diff options
| author | Dave Jiang <dave.jiang@intel.com> | 2020-01-21 16:43:53 -0700 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2020-01-24 11:18:45 +0530 |
| commit | e81274cd6b5264809384066e09a5253708822522 (patch) | |
| tree | cb5bf34db91411a0b06367a784484f93bf2e1ead /drivers/dma/dmaengine.c | |
| parent | d2fb0a0438384fee08a418025f743913020033ce (diff) | |
dmaengine: add support to dynamic register/unregister of channels
With the channel registration routines broken out, now add support code to
allow independent registering and unregistering of channels in a hotplug fashion.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/157965023364.73301.7821862091077299040.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma/dmaengine.c')
| -rw-r--r-- | drivers/dma/dmaengine.c | 34 |
1 files changed, 26 insertions, 8 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 2daf2ee9bebd..51a2f2b1b2de 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -986,6 +986,20 @@ static int __dma_async_device_channel_register(struct dma_device *device, 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) { @@ -993,12 +1007,22 @@ static void __dma_async_device_channel_unregister(struct dma_device *device, "%s called while %d clients hold a reference\n", __func__, chan->client_count); mutex_lock(&dma_list_mutex); + list_del(&chan->device_node); + device->chancnt--; 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 @@ -1121,12 +1145,6 @@ int dma_async_device_register(struct dma_device *device) goto err_out; } - if (!device->chancnt) { - dev_err(device->dev, "%s: device has no channels!\n", __func__); - rc = -ENODEV; - goto err_out; - } - mutex_lock(&dma_list_mutex); /* take references on public channels */ if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask)) @@ -1181,9 +1199,9 @@ EXPORT_SYMBOL(dma_async_device_register); */ void dma_async_device_unregister(struct dma_device *device) { - struct dma_chan *chan; + struct dma_chan *chan, *n; - list_for_each_entry(chan, &device->channels, device_node) + list_for_each_entry_safe(chan, n, &device->channels, device_node) __dma_async_device_channel_unregister(device, chan); mutex_lock(&dma_list_mutex); |