[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>

6 files changed, 88 insertions, 47 deletions

diff --git a/arch/arm/include/asm/mach/dma.h b/arch/arm/include/asm/mach/dma.h
index 281ae7e40a90..38a3693f1258 100644
--- a/arch/arm/include/asm/mach/dma.h
+++ b/arch/arm/include/asm/mach/dma.h
@@ -48,10 +48,12 @@ struct dma_struct {
         struct dma_ops  *d_ops;
 };
 
-/* Prototype: void arch_dma_init(dma)
- * Purpose  : Initialise architecture specific DMA
- * Params   : dma - pointer to array of DMA structures
+/*
+ * isa_dma_add - add an ISA-style DMA channel
  */
-extern void arch_dma_init(dma_t *dma);
+extern int isa_dma_add(unsigned int, dma_t *dma);
 
-extern void isa_init_dma(dma_t *dma);
+/*
+ * Add the ISA DMA controller.  Always takes channels 0-7.
+ */
+extern void isa_init_dma(void);
diff --git a/arch/arm/kernel/dma-isa.c b/arch/arm/kernel/dma-isa.c
index 29eca48925d8..da02a7ff3419 100644
--- a/arch/arm/kernel/dma-isa.c
+++ b/arch/arm/kernel/dma-isa.c
@@ -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);
+                }
         }
 }
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);
diff --git a/arch/arm/mach-footbridge/dma.c b/arch/arm/mach-footbridge/dma.c
index e7b8a6adaf7a..fdd94b182d78 100644
--- a/arch/arm/mach-footbridge/dma.c
+++ b/arch/arm/mach-footbridge/dma.c
@@ -41,7 +41,7 @@ static struct dma_ops fb_dma_ops = {
 };
 #endif
 
-void __init arch_dma_init(dma_t *dma)
+static int __init fb_dma_init(void)
 {
 #if 0
         dma[_DC21285_DMA(0)].d_ops = &fb_dma_ops;
@@ -49,6 +49,8 @@ void __init arch_dma_init(dma_t *dma)
 #endif
 #ifdef CONFIG_ISA_DMA
         if (footbridge_cfn_mode())
-                isa_init_dma(dma + _ISA_DMA(0));
+                isa_init_dma();
 #endif
+        return 0;
 }
+core_initcall(fb_dma_init);
diff --git a/arch/arm/mach-rpc/dma.c b/arch/arm/mach-rpc/dma.c
index a86d3ed859a7..efcf6718d1d0 100644
--- a/arch/arm/mach-rpc/dma.c
+++ b/arch/arm/mach-rpc/dma.c
@@ -302,8 +302,22 @@ static struct dma_ops sound_dma_ops = {
         .disable        = sound_enable_disable_dma,
 };
 
-void __init arch_dma_init(dma_t *dma)
+static dma_t iomd_dma[6];
+
+static dma_t floppy_dma = {
+        .dma_irq        = FIQ_FLOPPYDATA,
+        .d_ops          = &floppy_dma_ops,
+};
+
+static dma_t sound_dma = {
+        .d_ops          = &sound_dma_ops,
+};
+
+static int __init rpc_dma_init(void)
 {
+        unsigned int i;
+        int ret;
+
         iomd_writeb(0, IOMD_IO0CR);
         iomd_writeb(0, IOMD_IO1CR);
         iomd_writeb(0, IOMD_IO2CR);
@@ -311,31 +325,39 @@ void __init arch_dma_init(dma_t *dma)
 
         iomd_writeb(0xa0, IOMD_DMATCR);
 
-        dma[DMA_0].dma_base             = IOMD_IO0CURA;
-        dma[DMA_0].dma_irq              = IRQ_DMA0;
-        dma[DMA_0].d_ops                = &iomd_dma_ops;
-        dma[DMA_1].dma_base             = IOMD_IO1CURA;
-        dma[DMA_1].dma_irq              = IRQ_DMA1;
-        dma[DMA_1].d_ops                = &iomd_dma_ops;
-        dma[DMA_2].dma_base             = IOMD_IO2CURA;
-        dma[DMA_2].dma_irq              = IRQ_DMA2;
-        dma[DMA_2].d_ops                = &iomd_dma_ops;
-        dma[DMA_3].dma_base             = IOMD_IO3CURA;
-        dma[DMA_3].dma_irq              = IRQ_DMA3;
-        dma[DMA_3].d_ops                = &iomd_dma_ops;
-        dma[DMA_S0].dma_base            = IOMD_SD0CURA;
-        dma[DMA_S0].dma_irq             = IRQ_DMAS0;
-        dma[DMA_S0].d_ops               = &iomd_dma_ops;
-        dma[DMA_S1].dma_base            = IOMD_SD1CURA;
-        dma[DMA_S1].dma_irq             = IRQ_DMAS1;
-        dma[DMA_S1].d_ops               = &iomd_dma_ops;
-        dma[DMA_VIRTUAL_FLOPPY].dma_irq = FIQ_FLOPPYDATA;
-        dma[DMA_VIRTUAL_FLOPPY].d_ops   = &floppy_dma_ops;
-        dma[DMA_VIRTUAL_SOUND].d_ops    = &sound_dma_ops;
-
         /*
          * Setup DMA channels 2,3 to be for podules
          * and channels 0,1 for internal devices
          */
         iomd_writeb(DMA_EXT_IO3|DMA_EXT_IO2, IOMD_DMAEXT);
+
+        iomd_dma[DMA_0].dma_base        = IOMD_IO0CURA;
+        iomd_dma[DMA_0].dma_irq         = IRQ_DMA0;
+        iomd_dma[DMA_1].dma_base        = IOMD_IO1CURA;
+        iomd_dma[DMA_1].dma_irq         = IRQ_DMA1;
+        iomd_dma[DMA_2].dma_base        = IOMD_IO2CURA;
+        iomd_dma[DMA_2].dma_irq         = IRQ_DMA2;
+        iomd_dma[DMA_3].dma_base        = IOMD_IO3CURA;
+        iomd_dma[DMA_3].dma_irq         = IRQ_DMA3;
+        iomd_dma[DMA_S0].dma_base       = IOMD_SD0CURA;
+        iomd_dma[DMA_S0].dma_irq        = IRQ_DMAS0;
+        iomd_dma[DMA_S1].dma_base       = IOMD_SD1CURA;
+        iomd_dma[DMA_S1].dma_irq        = IRQ_DMAS1;
+
+        for (i = DMA_0; i <= DMA_S1; i++) {
+                iomd_dma[i].d_ops = &iomd_dma_ops;
+
+                ret = isa_dma_add(i, &iomd_dma[i]);
+                if (ret)
+                        printk("IOMDDMA%u: unable to register: %d\n", i, ret);
+        }
+
+        ret = isa_dma_add(DMA_VIRTUAL_FLOPPY, &floppy_dma);
+        if (ret)
+                printk("IOMDFLOPPY: unable to register: %d\n", ret);
+        ret = isa_dma_add(DMA_VIRTUAL_SOUND, &sound_dma);
+        if (ret)
+                printk("IOMDSOUND: unable to register: %d\n", ret);
+        return 0;
 }
+core_initcall(rpc_dma_init);
diff --git a/arch/arm/mach-shark/dma.c b/arch/arm/mach-shark/dma.c
index 6774b8d5d13d..10b5b8b3272a 100644
--- a/arch/arm/mach-shark/dma.c
+++ b/arch/arm/mach-shark/dma.c
@@ -13,9 +13,11 @@
 #include <asm/dma.h>
 #include <asm/mach/dma.h>
 
-void __init arch_dma_init(dma_t *dma)
+static int __init shark_dma_init(void)
 {
 #ifdef CONFIG_ISA_DMA
-        isa_init_dma(dma);
+        isa_init_dma();
 #endif
+        return 0;
 }
+core_initcall(shark_dma_init);