sh: Fix Dreamcast DMA issues.

The current SH DMA API is somewhat broken, not correctly matching
virtual channel to the correct SH DMAC. This wasn't noticeable when
using g2 DMA for the sound driver - one channel 0 is as good as any
other! - but caused the pvr2 driver to fail.

This patch fixes the pvr2 problem and consequently fixes the sound
driver to ensure it continues to function.

Signed-off by: Adrian McMenamin <[e-mail]>
Signed-off-by: Paul Mundt <[e-mail]>

arch/sh/drivers/dma/dma-api.c

···
 	 * the channel is.
 	 */
 	list_for_each_entry(info, &registered_dmac_list, list) {
-		if ((chan <  info->first_channel_nr) ||
-		    (chan >= info->first_channel_nr + info->nr_channels))
+		if ((chan <  info->first_vchannel_nr) ||
+		    (chan >= info->first_vchannel_nr + info->nr_channels))
 			continue;
 
 		return info;
···
 
 	for (i = 0; i < info->nr_channels; i++) {
 		channel = &info->channels[i];
-		if (channel->chan == chan)
+		if (channel->vchan == chan)
 			return channel;
 	}
 
···
 	}
 
 	total_channels = get_nr_channels();
+	info->first_vchannel_nr = total_channels;
 	for (i = 0; i < info->nr_channels; i++) {
 		struct dma_channel *chan = &info->channels[i];
 

include/asm-sh/dma.h

···
 
 	struct list_head list;
 	int first_channel_nr;
+	int first_vchannel_nr;
 };
 
 struct dma_chan_caps {

sound/sh/aica.h

···
 #define AICA_CHANNEL1_OFFSET 0x21000
 #define CHANNEL_OFFSET 0x10000
 
-#define AICA_DMA_CHANNEL 0
+#define AICA_DMA_CHANNEL 5
 #define AICA_DMA_MODE 5
 
 #define SND_AICA_DRIVER "AICA"