[ARM] dma: rejig DMA initialization

Rather than having the central DMA multiplexer call the architecture
specific DMA initialization function, have each architecture DMA
initialization function use core_initcall(), and register each DMA
channel separately with the multiplexer.

This removes the array of dma structures in the central multiplexer,
replacing it with an array of pointers instead; this is more flexible
since it allows the drivers to wrap the DMA structure (eventually
allowing us to transition non-ISA DMA drivers away.)

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 13 insertions, 12 deletions

diff --git a/arch/arm/kernel/dma.c b/arch/arm/kernel/dma.c
index 0ffea3fc22db..aab24f03ea14 100644
--- a/arch/arm/kernel/dma.c
+++ b/arch/arm/kernel/dma.c
@@ -23,16 +23,24 @@
 DEFINE_SPINLOCK(dma_spin_lock);
 EXPORT_SYMBOL(dma_spin_lock);
 
-static dma_t dma_chan[MAX_DMA_CHANNELS];
+static dma_t *dma_chan[MAX_DMA_CHANNELS];
 
 static inline dma_t *dma_channel(unsigned int chan)
 {
-        dma_t *dma = dma_chan + chan;
-
-        if (chan >= MAX_DMA_CHANNELS || !dma->d_ops)
+        if (chan >= MAX_DMA_CHANNELS)
                 return NULL;
 
-        return dma;
+        return dma_chan[chan];
+}
+
+int __init isa_dma_add(unsigned int chan, dma_t *dma)
+{
+        if (!dma->d_ops)
+                return -EINVAL;
+        if (dma_chan[chan])
+                return -EBUSY;
+        dma_chan[chan] = dma;
+        return 0;
 }
 
 /*
@@ -252,10 +260,3 @@ int get_dma_residue(unsigned int chan)
         return ret;
 }
 EXPORT_SYMBOL(get_dma_residue);
-
-static int __init init_dma(void)
-{
-        arch_dma_init(dma_chan);
-        return 0;
-}
-core_initcall(init_dma);