17e4660ae3
This builds on top of the MMU contexts introduced earlier. Instead of having one context per GPU core, each GPU client receives its own context. On MMUv1 this still means a single shared pagetable set is used by all clients, but on MMUv2 there is now a distinct set of pagetables for each client. As the command fetch is also translated via the MMU on MMUv2 the kernel command ringbuffer is mapped into each of the client pagetables. As the MMU context switch is a bit of a heavy operation, due to the needed cache and TLB flushing, this patch implements a lazy way of switching the MMU context. The kernel does not have its own MMU context, but reuses the last client context for all of its operations. This has some visible impact, as the GPU can now only be started once a client has submitted some work and we got the client MMU context assigned. Also the MMU context has a different lifetime than the general client context, as the GPU might still execute the kernel command buffer in the context of a client even after the client has completed all GPU work and has been terminated. Only when the GPU is runtime suspended or switches to another clients MMU context is the old context freed up. Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Reviewed-by: Guido Günther <agx@sigxcpu.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.