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[ARM] dma: rejig DMA initialization

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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>
This commit is contained in:
Russell King
2008-12-08 16:33:30 +00:00
committed by Russell King
parent 3afb6e9c63
commit 2f757f2ab7
6 changed files with 88 additions and 47 deletions
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18
arch/arm/kernel/dma-isa.c
View File

@@ -160,7 +160,12 @@ static struct resource dma_resources[] = { {
.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 @@ void __init isa_init_dma(dma_t *dma)
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 @@ void __init isa_init_dma(dma_t *dma)
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);
}
}
}

25
arch/arm/kernel/dma.c
View File

@@ -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);