* 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 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_put is done for each class_device registered. When the
+ * registered. A kref_get 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
* 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
+ * 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 unregesitered. 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
*/
#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>
static DEFINE_MUTEX(dma_list_mutex);
static LIST_HEAD(dma_device_list);
static ssize_t show_in_use(struct class_device *cd, char *buf)
{
struct dma_chan *chan = container_of(cd, struct dma_chan, class_dev);
+ int in_use = 0;
+
+ if (unlikely(chan->slow_ref) &&
+ atomic_read(&chan->refcount.refcount) > 1)
+ in_use = 1;
+ else {
+ if (local_read(&(per_cpu_ptr(chan->local,
+ get_cpu())->refcount)) > 0)
+ in_use = 1;
+ put_cpu();
+ }
- return sprintf(buf, "%d\n", (chan->client ? 1 : 0));
+ return sprintf(buf, "%d\n", in_use);
}
static struct class_device_attribute dma_class_attrs[] = {
/* --- client and device registration --- */
+#define dma_chan_satisfies_mask(chan, mask) \
+ __dma_chan_satisfies_mask((chan), &(mask))
+static int
+__dma_chan_satisfies_mask(struct dma_chan *chan, dma_cap_mask_t *want)
+{
+ dma_cap_mask_t has;
+
+ bitmap_and(has.bits, want->bits, chan->device->cap_mask.bits,
+ DMA_TX_TYPE_END);
+ return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
+}
+
/**
- * dma_client_chan_alloc - try to allocate a channel to a client
+ * dma_client_chan_alloc - try to allocate channels to a client
* @client: &dma_client
*
* Called with dma_list_mutex held.
*/
-static struct dma_chan *dma_client_chan_alloc(struct dma_client *client)
+static void dma_client_chan_alloc(struct dma_client *client)
{
struct dma_device *device;
struct dma_chan *chan;
- unsigned long flags;
int desc; /* allocated descriptor count */
+ enum dma_state_client ack;
- /* Find a channel, any DMA engine will do */
- list_for_each_entry(device, &dma_device_list, global_node) {
+ /* Find a channel */
+ list_for_each_entry(device, &dma_device_list, global_node)
list_for_each_entry(chan, &device->channels, device_node) {
- if (chan->client)
+ if (!dma_chan_satisfies_mask(chan, client->cap_mask))
continue;
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;
+ ack = client->event_callback(client,
+ chan,
+ DMA_RESOURCE_AVAILABLE);
+
+ /* we are done once this client rejects
+ * an available resource
+ */
+ if (ack == DMA_ACK) {
+ dma_chan_get(chan);
+ kref_get(&device->refcount);
+ } else if (ack == DMA_NAK)
+ return;
}
}
- }
+}
+
+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 NULL;
+ return status;
}
+EXPORT_SYMBOL(dma_sync_wait);
/**
* dma_chan_cleanup - release a DMA channel's resources
{
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);
}
EXPORT_SYMBOL(dma_chan_cleanup);
kref_put(&chan->refcount, dma_chan_cleanup);
}
-static void dma_client_chan_free(struct dma_chan *chan)
+static void dma_chan_release(struct dma_chan *chan)
{
atomic_add(0x7FFFFFFF, &chan->refcount.refcount);
chan->slow_ref = 1;
}
/**
- * dma_chans_rebalance - reallocate channels to clients
- *
- * When the number of DMA channel in the system changes,
- * channels need to be rebalanced among clients.
+ * dma_chans_notify_available - broadcast available channels to the clients
*/
-static void dma_chans_rebalance(void)
+static void dma_clients_notify_available(void)
{
struct dma_client *client;
- struct dma_chan *chan;
- unsigned long flags;
mutex_lock(&dma_list_mutex);
- 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);
- }
- 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(client, &dma_client_list, global_node)
+ dma_client_chan_alloc(client);
mutex_unlock(&dma_list_mutex);
}
/**
- * dma_async_client_register - allocate and register a &dma_client
- * @event_callback: callback for notification of channel addition/removal
+ * dma_chans_notify_available - tell the clients that a channel is going away
+ * @chan: channel on its way out
*/
-struct dma_client *dma_async_client_register(dma_event_callback event_callback)
+static void dma_clients_notify_removed(struct dma_chan *chan)
{
struct dma_client *client;
+ enum dma_state_client ack;
- client = kzalloc(sizeof(*client), GFP_KERNEL);
- if (!client)
- return NULL;
+ mutex_lock(&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;
+ list_for_each_entry(client, &dma_client_list, global_node) {
+ ack = client->event_callback(client, chan,
+ DMA_RESOURCE_REMOVED);
+
+ /* client was holding resources for this channel so
+ * free it
+ */
+ if (ack == DMA_ACK) {
+ dma_chan_put(chan);
+ kref_put(&chan->device->refcount,
+ dma_async_device_cleanup);
+ }
+ }
+ mutex_unlock(&dma_list_mutex);
+}
+
+/**
+ * dma_async_client_register - register a &dma_client
+ * @client: ptr to a client structure with valid 'event_callback' and 'cap_mask'
+ */
+void dma_async_client_register(struct dma_client *client)
+{
mutex_lock(&dma_list_mutex);
list_add_tail(&client->global_node, &dma_client_list);
mutex_unlock(&dma_list_mutex);
-
- return client;
}
EXPORT_SYMBOL(dma_async_client_register);
*/
void dma_async_client_unregister(struct dma_client *client)
{
+ struct dma_device *device;
struct dma_chan *chan;
+ enum dma_state_client ack;
if (!client)
return;
- rcu_read_lock();
- list_for_each_entry_rcu(chan, &client->channels, client_node)
- dma_client_chan_free(chan);
- rcu_read_unlock();
-
mutex_lock(&dma_list_mutex);
+ /* free all channels the client is holding */
+ list_for_each_entry(device, &dma_device_list, global_node)
+ list_for_each_entry(chan, &device->channels, device_node) {
+ ack = client->event_callback(client, chan,
+ DMA_RESOURCE_REMOVED);
+
+ if (ack == DMA_ACK) {
+ dma_chan_put(chan);
+ kref_put(&chan->device->refcount,
+ dma_async_device_cleanup);
+ }
+ }
+
list_del(&client->global_node);
mutex_unlock(&dma_list_mutex);
-
- kfree(client);
- dma_chans_rebalance();
}
EXPORT_SYMBOL(dma_async_client_unregister);
/**
- * 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.
+ * 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,
- unsigned int number)
+void dma_async_client_chan_request(struct dma_client *client)
{
- client->chans_desired = number;
- dma_chans_rebalance();
+ mutex_lock(&dma_list_mutex);
+ dma_client_chan_alloc(client);
+ mutex_unlock(&dma_list_mutex);
}
EXPORT_SYMBOL(dma_async_client_chan_request);
int dma_async_device_register(struct dma_device *device)
{
static int id;
- int chancnt = 0;
+ int chancnt = 0, rc;
struct dma_chan* chan;
if (!device)
return -ENODEV;
+ /* 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_ZERO_SUM, device->cap_mask) &&
+ !device->device_prep_dma_zero_sum);
+ BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
+ !device->device_prep_dma_memset);
+ BUG_ON(dma_has_cap(DMA_ZERO_SUM, device->cap_mask) &&
+ !device->device_prep_dma_interrupt);
+
+ BUG_ON(!device->device_alloc_chan_resources);
+ BUG_ON(!device->device_free_chan_resources);
+ BUG_ON(!device->device_dependency_added);
+ BUG_ON(!device->device_is_tx_complete);
+ BUG_ON(!device->device_issue_pending);
+ BUG_ON(!device->dev);
+
init_completion(&device->done);
kref_init(&device->refcount);
device->dev_id = id++;
snprintf(chan->class_dev.class_id, BUS_ID_SIZE, "dma%dchan%d",
device->dev_id, chan->chan_id);
+ rc = class_device_register(&chan->class_dev);
+ if (rc) {
+ chancnt--;
+ free_percpu(chan->local);
+ chan->local = NULL;
+ goto err_out;
+ }
+
kref_get(&device->refcount);
- class_device_register(&chan->class_dev);
+ kref_init(&chan->refcount);
+ chan->slow_ref = 0;
+ INIT_RCU_HEAD(&chan->rcu);
}
mutex_lock(&dma_list_mutex);
list_add_tail(&device->global_node, &dma_device_list);
mutex_unlock(&dma_list_mutex);
- dma_chans_rebalance();
+ dma_clients_notify_available();
return 0;
+
+err_out:
+ list_for_each_entry(chan, &device->channels, device_node) {
+ if (chan->local == NULL)
+ continue;
+ kref_put(&device->refcount, dma_async_device_cleanup);
+ class_device_unregister(&chan->class_dev);
+ chancnt--;
+ free_percpu(chan->local);
+ }
+ return rc;
}
EXPORT_SYMBOL(dma_async_device_register);
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);
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);
- }
+ dma_clients_notify_removed(chan);
class_device_unregister(&chan->class_dev);
+ dma_chan_release(chan);
}
- dma_chans_rebalance();
kref_put(&device->refcount, dma_async_device_cleanup);
wait_for_completion(&device->done);
}
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 addr;
+ dma_cookie_t cookie;
+ int cpu;
+
+ tx = dev->device_prep_dma_memcpy(chan, len, 0);
+ if (!tx)
+ return -ENOMEM;
+
+ tx->ack = 1;
+ tx->callback = NULL;
+ addr = dma_map_single(dev->dev, src, len, DMA_TO_DEVICE);
+ tx->tx_set_src(addr, tx, 0);
+ addr = dma_map_single(dev->dev, dest, len, DMA_FROM_DEVICE);
+ tx->tx_set_dest(addr, tx, 0);
+ cookie = tx->tx_submit(tx);
+
+ cpu = get_cpu();
+ per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
+ per_cpu_ptr(chan->local, cpu)->memcpy_count++;
+ put_cpu();
+
+ 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 addr;
+ dma_cookie_t cookie;
+ int cpu;
+
+ tx = dev->device_prep_dma_memcpy(chan, len, 0);
+ if (!tx)
+ return -ENOMEM;
+
+ tx->ack = 1;
+ tx->callback = NULL;
+ addr = dma_map_single(dev->dev, kdata, len, DMA_TO_DEVICE);
+ tx->tx_set_src(addr, tx, 0);
+ addr = dma_map_page(dev->dev, page, offset, len, DMA_FROM_DEVICE);
+ tx->tx_set_dest(addr, tx, 0);
+ cookie = tx->tx_submit(tx);
+
+ cpu = get_cpu();
+ per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
+ per_cpu_ptr(chan->local, cpu)->memcpy_count++;
+ put_cpu();
+
+ 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 addr;
+ dma_cookie_t cookie;
+ int cpu;
+
+ tx = dev->device_prep_dma_memcpy(chan, len, 0);
+ if (!tx)
+ return -ENOMEM;
+
+ tx->ack = 1;
+ tx->callback = NULL;
+ addr = dma_map_page(dev->dev, src_pg, src_off, len, DMA_TO_DEVICE);
+ tx->tx_set_src(addr, tx, 0);
+ addr = dma_map_page(dev->dev, dest_pg, dest_off, len, DMA_FROM_DEVICE);
+ tx->tx_set_dest(addr, tx, 0);
+ cookie = tx->tx_submit(tx);
+
+ cpu = get_cpu();
+ per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
+ per_cpu_ptr(chan->local, cpu)->memcpy_count++;
+ put_cpu();
+
+ 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;
+ spin_lock_init(&tx->lock);
+ INIT_LIST_HEAD(&tx->depend_node);
+ INIT_LIST_HEAD(&tx->depend_list);
+}
+EXPORT_SYMBOL(dma_async_tx_descriptor_init);
+
static int __init dma_bus_init(void)
{
mutex_init(&dma_list_mutex);
git.samba.org / sfrench / cifs-2.6.git / blobdiff