diff options
| author | Geert Uytterhoeven | 2020-01-17 16:30:56 +0100 |
|---|---|---|
| committer | Vinod Koul | 2020-01-24 11:41:32 +0530 |
| commit | 71723a96b8b1367fefc18f60025dae792477d602 (patch) | |
| tree | 3b1f3f47cfa643fbbcac9d3c15fbac210f808382 /include/linux | |
| parent | e9f08b65250d73ab70e79e194813f52b8d306784 (diff) | |
dmaengine: Create symlinks between DMA channels and slaves
Currently it is not easy to find out which DMA channels are in use, and
which slave devices are using which channels.
Fix this by creating two symlinks between the DMA channel and the actual
slave device when a channel is requested:
1. A "slave" symlink from DMA channel to slave device,
2. A "dma:<name>" symlink slave device to DMA channel.
When the channel is released, the symlinks are removed again.
The latter requires keeping track of the slave device and the channel
name in the dma_chan structure.
Note that this is limited to channel request functions for requesting an
exclusive slave channel that take a device pointer (dma_request_chan()
and dma_request_slave_channel*()).
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Link: https://lore.kernel.org/r/20200117153056.31363-1-geert+renesas@glider.be
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/dmaengine.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index f52f274773ed..fef69a9c5824 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -294,10 +294,12 @@ struct dma_router { /** * struct dma_chan - devices supply DMA channels, clients use them * @device: ptr to the dma device who supplies this channel, always !%NULL + * @slave: ptr to the device using this channel * @cookie: last cookie value returned to client * @completed_cookie: last completed cookie for this channel * @chan_id: channel ID for sysfs * @dev: class device for sysfs + * @name: backlink name for sysfs * @device_node: used to add this to the device chan list * @local: per-cpu pointer to a struct dma_chan_percpu * @client_count: how many clients are using this channel @@ -308,12 +310,14 @@ struct dma_router { */ struct dma_chan { struct dma_device *device; + struct device *slave; dma_cookie_t cookie; dma_cookie_t completed_cookie; /* sysfs */ int chan_id; struct dma_chan_dev *dev; + const char *name; struct list_head device_node; struct dma_chan_percpu __percpu *local; |