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authorDave Jiang <dave.jiang@intel.com>2020-01-22 02:43:53 +0300
committerVinod Koul <vkoul@kernel.org>2020-01-24 08:48:45 +0300
commite81274cd6b5264809384066e09a5253708822522 (patch)
treecb5bf34db91411a0b06367a784484f93bf2e1ead /drivers/dma
parentd2fb0a0438384fee08a418025f743913020033ce (diff)
downloadlinux-e81274cd6b5264809384066e09a5253708822522.tar.xz
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')
-rw-r--r--drivers/dma/dmaengine.c34
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);