[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>
diff --git a/arch/arm/kernel/dma-isa.c b/arch/arm/kernel/dma-isa.c
index 29eca48..da02a7f 100644
--- a/arch/arm/kernel/dma-isa.c
+++ b/arch/arm/kernel/dma-isa.c
@@ -160,7 +160,12 @@
.end = 0x048f
} };
-void __init isa_init_dma(dma_t *dma)
+static dma_t isa_dma[8];
+
+/*
+ * ISA DMA always starts at channel 0
+ */
+void __init isa_init_dma(void)
{
/*
* Try to autodetect presence of an ISA DMA controller.
@@ -178,10 +183,10 @@
outb(0xaa, 0x00);
if (inb(0) == 0x55 && inb(0) == 0xaa) {
- int chan, i;
+ unsigned int chan, i;
for (chan = 0; chan < 8; chan++) {
- dma[chan].d_ops = &isa_dma_ops;
+ isa_dma[chan].d_ops = &isa_dma_ops;
isa_disable_dma(chan, NULL);
}
@@ -217,5 +222,12 @@
for (i = 0; i < ARRAY_SIZE(dma_resources); i++)
request_resource(&ioport_resource, dma_resources + i);
+
+ for (chan = 0; chan < 8; chan++) {
+ int ret = isa_dma_add(chan, &isa_dma[chan]);
+ if (ret)
+ printk(KERN_ERR "ISADMA%u: unable to register: %d\n",
+ chan, ret);
+ }
}
}
diff --git a/arch/arm/kernel/dma.c b/arch/arm/kernel/dma.c
index 0ffea3f..aab24f0 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 @@
return ret;
}
EXPORT_SYMBOL(get_dma_residue);
-
-static int __init init_dma(void)
-{
- arch_dma_init(dma_chan);
- return 0;
-}
-core_initcall(init_dma);