dmaengine updates for v5.6-rc1

 - Core:
   - Support for dynamic channels
   - Removal of various slave wrappers
   - Make few slave request APIs as private to dmaengine
   - Symlinks between channels and slaves
   - Support for hotplug of controllers
   - Support for metadata_ops for dma_async_tx_descriptor
   - Reporting DMA cached data amount
   - Virtual dma channel locking updates

 - New drivers/device/feature support support:
   - Driver for Intel data accelerators
   - Driver for TI K3 UDMA
   - Driver for PLX DMA engine
   - Driver for hisilicon Kunpeng DMA engine
   - Support for eDMA support for QorIQ LS1028A in fsl edma driver
   - Support for cyclic dma in sun4i driver
   - Support for X1830 in JZ4780 driver
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>
2 files changed