aica.c

linux 内核源代码

/*
* This code is licenced under 
* the General Public Licence
* version 2
*
* Copyright Adrian McMenamin 2005, 2006, 2007
* <[e-mail]>
* Requires firmware (BSD licenced) available from:
* http://linuxdc.cvs.sourceforge.net/linuxdc/linux-sh-dc/sound/oss/aica/firmware/
* or the maintainer
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*
*/

#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/wait.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/firmware.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/workqueue.h>
#include <sound/driver.h>
#include <sound/core.h>
#include <sound/control.h>
#include <sound/pcm.h>
#include <sound/initval.h>
#include <sound/info.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/dreamcast/sysasic.h>
#include "aica.h"

MODULE_AUTHOR("Adrian McMenamin <[e-mail]>");
MODULE_DESCRIPTION("Dreamcast AICA sound (pcm) driver");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{Yamaha/SEGA, AICA}}");

/* module parameters */
#define CARD_NAME "AICA"
static int index = -1;
static char *id;
static int enable = 1;
module_param(index, int, 0444);
MODULE_PARM_DESC(index, "Index value for " CARD_NAME " soundcard.");
module_param(id, charp, 0444);
MODULE_PARM_DESC(id, "ID string for " CARD_NAME " soundcard.");
module_param(enable, bool, 0644);
MODULE_PARM_DESC(enable, "Enable " CARD_NAME " soundcard.");

/* Use workqueue */
static struct workqueue_struct *aica_queue;

/* Simple platform device */
static struct platform_device *pd;
static struct resource aica_memory_space[2] = {
	{
	 .name = "AICA ARM CONTROL",
	 .start = ARM_RESET_REGISTER,
	 .flags = IORESOURCE_MEM,
	 .end = ARM_RESET_REGISTER + 3,
	 },
	{
	 .name = "AICA Sound RAM",
	 .start = SPU_MEMORY_BASE,
	 .flags = IORESOURCE_MEM,
	 .end = SPU_MEMORY_BASE + 0x200000 - 1,
	 },
};

/* SPU specific functions */
/* spu_write_wait - wait for G2-SH FIFO to clear */
static void spu_write_wait(void)
{
	int time_count;
	time_count = 0;
	while (1) {
		if (!(readl(G2_FIFO) & 0x11))
			break;
		/* To ensure hardware failure doesn't wedge kernel */
		time_count++;
		if (time_count > 0x10000) {
			snd_printk
			    ("WARNING: G2 FIFO appears to be blocked.\n");
			break;
		}
	}
}

/* spu_memset - write to memory in SPU address space */
static void spu_memset(u32 toi, u32 what, int length)
{
	int i;
	unsigned long flags;
	snd_assert(length % 4 == 0, return);
	for (i = 0; i < length; i++) {
		if (!(i % 8))
			spu_write_wait();
		local_irq_save(flags);
		writel(what, toi + SPU_MEMORY_BASE);
		local_irq_restore(flags);
		toi++;
	}
}

/* spu_memload - write to SPU address space */
static void spu_memload(u32 toi, void *from, int length)
{
	unsigned long flags;
	u32 *froml = from;
	u32 __iomem *to = (u32 __iomem *) (SPU_MEMORY_BASE + toi);
	int i;
	u32 val;
	length = DIV_ROUND_UP(length, 4);
	spu_write_wait();
	for (i = 0; i < length; i++) {
		if (!(i % 8))
			spu_write_wait();
		val = *froml;
		local_irq_save(flags);
		writel(val, to);
		local_irq_restore(flags);
		froml++;
		to++;
	}
}

/* spu_disable - set spu registers to stop sound output */
static void spu_disable(void)
{
	int i;
	unsigned long flags;
	u32 regval;
	spu_write_wait();
	regval = readl(ARM_RESET_REGISTER);
	regval |= 1;
	spu_write_wait();
	local_irq_save(flags);
	writel(regval, ARM_RESET_REGISTER);
	local_irq_restore(flags);
	for (i = 0; i < 64; i++) {
		spu_write_wait();
		regval = readl(SPU_REGISTER_BASE + (i * 0x80));
		regval = (regval & ~0x4000) | 0x8000;
		spu_write_wait();
		local_irq_save(flags);
		writel(regval, SPU_REGISTER_BASE + (i * 0x80));
		local_irq_restore(flags);
	}
}

/* spu_enable - set spu registers to enable sound output */
static void spu_enable(void)
{
	unsigned long flags;
	u32 regval = readl(ARM_RESET_REGISTER);
	regval &= ~1;
	spu_write_wait();
	local_irq_save(flags);
	writel(regval, ARM_RESET_REGISTER);
	local_irq_restore(flags);
}

/* 
 * Halt the sound processor, clear the memory,
 * load some default ARM7 code, and then restart ARM7
*/
static void spu_reset(void)
{
	unsigned long flags;
	spu_disable();
	spu_memset(0, 0, 0x200000 / 4);
	/* Put ARM7 in endless loop */
	local_irq_save(flags);
	ctrl_outl(0xea000002, SPU_MEMORY_BASE);
	local_irq_restore(flags);
	spu_enable();
}

/* aica_chn_start - write to spu to start playback */
static void aica_chn_start(void)
{
	unsigned long flags;
	spu_write_wait();
	local_irq_save(flags);
	writel(AICA_CMD_KICK | AICA_CMD_START, (u32 *) AICA_CONTROL_POINT);
	local_irq_restore(flags);
}

/* aica_chn_halt - write to spu to halt playback */
static void aica_chn_halt(void)
{
	unsigned long flags;
	spu_write_wait();
	local_irq_save(flags);
	writel(AICA_CMD_KICK | AICA_CMD_STOP, (u32 *) AICA_CONTROL_POINT);
	local_irq_restore(flags);
}

/* ALSA code below */
static struct snd_pcm_hardware snd_pcm_aica_playback_hw = {
	.info = (SNDRV_PCM_INFO_NONINTERLEAVED),
	.formats =
	    (SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_LE |
	     SNDRV_PCM_FMTBIT_IMA_ADPCM),
	.rates = SNDRV_PCM_RATE_8000_48000,
	.rate_min = 8000,
	.rate_max = 48000,
	.channels_min = 1,
	.channels_max = 2,
	.buffer_bytes_max = AICA_BUFFER_SIZE,
	.period_bytes_min = AICA_PERIOD_SIZE,
	.period_bytes_max = AICA_PERIOD_SIZE,
	.periods_min = AICA_PERIOD_NUMBER,
	.periods_max = AICA_PERIOD_NUMBER,
};

static int aica_dma_transfer(int channels, int buffer_size,
			     struct snd_pcm_substream *substream)
{
	int q, err, period_offset;
	struct snd_card_aica *dreamcastcard;
	struct snd_pcm_runtime *runtime;
	unsigned long flags;
	dreamcastcard = substream->pcm->private_data;
	period_offset = dreamcastcard->clicks;
	period_offset %= (AICA_PERIOD_NUMBER / channels);
	runtime = substream->runtime;
	for (q = 0; q < channels; q++) {
		local_irq_save(flags);
		err = dma_xfer(AICA_DMA_CHANNEL,
			       (unsigned long) (runtime->dma_area +
						(AICA_BUFFER_SIZE * q) /
						channels +
						AICA_PERIOD_SIZE *
						period_offset),
			       AICA_CHANNEL0_OFFSET + q * CHANNEL_OFFSET +
			       AICA_PERIOD_SIZE * period_offset,
			       buffer_size / channels, AICA_DMA_MODE);
		if (unlikely(err < 0)) {
			local_irq_restore(flags);
			break;
		}
		dma_wait_for_completion(AICA_DMA_CHANNEL);
		local_irq_restore(flags);
	}
	return err;
}

static void startup_aica(struct snd_card_aica *dreamcastcard)
{
	spu_memload(AICA_CHANNEL0_CONTROL_OFFSET,
		    dreamcastcard->channel, sizeof(struct aica_channel));
	aica_chn_start();
}

static void run_spu_dma(struct work_struct *work)
{
	int buffer_size;
	struct snd_pcm_runtime *runtime;
	struct snd_card_aica *dreamcastcard;
	dreamcastcard =
	    container_of(work, struct snd_card_aica, spu_dma_work);
	runtime = dreamcastcard->substream->runtime;
	if (unlikely(dreamcastcard->dma_check == 0)) {
		buffer_size =
		    frames_to_bytes(runtime, runtime->buffer_size);
		if (runtime->channels > 1)
			dreamcastcard->channel->flags |= 0x01;
		aica_dma_transfer(runtime->channels, buffer_size,
				  dreamcastcard->substream);
		startup_aica(dreamcastcard);
		dreamcastcard->clicks =
		    buffer_size / (AICA_PERIOD_SIZE * runtime->channels);
		return;
	} else {
		aica_dma_transfer(runtime->channels,
				  AICA_PERIOD_SIZE * runtime->channels,
				  dreamcastcard->substream);
		snd_pcm_period_elapsed(dreamcastcard->substream);
		dreamcastcard->clicks++;
		if (unlikely(dreamcastcard->clicks >= AICA_PERIOD_NUMBER))
			dreamcastcard->clicks %= AICA_PERIOD_NUMBER;
		mod_timer(&dreamcastcard->timer, jiffies + 1);
	}
}

static void aica_period_elapsed(unsigned long timer_var)
{
	/*timer function - so cannot sleep */
	int play_period;
	struct snd_pcm_runtime *runtime;
	struct snd_pcm_substream *substream;
	struct snd_card_aica *dreamcastcard;
	substream = (struct snd_pcm_substream *) timer_var;
	runtime = substream->runtime;
	dreamcastcard = substream->pcm->private_data;
	/* Have we played out an additional period? */
	play_period =
	    frames_to_bytes(runtime,
			    readl
			    (AICA_CONTROL_CHANNEL_SAMPLE_NUMBER)) /
	    AICA_PERIOD_SIZE;
	if (play_period == dreamcastcard->current_period) {
		/* reschedule the timer */
		mod_timer(&(dreamcastcard->timer), jiffies + 1);
		return;
	}
	if (runtime->channels > 1)
		dreamcastcard->current_period = play_period;
	if (unlikely(dreamcastcard->dma_check == 0))
		dreamcastcard->dma_check = 1;
	queue_work(aica_queue, &(dreamcastcard->spu_dma_work));
}

static void spu_begin_dma(struct snd_pcm_substream *substream)
{
	struct snd_card_aica *dreamcastcard;
	struct snd_pcm_runtime *runtime;
	runtime = substream->runtime;
	dreamcastcard = substream->pcm->private_data;
	/*get the queue to do the work */
	queue_work(aica_queue, &(dreamcastcard->spu_dma_work));
	/* Timer may already be running */
	if (unlikely(dreamcastcard->timer.data)) {
		mod_timer(&dreamcastcard->timer, jiffies + 4);
		return;
	}