*
* LOCKING:
*
- * The subsystem keeps two global lists, dma_device_list and dma_client_list.
- * Both of these are protected by a mutex, dma_list_mutex.
+ * The subsystem keeps a global list of dma_device structs it is protected by a
+ * mutex, dma_list_mutex.
+ *
+ * A subsystem can get access to a channel by calling dmaengine_get() followed
+ * by dma_find_channel(), or if it has need for an exclusive channel it can call
+ * dma_request_channel(). Once a channel is allocated a reference is taken
+ * against its corresponding driver to disable removal.
*
* Each device has a channels list, which runs unlocked but is never modified
* once the device is registered, it's just setup by the driver.
*
- * Each client is responsible for keeping track of the channels it uses. See
- * the definition of dma_event_callback in dmaengine.h.
- *
- * Each device has a kref, which is initialized to 1 when the device is
- * registered. A kref_get is done for each device registered. When the
- * device is released, the corresponding kref_put is done in the release
- * method. Every time one of the device's channels is allocated to a client,
- * a kref_get occurs. When the channel is freed, the corresponding kref_put
- * happens. The device's release function does a completion, so
- * unregister_device does a remove event, device_unregister, a kref_put
- * for the first reference, then waits on the completion for all other
- * references to finish.
- *
- * Each channel has an open-coded implementation of Rusty Russell's "bigref,"
- * with a kref and a per_cpu local_t. A dma_chan_get is called when a client
- * signals that it wants to use a channel, and dma_chan_put is called when
- * a channel is removed or a client using it is unregistered. A client can
- * take extra references per outstanding transaction, as is the case with
- * the NET DMA client. The release function does a kref_put on the device.
- * -ChrisL, DanW
+ * See Documentation/dmaengine.txt for more details
*/
#include <linux/init.h>
#include <linux/rcupdate.h>
#include <linux/mutex.h>
#include <linux/jiffies.h>
+#include <linux/rculist.h>
+#include <linux/idr.h>
static DEFINE_MUTEX(dma_list_mutex);
static LIST_HEAD(dma_device_list);
-static LIST_HEAD(dma_client_list);
static long dmaengine_ref_count;
+static struct idr dma_idr;
/* --- sysfs implementation --- */
+/**
+ * dev_to_dma_chan - convert a device pointer to the its sysfs container object
+ * @dev - device node
+ *
+ * Must be called under dma_list_mutex
+ */
+static struct dma_chan *dev_to_dma_chan(struct device *dev)
+{
+ struct dma_chan_dev *chan_dev;
+
+ chan_dev = container_of(dev, typeof(*chan_dev), device);
+ return chan_dev->chan;
+}
+
static ssize_t show_memcpy_count(struct device *dev, struct device_attribute *attr, char *buf)
{
- struct dma_chan *chan = to_dma_chan(dev);
+ struct dma_chan *chan;
unsigned long count = 0;
int i;
+ int err;
- for_each_possible_cpu(i)
- count += per_cpu_ptr(chan->local, i)->memcpy_count;
+ mutex_lock(&dma_list_mutex);
+ chan = dev_to_dma_chan(dev);
+ if (chan) {
+ for_each_possible_cpu(i)
+ count += per_cpu_ptr(chan->local, i)->memcpy_count;
+ err = sprintf(buf, "%lu\n", count);
+ } else
+ err = -ENODEV;
+ mutex_unlock(&dma_list_mutex);
- return sprintf(buf, "%lu\n", count);
+ return err;
}
static ssize_t show_bytes_transferred(struct device *dev, struct device_attribute *attr,
char *buf)
{
- struct dma_chan *chan = to_dma_chan(dev);
+ struct dma_chan *chan;
unsigned long count = 0;
int i;
+ int err;
- for_each_possible_cpu(i)
- count += per_cpu_ptr(chan->local, i)->bytes_transferred;
+ mutex_lock(&dma_list_mutex);
+ chan = dev_to_dma_chan(dev);
+ if (chan) {
+ for_each_possible_cpu(i)
+ count += per_cpu_ptr(chan->local, i)->bytes_transferred;
+ err = sprintf(buf, "%lu\n", count);
+ } else
+ err = -ENODEV;
+ mutex_unlock(&dma_list_mutex);
- return sprintf(buf, "%lu\n", count);
+ return err;
}
static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, char *buf)
{
- struct dma_chan *chan = to_dma_chan(dev);
+ struct dma_chan *chan;
+ int err;
+
+ mutex_lock(&dma_list_mutex);
+ chan = dev_to_dma_chan(dev);
+ if (chan)
+ err = sprintf(buf, "%d\n", chan->client_count);
+ else
+ err = -ENODEV;
+ mutex_unlock(&dma_list_mutex);
- return sprintf(buf, "%d\n", chan->client_count);
+ return err;
}
static struct device_attribute dma_attrs[] = {
__ATTR_NULL
};
-static void dma_async_device_cleanup(struct kref *kref);
-
-static void dma_dev_release(struct device *dev)
+static void chan_dev_release(struct device *dev)
{
- struct dma_chan *chan = to_dma_chan(dev);
- kref_put(&chan->device->refcount, dma_async_device_cleanup);
+ struct dma_chan_dev *chan_dev;
+
+ chan_dev = container_of(dev, typeof(*chan_dev), device);
+ if (atomic_dec_and_test(chan_dev->idr_ref)) {
+ mutex_lock(&dma_list_mutex);
+ idr_remove(&dma_idr, chan_dev->dev_id);
+ mutex_unlock(&dma_list_mutex);
+ kfree(chan_dev->idr_ref);
+ }
+ kfree(chan_dev);
}
static struct class dma_devclass = {
.name = "dma",
.dev_attrs = dma_attrs,
- .dev_release = dma_dev_release,
+ .dev_release = chan_dev_release,
};
/* --- client and device registration --- */
-#define dma_chan_satisfies_mask(chan, mask) \
- __dma_chan_satisfies_mask((chan), &(mask))
+#define dma_device_satisfies_mask(device, mask) \
+ __dma_device_satisfies_mask((device), &(mask))
static int
-__dma_chan_satisfies_mask(struct dma_chan *chan, dma_cap_mask_t *want)
+__dma_device_satisfies_mask(struct dma_device *device, dma_cap_mask_t *want)
{
dma_cap_mask_t has;
- bitmap_and(has.bits, want->bits, chan->device->cap_mask.bits,
+ bitmap_and(has.bits, want->bits, device->cap_mask.bits,
DMA_TX_TYPE_END);
return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
}
/* allocate upon first client reference */
if (chan->client_count == 1 && err == 0) {
- int desc_cnt = chan->device->device_alloc_chan_resources(chan, NULL);
+ int desc_cnt = chan->device->device_alloc_chan_resources(chan);
if (desc_cnt < 0) {
err = desc_cnt;
chan->client_count = 0;
module_put(owner);
- } else
+ } else if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
balance_ref_count(chan);
}
chan->device->device_free_chan_resources(chan);
}
-/**
- * dma_client_chan_alloc - try to allocate channels to a client
- * @client: &dma_client
- *
- * Called with dma_list_mutex held.
- */
-static void dma_client_chan_alloc(struct dma_client *client)
-{
- struct dma_device *device;
- struct dma_chan *chan;
- enum dma_state_client ack;
-
- /* Find a channel */
- list_for_each_entry(device, &dma_device_list, global_node) {
- /* Does the client require a specific DMA controller? */
- if (client->slave && client->slave->dma_dev
- && client->slave->dma_dev != device->dev)
- continue;
-
- list_for_each_entry(chan, &device->channels, device_node) {
- if (!dma_chan_satisfies_mask(chan, client->cap_mask))
- continue;
- if (!chan->client_count)
- continue;
- ack = client->event_callback(client, chan,
- DMA_RESOURCE_AVAILABLE);
-
- /* we are done once this client rejects
- * an available resource
- */
- if (ack == DMA_NAK)
- return;
- }
- }
-}
-
enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
{
enum dma_status status;
EXPORT_SYMBOL(dma_sync_wait);
/**
- * dma_chan_cleanup - release a DMA channel's resources
- * @kref: kernel reference structure that contains the DMA channel device
- */
-void dma_chan_cleanup(struct kref *kref)
-{
- struct dma_chan *chan = container_of(kref, struct dma_chan, refcount);
- kref_put(&chan->device->refcount, dma_async_device_cleanup);
-}
-EXPORT_SYMBOL(dma_chan_cleanup);
-
-static void dma_chan_free_rcu(struct rcu_head *rcu)
-{
- struct dma_chan *chan = container_of(rcu, struct dma_chan, rcu);
-
- kref_put(&chan->refcount, dma_chan_cleanup);
-}
-
-static void dma_chan_release(struct dma_chan *chan)
-{
- call_rcu(&chan->rcu, dma_chan_free_rcu);
-}
-
-/**
* dma_cap_mask_all - enable iteration over all operation types
*/
static dma_cap_mask_t dma_cap_mask_all;
bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
- /* 'interrupt' and 'slave' are channel capabilities, but are not
- * associated with an operation so they do not need an entry in the
- * channel_table
+ /* 'interrupt', 'private', and 'slave' are channel capabilities,
+ * but are not associated with an operation so they do not need
+ * an entry in the channel_table
*/
clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
+ clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
for_each_dma_cap_mask(cap, dma_cap_mask_all) {
return err;
}
-subsys_initcall(dma_channel_table_init);
+arch_initcall(dma_channel_table_init);
/**
* dma_find_channel - find a channel to carry out the operation
struct dma_chan *chan;
int cpu;
- WARN_ONCE(dmaengine_ref_count == 0,
- "client called %s without a reference", __func__);
-
cpu = get_cpu();
chan = per_cpu_ptr(channel_table[tx_type], cpu)->chan;
put_cpu();
EXPORT_SYMBOL(dma_find_channel);
/**
+ * dma_issue_pending_all - flush all pending operations across all channels
+ */
+void dma_issue_pending_all(void)
+{
+ struct dma_device *device;
+ struct dma_chan *chan;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(device, &dma_device_list, global_node) {
+ if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+ continue;
+ list_for_each_entry(chan, &device->channels, device_node)
+ if (chan->client_count)
+ device->device_issue_pending(chan);
+ }
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL(dma_issue_pending_all);
+
+/**
* nth_chan - returns the nth channel of the given capability
* @cap: capability to match
* @n: nth channel desired
struct dma_chan *min = NULL;
list_for_each_entry(device, &dma_device_list, global_node) {
- if (!dma_has_cap(cap, device->cap_mask))
+ if (!dma_has_cap(cap, device->cap_mask) ||
+ dma_has_cap(DMA_PRIVATE, device->cap_mask))
continue;
list_for_each_entry(chan, &device->channels, device_node) {
if (!chan->client_count)
for_each_possible_cpu(cpu)
per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
- list_for_each_entry(device, &dma_device_list, global_node)
+ list_for_each_entry(device, &dma_device_list, global_node) {
+ if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+ continue;
list_for_each_entry(chan, &device->channels, device_node)
chan->table_count = 0;
+ }
/* don't populate the channel_table if no clients are available */
if (!dmaengine_ref_count)
}
}
+static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_device *dev,
+ dma_filter_fn fn, void *fn_param)
+{
+ struct dma_chan *chan;
+
+ if (!__dma_device_satisfies_mask(dev, mask)) {
+ pr_debug("%s: wrong capabilities\n", __func__);
+ return NULL;
+ }
+ /* devices with multiple channels need special handling as we need to
+ * ensure that all channels are either private or public.
+ */
+ if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
+ list_for_each_entry(chan, &dev->channels, device_node) {
+ /* some channels are already publicly allocated */
+ if (chan->client_count)
+ return NULL;
+ }
+
+ list_for_each_entry(chan, &dev->channels, device_node) {
+ if (chan->client_count) {
+ pr_debug("%s: %s busy\n",
+ __func__, dma_chan_name(chan));
+ continue;
+ }
+ if (fn && !fn(chan, fn_param)) {
+ pr_debug("%s: %s filter said false\n",
+ __func__, dma_chan_name(chan));
+ continue;
+ }
+ return chan;
+ }
+
+ return NULL;
+}
+
/**
- * dma_chans_notify_available - broadcast available channels to the clients
+ * dma_request_channel - try to allocate an exclusive channel
+ * @mask: capabilities that the channel must satisfy
+ * @fn: optional callback to disposition available channels
+ * @fn_param: opaque parameter to pass to dma_filter_fn
*/
-static void dma_clients_notify_available(void)
+struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param)
{
- struct dma_client *client;
+ struct dma_device *device, *_d;
+ struct dma_chan *chan = NULL;
+ int err;
+ /* Find a channel */
mutex_lock(&dma_list_mutex);
+ list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
+ chan = private_candidate(mask, device, fn, fn_param);
+ if (chan) {
+ /* Found a suitable channel, try to grab, prep, and
+ * return it. We first set DMA_PRIVATE to disable
+ * balance_ref_count as this channel will not be
+ * published in the general-purpose allocator
+ */
+ dma_cap_set(DMA_PRIVATE, device->cap_mask);
+ device->privatecnt++;
+ err = dma_chan_get(chan);
+
+ if (err == -ENODEV) {
+ pr_debug("%s: %s module removed\n", __func__,
+ dma_chan_name(chan));
+ list_del_rcu(&device->global_node);
+ } else if (err)
+ pr_err("dmaengine: failed to get %s: (%d)\n",
+ dma_chan_name(chan), err);
+ else
+ break;
+ if (--device->privatecnt == 0)
+ dma_cap_clear(DMA_PRIVATE, device->cap_mask);
+ chan->private = NULL;
+ chan = NULL;
+ }
+ }
+ mutex_unlock(&dma_list_mutex);
+
+ pr_debug("%s: %s (%s)\n", __func__, chan ? "success" : "fail",
+ chan ? dma_chan_name(chan) : NULL);
- list_for_each_entry(client, &dma_client_list, global_node)
- dma_client_chan_alloc(client);
+ return chan;
+}
+EXPORT_SYMBOL_GPL(__dma_request_channel);
+void dma_release_channel(struct dma_chan *chan)
+{
+ mutex_lock(&dma_list_mutex);
+ WARN_ONCE(chan->client_count != 1,
+ "chan reference count %d != 1\n", chan->client_count);
+ dma_chan_put(chan);
+ /* drop PRIVATE cap enabled by __dma_request_channel() */
+ if (--chan->device->privatecnt == 0)
+ dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
+ chan->private = NULL;
mutex_unlock(&dma_list_mutex);
}
+EXPORT_SYMBOL_GPL(dma_release_channel);
/**
- * dma_async_client_register - register a &dma_client
- * @client: ptr to a client structure with valid 'event_callback' and 'cap_mask'
+ * dmaengine_get - register interest in dma_channels
*/
-void dma_async_client_register(struct dma_client *client)
+void dmaengine_get(void)
{
struct dma_device *device, *_d;
struct dma_chan *chan;
int err;
- /* validate client data */
- BUG_ON(dma_has_cap(DMA_SLAVE, client->cap_mask) &&
- !client->slave);
-
mutex_lock(&dma_list_mutex);
dmaengine_ref_count++;
/* try to grab channels */
- list_for_each_entry_safe(device, _d, &dma_device_list, global_node)
+ list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
+ if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+ continue;
list_for_each_entry(chan, &device->channels, device_node) {
err = dma_chan_get(chan);
if (err == -ENODEV) {
/* module removed before we could use it */
- list_del_init(&device->global_node);
+ list_del_rcu(&device->global_node);
break;
} else if (err)
pr_err("dmaengine: failed to get %s: (%d)\n",
- dev_name(&chan->dev), err);
+ dma_chan_name(chan), err);
}
+ }
/* if this is the first reference and there were channels
* waiting we need to rebalance to get those channels
*/
if (dmaengine_ref_count == 1)
dma_channel_rebalance();
- list_add_tail(&client->global_node, &dma_client_list);
mutex_unlock(&dma_list_mutex);
}
-EXPORT_SYMBOL(dma_async_client_register);
+EXPORT_SYMBOL(dmaengine_get);
/**
- * dma_async_client_unregister - unregister a client and free the &dma_client
- * @client: &dma_client to free
- *
- * Force frees any allocated DMA channels, frees the &dma_client memory
+ * dmaengine_put - let dma drivers be removed when ref_count == 0
*/
-void dma_async_client_unregister(struct dma_client *client)
+void dmaengine_put(void)
{
struct dma_device *device;
struct dma_chan *chan;
- if (!client)
- return;
-
mutex_lock(&dma_list_mutex);
dmaengine_ref_count--;
BUG_ON(dmaengine_ref_count < 0);
/* drop channel references */
- list_for_each_entry(device, &dma_device_list, global_node)
+ list_for_each_entry(device, &dma_device_list, global_node) {
+ if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+ continue;
list_for_each_entry(chan, &device->channels, device_node)
dma_chan_put(chan);
-
- list_del(&client->global_node);
+ }
mutex_unlock(&dma_list_mutex);
}
-EXPORT_SYMBOL(dma_async_client_unregister);
+EXPORT_SYMBOL(dmaengine_put);
-/**
- * dma_async_client_chan_request - send all available channels to the
- * client that satisfy the capability mask
- * @client - requester
- */
-void dma_async_client_chan_request(struct dma_client *client)
+static int get_dma_id(struct dma_device *device)
{
+ int rc;
+
+ idr_retry:
+ if (!idr_pre_get(&dma_idr, GFP_KERNEL))
+ return -ENOMEM;
mutex_lock(&dma_list_mutex);
- dma_client_chan_alloc(client);
+ rc = idr_get_new(&dma_idr, NULL, &device->dev_id);
mutex_unlock(&dma_list_mutex);
+ if (rc == -EAGAIN)
+ goto idr_retry;
+ else if (rc != 0)
+ return rc;
+
+ return 0;
}
-EXPORT_SYMBOL(dma_async_client_chan_request);
/**
* dma_async_device_register - registers DMA devices found
*/
int dma_async_device_register(struct dma_device *device)
{
- static int id;
int chancnt = 0, rc;
struct dma_chan* chan;
+ atomic_t *idr_ref;
if (!device)
return -ENODEV;
!device->device_prep_dma_memcpy);
BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
!device->device_prep_dma_xor);
- BUG_ON(dma_has_cap(DMA_ZERO_SUM, device->cap_mask) &&
- !device->device_prep_dma_zero_sum);
+ BUG_ON(dma_has_cap(DMA_XOR_VAL, device->cap_mask) &&
+ !device->device_prep_dma_xor_val);
BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
!device->device_prep_dma_memset);
BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
BUG_ON(!device->device_issue_pending);
BUG_ON(!device->dev);
- init_completion(&device->done);
- kref_init(&device->refcount);
+ idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
+ if (!idr_ref)
+ return -ENOMEM;
+ rc = get_dma_id(device);
+ if (rc != 0) {
+ kfree(idr_ref);
+ return rc;
+ }
- mutex_lock(&dma_list_mutex);
- device->dev_id = id++;
- mutex_unlock(&dma_list_mutex);
+ atomic_set(idr_ref, 0);
/* represent channels in sysfs. Probably want devs too */
list_for_each_entry(chan, &device->channels, device_node) {
+ rc = -ENOMEM;
chan->local = alloc_percpu(typeof(*chan->local));
if (chan->local == NULL)
- continue;
+ goto err_out;
+ chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
+ if (chan->dev == NULL) {
+ free_percpu(chan->local);
+ chan->local = NULL;
+ goto err_out;
+ }
chan->chan_id = chancnt++;
- chan->dev.class = &dma_devclass;
- chan->dev.parent = device->dev;
- dev_set_name(&chan->dev, "dma%dchan%d",
+ chan->dev->device.class = &dma_devclass;
+ chan->dev->device.parent = device->dev;
+ chan->dev->chan = chan;
+ chan->dev->idr_ref = idr_ref;
+ chan->dev->dev_id = device->dev_id;
+ atomic_inc(idr_ref);
+ dev_set_name(&chan->dev->device, "dma%dchan%d",
device->dev_id, chan->chan_id);
- rc = device_register(&chan->dev);
+ rc = device_register(&chan->dev->device);
if (rc) {
- chancnt--;
free_percpu(chan->local);
chan->local = NULL;
+ kfree(chan->dev);
+ atomic_dec(idr_ref);
goto err_out;
}
-
- /* One for the channel, one of the class device */
- kref_get(&device->refcount);
- kref_get(&device->refcount);
- kref_init(&chan->refcount);
chan->client_count = 0;
- chan->slow_ref = 0;
- INIT_RCU_HEAD(&chan->rcu);
}
+ device->chancnt = chancnt;
mutex_lock(&dma_list_mutex);
- if (dmaengine_ref_count)
+ /* take references on public channels */
+ if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
list_for_each_entry(chan, &device->channels, device_node) {
/* if clients are already waiting for channels we need
* to take references on their behalf
goto err_out;
}
}
- list_add_tail(&device->global_node, &dma_device_list);
+ list_add_tail_rcu(&device->global_node, &dma_device_list);
+ if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+ device->privatecnt++; /* Always private */
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
- dma_clients_notify_available();
-
return 0;
err_out:
+ /* if we never registered a channel just release the idr */
+ if (atomic_read(idr_ref) == 0) {
+ mutex_lock(&dma_list_mutex);
+ idr_remove(&dma_idr, device->dev_id);
+ mutex_unlock(&dma_list_mutex);
+ kfree(idr_ref);
+ return rc;
+ }
+
list_for_each_entry(chan, &device->channels, device_node) {
if (chan->local == NULL)
continue;
- kref_put(&device->refcount, dma_async_device_cleanup);
- device_unregister(&chan->dev);
- chancnt--;
+ mutex_lock(&dma_list_mutex);
+ chan->dev->chan = NULL;
+ mutex_unlock(&dma_list_mutex);
+ device_unregister(&chan->dev->device);
free_percpu(chan->local);
}
return rc;
EXPORT_SYMBOL(dma_async_device_register);
/**
- * dma_async_device_cleanup - function called when all references are released
- * @kref: kernel reference object
- */
-static void dma_async_device_cleanup(struct kref *kref)
-{
- struct dma_device *device;
-
- device = container_of(kref, struct dma_device, refcount);
- complete(&device->done);
-}
-
-/**
* dma_async_device_unregister - unregister a DMA device
* @device: &dma_device
+ *
+ * This routine is called by dma driver exit routines, dmaengine holds module
+ * references to prevent it being called while channels are in use.
*/
void dma_async_device_unregister(struct dma_device *device)
{
struct dma_chan *chan;
mutex_lock(&dma_list_mutex);
- list_del(&device->global_node);
+ list_del_rcu(&device->global_node);
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
WARN_ONCE(chan->client_count,
"%s called while %d clients hold a reference\n",
__func__, chan->client_count);
- device_unregister(&chan->dev);
- dma_chan_release(chan);
+ mutex_lock(&dma_list_mutex);
+ chan->dev->chan = NULL;
+ mutex_unlock(&dma_list_mutex);
+ device_unregister(&chan->dev->device);
}
-
- kref_put(&device->refcount, dma_async_device_cleanup);
- wait_for_completion(&device->done);
}
EXPORT_SYMBOL(dma_async_device_unregister);
{
tx->chan = chan;
spin_lock_init(&tx->lock);
+ INIT_LIST_HEAD(&tx->tx_list);
}
EXPORT_SYMBOL(dma_async_tx_descriptor_init);
/* dma_wait_for_async_tx - spin wait for a transaction to complete
* @tx: in-flight transaction to wait on
- *
- * This routine assumes that tx was obtained from a call to async_memcpy,
- * async_xor, async_memset, etc which ensures that tx is "in-flight" (prepped
- * and submitted). Walking the parent chain is only meant to cover for DMA
- * drivers that do not implement the DMA_INTERRUPT capability and may race with
- * the driver's descriptor cleanup routine.
*/
enum dma_status
dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
{
- enum dma_status status;
- struct dma_async_tx_descriptor *iter;
- struct dma_async_tx_descriptor *parent;
+ unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
if (!tx)
return DMA_SUCCESS;
- WARN_ONCE(tx->parent, "%s: speculatively walking dependency chain for"
- " %s\n", __func__, dev_name(&tx->chan->dev));
-
- /* poll through the dependency chain, return when tx is complete */
- do {
- iter = tx;
-
- /* find the root of the unsubmitted dependency chain */
- do {
- parent = iter->parent;
- if (!parent)
- break;
- else
- iter = parent;
- } while (parent);
-
- /* there is a small window for ->parent == NULL and
- * ->cookie == -EBUSY
- */
- while (iter->cookie == -EBUSY)
- cpu_relax();
-
- status = dma_sync_wait(iter->chan, iter->cookie);
- } while (status == DMA_IN_PROGRESS || (iter != tx));
-
- return status;
+ while (tx->cookie == -EBUSY) {
+ if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
+ pr_err("%s timeout waiting for descriptor submission\n",
+ __func__);
+ return DMA_ERROR;
+ }
+ cpu_relax();
+ }
+ return dma_sync_wait(tx->chan, tx->cookie);
}
EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
if (!dep)
return;
+ /* we'll submit tx->next now, so clear the link */
+ tx->next = NULL;
chan = dep->chan;
/* keep submitting up until a channel switch is detected
static int __init dma_bus_init(void)
{
+ idr_init(&dma_idr);
mutex_init(&dma_list_mutex);
return class_register(&dma_devclass);
}
-subsys_initcall(dma_bus_init);
+arch_initcall(dma_bus_init);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff