[PATCH] dmaengine: omap-dma: Fix dynamic lch_map alocation

Peter Ujfalusi
2017-01-02T10:07:38Z

The original patch did not done what it was supposed to be doing and even
worst it broke legacy boot (OMAP1).

The lch_map size should be the number of available logical channels in sDMA
and the od->dma_requests should store the number of available DMA request
lines usable in sDMA.

In legacy mode we do not have a way to get the DMA request count, in that
case we use OMAP_SDMA_REQUESTS (127), despite the fact that OMAP1510 have
only 31 DMA request line.

Fixes: 2d1a9a946fae ("dmaengine: omap-dma: Dynamically allocate memory for lch_map")
Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: stable@vger.kernel.org # v4.9
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
drivers/dma/omap-dma.c | 30 +++++++++++++++++++++---------
1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
index ac68666cd3f4..4ad101a47e0a 100644
--- a/drivers/dma/omap-dma.c
+++ b/drivers/dma/omap-dma.c
@@ -1452,6 +1452,7 @@ static int omap_dma_probe(struct platform_device *pdev)
struct omap_dmadev *od;
struct resource *res;
int rc, i, irq;
+ u32 lch_count;

od = devm_kzalloc(&pdev->dev, sizeof(*od), GFP_KERNEL);
if (!od)
@@ -1494,20 +1495,31 @@ static int omap_dma_probe(struct platform_device *pdev)
spin_lock_init(&od->lock);
spin_lock_init(&od->irq_lock);

- if (!pdev->dev.of_node) {
- od->dma_requests = od->plat->dma_attr->lch_count;
- if (unlikely(!od->dma_requests))
- od->dma_requests = OMAP_SDMA_REQUESTS;
- } else if (of_property_read_u32(pdev->dev.of_node, "dma-requests",
- &od->dma_requests)) {
+ /* Number of DMA requests */
+ od->dma_requests = OMAP_SDMA_REQUESTS;
+ if (pdev->dev.of_node && of_property_read_u32(pdev->dev.of_node,
+ "dma-requests",
+ &od->dma_requests)) {
dev_info(&pdev->dev,
"Missing dma-requests property, using %u.\n",
OMAP_SDMA_REQUESTS);
- od->dma_requests = OMAP_SDMA_REQUESTS;
}

- od->lch_map = devm_kcalloc(&pdev->dev, od->dma_requests,
- sizeof(*od->lch_map), GFP_KERNEL);
+ /* Number of available logical channels */
+ if (!pdev->dev.of_node) {
+ lch_count = od->plat->dma_attr->lch_count;
+ if (unlikely(!lch_count))
+ lch_count = OMAP_SDMA_CHANNELS;
+ } else if (of_property_read_u32(pdev->dev.of_node, "dma-channels",
+ &lch_count)) {
+ dev_info(&pdev->dev,
+ "Missing dma-channels property, using %u.\n",
+ OMAP_SDMA_CHANNELS);
+ lch_count = OMAP_SDMA_CHANNELS;
+ }
+
+ od->lch_map = devm_kcalloc(&pdev->dev, lch_count, sizeof(*od->lch_map),
+ GFP_KERNEL);
if (!od->lch_map)
return -ENOMEM;

--
2.11.0