[PATCH] sh: sh_dac_audio fixes

Magnus Damm
2009-05-14T11:25:57Z

From: Magnus Damm <damm@igel.co.jp>

This patch modifies sh_dac_audio in the following ways:
- use high resolution timer instead of TMU1
- fix cpu/dac.h include
- add CONFIG_SH_HP6XX ifdefs
- add future rewrite comment

Signed-off-by: Magnus Damm <damm@igel.co.jp>
---

sound/oss/Kconfig | 2 -
sound/oss/sh_dac_audio.c | 81 +++++++++++++++++-----------------------------
2 files changed, 32 insertions(+), 51 deletions(-)

--- 0001/sound/oss/Kconfig
+++ work/sound/oss/Kconfig 2009-05-14 19:14:45.000000000 +0900
@@ -561,7 +561,7 @@ endif # SOUND_OSS

config SOUND_SH_DAC_AUDIO
tristate "SuperH DAC audio support"
- depends on CPU_SH3
+ depends on CPU_SH3 && HIGH_RES_TIMERS

config SOUND_SH_DAC_AUDIO_CHANNEL
int "DAC channel"
--- 0001/sound/oss/sh_dac_audio.c
+++ work/sound/oss/sh_dac_audio.c 2009-05-14 19:13:48.000000000 +0900
@@ -18,47 +18,36 @@
#include <linux/sound.h>
#include <linux/soundcard.h>
#include <linux/interrupt.h>
+#include <linux/hrtimer.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/delay.h>
#include <asm/clock.h>
-#include <asm/cpu/dac.h>
-#include <asm/cpu/timer.h>
+#include <cpu/dac.h>
#include <asm/machvec.h>
#include <mach/hp6xx.h>
#include <asm/hd64461.h>

#define MODNAME "sh_dac_audio"

-#define TMU_TOCR_INIT 0x00
-
-#define TMU1_TCR_INIT 0x0020 /* Clock/4, rising edge; interrupt on */
-#define TMU1_TSTR_INIT 0x02 /* Bit to turn on TMU1 */
-
#define BUFFER_SIZE 48000

static int rate;
static int empty;
static char *data_buffer, *buffer_begin, *buffer_end;
static int in_use, device_major;
+static struct hrtimer hrtimer;
+static ktime_t wakeups_per_second;

static void dac_audio_start_timer(void)
{
- u8 tstr;
-
- tstr = ctrl_inb(TMU_TSTR);
- tstr |= TMU1_TSTR_INIT;
- ctrl_outb(tstr, TMU_TSTR);
+ hrtimer_start(&hrtimer, wakeups_per_second, HRTIMER_MODE_REL);
}

static void dac_audio_stop_timer(void)
{
- u8 tstr;
-
- tstr = ctrl_inb(TMU_TSTR);
- tstr &= ~TMU1_TSTR_INIT;
- ctrl_outb(tstr, TMU_TSTR);
+ hrtimer_cancel(&hrtimer);
}

static void dac_audio_reset(void)
@@ -76,39 +65,33 @@ static void dac_audio_sync(void)

static void dac_audio_start(void)
{
+#ifdef CONFIG_SH_HP6XX
if (mach_is_hp6xx()) {
u16 v = inw(HD64461_GPADR);
v &= ~HD64461_GPADR_SPEAKER;
outw(v, HD64461_GPADR);
}
-
+#endif
sh_dac_enable(CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
- ctrl_outw(TMU1_TCR_INIT, TMU1_TCR);
}
static void dac_audio_stop(void)
{
dac_audio_stop_timer();

+#ifdef CONFIG_SH_HP6XX
if (mach_is_hp6xx()) {
u16 v = inw(HD64461_GPADR);
v |= HD64461_GPADR_SPEAKER;
outw(v, HD64461_GPADR);
}
-
+#endif
sh_dac_output(0, CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
sh_dac_disable(CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
}

static void dac_audio_set_rate(void)
{
- unsigned long interval;
- struct clk *clk;
-
- clk = clk_get(NULL, "module_clk");
- interval = (clk_get_rate(clk) / 4) / rate;
- clk_put(clk);
- ctrl_outl(interval, TMU1_TCOR);
- ctrl_outl(interval, TMU1_TCNT);
+ wakeups_per_second = ktime_set(0, 1000000000 / rate);
}

static int dac_audio_ioctl(struct inode *inode, struct file *file,
@@ -265,32 +248,26 @@ const struct file_operations dac_audio_f
.release = dac_audio_release,
};

-static irqreturn_t timer1_interrupt(int irq, void *dev)
+static enum hrtimer_restart sh_dac_audio_timer(struct hrtimer *handle)
{
- unsigned long timer_status;
-
- timer_status = ctrl_inw(TMU1_TCR);
- timer_status &= ~0x100;
- ctrl_outw(timer_status, TMU1_TCR);
-
if (!empty) {
sh_dac_output(*buffer_begin, CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
buffer_begin++;

if (buffer_begin = data_buffer + BUFFER_SIZE)
buffer_begin = data_buffer;
- if (buffer_begin = buffer_end) {
+ if (buffer_begin = buffer_end)
empty = 1;
- dac_audio_stop_timer();
- }
}
- return IRQ_HANDLED;
+
+ if (!empty)
+ hrtimer_start(&hrtimer, wakeups_per_second, HRTIMER_MODE_REL);
+
+ return HRTIMER_NORESTART;
}

static int __init dac_audio_init(void)
{
- int retval;
-
if ((device_major = register_sound_dsp(&dac_audio_fops, -1)) < 0) {
printk(KERN_ERR "Cannot register dsp device");
return device_major;
@@ -306,21 +283,25 @@ static int __init dac_audio_init(void)
rate = 8000;
dac_audio_set_rate();

- retval - request_irq(TIMER1_IRQ, timer1_interrupt, IRQF_DISABLED, MODNAME, 0);
- if (retval < 0) {
- printk(KERN_ERR "sh_dac_audio: IRQ %d request failed\n",
- TIMER1_IRQ);
- return retval;
- }
+ /* Today: High Resolution Timer driven DAC playback.
+ * The timer callback gets called once per sample. Ouch.
+ *
+ * Future: A much better approach would be to use the
+ * SH7720 CMT+DMAC+DAC hardware combination like this:
+ * - Program sample rate using CMT0 or CMT1
+ * - Program DMAC to use CMT for timing and output to DAC
+ * - Play sound using DMAC, let CPU sleep.
+ * - While at it, rewrite this driver to use ALSA.
+ */
+
+ hrtimer_init(&hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hrtimer.function = sh_dac_audio_timer;

return 0;
}

static void __exit dac_audio_exit(void)
{
- free_irq(TIMER1_IRQ, 0);
-
unregister_sound_dsp(device_major);
kfree((void *)data_buffer);
}