sound: oss: sh_dac_audio timer fixes.

This patch modifies sh_dac_audio in the following ways:

- use high resolution timer instead of TMU1
- fix cpu/dac.h include
- add future rewrite comment

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

2 files changed, 33 insertions, 54 deletions

diff --git a/sound/oss/Kconfig b/sound/oss/Kconfig
index 1ca7427c4b6..bcf2a0698d5 100644
--- a/sound/oss/Kconfig
+++ b/sound/oss/Kconfig
@@ -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"
diff --git a/sound/oss/sh_dac_audio.c b/sound/oss/sh_dac_audio.c
index 78cfb66e4c5..b2ed8757542 100644
--- a/sound/oss/sh_dac_audio.c
+++ b/sound/oss/sh_dac_audio.c
@@ -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)
@@ -77,38 +66,30 @@ static void dac_audio_sync(void)
 static void dac_audio_start(void)
 {
         if (mach_is_hp6xx()) {
-                u16 v = inw(HD64461_GPADR);
+                u16 v = __raw_readw(HD64461_GPADR);
                 v &= ~HD64461_GPADR_SPEAKER;
-                outw(v, HD64461_GPADR);
+                __raw_writew(v, HD64461_GPADR);
         }
 
         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();
 
         if (mach_is_hp6xx()) {
-                u16 v = inw(HD64461_GPADR);
+                u16 v = __raw_readw(HD64461_GPADR);
                 v |= HD64461_GPADR_SPEAKER;
-                outw(v, HD64461_GPADR);
+                __raw_writew(v, HD64461_GPADR);
         }
 
-        sh_dac_output(0, CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
+        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 +246,26 @@ const struct file_operations dac_audio_fops = {
       .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 +281,25 @@ 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);
 }