[ALSA] oxygen: use AC97 interrupt

After an AC97 register read or write, use the AC97 interrupt instead of
polling to wait for the access to be completed.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

3 files changed, 28 insertions, 11 deletions

diff --git a/sound/pci/oxygen/oxygen.h b/sound/pci/oxygen/oxygen.h
index 8fc9e7ca1182..55ce2448805d 100644
--- a/sound/pci/oxygen/oxygen.h
+++ b/sound/pci/oxygen/oxygen.h
@@ -3,6 +3,7 @@
 
 #include <linux/mutex.h>
 #include <linux/spinlock.h>
+#include <linux/wait.h>
 #include <linux/workqueue.h>
 #include "oxygen_regs.h"
 
@@ -65,6 +66,7 @@ struct oxygen {
         struct snd_pcm_substream *streams[PCM_COUNT];
         struct snd_kcontrol *controls[CONTROL_COUNT];
         struct work_struct spdif_input_bits_work;
+        wait_queue_head_t ac97_waitqueue;
 };
 
 struct oxygen_model {
diff --git a/sound/pci/oxygen/oxygen_io.c b/sound/pci/oxygen/oxygen_io.c
index d0cdce041dd8..74e23ef9c946 100644
--- a/sound/pci/oxygen/oxygen_io.c
+++ b/sound/pci/oxygen/oxygen_io.c
@@ -85,14 +85,22 @@ EXPORT_SYMBOL(oxygen_write32_masked);
 
 static int oxygen_ac97_wait(struct oxygen *chip, unsigned int mask)
 {
-        unsigned long timeout = jiffies + msecs_to_jiffies(1);
-        do {
-                udelay(5);
-                cond_resched();
-                if (oxygen_read8(chip, OXYGEN_AC97_INTERRUPT_STATUS) & mask)
-                        return 0;
-        } while (time_after_eq(timeout, jiffies));
-        return -EIO;
+        u8 status = 0;
+
+        /*
+         * Reading the status register also clears the bits, so we have to save
+         * the read bits in status.
+         */
+        wait_event_timeout(chip->ac97_waitqueue,
+                           ({ status |= oxygen_read8(chip, OXYGEN_AC97_INTERRUPT_STATUS);
+                              status & mask; }),
+                           msecs_to_jiffies(1) + 1);
+        /*
+         * Check even after a timeout because this function should not require
+         * the AC'97 interrupt to be enabled.
+         */
+        status |= oxygen_read8(chip, OXYGEN_AC97_INTERRUPT_STATUS);
+        return status & mask ? 0 : -EIO;
 }
 
 /*
diff --git a/sound/pci/oxygen/oxygen_lib.c b/sound/pci/oxygen/oxygen_lib.c
index d98867c1f2d4..de6bf41c3e96 100644
--- a/sound/pci/oxygen/oxygen_lib.c
+++ b/sound/pci/oxygen/oxygen_lib.c
@@ -53,7 +53,8 @@ static irqreturn_t oxygen_interrupt(int dummy, void *dev_id)
                           OXYGEN_CHANNEL_MULTICH |
                           OXYGEN_CHANNEL_AC97 |
                           OXYGEN_INT_SPDIF_IN_DETECT |
-                          OXYGEN_INT_GPIO);
+                          OXYGEN_INT_GPIO |
+                          OXYGEN_INT_AC97);
         if (clear) {
                 if (clear & OXYGEN_INT_SPDIF_IN_DETECT)
                         chip->interrupt_mask &= ~OXYGEN_INT_SPDIF_IN_DETECT;
@@ -89,6 +90,9 @@ static irqreturn_t oxygen_interrupt(int dummy, void *dev_id)
         if ((status & OXYGEN_INT_MIDI) && chip->midi)
                 snd_mpu401_uart_interrupt(0, chip->midi->private_data);
 
+        if (status & OXYGEN_INT_AC97)
+                wake_up(&chip->ac97_waitqueue);
+
         return IRQ_HANDLED;
 }
 
@@ -306,7 +310,9 @@ static void __devinit oxygen_init(struct oxygen *chip)
                       (2 << OXYGEN_A_MONITOR_ROUTE_2_SHIFT) |
                       (3 << OXYGEN_A_MONITOR_ROUTE_3_SHIFT));
 
-        oxygen_write8(chip, OXYGEN_AC97_INTERRUPT_MASK, 0);
+        oxygen_write8(chip, OXYGEN_AC97_INTERRUPT_MASK,
+                      OXYGEN_AC97_INT_READ_DONE |
+                      OXYGEN_AC97_INT_WRITE_DONE);
         oxygen_write32(chip, OXYGEN_AC97_OUT_CONFIG, 0);
         oxygen_write32(chip, OXYGEN_AC97_IN_CONFIG, 0);
         if (!(chip->has_ac97_0 | chip->has_ac97_1))
@@ -408,6 +414,7 @@ int __devinit oxygen_pci_probe(struct pci_dev *pci, int index, char *id,
         mutex_init(&chip->mutex);
         INIT_WORK(&chip->spdif_input_bits_work,
                   oxygen_spdif_input_bits_changed);
+        init_waitqueue_head(&chip->ac97_waitqueue);
 
         err = pci_enable_device(pci);
         if (err < 0)
@@ -471,7 +478,7 @@ int __devinit oxygen_pci_probe(struct pci_dev *pci, int index, char *id,
         oxygen_proc_init(chip);
 
         spin_lock_irq(&chip->reg_lock);
-        chip->interrupt_mask |= OXYGEN_INT_SPDIF_IN_DETECT;
+        chip->interrupt_mask |= OXYGEN_INT_SPDIF_IN_DETECT | OXYGEN_INT_AC97;
         oxygen_write16(chip, OXYGEN_INTERRUPT_MASK, chip->interrupt_mask);
         spin_unlock_irq(&chip->reg_lock);