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Subject[PATCH RFC v3 02/14] dmaengine: break out channel registration
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Date
In preparation for dynamic channel registration, the code segment that
does the channel registration is broken out to its own function.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
drivers/dma/dmaengine.c | 157 ++++++++++++++++++++++++++++++---------------
include/linux/dmaengine.h | 4 +
2 files changed, 107 insertions(+), 54 deletions(-)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 03ac4b96117c..a20ab568b637 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -900,15 +900,109 @@ static int get_dma_id(struct dma_device *device)
return 0;
}

+static int __dma_async_device_channel_register(struct dma_device *device,
+ struct dma_chan *chan,
+ int chan_id)
+{
+ int rc = 0;
+ int chancnt = device->chancnt;
+ atomic_t *idr_ref;
+ struct dma_chan *tchan;
+
+ tchan = list_first_entry_or_null(&device->channels,
+ struct dma_chan, device_node);
+ if (tchan->dev) {
+ idr_ref = tchan->dev->idr_ref;
+ } else {
+ idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
+ if (!idr_ref)
+ return -ENOMEM;
+ atomic_set(idr_ref, 0);
+ }
+
+ chan->local = alloc_percpu(typeof(*chan->local));
+ if (!chan->local)
+ goto err_out;
+ chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
+ if (!chan->dev) {
+ free_percpu(chan->local);
+ chan->local = NULL;
+ goto err_out;
+ }
+
+ /*
+ * When the chan_id is a negative value, we are dynamically adding
+ * the channel. Otherwise we are static enumerating.
+ */
+ chan->chan_id = chan_id < 0 ? chancnt : 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);
+
+ rc = device_register(&chan->dev->device);
+ if (rc)
+ goto err_out;
+ chan->client_count = 0;
+ device->chancnt = chan->chan_id + 1;
+
+ return 0;
+
+ err_out:
+ free_percpu(chan->local);
+ kfree(chan->dev);
+ if (atomic_dec_return(idr_ref) == 0)
+ kfree(idr_ref);
+ return rc;
+}
+
+int dma_async_device_channel_register(struct dma_device *device,
+ struct dma_chan *chan)
+{
+ int rc;
+
+ rc = __dma_async_device_channel_register(device, chan, -1);
+ if (rc < 0)
+ return rc;
+
+ dma_channel_rebalance();
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dma_async_device_channel_register);
+
+static void __dma_async_device_channel_unregister(struct dma_device *device,
+ struct dma_chan *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);
+}
+
+void dma_async_device_channel_unregister(struct dma_device *device,
+ struct dma_chan *chan)
+{
+ __dma_async_device_channel_unregister(device, chan);
+ dma_channel_rebalance();
+}
+EXPORT_SYMBOL_GPL(dma_async_device_channel_unregister);
+
/**
* dma_async_device_register - registers DMA devices found
* @device: &dma_device
*/
int dma_async_device_register(struct dma_device *device)
{
- int chancnt = 0, rc;
+ int rc, i = 0;
struct dma_chan* chan;
- atomic_t *idr_ref;

if (!device)
return -ENODEV;
@@ -1000,59 +1094,23 @@ int dma_async_device_register(struct dma_device *device)
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);
+ if (rc != 0)
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)
+ rc = __dma_async_device_channel_register(device, chan, i++);
+ if (rc < 0)
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->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->device);
- if (rc) {
- free_percpu(chan->local);
- chan->local = NULL;
- kfree(chan->dev);
- atomic_dec(idr_ref);
- goto err_out;
- }
- chan->client_count = 0;
}

- if (!chancnt) {
+ if (!device->chancnt) {
dev_err(device->dev, "%s: device has no channels!\n", __func__);
rc = -ENODEV;
goto err_out;
}

- device->chancnt = chancnt;
-
mutex_lock(&dma_list_mutex);
/* take references on public channels */
if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
@@ -1080,9 +1138,8 @@ int dma_async_device_register(struct dma_device *device)

err_out:
/* if we never registered a channel just release the idr */
- if (atomic_read(idr_ref) == 0) {
+ if (!device->chancnt) {
ida_free(&dma_ida, device->dev_id);
- kfree(idr_ref);
return rc;
}

@@ -1115,16 +1172,8 @@ void dma_async_device_unregister(struct dma_device *device)
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);

- list_for_each_entry(chan, &device->channels, device_node) {
- 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);
- }
+ list_for_each_entry(chan, &device->channels, device_node)
+ __dma_async_device_channel_unregister(device, chan);
}
EXPORT_SYMBOL(dma_async_device_unregister);

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 8fcdee1c0cf9..0202d44a17a5 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -1399,6 +1399,10 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
int dma_async_device_register(struct dma_device *device);
int dmaenginem_async_device_register(struct dma_device *device);
void dma_async_device_unregister(struct dma_device *device);
+int dma_async_device_channel_register(struct dma_device *device,
+ struct dma_chan *chan);
+void dma_async_device_channel_unregister(struct dma_device *device,
+ struct dma_chan *chan);
void dma_run_dependencies(struct dma_async_tx_descriptor *tx);
struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);
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