fbe05149e4
The K3 platforms configure the DMA resources with the help of the TI's System Firmware's Device Manager(DM) over TISCI. The group of DMA related Resource Manager[1] TISCI messages includes: INTA, RINGACC, UDMAP, and PSI-L. This configuration however, does not persist in the DM after leaving from Suspend-to-RAM state. We have to restore the DMA channel configuration over TISCI for all configured channels when returning from suspend. The TISCI resource management calls for each DMA type (UDMA, PKTDMA, BCDMA) happen in device_free_chan_resources() and device_alloc_chan_resources(). In pm_suspend() we store the current udma_chan_config for channels that still have attached clients and call device_free_chan_resources(). In pm_resume() restore the udma_channel_config from backup and call device_alloc_chan_resources() for those channels. Drivers like CPSW that use k3-udma-glue already do their own DMA resource management so use the late system suspend/resume hooks. [1] https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/index.html#resource-management-rm Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com> [g-vlaev@ti.com: Add patch description and config backup] [g-vlaev@ti.com: Supend only channels with clients] Signed-off-by: Georgi Vlaev <g-vlaev@ti.com> Acked-by: Peter Ujfalusi <peter.ujfalusi@gmail.com> Link: https://lore.kernel.org/r/20230329155349.2566010-1-vigneshr@ti.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.