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Subject[PATCH 2/2] dmaengine i.MX SDMA: protect channel0
Date
Channel 0 of the SDMA engine is a shared resource used by the
other channels, thus we have to protect it with a mutex.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
drivers/dma/imx-sdma.c | 11 +++++++++++
1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 01c4a5f..b1f5947 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -355,6 +355,7 @@ struct sdma_engine {
struct dma_device dma_device;
struct clk *clk;
struct sdma_script_start_addrs *script_addrs;
+ struct mutex channel0_mutex;
};

#define SDMA_H_CONFIG_DSPDMA (1 << 12) /* indicates if the DSPDMA is used */
@@ -437,6 +438,8 @@ static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size,
if (!buf_virt)
return -ENOMEM;

+ mutex_lock(&sdma->channel0_mutex);
+
bd0->mode.command = C0_SETPM;
bd0->mode.status = BD_DONE | BD_INTR | BD_WRAP | BD_EXTD;
bd0->mode.count = size / 2;
@@ -447,6 +450,8 @@ static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size,

ret = sdma_run_channel(&sdma->channel[0]);

+ mutex_unlock(&sdma->channel0_mutex);
+
dma_free_coherent(NULL, size, buf_virt, buf_phys);

return ret;
@@ -684,6 +689,8 @@ static int sdma_load_context(struct sdma_channel *sdmac)
context->gReg[6] = sdmac->shp_addr;
context->gReg[7] = sdmac->watermark_level;

+ mutex_lock(&sdma->channel0_mutex);
+
bd0->mode.command = C0_SETDM;
bd0->mode.status = BD_DONE | BD_INTR | BD_WRAP | BD_EXTD;
bd0->mode.count = sizeof(*context) / 4;
@@ -692,6 +699,8 @@ static int sdma_load_context(struct sdma_channel *sdmac)

ret = sdma_run_channel(&sdma->channel[0]);

+ mutex_unlock(&sdma->channel0_mutex);
+
return ret;
}

@@ -1297,6 +1306,8 @@ static int __init sdma_probe(struct platform_device *pdev)

sdma->version = pdata->sdma_version;

+ mutex_init(&sdma->channel0_mutex);
+
INIT_LIST_HEAD(&sdma->dma_device.channels);
/* Initialize channel parameters */
for (i = 0; i < MAX_DMA_CHANNELS; i++) {
--
1.7.2.3


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