*
* 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 has a channels list, it's only modified under the client->lock
- * and in an RCU callback, so it's safe to read under rcu_read_lock().
- *
- * Each device has a kref, which is initialized to 1 when the device is
- * registered. A kref_put is done for each class_device registered. When the
- * class_device is released, the coresponding 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 coresponding kref_put
- * happens. The device's release function does a completion, so
- * unregister_device does a remove event, class_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 single reference is set when on an
- * ADDED event, and removed with a REMOVE event. Net DMA client takes an
- * extra reference per outstanding transaction. The relase function does a
- * kref_put on the device. -ChrisL
+ * See Documentation/dmaengine.txt for more details
*/
#include <linux/init.h>
#include <linux/module.h>
+#include <linux/mm.h>
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/hardirq.h>
#include <linux/percpu.h>
#include <linux/rcupdate.h>
#include <linux/mutex.h>
+#include <linux/jiffies.h>
+#include <linux/rculist.h>
+#include <linux/idr.h>
+#include <linux/slab.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 --- */
-static ssize_t show_memcpy_count(struct class_device *cd, char *buf)
+/**
+ * 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 = container_of(cd, struct dma_chan, class_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 class_device *cd, char *buf)
+static ssize_t show_bytes_transferred(struct device *dev, struct device_attribute *attr,
+ char *buf)
{
- struct dma_chan *chan = container_of(cd, struct dma_chan, class_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 class_device *cd, char *buf)
+static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, char *buf)
{
- struct dma_chan *chan = container_of(cd, struct dma_chan, class_dev);
+ struct dma_chan *chan;
+ int err;
- return sprintf(buf, "%d\n", (chan->client ? 1 : 0));
+ 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 err;
}
-static struct class_device_attribute dma_class_attrs[] = {
+static struct device_attribute dma_attrs[] = {
__ATTR(memcpy_count, S_IRUGO, show_memcpy_count, NULL),
__ATTR(bytes_transferred, S_IRUGO, show_bytes_transferred, NULL),
__ATTR(in_use, S_IRUGO, show_in_use, NULL),
__ATTR_NULL
};
-static void dma_async_device_cleanup(struct kref *kref);
-
-static void dma_class_dev_release(struct class_device *cd)
+static void chan_dev_release(struct device *dev)
{
- struct dma_chan *chan = container_of(cd, struct dma_chan, class_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",
- .class_dev_attrs = dma_class_attrs,
- .release = dma_class_dev_release,
+ .name = "dma",
+ .dev_attrs = dma_attrs,
+ .dev_release = chan_dev_release,
};
/* --- client and device registration --- */
+#define dma_device_satisfies_mask(device, mask) \
+ __dma_device_satisfies_mask((device), &(mask))
+static int
+__dma_device_satisfies_mask(struct dma_device *device, dma_cap_mask_t *want)
+{
+ dma_cap_mask_t has;
+
+ 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);
+}
+
+static struct module *dma_chan_to_owner(struct dma_chan *chan)
+{
+ return chan->device->dev->driver->owner;
+}
+
/**
- * dma_client_chan_alloc - try to allocate a channel to a client
- * @client: &dma_client
+ * balance_ref_count - catch up the channel reference count
+ * @chan - channel to balance ->client_count versus dmaengine_ref_count
*
- * Called with dma_list_mutex held.
+ * balance_ref_count must be called under dma_list_mutex
*/
-static struct dma_chan *dma_client_chan_alloc(struct dma_client *client)
+static void balance_ref_count(struct dma_chan *chan)
{
- struct dma_device *device;
+ struct module *owner = dma_chan_to_owner(chan);
+
+ while (chan->client_count < dmaengine_ref_count) {
+ __module_get(owner);
+ chan->client_count++;
+ }
+}
+
+/**
+ * dma_chan_get - try to grab a dma channel's parent driver module
+ * @chan - channel to grab
+ *
+ * Must be called under dma_list_mutex
+ */
+static int dma_chan_get(struct dma_chan *chan)
+{
+ int err = -ENODEV;
+ struct module *owner = dma_chan_to_owner(chan);
+
+ if (chan->client_count) {
+ __module_get(owner);
+ err = 0;
+ } else if (try_module_get(owner))
+ err = 0;
+
+ if (err == 0)
+ chan->client_count++;
+
+ /* allocate upon first client reference */
+ if (chan->client_count == 1 && err == 0) {
+ 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 if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
+ balance_ref_count(chan);
+ }
+
+ return err;
+}
+
+/**
+ * dma_chan_put - drop a reference to a dma channel's parent driver module
+ * @chan - channel to release
+ *
+ * Must be called under dma_list_mutex
+ */
+static void dma_chan_put(struct dma_chan *chan)
+{
+ if (!chan->client_count)
+ return; /* this channel failed alloc_chan_resources */
+ chan->client_count--;
+ module_put(dma_chan_to_owner(chan));
+ if (chan->client_count == 0)
+ chan->device->device_free_chan_resources(chan);
+}
+
+enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
+{
+ enum dma_status status;
+ unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
+
+ dma_async_issue_pending(chan);
+ do {
+ status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
+ if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
+ printk(KERN_ERR "dma_sync_wait_timeout!\n");
+ return DMA_ERROR;
+ }
+ } while (status == DMA_IN_PROGRESS);
+
+ return status;
+}
+EXPORT_SYMBOL(dma_sync_wait);
+
+/**
+ * dma_cap_mask_all - enable iteration over all operation types
+ */
+static dma_cap_mask_t dma_cap_mask_all;
+
+/**
+ * dma_chan_tbl_ent - tracks channel allocations per core/operation
+ * @chan - associated channel for this entry
+ */
+struct dma_chan_tbl_ent {
struct dma_chan *chan;
- unsigned long flags;
- int desc; /* allocated descriptor count */
+};
- /* Find a channel, any DMA engine will do */
- list_for_each_entry(device, &dma_device_list, global_node) {
- list_for_each_entry(chan, &device->channels, device_node) {
- if (chan->client)
- continue;
+/**
+ * channel_table - percpu lookup table for memory-to-memory offload providers
+ */
+static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
- desc = chan->device->device_alloc_chan_resources(chan);
- if (desc >= 0) {
- kref_get(&device->refcount);
- kref_init(&chan->refcount);
- chan->slow_ref = 0;
- INIT_RCU_HEAD(&chan->rcu);
- chan->client = client;
- spin_lock_irqsave(&client->lock, flags);
- list_add_tail_rcu(&chan->client_node,
- &client->channels);
- spin_unlock_irqrestore(&client->lock, flags);
- return chan;
- }
+static int __init dma_channel_table_init(void)
+{
+ enum dma_transaction_type cap;
+ int err = 0;
+
+ bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
+
+ /* '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) {
+ channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
+ if (!channel_table[cap]) {
+ err = -ENOMEM;
+ break;
}
}
- return NULL;
+ if (err) {
+ pr_err("dmaengine: initialization failure\n");
+ for_each_dma_cap_mask(cap, dma_cap_mask_all)
+ if (channel_table[cap])
+ free_percpu(channel_table[cap]);
+ }
+
+ return err;
}
+arch_initcall(dma_channel_table_init);
/**
- * dma_chan_cleanup - release a DMA channel's resources
- * @kref: kernel reference structure that contains the DMA channel device
+ * dma_find_channel - find a channel to carry out the operation
+ * @tx_type: transaction type
*/
-void dma_chan_cleanup(struct kref *kref)
+struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
{
- struct dma_chan *chan = container_of(kref, struct dma_chan, refcount);
- chan->device->device_free_chan_resources(chan);
- chan->client = NULL;
- kref_put(&chan->device->refcount, dma_async_device_cleanup);
+ return this_cpu_read(channel_table[tx_type]->chan);
}
+EXPORT_SYMBOL(dma_find_channel);
-static void dma_chan_free_rcu(struct rcu_head *rcu)
+/**
+ * dma_issue_pending_all - flush all pending operations across all channels
+ */
+void dma_issue_pending_all(void)
{
- struct dma_chan *chan = container_of(rcu, struct dma_chan, rcu);
- int bias = 0x7FFFFFFF;
- int i;
- for_each_possible_cpu(i)
- bias -= local_read(&per_cpu_ptr(chan->local, i)->refcount);
- atomic_sub(bias, &chan->refcount.refcount);
- kref_put(&chan->refcount, dma_chan_cleanup);
+ 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);
-static void dma_client_chan_free(struct dma_chan *chan)
+/**
+ * nth_chan - returns the nth channel of the given capability
+ * @cap: capability to match
+ * @n: nth channel desired
+ *
+ * Defaults to returning the channel with the desired capability and the
+ * lowest reference count when 'n' cannot be satisfied. Must be called
+ * under dma_list_mutex.
+ */
+static struct dma_chan *nth_chan(enum dma_transaction_type cap, int n)
{
- atomic_add(0x7FFFFFFF, &chan->refcount.refcount);
- chan->slow_ref = 1;
- call_rcu(&chan->rcu, dma_chan_free_rcu);
+ struct dma_device *device;
+ struct dma_chan *chan;
+ struct dma_chan *ret = NULL;
+ struct dma_chan *min = NULL;
+
+ list_for_each_entry(device, &dma_device_list, global_node) {
+ 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)
+ continue;
+ if (!min)
+ min = chan;
+ else if (chan->table_count < min->table_count)
+ min = chan;
+
+ if (n-- == 0) {
+ ret = chan;
+ break; /* done */
+ }
+ }
+ if (ret)
+ break; /* done */
+ }
+
+ if (!ret)
+ ret = min;
+
+ if (ret)
+ ret->table_count++;
+
+ return ret;
}
/**
- * dma_chans_rebalance - reallocate channels to clients
+ * dma_channel_rebalance - redistribute the available channels
*
- * When the number of DMA channel in the system changes,
- * channels need to be rebalanced among clients.
+ * Optimize for cpu isolation (each cpu gets a dedicated channel for an
+ * operation type) in the SMP case, and operation isolation (avoid
+ * multi-tasking channels) in the non-SMP case. Must be called under
+ * dma_list_mutex.
*/
-static void dma_chans_rebalance(void)
+static void dma_channel_rebalance(void)
{
- struct dma_client *client;
struct dma_chan *chan;
- unsigned long flags;
+ struct dma_device *device;
+ int cpu;
+ int cap;
+ int n;
- mutex_lock(&dma_list_mutex);
+ /* undo the last distribution */
+ for_each_dma_cap_mask(cap, dma_cap_mask_all)
+ for_each_possible_cpu(cpu)
+ per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
- list_for_each_entry(client, &dma_client_list, global_node) {
- while (client->chans_desired > client->chan_count) {
- chan = dma_client_chan_alloc(client);
- if (!chan)
- break;
- client->chan_count++;
- client->event_callback(client,
- chan,
- DMA_RESOURCE_ADDED);
+ 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)
+ return;
+
+ /* redistribute available channels */
+ n = 0;
+ for_each_dma_cap_mask(cap, dma_cap_mask_all)
+ for_each_online_cpu(cpu) {
+ if (num_possible_cpus() > 1)
+ chan = nth_chan(cap, n++);
+ else
+ chan = nth_chan(cap, -1);
+
+ per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
+ }
+}
+
+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;
}
- while (client->chans_desired < client->chan_count) {
- spin_lock_irqsave(&client->lock, flags);
- chan = list_entry(client->channels.next,
- struct dma_chan,
- client_node);
- list_del_rcu(&chan->client_node);
- spin_unlock_irqrestore(&client->lock, flags);
- client->chan_count--;
- client->event_callback(client,
- chan,
- DMA_RESOURCE_REMOVED);
- dma_client_chan_free(chan);
+
+ 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;
}
- mutex_unlock(&dma_list_mutex);
+ return NULL;
}
/**
- * dma_async_client_register - allocate and register a &dma_client
- * @event_callback: callback for notification of channel addition/removal
+ * 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
*/
-struct dma_client *dma_async_client_register(dma_event_callback event_callback)
+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;
- client = kzalloc(sizeof(*client), GFP_KERNEL);
- if (!client)
- return NULL;
+ /* 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 = NULL;
+ }
+ }
+ mutex_unlock(&dma_list_mutex);
- INIT_LIST_HEAD(&client->channels);
- spin_lock_init(&client->lock);
- client->chans_desired = 0;
- client->chan_count = 0;
- client->event_callback = event_callback;
+ pr_debug("%s: %s (%s)\n", __func__, chan ? "success" : "fail",
+ chan ? dma_chan_name(chan) : NULL);
+ return chan;
+}
+EXPORT_SYMBOL_GPL(__dma_request_channel);
+
+void dma_release_channel(struct dma_chan *chan)
+{
mutex_lock(&dma_list_mutex);
- list_add_tail(&client->global_node, &dma_client_list);
+ 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);
mutex_unlock(&dma_list_mutex);
-
- return client;
}
+EXPORT_SYMBOL_GPL(dma_release_channel);
/**
- * 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_get - register interest in dma_channels
*/
-void dma_async_client_unregister(struct dma_client *client)
+void dmaengine_get(void)
{
+ struct dma_device *device, *_d;
struct dma_chan *chan;
+ int err;
- if (!client)
- return;
+ mutex_lock(&dma_list_mutex);
+ dmaengine_ref_count++;
- rcu_read_lock();
- list_for_each_entry_rcu(chan, &client->channels, client_node)
- dma_client_chan_free(chan);
- rcu_read_unlock();
+ /* try to grab channels */
+ 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_rcu(&device->global_node);
+ break;
+ } else if (err)
+ pr_err("dmaengine: failed to get %s: (%d)\n",
+ dma_chan_name(chan), err);
+ }
+ }
- mutex_lock(&dma_list_mutex);
- list_del(&client->global_node);
+ /* if this is the first reference and there were channels
+ * waiting we need to rebalance to get those channels
+ * incorporated into the channel table
+ */
+ if (dmaengine_ref_count == 1)
+ dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
-
- kfree(client);
- dma_chans_rebalance();
}
+EXPORT_SYMBOL(dmaengine_get);
/**
- * dma_async_client_chan_request - request DMA channels
- * @client: &dma_client
- * @number: count of DMA channels requested
- *
- * Clients call dma_async_client_chan_request() to specify how many
- * DMA channels they need, 0 to free all currently allocated.
- * The resulting allocations/frees are indicated to the client via the
- * event callback.
+ * dmaengine_put - let dma drivers be removed when ref_count == 0
*/
-void dma_async_client_chan_request(struct dma_client *client,
- unsigned int number)
+void dmaengine_put(void)
{
- client->chans_desired = number;
- dma_chans_rebalance();
+ struct dma_device *device;
+ struct dma_chan *chan;
+
+ 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) {
+ if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+ continue;
+ list_for_each_entry(chan, &device->channels, device_node)
+ dma_chan_put(chan);
+ }
+ mutex_unlock(&dma_list_mutex);
+}
+EXPORT_SYMBOL(dmaengine_put);
+
+static bool device_has_all_tx_types(struct dma_device *device)
+{
+ /* A device that satisfies this test has channels that will never cause
+ * an async_tx channel switch event as all possible operation types can
+ * be handled.
+ */
+ #ifdef CONFIG_ASYNC_TX_DMA
+ if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
+ return false;
+ #endif
+
+ #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
+ if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
+ return false;
+ #endif
+
+ #if defined(CONFIG_ASYNC_MEMSET) || defined(CONFIG_ASYNC_MEMSET_MODULE)
+ if (!dma_has_cap(DMA_MEMSET, device->cap_mask))
+ return false;
+ #endif
+
+ #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
+ if (!dma_has_cap(DMA_XOR, device->cap_mask))
+ return false;
+
+ #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
+ if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
+ return false;
+ #endif
+ #endif
+
+ #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
+ if (!dma_has_cap(DMA_PQ, device->cap_mask))
+ return false;
+
+ #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
+ if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
+ return false;
+ #endif
+ #endif
+
+ return true;
+}
+
+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);
+ 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;
}
/**
*/
int dma_async_device_register(struct dma_device *device)
{
- static int id;
- int chancnt = 0;
+ int chancnt = 0, rc;
struct dma_chan* chan;
+ atomic_t *idr_ref;
if (!device)
return -ENODEV;
- init_completion(&device->done);
- kref_init(&device->refcount);
- device->dev_id = id++;
+ /* validate device routines */
+ BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
+ !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_XOR_VAL, device->cap_mask) &&
+ !device->device_prep_dma_xor_val);
+ BUG_ON(dma_has_cap(DMA_PQ, device->cap_mask) &&
+ !device->device_prep_dma_pq);
+ BUG_ON(dma_has_cap(DMA_PQ_VAL, device->cap_mask) &&
+ !device->device_prep_dma_pq_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) &&
+ !device->device_prep_dma_interrupt);
+ BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
+ !device->device_prep_slave_sg);
+ BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
+ !device->device_control);
+
+ BUG_ON(!device->device_alloc_chan_resources);
+ BUG_ON(!device->device_free_chan_resources);
+ BUG_ON(!device->device_tx_status);
+ BUG_ON(!device->device_issue_pending);
+ BUG_ON(!device->dev);
+
+ /* note: this only matters in the
+ * CONFIG_ASYNC_TX_DISABLE_CHANNEL_SWITCH=y case
+ */
+ if (device_has_all_tx_types(device))
+ dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
+
+ 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;
+ }
+
+ 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->class_dev.class = &dma_devclass;
- chan->class_dev.dev = NULL;
- snprintf(chan->class_dev.class_id, BUS_ID_SIZE, "dma%dchan%d",
- device->dev_id, chan->chan_id);
+ 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);
- kref_get(&device->refcount);
- class_device_register(&chan->class_dev);
+ rc = device_register(&chan->dev->device);
+ if (rc) {
+ free_percpu(chan->local);
+ chan->local = NULL;
+ kfree(chan->dev);
+ atomic_dec(idr_ref);
+ goto err_out;
+ }
+ chan->client_count = 0;
}
+ device->chancnt = chancnt;
mutex_lock(&dma_list_mutex);
- list_add_tail(&device->global_node, &dma_device_list);
+ /* 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
+ */
+ if (dma_chan_get(chan) == -ENODEV) {
+ /* note we can only get here for the first
+ * channel as the remaining channels are
+ * guaranteed to get a reference
+ */
+ rc = -ENODEV;
+ mutex_unlock(&dma_list_mutex);
+ goto err_out;
+ }
+ }
+ 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_chans_rebalance();
-
return 0;
-}
-/**
- * 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;
+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;
+ }
- device = container_of(kref, struct dma_device, refcount);
- complete(&device->done);
+ list_for_each_entry(chan, &device->channels, device_node) {
+ if (chan->local == NULL)
+ continue;
+ 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_unregister - unregisters DMA devices
+ * 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;
- unsigned long flags;
mutex_lock(&dma_list_mutex);
- list_del(&device->global_node);
+ list_del_rcu(&device->global_node);
+ dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
list_for_each_entry(chan, &device->channels, device_node) {
- if (chan->client) {
- spin_lock_irqsave(&chan->client->lock, flags);
- list_del(&chan->client_node);
- chan->client->chan_count--;
- spin_unlock_irqrestore(&chan->client->lock, flags);
- chan->client->event_callback(chan->client,
- chan,
- DMA_RESOURCE_REMOVED);
- dma_client_chan_free(chan);
+ WARN_ONCE(chan->client_count,
+ "%s called while %d clients hold a reference\n",
+ __func__, chan->client_count);
+ mutex_lock(&dma_list_mutex);
+ chan->dev->chan = NULL;
+ mutex_unlock(&dma_list_mutex);
+ device_unregister(&chan->dev->device);
+ free_percpu(chan->local);
+ }
+}
+EXPORT_SYMBOL(dma_async_device_unregister);
+
+/**
+ * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
+ * @chan: DMA channel to offload copy to
+ * @dest: destination address (virtual)
+ * @src: source address (virtual)
+ * @len: length
+ *
+ * Both @dest and @src must be mappable to a bus address according to the
+ * DMA mapping API rules for streaming mappings.
+ * Both @dest and @src must stay memory resident (kernel memory or locked
+ * user space pages).
+ */
+dma_cookie_t
+dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest,
+ void *src, size_t len)
+{
+ struct dma_device *dev = chan->device;
+ struct dma_async_tx_descriptor *tx;
+ dma_addr_t dma_dest, dma_src;
+ dma_cookie_t cookie;
+ unsigned long flags;
+
+ dma_src = dma_map_single(dev->dev, src, len, DMA_TO_DEVICE);
+ dma_dest = dma_map_single(dev->dev, dest, len, DMA_FROM_DEVICE);
+ flags = DMA_CTRL_ACK |
+ DMA_COMPL_SRC_UNMAP_SINGLE |
+ DMA_COMPL_DEST_UNMAP_SINGLE;
+ tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
+
+ if (!tx) {
+ dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
+ dma_unmap_single(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
+ return -ENOMEM;
+ }
+
+ tx->callback = NULL;
+ cookie = tx->tx_submit(tx);
+
+ preempt_disable();
+ __this_cpu_add(chan->local->bytes_transferred, len);
+ __this_cpu_inc(chan->local->memcpy_count);
+ preempt_enable();
+
+ return cookie;
+}
+EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
+
+/**
+ * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
+ * @chan: DMA channel to offload copy to
+ * @page: destination page
+ * @offset: offset in page to copy to
+ * @kdata: source address (virtual)
+ * @len: length
+ *
+ * Both @page/@offset and @kdata must be mappable to a bus address according
+ * to the DMA mapping API rules for streaming mappings.
+ * Both @page/@offset and @kdata must stay memory resident (kernel memory or
+ * locked user space pages)
+ */
+dma_cookie_t
+dma_async_memcpy_buf_to_pg(struct dma_chan *chan, struct page *page,
+ unsigned int offset, void *kdata, size_t len)
+{
+ struct dma_device *dev = chan->device;
+ struct dma_async_tx_descriptor *tx;
+ dma_addr_t dma_dest, dma_src;
+ dma_cookie_t cookie;
+ unsigned long flags;
+
+ dma_src = dma_map_single(dev->dev, kdata, len, DMA_TO_DEVICE);
+ dma_dest = dma_map_page(dev->dev, page, offset, len, DMA_FROM_DEVICE);
+ flags = DMA_CTRL_ACK | DMA_COMPL_SRC_UNMAP_SINGLE;
+ tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
+
+ if (!tx) {
+ dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
+ dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
+ return -ENOMEM;
+ }
+
+ tx->callback = NULL;
+ cookie = tx->tx_submit(tx);
+
+ preempt_disable();
+ __this_cpu_add(chan->local->bytes_transferred, len);
+ __this_cpu_inc(chan->local->memcpy_count);
+ preempt_enable();
+
+ return cookie;
+}
+EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
+
+/**
+ * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
+ * @chan: DMA channel to offload copy to
+ * @dest_pg: destination page
+ * @dest_off: offset in page to copy to
+ * @src_pg: source page
+ * @src_off: offset in page to copy from
+ * @len: length
+ *
+ * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
+ * address according to the DMA mapping API rules for streaming mappings.
+ * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
+ * (kernel memory or locked user space pages).
+ */
+dma_cookie_t
+dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
+ unsigned int dest_off, struct page *src_pg, unsigned int src_off,
+ size_t len)
+{
+ struct dma_device *dev = chan->device;
+ struct dma_async_tx_descriptor *tx;
+ dma_addr_t dma_dest, dma_src;
+ dma_cookie_t cookie;
+ unsigned long flags;
+
+ dma_src = dma_map_page(dev->dev, src_pg, src_off, len, DMA_TO_DEVICE);
+ dma_dest = dma_map_page(dev->dev, dest_pg, dest_off, len,
+ DMA_FROM_DEVICE);
+ flags = DMA_CTRL_ACK;
+ tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
+
+ if (!tx) {
+ dma_unmap_page(dev->dev, dma_src, len, DMA_TO_DEVICE);
+ dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
+ return -ENOMEM;
+ }
+
+ tx->callback = NULL;
+ cookie = tx->tx_submit(tx);
+
+ preempt_disable();
+ __this_cpu_add(chan->local->bytes_transferred, len);
+ __this_cpu_inc(chan->local->memcpy_count);
+ preempt_enable();
+
+ return cookie;
+}
+EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
+
+void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
+ struct dma_chan *chan)
+{
+ tx->chan = chan;
+ #ifndef CONFIG_ASYNC_TX_DISABLE_CHANNEL_SWITCH
+ spin_lock_init(&tx->lock);
+ #endif
+}
+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
+ */
+enum dma_status
+dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
+{
+ unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
+
+ if (!tx)
+ return DMA_SUCCESS;
+
+ 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;
}
- class_device_unregister(&chan->class_dev);
+ cpu_relax();
}
- dma_chans_rebalance();
+ return dma_sync_wait(tx->chan, tx->cookie);
+}
+EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
+
+/* dma_run_dependencies - helper routine for dma drivers to process
+ * (start) dependent operations on their target channel
+ * @tx: transaction with dependencies
+ */
+void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
+{
+ struct dma_async_tx_descriptor *dep = txd_next(tx);
+ struct dma_async_tx_descriptor *dep_next;
+ struct dma_chan *chan;
+
+ if (!dep)
+ return;
+
+ /* we'll submit tx->next now, so clear the link */
+ txd_clear_next(tx);
+ chan = dep->chan;
- kref_put(&device->refcount, dma_async_device_cleanup);
- wait_for_completion(&device->done);
+ /* keep submitting up until a channel switch is detected
+ * in that case we will be called again as a result of
+ * processing the interrupt from async_tx_channel_switch
+ */
+ for (; dep; dep = dep_next) {
+ txd_lock(dep);
+ txd_clear_parent(dep);
+ dep_next = txd_next(dep);
+ if (dep_next && dep_next->chan == chan)
+ txd_clear_next(dep); /* ->next will be submitted */
+ else
+ dep_next = NULL; /* submit current dep and terminate */
+ txd_unlock(dep);
+
+ dep->tx_submit(dep);
+ }
+
+ chan->device->device_issue_pending(chan);
}
+EXPORT_SYMBOL_GPL(dma_run_dependencies);
static int __init dma_bus_init(void)
{
+ idr_init(&dma_idr);
mutex_init(&dma_list_mutex);
return class_register(&dma_devclass);
}
+arch_initcall(dma_bus_init);
-subsys_initcall(dma_bus_init);
-EXPORT_SYMBOL(dma_async_client_register);
-EXPORT_SYMBOL(dma_async_client_unregister);
-EXPORT_SYMBOL(dma_async_client_chan_request);
-EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
-EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
-EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
-EXPORT_SYMBOL(dma_async_memcpy_complete);
-EXPORT_SYMBOL(dma_async_memcpy_issue_pending);
-EXPORT_SYMBOL(dma_async_device_register);
-EXPORT_SYMBOL(dma_async_device_unregister);
-EXPORT_SYMBOL(dma_chan_cleanup);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff