ALSA: sh: add SuperH DAC audio driver for ALSA V4

This is a port of the sound/oss/sh_dac_audio.c driver.
The driver uses an on-chip 8-bit D/A converter, which has a speaker connected
to one of its channels, found in several ancient HP machines.
For interrupts it uses a high-resolution timer (hrtimer).
Tested on SH7709 based hp6xx (HP Jornada 680/690 and HP Palmtop 620lx/660lx).

Also, since OSS Emulation works, the old OSS sound/oss/sh_dac_audio.c driver
would be obsolete soon, and it could be removed.

Signed-off-by: Rafael Ignacio Zurita <[e-mail]>
Acked-by: Paul Mundt <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>

arch/sh/boards/mach-hp6xx/setup.c

···
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/irq.h>
+#include <sound/sh_dac_audio.h>
 #include <asm/hd64461.h>
 #include <asm/io.h>
 #include <mach/hp6xx.h>
···
 	.id		= -1,
 };
 
+static void dac_audio_start(struct dac_audio_pdata *pdata)
+{
+	u16 v;
+	u8 v8;
+
+	/* HP Jornada 680/690 speaker on */
+	v = inw(HD64461_GPADR);
+	v &= ~HD64461_GPADR_SPEAKER;
+	outw(v, HD64461_GPADR);
+
+	/* HP Palmtop 620lx/660lx speaker on */
+	v8 = inb(PKDR);
+	v8 &= ~PKDR_SPEAKER;
+	outb(v8, PKDR);
+
+	sh_dac_enable(pdata->channel);
+}
+
+static void dac_audio_stop(struct dac_audio_pdata *pdata)
+{
+	u16 v;
+	u8 v8;
+
+	/* HP Jornada 680/690 speaker off */
+	v = inw(HD64461_GPADR);
+	v |= HD64461_GPADR_SPEAKER;
+	outw(v, HD64461_GPADR);
+
+	/* HP Palmtop 620lx/660lx speaker off */
+	v8 = inb(PKDR);
+	v8 |= PKDR_SPEAKER;
+	outb(v8, PKDR);
+
+	sh_dac_output(0, pdata->channel);
+	sh_dac_disable(pdata->channel);
+}
+
+static struct dac_audio_pdata dac_audio_platform_data = {
+	.buffer_size		= 64000,
+	.channel		= 1,
+	.start			= dac_audio_start,
+	.stop			= dac_audio_stop,
+};
+
+static struct platform_device dac_audio_device = {
+	.name		= "dac_audio",
+	.id		= -1,
+	.dev		= {
+		.platform_data	= &dac_audio_platform_data,
+	}
+
+};
+
 static struct platform_device *hp6xx_devices[] __initdata = {
 	&cf_ide_device,
 	&jornadakbd_device,
+	&dac_audio_device,
 };
 
 static void __init hp6xx_init_irq(void)

arch/sh/include/mach-common/mach/hp6xx.h

···
 
 #define PKDR_LED_GREEN		0x10
 
+/* HP Palmtop 620lx/660lx speaker on/off */
+#define PKDR_SPEAKER		0x20
+
 #define SCPDR_TS_SCAN_ENABLE	0x20
 #define SCPDR_TS_SCAN_Y		0x02
 #define SCPDR_TS_SCAN_X		0x01
···
 #define ADC_CHANNEL_BACKUP	4
 #define ADC_CHANNEL_CHARGE	5
 
+/* HP Jornada 680/690 speaker on/off */
 #define HD64461_GPADR_SPEAKER	0x01
 #define HD64461_GPADR_PCMCIA0	(0x02|0x08)
 

include/sound/sh_dac_audio.h

···
+/*
+ * SH_DAC specific configuration, for the dac_audio platform_device
+ *
+ * Copyright (C) 2009 Rafael Ignacio Zurita <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#ifndef __INCLUDE_SH_DAC_AUDIO_H
+#define __INCLUDE_SH_DAC_AUDIO_H
+
+struct dac_audio_pdata {
+	int buffer_size;
+	int channel;
+	void (*start)(struct dac_audio_pdata *pd);
+	void (*stop)(struct dac_audio_pdata *pd);
+};
+
+#endif /* __INCLUDE_SH_DAC_AUDIO_H */

sound/sh/Kconfig

···
 	help
 	  ALSA Sound driver for the SEGA Dreamcast console.
 
+config SND_SH_DAC_AUDIO
+	tristate "SuperH DAC audio support"
+	depends on SND
+	depends on CPU_SH3 && HIGH_RES_TIMERS
+	select SND_PCM
+	help
+	  Say Y here to include support for the on-chip DAC.
+
 endif	# SND_SUPERH
 

sound/sh/Makefile

···
 #
 
 snd-aica-objs := aica.o
+snd-sh_dac_audio-objs := sh_dac_audio.o
 
 # Toplevel Module Dependency
 obj-$(CONFIG_SND_AICA) += snd-aica.o
+obj-$(CONFIG_SND_SH_DAC_AUDIO) += snd-sh_dac_audio.o

sound/sh/sh_dac_audio.c

···
+/*
+ * sh_dac_audio.c - SuperH DAC audio driver for ALSA
+ *
+ * Copyright (c) 2009 by Rafael Ignacio Zurita <[e-mail]>
+ *
+ *
+ * Based on sh_dac_audio.c (Copyright (C) 2004, 2005 by Andriy Skulysh)
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   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/hrtimer.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/sh_dac_audio.h>
+#include <asm/clock.h>
+#include <asm/hd64461.h>
+#include <mach/hp6xx.h>
+#include <cpu/dac.h>
+
+MODULE_AUTHOR("Rafael Ignacio Zurita <[e-mail]>");
+MODULE_DESCRIPTION("SuperH DAC audio driver");
+MODULE_LICENSE("GPL");
+MODULE_SUPPORTED_DEVICE("{{SuperH DAC audio support}}");
+
+/* Module Parameters */
+static int index = SNDRV_DEFAULT_IDX1;
+static char *id = SNDRV_DEFAULT_STR1;
+module_param(index, int, 0444);
+MODULE_PARM_DESC(index, "Index value for SuperH DAC audio.");
+module_param(id, charp, 0444);
+MODULE_PARM_DESC(id, "ID string for SuperH DAC audio.");
+
+/* main struct */
+struct snd_sh_dac {
+	struct snd_card *card;
+	struct snd_pcm_substream *substream;
+	struct hrtimer hrtimer;
+	ktime_t wakeups_per_second;
+
+	int rate;
+	int empty;
+	char *data_buffer, *buffer_begin, *buffer_end;
+	int processed; /* bytes proccesed, to compare with period_size */
+	int buffer_size;
+	struct dac_audio_pdata *pdata;
+};
+
+
+static void dac_audio_start_timer(struct snd_sh_dac *chip)
+{
+	hrtimer_start(&chip->hrtimer, chip->wakeups_per_second,
+		      HRTIMER_MODE_REL);
+}
+
+static void dac_audio_stop_timer(struct snd_sh_dac *chip)
+{
+	hrtimer_cancel(&chip->hrtimer);
+}
+
+static void dac_audio_reset(struct snd_sh_dac *chip)
+{
+	dac_audio_stop_timer(chip);
+	chip->buffer_begin = chip->buffer_end = chip->data_buffer;
+	chip->processed = 0;
+	chip->empty = 1;
+}
+
+static void dac_audio_set_rate(struct snd_sh_dac *chip)
+{
+	chip->wakeups_per_second = ktime_set(0, 1000000000 / chip->rate);
+}
+
+
+/* PCM INTERFACE */
+
+static struct snd_pcm_hardware snd_sh_dac_pcm_hw = {
+	.info			= (SNDRV_PCM_INFO_MMAP |
+					SNDRV_PCM_INFO_MMAP_VALID |
+					SNDRV_PCM_INFO_INTERLEAVED |
+					SNDRV_PCM_INFO_HALF_DUPLEX),
+	.formats		= SNDRV_PCM_FMTBIT_U8,
+	.rates			= SNDRV_PCM_RATE_8000,
+	.rate_min		= 8000,
+	.rate_max		= 8000,
+	.channels_min		= 1,
+	.channels_max		= 1,
+	.buffer_bytes_max	= (48*1024),
+	.period_bytes_min	= 1,
+	.period_bytes_max	= (48*1024),
+	.periods_min		= 1,
+	.periods_max		= 1024,
+};
+
+static int snd_sh_dac_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	runtime->hw = snd_sh_dac_pcm_hw;
+
+	chip->substream = substream;
+	chip->buffer_begin = chip->buffer_end = chip->data_buffer;
+	chip->processed = 0;
+	chip->empty = 1;
+
+	chip->pdata->start(chip->pdata);
+
+	return 0;
+}
+
+static int snd_sh_dac_pcm_close(struct snd_pcm_substream *substream)
+{
+	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
+
+	chip->substream = NULL;
+
+	dac_audio_stop_timer(chip);
+	chip->pdata->stop(chip->pdata);
+
+	return 0;
+}
+
+static int snd_sh_dac_pcm_hw_params(struct snd_pcm_substream *substream,
+				struct snd_pcm_hw_params *hw_params)
+{
+	return snd_pcm_lib_malloc_pages(substream,
+			params_buffer_bytes(hw_params));
+}
+
+static int snd_sh_dac_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	return snd_pcm_lib_free_pages(substream);
+}
+
+static int snd_sh_dac_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = chip->substream->runtime;
+
+	chip->buffer_size = runtime->buffer_size;
+	memset(chip->data_buffer, 0, chip->pdata->buffer_size);
+
+	return 0;
+}
+
+static int snd_sh_dac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		dac_audio_start_timer(chip);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+		chip->buffer_begin = chip->buffer_end = chip->data_buffer;
+		chip->processed = 0;
+		chip->empty = 1;
+		dac_audio_stop_timer(chip);
+		break;
+	default:
+		 return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int snd_sh_dac_pcm_copy(struct snd_pcm_substream *substream, int channel,
+	snd_pcm_uframes_t pos, void __user *src, snd_pcm_uframes_t count)
+{
+	/* channel is not used (interleaved data) */
+	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	ssize_t b_count = frames_to_bytes(runtime , count);
+	ssize_t b_pos = frames_to_bytes(runtime , pos);
+
+	if (count < 0)
+		return -EINVAL;
+
+	if (!count)
+		return 0;
+
+	memcpy_toio(chip->data_buffer + b_pos, src, b_count);
+	chip->buffer_end = chip->data_buffer + b_pos + b_count;
+
+	if (chip->empty) {
+		chip->empty = 0;
+		dac_audio_start_timer(chip);
+	}
+
+	return 0;
+}
+
+static int snd_sh_dac_pcm_silence(struct snd_pcm_substream *substream,
+				  int channel, snd_pcm_uframes_t pos,
+				  snd_pcm_uframes_t count)
+{
+	/* channel is not used (interleaved data) */
+	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	ssize_t b_count = frames_to_bytes(runtime , count);
+	ssize_t b_pos = frames_to_bytes(runtime , pos);
+
+	if (count < 0)
+		return -EINVAL;
+
+	if (!count)
+		return 0;
+
+	memset_io(chip->data_buffer + b_pos, 0, b_count);
+	chip->buffer_end = chip->data_buffer + b_pos + b_count;
+
+	if (chip->empty) {
+		chip->empty = 0;
+		dac_audio_start_timer(chip);
+	}
+
+	return 0;
+}
+
+static
+snd_pcm_uframes_t snd_sh_dac_pcm_pointer(struct snd_pcm_substream *substream)
+{
+	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
+	int pointer = chip->buffer_begin - chip->data_buffer;
+
+	return pointer;
+}
+
+/* pcm ops */
+static struct snd_pcm_ops snd_sh_dac_pcm_ops = {
+	.open		= snd_sh_dac_pcm_open,
+	.close		= snd_sh_dac_pcm_close,
+	.ioctl		= snd_pcm_lib_ioctl,
+	.hw_params	= snd_sh_dac_pcm_hw_params,
+	.hw_free	= snd_sh_dac_pcm_hw_free,
+	.prepare	= snd_sh_dac_pcm_prepare,
+	.trigger	= snd_sh_dac_pcm_trigger,
+	.pointer	= snd_sh_dac_pcm_pointer,
+	.copy		= snd_sh_dac_pcm_copy,
+	.silence	= snd_sh_dac_pcm_silence,
+	.mmap		= snd_pcm_lib_mmap_iomem,
+};
+
+static int __devinit snd_sh_dac_pcm(struct snd_sh_dac *chip, int device)
+{
+	int err;
+	struct snd_pcm *pcm;
+
+	/* device should be always 0 for us */
+	err = snd_pcm_new(chip->card, "SH_DAC PCM", device, 1, 0, &pcm);
+	if (err < 0)
+		return err;
+
+	pcm->private_data = chip;
+	strcpy(pcm->name, "SH_DAC PCM");
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_sh_dac_pcm_ops);
+
+	/* buffer size=48K */
+	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
+					  snd_dma_continuous_data(GFP_KERNEL),
+							48 * 1024,
+							48 * 1024);
+
+	return 0;
+}
+/* END OF PCM INTERFACE */
+
+
+/* driver .remove  --  destructor */
+static int snd_sh_dac_remove(struct platform_device *devptr)
+{
+	snd_card_free(platform_get_drvdata(devptr));
+	platform_set_drvdata(devptr, NULL);
+
+	return 0;
+}
+
+/* free -- it has been defined by create */
+static int snd_sh_dac_free(struct snd_sh_dac *chip)
+{
+	/* release the data */
+	kfree(chip->data_buffer);
+	kfree(chip);
+
+	return 0;
+}
+
+static int snd_sh_dac_dev_free(struct snd_device *device)
+{
+	struct snd_sh_dac *chip = device->device_data;
+
+	return snd_sh_dac_free(chip);
+}
+
+static enum hrtimer_restart sh_dac_audio_timer(struct hrtimer *handle)
+{
+	struct snd_sh_dac *chip = container_of(handle, struct snd_sh_dac,
+					       hrtimer);
+	struct snd_pcm_runtime *runtime = chip->substream->runtime;
+	ssize_t b_ps = frames_to_bytes(runtime, runtime->period_size);
+
+	if (!chip->empty) {
+		sh_dac_output(*chip->buffer_begin, chip->pdata->channel);
+		chip->buffer_begin++;
+
+		chip->processed++;
+		if (chip->processed >= b_ps) {
+			chip->processed -= b_ps;
+			snd_pcm_period_elapsed(chip->substream);
+		}
+
+		if (chip->buffer_begin == (chip->data_buffer +
+					   chip->buffer_size - 1))
+			chip->buffer_begin = chip->data_buffer;
+
+		if (chip->buffer_begin == chip->buffer_end)
+			chip->empty = 1;
+
+	}
+
+	if (!chip->empty)
+		hrtimer_start(&chip->hrtimer, chip->wakeups_per_second,
+			      HRTIMER_MODE_REL);
+
+	return HRTIMER_NORESTART;
+}
+
+/* create  --  chip-specific constructor for the cards components */
+static int __devinit snd_sh_dac_create(struct snd_card *card,
+				       struct platform_device *devptr,
+				       struct snd_sh_dac **rchip)
+{
+	struct snd_sh_dac *chip;
+	int err;
+
+	static struct snd_device_ops ops = {
+		   .dev_free = snd_sh_dac_dev_free,
+	};
+
+	*rchip = NULL;
+
+	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+	if (chip == NULL)
+		return -ENOMEM;
+
+	chip->card = card;
+
+	hrtimer_init(&chip->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	chip->hrtimer.function = sh_dac_audio_timer;
+
+	dac_audio_reset(chip);
+	chip->rate = 8000;
+	dac_audio_set_rate(chip);
+
+	chip->pdata = devptr->dev.platform_data;
+
+	chip->data_buffer = kmalloc(chip->pdata->buffer_size, GFP_KERNEL);
+	if (chip->data_buffer == NULL) {
+		kfree(chip);
+		return -ENOMEM;
+	}
+
+	err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops);
+	if (err < 0) {
+		snd_sh_dac_free(chip);
+		return err;
+	}
+
+	*rchip = chip;
+
+	return 0;
+}
+
+/* driver .probe  --  constructor */
+static int __devinit snd_sh_dac_probe(struct platform_device *devptr)
+{
+	struct snd_sh_dac *chip;
+	struct snd_card *card;
+	int err;
+
+	err = snd_card_create(index, id, THIS_MODULE, 0, &card);
+	if (err < 0) {
+			snd_printk(KERN_ERR "cannot allocate the card\n");
+			return err;
+	}
+
+	err = snd_sh_dac_create(card, devptr, &chip);
+	if (err < 0)
+		goto probe_error;
+
+	err = snd_sh_dac_pcm(chip, 0);
+	if (err < 0)
+		goto probe_error;
+
+	strcpy(card->driver, "snd_sh_dac");
+	strcpy(card->shortname, "SuperH DAC audio driver");
+	printk(KERN_INFO "%s %s", card->longname, card->shortname);
+
+	err = snd_card_register(card);
+	if (err < 0)
+		goto probe_error;
+
+	snd_printk("ALSA driver for SuperH DAC audio");
+
+	platform_set_drvdata(devptr, card);
+	return 0;
+
+probe_error:
+	snd_card_free(card);
+	return err;
+}
+
+/*
+ * "driver" definition
+ */
+static struct platform_driver driver = {
+	.probe	= snd_sh_dac_probe,
+	.remove = snd_sh_dac_remove,
+	.driver = {
+		.name = "dac_audio",
+	},
+};
+
+static int __init sh_dac_init(void)
+{
+	return platform_driver_register(&driver);
+}
+
+static void __exit sh_dac_exit(void)
+{
+	platform_driver_unregister(&driver);
+}
+
+module_init(sh_dac_init);
+module_exit(sh_dac_exit);