[alsa-devel] [PATCH] Patch Dreamcast AICA driver to handle Maple bus support

[Adrian McMenamin]

This patches the AICA sound driver for the Dreamcast to handle the
well known flakiness of the Dreamcast's G2 bus.

This is dependent on getting Maple bus support (see
http://lkml.org/lkml/2007/9/9/70) into the kernel.

Signed-off by: Adrian McMenamin <adrian at mcmen.demon.co.uk>

diff --git a/sound/sh/aica.c b/sound/sh/aica.c
index 7397865..a42c58f 100644
--- a/sound/sh/aica.c
+++ b/sound/sh/aica.c
@@ -35,6 +35,7 @@
 #include <linux/timer.h>
 #include <linux/delay.h>
 #include <linux/workqueue.h>
+#include <linux/maple.h>
 #include <sound/driver.h>
 #include <sound/core.h>
 #include <sound/control.h>
@@ -43,7 +44,7 @@
 #include <sound/info.h>
 #include <asm/io.h>
 #include <asm/dma.h>
-#include <asm/dreamcast/sysasic.h>
+#include <asm/mach/sysasic.h>
 #include "aica.h"

 MODULE_AUTHOR("Adrian McMenamin <adrian at mcmen.demon.co.uk>");
@@ -218,6 +219,12 @@ static int aica_dma_transfer(int channels, int buffer_size,
 	period_offset = dreamcastcard->clicks;
 	period_offset %= (AICA_PERIOD_NUMBER / channels);
 	runtime = substream->runtime;
+	/* If maple dma is running, wait for it to finish */
+	do{ cpu_relax();}
+	while (!maple_dma_done());
+	/* Turn off the maple dma now */
+	ctrl_outl(0, MAPLE_ENABLE);
+	local_irq_disable();	
 	for (q = 0; q < channels; q++) {
 		err = dma_xfer(AICA_DMA_CHANNEL,
 			       (unsigned long) (runtime->dma_area +
@@ -232,6 +239,9 @@ static int aica_dma_transfer(int channels, int buffer_size,
 			break;
 		dma_wait_for_completion(AICA_DMA_CHANNEL);
 	}
+	/* restore maple dma */
+	local_irq_enable();
+	maplebus_init_hardware();
 	return err;
 }