drm/etnaviv: reference MMU context when setting up hardware state

Move the refcount manipulation of the MMU context to the point where the
hardware state is programmed. At that point it is also known if a previous
MMU state is still there, or the state needs to be reprogrammed with a
potentially different context.

Cc: stable@vger.kernel.org # 5.4
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Michael Walle <michael@walle.cc>
Tested-by: Marek Vasut <marex@denx.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

drm/etnaviv: fix dumping of iommuv2

etnaviv_iommuv2_dump_size(..) returns the number of PTE * SZ_4K but
etnaviv_iommuv2_dump(..) increments buf pointer even if there is no PTE.
This results in a bad buf pointer which gets used for memcpy(..), when
copying the MMU state in the coredump buffer.

Fixes: afb7b3b1deb4 ("drm/etnaviv: implement IOMMUv2 translation")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: implement per-process address spaces on MMUv2

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>

drm/etnaviv: rework MMU handling

This reworks the MMU handling to make it possible to have multiple MMU contexts.
A context is basically one instance of GPU page tables. Currently we have one
set of page tables per GPU, which isn't all that clever, as it has the
following two consequences:

1. All GPU clients (aka processes) are sharing the same pagetables, which means
there is no isolation between clients, but only between GPU assigned memory
spaces and the rest of the system. Better than nothing, but also not great.

2. Clients operating on the same set of buffers with different etnaviv GPU
cores, e.g. a workload using both the 2D and 3D GPU, need to map the used
buffers into the pagetable sets of each used GPU.

This patch reworks all the MMU handling to introduce the abstraction of the
MMU context. A context can be shared across different GPU cores, as long as
they have compatible MMU implementations, which is the case for all systems
with Vivante GPUs seen in the wild.

As MMUv1 is not able to change pagetables on the fly, without a
"stop the world" operation, which stops GPU, changes pagetables via CPU
interaction, restarts GPU, the implementation introduces a shared context on
MMUv1, which is returned whenever there is a request for a new context.

This patch assigns a MMU context to each GPU, so on MMUv2 systems there is
still one set of pagetables per GPU, but due to the shared context MMUv1
systems see a change in behavior as now a single pagetable set is used
across all GPU cores.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Guido Günther <agx@sigxcpu.org>

drm/etnaviv: drop use of drmP.h

Drop use of the deprecated drmP.h header file.
Fix fallout in all .c files.

The etnaviv_drv.h header file was made self-contained,
and missing includes was then added to the .c files that needed them.
In a few cases the list of include files was sorted.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Russell King <linux+etnaviv@armlinux.org.uk>
Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: etnaviv@lists.freedesktop.org
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: mmuv2: don't map zero page

Keep the page at address 0 as faulting to catch any potential state
setup issues early.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

drm/etnaviv: mmuv2: use memset32 to init scratch page

Replace the open-coded scratch page initialization loop with memset32

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: replace license text with SPDX tags

This replaces the repetitive GPL-2.0 license text in code and header files
with the SPDX tags. Generated hardware headers aren't changed, as any changes
there need to be done in the upstream rnndb repository.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

drm/etnaviv: mmuv2: support 40 bit phys address

MMUv2 supports up to 40 bits of physical address by folding the upper
8 bits into bits [4:11] of the PTE.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: mmuv2: allocate 2nd level page tables on demand

With etnaviv not being tied into the IOMMU framework anymore, the MMU
functions will only be called under sleeping locks. Thus we are able
to allocate the memory for the 2nd level page tables on demand without
having to deal with memory allocation in atomic context.

This speeds up driver intitialization on MMUv2 GPU cores, as we don't
need to preallocate all the page table memory and also reduces memory
consumption for most workloads, as most of them won't use the full
GPU virtual address space.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

drm/etnaviv: switch MMU page tables to writecombine memory

We are likely to write multiple page entries at once and already ensure
proper write buffer flushing before GPU submit, so this improves CPU
time usage in the submit path without any downsides.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

drm/etnaviv: add PTA handling to MMUv2

The Page Table Array is a new first level structure above the MTLB
availabale on GPUs with the security feature. Use the PTa to set up
the MMU when the security related states are handled by the kernel driver.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: make local symbols static

Fixes the following sparse warnings:

drivers/gpu/drm/etnaviv/etnaviv_iommu.c:161:39: warning:
symbol 'etnaviv_iommuv1_ops' was not declared. Should it be static?
drivers/gpu/drm/etnaviv/etnaviv_iommu_v2.c:239:39: warning:
symbol 'etnaviv_iommuv2_ops' was not declared. Should it be static?

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: move cmdbuf into submit object

Less dynamic allocations and slims down the cmdbuf object to only the
required information, as everything else is already available in the
submit object.

This also simplifies buffer and mappings lifetime management, as they
are now exlusively attached to the submit object and not additionally
to the cmdbuf.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: remove IOMMU dependency

Using the IOMMU API to manage the internal GPU MMU has been an
historical accident and it keeps getting in the way, as well as
entangling the driver with the inner workings of the IOMMU
subsystem.

Clean this up by removing the usage of iommu_domain, which is the
last piece linking etnaviv to the IOMMU subsystem.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: remove iova_to_phys iommu ops

They are not used in any way, so can go away.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-By: Wladimir J. van der Laan <laanwj@gmail.com>

drm/etnaviv: get cmdbuf physical address through the cmdbuf abstraction

Don't allow IOMMUv2 to peek directly into the cmdbuf, but get the
needed PA through a dedicated function.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

drm/etnaviv: move cmdbuf de-/allocation into own file

This will get more complex with the following changes, so move it
into its own place.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

drm/etnaviv: constify etnaviv_iommu_ops structures

Declare etnaviv_iommu_ops structure as const as it is only used when
the reference of one of its field is stored in the ops field of a
iommu_domain structure. This ops field is of type const, so
etnaviv_iommu_ops structures having similar properties can be declared
const too.

Done using Coccinelle.
Before and after size details of .o file remains the same after
cross compiling for arm architecture.

lst: Trimmed commit message, apply the same change to iommu_v2.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: implement IOMMUv2 translation

All other parts are now in place, so implement the actual translation
step and hook it up, so the driver claims support for cores with
the new MMU.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: move IOMMU domain allocation into etnaviv MMU

The GPU code doesn't need to deal with the IOMMU directly, instead
it can all be hidden behind the etnaviv mmu interface. Move the
last remaining part into etnaviv mmu.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: add initial etnaviv DRM driver

This adds the etnaviv DRM driver and hooks it up in Makefiles
and Kconfig.

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>