The dma-mapping core and the implementations do not change the DMA
attributes passed by pointer.  Thus the pointer can point to const data.
However the attributes do not have to be a bitfield.  Instead unsigned
long will do fine:

1. This is just simpler.  Both in terms of reading the code and setting
   attributes.  Instead of initializing local attributes on the stack
   and passing pointer to it to dma_set_attr(), just set the bits.

2. It brings safeness and checking for const correctness because the
   attributes are passed by value.

Semantic patches for this change (at least most of them):

    virtual patch
    virtual context

    @r@
    identifier f, attrs;

    @@
    f(...,
    - struct dma_attrs *attrs
    + unsigned long attrs
    , ...)
    {
    ...
    }

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

and

    // Options: --all-includes
    virtual patch
    virtual context

    @r@
    identifier f, attrs;
    type t;

    @@
    t f(..., struct dma_attrs *attrs);

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

Link: http://lkml.kernel.org/r/1468399300-5399-2-git-send-email-k.kozlowski@samsung.comSigned-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: NVineet Gupta <vgupta@synopsys.com>
Acked-by: NRobin Murphy <robin.murphy@arm.com>
Acked-by: NHans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Acked-by: Mark Salter <msalter@redhat.com> [c6x]
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> [cris]
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> [drm]
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Fabien Dessenne <fabien.dessenne@st.com> [bdisp]
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> [vb2-core]
Acked-by: David Vrabel <david.vrabel@citrix.com> [xen]
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen swiotlb]
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Acked-by: NBjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> [avr32]
Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc]
Acked-by: Robin Murphy <robin.murphy@arm.com> [arm64 and dma-iommu]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Rockchip DRM does not yet build properly for ARM64, but we might as well
get the printf formatting correct now, to avoid the following warnings:

drivers/gpu/drm/rockchip/rockchip_drm_fbdev.c: In function 'rockchip_drm_fbdev_create':
drivers/gpu/drm/rockchip/rockchip_drm_fbdev.c:111:2: warning: format '%d' expects argument of type 'int', but argument 8 has type 'size_t' [-Wformat=]
  DRM_DEBUG_KMS("FB [%dx%d]-%d kvaddr=%p offset=%ld size=%d\n",
  ^

drivers/gpu/drm/rockchip/rockchip_drm_gem.c: In function 'rockchip_gem_alloc_buf':
drivers/gpu/drm/rockchip/rockchip_drm_gem.c:41:3: warning: format '%x' expects argument of type 'unsigned int', but argument 2 has type 'size_t' [-Wformat=]
   DRM_ERROR("failed to allocate %#x byte dma buffer", obj->size);
   ^
Signed-off-by: NBrian Norris <briannorris@chromium.org>
Reviewed-by: NDouglas Anderson <dianders@chromium.org>
Tested-by: NCaesar Wang <wxt@rock-chips.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1465494392-92489-1-git-send-email-briannorris@chromium.org

drm_gem_object_lookup() has never required the drm_device for its file
local translation of the user handle to the GEM object. Let's remove the
unused parameter and save some space.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: dri-devel@lists.freedesktop.org
Cc: Dave Airlie <airlied@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: Fixup kerneldoc too.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

args->pitch and args->size may not be set by userspace, sometimes
userspace only malloc args and not memset args to zero, then
args->pitch and args->size is random, it is very danger to use
pitch/size on gem.

pitch's type is u32, and min_pitch's type is int, example,
pitch is 0xffffffff, then pitch < min_pitch return true, then gem will
alloc very very big bufffer, it would eat all the memory and cause kernel
crash.

Stop using pitch/size from args, calc them from other args.
Signed-off-by: NMark Yao <mark.yao@rock-chips.com>

Commit 371f0f08 ("ARM: 8426/1: dma-mapping: add missing range check
 in dma_mmap()") introduced offset-checking for mappings, which collides
with the fake-offset the drm sets for gems.

Other drm-drivers set this offset to 0 before doing the mapping, so
this looks like the correct way to go for rockchip as well.

Fixes: 371f0f08 ("ARM: 8426/1: dma-mapping: add missing range check in dma_mmap()")
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>

Since

commit 131e663b
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Jul 9 23:32:33 2015 +0200

    drm/gem: rip out drm vma accounting for gem mmaps

there is no need for this any more.

v2: Fixup compile noise spotted by 0-day build.

Link: http://mid.gmane.org/1444894601-5200-9-git-send-email-daniel.vetter@ffwll.chReviewed-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

Since David Herrmann's mmap vma manager rework we don't need to grab
dev->struct_mutex any more to prevent races when looking up the mmap
offset. Drop it and instead don't forget to use the unref_unlocked
variant (since the drm core still cares).

Aside: I stumbled over the mmap handler which directly does a
dma_mmap_attrs. But totally fails to grab a reference on the
underlying object and hence looks like it happily just leaks the ptes
since there's no guarantee the mmap isn't still around when
gem_free_object is called. Which the kerneldoc of dma_mmap_attrs
explicitly forbids.

v2: Fixup compile fail 0-day spotted.

Cc: Mark Yao <mark.yao@rock-chips.com>
Reviewed-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

Rather than (incompletely [0]) re-implementing drm_gem_mmap() and
drm_gem_mmap_obj() helpers, call them directly from the rockchip mmap
routines.

Once the core functions return successfully, the rockchip mmap routines
can still use dma_mmap_attrs() to simply mmap the entire buffer.

[0] Previously, we were performing the mmap() without first taking a
reference on the underlying gem buffer.  This could leak ptes if the gem
object is destroyed while userspace is still holding the mapping.
Signed-off-by: NDaniel Kurtz <djkurtz@chromium.org>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org

Rather than (incompletely [0]) re-implementing drm_gem_mmap() and
drm_gem_mmap_obj() helpers, call them directly from the rockchip mmap
routines.

Once the core functions return successfully, the rockchip mmap routines
can still use dma_mmap_attrs() to simply mmap the entire buffer.

[0] Previously, we were performing the mmap() without first taking a
reference on the underlying gem buffer.  This could leak ptes if the gem
object is destroyed while userspace is still holding the mapping.
Signed-off-by: NDaniel Kurtz <djkurtz@chromium.org>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In general, the data in drm/rockchip GEM objects is never accessed by
the kernel.  The objects are either accessed by a GPU, by display
controller DMA, or by mmap'ing them to user space.  Thus, these
buffers need not be mapped into kernel address space.

The only exception is the fbdev framebuffer(s), which may be written
in-kernel by fbcon.
Signed-off-by: NDaniel Kurtz <djkurtz@chromium.org>
Signed-off-by: NMark Yao <mark.yao@rock-chips.com>

dma_alloc_attrs() returns NULL if it cannot allocate a dma buffer (or
mapping), not a negative error code.
Rerported-by: NPawel Osciak <posciak@chromium.org>
Signed-off-by: NDaniel Kurtz <djkurtz@chromium.org>
Signed-off-by: NMark Yao <mark.yao@rock-chips.com>

This patch adds the basic structure of a DRM Driver for Rockchip Socs.
Signed-off-by: NMark Yao <mark.yao@rock-chips.com>
Signed-off-by: NDaniel Kurtz <djkurtz@chromium.org>
Acked-by: NDaniel Vetter <daniel@ffwll.ch>
Reviewed-by: NRob Clark <robdclark@gmail.com>