ALSA: dice: implement hwdep device
authorClemens Ladisch <clemens@ladisch.de>
Sun, 4 Sep 2011 20:14:15 +0000 (22:14 +0200)
committerClemens Ladisch <clemens@ladisch.de>
Sun, 20 Oct 2013 20:07:57 +0000 (22:07 +0200)
Implement the hwdep locking and notification mechanisms.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
sound/firewire/dice.c

index d0575a96ea70c636912fa5d3d0201b79ac0a9a48..7225878a09cc5b1d45539262851784da6e0e9b42 100644 (file)
@@ -5,6 +5,7 @@
  * Licensed under the terms of the GNU General Public License, version 2.
  */
 
+#include <linux/compat.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/firewire.h>
 #include <linux/mod_devicetable.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
 #include <sound/control.h>
 #include <sound/core.h>
+#include <sound/firewire.h>
 #include <sound/hwdep.h>
 #include <sound/initval.h>
 #include <sound/pcm.h>
 struct dice {
        struct snd_card *card;
        struct fw_unit *unit;
+       spinlock_t lock;
        struct mutex mutex;
        unsigned int global_offset;
        unsigned int rx_offset;
        struct fw_address_handler notification_handler;
        int owner_generation;
+       int dev_lock_count; /* > 0 driver, < 0 userspace */
+       bool dev_lock_changed;
        bool global_enabled;
        bool stream_running;
+       wait_queue_head_t hwdep_wait;
+       u32 notification_bits;
        struct snd_pcm_substream *pcm;
        struct fw_iso_resources resources;
        struct amdtp_out_stream stream;
@@ -259,6 +268,47 @@ static const unsigned int dice_rates[] = {
        [6] = 192000,
 };
 
+static void dice_lock_changed(struct dice *dice)
+{
+       dice->dev_lock_changed = true;
+       wake_up(&dice->hwdep_wait);
+}
+
+static int dice_try_lock(struct dice *dice)
+{
+       int err;
+
+       spin_lock_irq(&dice->lock);
+
+       if (dice->dev_lock_count < 0) {
+               err = -EBUSY;
+               goto out;
+       }
+
+       if (dice->dev_lock_count++ == 0)
+               dice_lock_changed(dice);
+       err = 0;
+
+out:
+       spin_unlock_irq(&dice->lock);
+
+       return err;
+}
+
+static void dice_unlock(struct dice *dice)
+{
+       spin_lock_irq(&dice->lock);
+
+       if (WARN_ON(dice->dev_lock_count <= 0))
+               goto out;
+
+       if (--dice->dev_lock_count == 0)
+               dice_lock_changed(dice);
+
+out:
+       spin_unlock_irq(&dice->lock);
+}
+
 static inline u64 global_address(struct dice *dice, unsigned int offset)
 {
        return DICE_PRIVATE_SPACE + dice->global_offset + offset;
@@ -496,6 +546,7 @@ static void dice_notification(struct fw_card *card, struct fw_request *request,
                              void *data, size_t length, void *callback_data)
 {
        struct dice *dice = callback_data;
+       unsigned long flags;
 
        if (tcode != TCODE_WRITE_QUADLET_REQUEST) {
                fw_send_response(card, request, RCODE_TYPE_ERROR);
@@ -505,9 +556,11 @@ static void dice_notification(struct fw_card *card, struct fw_request *request,
                fw_send_response(card, request, RCODE_ADDRESS_ERROR);
                return;
        }
-       dev_dbg(&dice->unit->device,
-               "notification: %08x\n", be32_to_cpup(data));
+       spin_lock_irqsave(&dice->lock, flags);
+       dice->notification_bits |= be32_to_cpup(data);
+       spin_unlock_irqrestore(&dice->lock, flags);
        fw_send_response(card, request, RCODE_COMPLETE);
+       wake_up(&dice->hwdep_wait);
 }
 
 static int dice_open(struct snd_pcm_substream *substream)
@@ -531,26 +584,32 @@ static int dice_open(struct snd_pcm_substream *substream)
        unsigned int rate;
        int err;
 
+       err = dice_try_lock(dice);
+       if (err < 0)
+               goto error;
+
        err = snd_fw_transaction(dice->unit, TCODE_READ_QUADLET_REQUEST,
                                 global_address(dice, GLOBAL_CLOCK_SELECT),
                                 &clock_sel, 4);
        if (err < 0)
-               return err;
+               goto err_lock;
        rate = (be32_to_cpu(clock_sel) & CLOCK_RATE_MASK) >> CLOCK_RATE_SHIFT;
-       if (rate >= ARRAY_SIZE(dice_rates))
-               return -ENXIO;
+       if (rate >= ARRAY_SIZE(dice_rates)) {
+               err = -ENXIO;
+               goto err_lock;
+       }
        rate = dice_rates[rate];
 
        err = snd_fw_transaction(dice->unit, TCODE_READ_QUADLET_REQUEST,
                                 rx_address(dice, RX_NUMBER_AUDIO),
                                 &number_audio, 4);
        if (err < 0)
-               return err;
+               goto err_lock;
        err = snd_fw_transaction(dice->unit, TCODE_READ_QUADLET_REQUEST,
                                 rx_address(dice, RX_NUMBER_MIDI),
                                 &number_midi, 4);
        if (err < 0)
-               return err;
+               goto err_lock;
 
        runtime->hw = hardware;
 
@@ -568,17 +627,26 @@ static int dice_open(struct snd_pcm_substream *substream)
                                           SNDRV_PCM_HW_PARAM_PERIOD_TIME,
                                           5000, 8192000);
        if (err < 0)
-               return err;
+               goto err_lock;
 
        err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
        if (err < 0)
-               return err;
+               goto err_lock;
 
        return 0;
+
+err_lock:
+       dice_unlock(dice);
+error:
+       return err;
 }
 
 static int dice_close(struct snd_pcm_substream *substream)
 {
+       struct dice *dice = substream->private_data;
+
+       dice_unlock(dice);
+
        return 0;
 }
 
@@ -783,45 +851,156 @@ static int dice_create_pcm(struct dice *dice)
        return 0;
 }
 
-// TODO: implement these
-
 static long dice_hwdep_read(struct snd_hwdep *hwdep, char __user *buf,
                            long count, loff_t *offset)
 {
-       return -EIO;
+       struct dice *dice = hwdep->private_data;
+       DEFINE_WAIT(wait);
+       union snd_firewire_event event;
+
+       spin_lock_irq(&dice->lock);
+
+       while (!dice->dev_lock_changed && dice->notification_bits == 0) {
+               prepare_to_wait(&dice->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
+               spin_unlock_irq(&dice->lock);
+               schedule();
+               finish_wait(&dice->hwdep_wait, &wait);
+               if (signal_pending(current))
+                       return -ERESTARTSYS;
+               spin_lock_irq(&dice->lock);
+       }
+
+       memset(&event, 0, sizeof(event));
+       if (dice->dev_lock_changed) {
+               event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
+               event.lock_status.status = dice->dev_lock_count > 0;
+               dice->dev_lock_changed = false;
+
+               count = min(count, (long)sizeof(event.lock_status));
+       } else {
+               event.dice_notification.type = SNDRV_FIREWIRE_EVENT_DICE_NOTIFICATION;
+               event.dice_notification.notification = dice->notification_bits;
+               dice->notification_bits = 0;
+
+               count = min(count, (long)sizeof(event.dice_notification));
+       }
+
+       spin_unlock_irq(&dice->lock);
+
+       if (copy_to_user(buf, &event, count))
+               return -EFAULT;
+
+       return count;
 }
 
-static int dice_hwdep_open(struct snd_hwdep *hwdep, struct file *file)
+static unsigned int dice_hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
+                                   poll_table *wait)
 {
-       return -EIO;
+       struct dice *dice = hwdep->private_data;
+       unsigned int events;
+
+       poll_wait(file, &dice->hwdep_wait, wait);
+
+       spin_lock_irq(&dice->lock);
+       if (dice->dev_lock_changed || dice->notification_bits != 0)
+               events = POLLIN | POLLRDNORM;
+       else
+               events = 0;
+       spin_unlock_irq(&dice->lock);
+
+       return events;
 }
 
-static int dice_hwdep_release(struct snd_hwdep *hwdep, struct file *file)
+static int dice_hwdep_get_info(struct dice *dice, void __user *arg)
 {
+       struct fw_device *dev = fw_parent_device(dice->unit);
+       struct snd_firewire_get_info info;
+
+       memset(&info, 0, sizeof(info));
+       info.type = SNDRV_FIREWIRE_TYPE_DICE;
+       info.card = dev->card->index;
+       *(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
+       *(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
+       strlcpy(info.device_name, dev_name(&dev->device),
+               sizeof(info.device_name));
+
+       if (copy_to_user(arg, &info, sizeof(info)))
+               return -EFAULT;
+
        return 0;
 }
 
-static unsigned int dice_hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
-                                   poll_table *wait)
+static int dice_hwdep_lock(struct dice *dice)
+{
+       int err;
+
+       spin_lock_irq(&dice->lock);
+
+       if (dice->dev_lock_count == 0) {
+               dice->dev_lock_count = -1;
+               err = 0;
+       } else {
+               err = -EBUSY;
+       }
+
+       spin_unlock_irq(&dice->lock);
+
+       return err;
+}
+
+static int dice_hwdep_unlock(struct dice *dice)
 {
-       return POLLERR | POLLHUP;
+       int err;
+
+       spin_lock_irq(&dice->lock);
+
+       if (dice->dev_lock_count == -1) {
+               dice->dev_lock_count = 0;
+               err = 0;
+       } else {
+               err = -EBADFD;
+       }
+
+       spin_unlock_irq(&dice->lock);
+
+       return err;
 }
 
 static int dice_hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
                            unsigned int cmd, unsigned long arg)
 {
-       return -EIO;
+       struct dice *dice = hwdep->private_data;
+
+       switch (cmd) {
+       case SNDRV_FIREWIRE_IOCTL_GET_INFO:
+               return dice_hwdep_get_info(dice, (void __user *)arg);
+       case SNDRV_FIREWIRE_IOCTL_LOCK:
+               return dice_hwdep_lock(dice);
+       case SNDRV_FIREWIRE_IOCTL_UNLOCK:
+               return dice_hwdep_unlock(dice);
+       default:
+               return -ENOIOCTLCMD;
+       }
+}
+
+#ifdef CONFIG_COMPAT
+static int dice_hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
+                                  unsigned int cmd, unsigned long arg)
+{
+       return dice_hwdep_ioctl(hwdep, file, cmd,
+                               (unsigned long)compat_ptr(arg));
 }
+#else
+#define dice_hwdep_compat_ioctl NULL
+#endif
 
 static int dice_create_hwdep(struct dice *dice)
 {
        static const struct snd_hwdep_ops ops = {
                .read         = dice_hwdep_read,
-               .open         = dice_hwdep_open,
-               .release      = dice_hwdep_release,
                .poll         = dice_hwdep_poll,
                .ioctl        = dice_hwdep_ioctl,
-               .ioctl_compat = dice_hwdep_ioctl,
+               .ioctl_compat = dice_hwdep_compat_ioctl,
        };
        struct snd_hwdep *hwdep;
        int err;
@@ -922,8 +1101,10 @@ static int dice_probe(struct fw_unit *unit, const struct ieee1394_device_id *id)
 
        dice = card->private_data;
        dice->card = card;
+       spin_lock_init(&dice->lock);
        mutex_init(&dice->mutex);
        dice->unit = unit;
+       init_waitqueue_head(&dice->hwdep_wait);
 
        err = dice_init_offsets(dice);
        if (err < 0)