[alsa-devel] [PATCH] [07/29] ALSA: dice: implement hwdep device
Clemens Ladisch
clemens at ladisch.de
Mon Oct 21 21:24:49 CEST 2013
Implement the hwdep locking and notification mechanisms.
Signed-off-by: Clemens Ladisch <clemens at ladisch.de>
---
sound/firewire/dice.c | 225 ++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 203 insertions(+), 22 deletions(-)
diff --git a/sound/firewire/dice.c b/sound/firewire/dice.c
index d0575a9..7225878 100644
--- a/sound/firewire/dice.c
+++ b/sound/firewire/dice.c
@@ -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>
@@ -13,8 +14,11 @@
#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>
@@ -233,13 +237,18 @@
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)
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