[PATCH] davinci: check for presence of channel controller on slot alloc

From: Cyril Chemparathy
Date: Wed Sep 12 2012 - 14:14:06 EST

This patch adds a check for the presence of the channel controller when
trying to allocate a slot. Without this fix, the kernel panics with a NULL
pointer dereference when the dma-engine drivers are probed.

Signed-off-by: Cyril Chemparathy <cyril@xxxxxx>
arch/arm/mach-davinci/dma.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/arm/mach-davinci/dma.c b/arch/arm/mach-davinci/dma.c
index a685e97..2fee31e 100644
--- a/arch/arm/mach-davinci/dma.c
+++ b/arch/arm/mach-davinci/dma.c
@@ -743,6 +743,9 @@ EXPORT_SYMBOL(edma_free_channel);
int edma_alloc_slot(unsigned ctlr, int slot)
+ if (!edma_cc[ctlr])
+ return -ENODEV;
if (slot >= 0)
slot = EDMA_CHAN_SLOT(slot);


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