_con
 	if (spi_imx->dma_is_inited) {
 		dma = readl(spi_imx->base + MX51_ECSPI_DMA);
 
-		spi_imx->tx_wml = spi_imx_get_fifosize(spi_imx) / 2;
-		spi_imx->rx_wml = spi_imx_get_fifosize(spi_imx) / 2;
 		spi_imx->rxt_wml = spi_imx_get_fifosize(spi_imx) / 2;
 		rx_wml_cfg = spi_imx->rx_wml << MX51_ECSPI_DMA_RX_WML_OFFSET;
 		tx_wml_cfg = spi_imx->tx_wml << MX51_ECSPI_DMA_TX_WML_OFFSET;
@@ -868,6 +866,8 @@ static int spi_imx_sdma_init(struct devi
 	master->max_dma_len = MAX_SDMA_BD_BYTES;
 	spi_imx->bitbang.master->flags = SPI_MASTER_MUST_RX |
 					 SPI_MASTER_MUST_TX;
+	spi_imx->tx_wml = spi_imx_get_fifosize(spi_imx) / 2;
+	spi_imx->rx_wml = spi_imx_get_fifosize(spi_imx) / 2;
 	spi_imx->dma_is_inited = 1;
 
 	return 0;


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