drm/exynos: Implement mmap as GEM object function

Moving the driver-specific mmap code into a GEM object function allows
for using DRM helpers for various mmap callbacks.

The respective exynos functions are being removed. The file_operations
structure exynos_drm_driver_fops is now being created by the helper macro
DEFINE_DRM_GEM_FOPS().

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Fixed merge conflict.
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: Remove empty exynos_drm_gem_prime_{vmap,vunmap}()

The functions exynos_drm_gem_prime_{vmap,vunmap}() are empty. Remove
them before changing the interface to use struct drm_buf_map. As a side
effect of removing drm_gem_prime_vmap(), the error code changes from
ENOMEM to EOPNOTSUPP.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Christian König <christian.koenig@amd.com>
Tested-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-5-tzimmermann@suse.de

drm/exynos: gem: Fix sparse warning

kvaddr element of the exynos_gem object points to a memory buffer, thus
it should not have a __iomem annotation. Then, to avoid a warning or
casting on assignment to fbi structure, the screen_buffer element of the
union should be used instead of the screen_base.

Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: remove _unlocked suffix in drm_gem_object_put_unlocked

Spelling out _unlocked for each and every driver is a annoying.
Especially if we consider how many drivers, do not know (or need to)
about the horror stories involving struct_mutex.

Just drop the suffix. It makes the API cleaner.

Done via the following script:

__from=drm_gem_object_put_unlocked
__to=drm_gem_object_put
for __file in $(git grep --name-only $__from); do
sed -i "s/$__from/$__to/g" $__file;
done

Cc: Inki Dae <inki.dae@samsung.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20200515095118.2743122-19-emil.l.velikov@gmail.com

drm/exynos: gem: Get rid of the internal 'pages' array

Internal pages array and scatter-list for them is not really needed for
anything. FBDev emulation can simply rely on the DMA-mapping framework
to create a proper kernel mapping for the buffer, while all other buffer
use cases don't really need that array at all.

Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: gem: Remove dead-code

The ExynosDRM page fault handler is never used, drm_gem_mmap()
always calls exynos_drm_gem_mmap() function, which perform
complete mapping for the given virtual address-space area.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drm/exynos: gem: Simplify access to exynos GEM objects

Replace all calls to exynos_drm_gem_get_{dma_addr,size}, by a simpler
function exynos_drm_gem_get(). This lets the caller to get access to
exynos_drm_gem object and extract any information about GEM object
without searching object tree for getting each parameter.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

gpu: drm: exynos: Change return type to vm_fault_t

Use new return type vm_fault_t for fault handler
in struct vm_operations_struct.

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: Fix dma-buf import

When IOMMU support was enabled, dma-buf import in Exynos DRM was broken
since commit f43c35966a5a ("drm/exynos: use real device for DMA-mapping
operations") due to using wrong struct device in drm_gem_prime_import()
function. This patch fixes following kernel BUG caused by incorrect buffer
mapping to DMA address space:

exynos-sysmmu 14650000.sysmmu: 14450000.mixer: PAGE FAULT occurred at 0xb2e00000
------------[ cut here ]------------
kernel BUG at drivers/iommu/exynos-iommu.c:449!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.0-rc4-next-20171016-00033-g990d723669fd #3165
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
task: c0e0b7c0 task.stack: c0e00000
PC is at exynos_sysmmu_irq+0x1d0/0x24c
LR is at exynos_sysmmu_irq+0x154/0x24c
------------[ cut here ]------------

Reported-by: Marian Mihailescu <mihailescu2m@gmail.com>
Fixes: f43c35966a5a ("drm/exynos: use real device for DMA-mapping operations")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: Use .dumb_map_offset and .dumb_destroy defaults

This driver can use the drm_driver.dumb_destroy and
drm_driver.dumb_map_offset defaults, so no need to set them.
Use drm_gem_dumb_map_offset() in exynos_drm_gem_map_ioctl() and
remove exynos_drm_gem_dumb_map_offset().

Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1502034068-51384-14-git-send-email-noralf@tronnes.org

mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf

->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to
take a vma and vmf parameter when the vma already resides in vmf.

Remove the vma parameter to simplify things.

[arnd@arndb.de: fix ARM build]
Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: use unsigned long for dma_attrs

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.com
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Hans-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: Bart 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: Bjorn 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drm/exynos: use directly DMA mapping APIs on g2d

There is no reason to be wapper functions to use DMA mapping APIs. Use
directly DMA mapping APIs and remove the wapper functions.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: support gem_prime_mmap

This allows exported dma-bufs to be mapped using gem_prime_mmap.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: add DRM_EXYNOS_GEM_MAP ioctl

The commit d931589c01a2 ("drm/exynos: remove DRM_EXYNOS_GEM_MAP_OFFSET
ioctl") removed it same with the ioctl that this patch adds. The reason
that removed DRM_EXYNOS_GEM_MAP_OFFSET was we could use
DRM_IOCTL_MODE_MAP_DUMB. Both did exactly same thing.

Now we again will revive it as DRM_EXYNOS_GEM_MAP because of render
node. DRM_IOCTL_MODE_MAP_DUMB isn't permitted in render node.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: gem: remove old unused prototypes

This patch removes old, unused function prototypes from exynos_drm_gem.h.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: cleanup name of gem object for exynos_drm

Struct of gem object in exynos_drm driver is struct exynos_drm_gem_obj.
It's too long and we can know its meaning of name without _obj postfix.

We use several names to variable name of gem object for exynos_drm -
exynos_gem_obj, gem_obj and obj. Especially "obj" name can cause
misunderstanding with variable name "obj" of struct drm_gem_object.

This will clean about name of gem object for exynos_drm as follows.
s/struct exynos_drm_gem_obj/struct exynos_drm_gem
s/exynos_gem_obj or gem_obj or obj/exynos_gem

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: staticize exynos_drm_gem_init()

The exynos_drm_gem_init() is used only in exynos_drm_gem.c file. Make it
static and don't export it.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: fix missed calling of drm_prime_gem_destroy()

When obj->import_attach is existed, code calling drm_prime_gem_destroy()
was removed from commit 67e93c808b48 ("drm/exynos: stop copying sg
table"), and it's a fault.

The drm_prime_gem_destroy() is cleanup function which GEM drivers need
to call when they use drm_gem_prime_import() to import dma-bufs, so
exynos-drm driver using drm_gem_prime_import() needs calling
drm_prime_gem_destroy().

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: merge exynos_drm_buf.c to exynos_drm_gem.c

The struct exynos_drm_gem_obj can have fields of the struct
exynos_drm_gem_buf then don't need to use exynos_drm_buf.c file.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: use prime helpers

The dma-buf codes of exynos drm is almost same with prime helpers. A
difference is that consider DMA_NONE when import dma-buf, but it's wrong
and we don't consider it any more, so we can use prime interface.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: remove unused fields of struct exynos_drm_gem_buf

The userptr, write and pfnmap of struct exynos_drm_gem_buf are not used
anywhere.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: stop copying sg table

Already struct exynos_drm_gem_buf has pages of the buffer, so we don't
need to copy from sg table of the buffer to sg table of dma-buf
attachment, just can make sg table from pages of the buffer.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: Remove unused vma field of exynos_drm_gem_obj

The field 'vma' of 'exynos_drm_gem_obj' structure was introduced in
2a3098ff6c21 ("drm/exynos: add userptr feature for g2d module") but is
not referenced anywhere.

One instance of 'exynos_drm_gem_obj' may be mapped to multiple
user-space VMAs so 'vma' field does not look useful anyway.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: fix DMA_ATTR_NO_KERNEL_MAPPING usage

The Exynos DRM driver doesn't follow the correct API when dealing with
dma_{alloc, mmap, free}_attrs functions and the
DMA_ATTR_NO_KERNEL_MAPPING attribute.

When a IOMMU is not available and the DMA_ATTR_NO_KERNEL_MAPPING is
used, the driver should use the pointer returned by dma_alloc_attr() as
a cookie.

The Exynos DRM driver directly uses the non-requested virtual kernel
address returned by the DMA mapping subsystem. This just works now
because the non-IOMMU codepath doesn't obey DMA_ATTR_NO_KERNEL_MAPPING
but we need to fix it before fixing the DMA layer.

Signed-off-by: Carlo Caione <carlo@caione.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm: Extract <drm/drm_gem.h>

v2: Don't forget git add, noticed by David.

Cc: David Herrmann <dh.herrmann@gmail.com>

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drm/exynos: use drm generic mmap interface

This patch removes DRM_EXYNOS_GEM_MMAP ictrl feature specific
to Exynos drm and instead uses drm generic mmap.

We had used the interface specific to Exynos drm to do mmap directly,
not to use demand paging which maps each page with physical memory
at page fault handler. We don't need the specific mmap interface
because the drm generic mmap which uses vm offset manager stuff can
also do mmap directly.

This patch makes a userspace region to be mapped with whole physical
memory region allocated by userspace request when mmap system call is
requested.

Changelog v2:
- do not set VM_IO, VM_DONTEXPEND and VM_DONTDUMP. These flags were already
set by drm_gem_mmap
- do not include <linux/anon_inodes.h>, which isn't needed anymore.

Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: remove DRM_EXYNOS_GEM_MAP_OFFSET ioctl

This interface and relevant codes aren't used anymore.

Signed-off-by: Inki Dae <inki.dae@samsung.com>

drm/exynos: use a new anon file for exynos gem mmaper

This patch resolves potential deadlock issue that can be incurred
by changing file->f_op and filp->private_data to exynos specific
mapper ops and gem object temporarily.

To resolve this issue, this patch creates a new anon file dedicated
to exynos specific mmaper, and making it used instead of existing one.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm: fix typos in comment in /gpu/drm/exynos

Correct spelling typo in drivers/gpu/drm/exynos

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drm: kill ->gem_init_object() and friends

All drivers embed gem-objects into their own buffer objects. There is no
reason to keep drm_gem_object_alloc(), gem->driver_private and
->gem_init_object() anymore.

New drivers are highly encouraged to do the same. There is no benefit in
allocating gem-objects separately.

Cc: Dave Airlie <airlied@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Ben Skeggs <skeggsb@gmail.com>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drm/gem: create drm_gem_dumb_destroy

All the gem based kms drivers really want the same function to
destroy a dumb framebuffer backing storage object.

So give it to them and roll it out in all drivers.

This still leaves the option open for kms drivers which don't use GEM
for backing storage, but it does decently simplify matters for gem
drivers.

Acked-by: Inki Dae <inki.dae@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Cc: Ben Skeggs <skeggsb@gmail.com>
Reviwed-by: Rob Clark <robdclark@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drm/exynos: Add a new function to get gem buffer size

This patch adds a new function to get gem buffer size. And this
funtion could be used for g2d driver or others can get gem buffer
size to check if the buffer is valid or not.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <inki.dae@samsung.com>

drm/exynos: change file license to GPL

This patch changes file license to GPL

Most of exynos files had been copied from some random
file and not updated correctly. So this patch corrects
the file license.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: use DMA_ATTR_NO_KERNEL_MAPPING attribute

Changelog v3:
just code cleanup.

Changelog v2:
fix argument to dma_mmap_attr function.
- use pages instead of kvaddr because kvaddr is 0 with
DMA_ATTR_NO_KERNEL_MAPPING.

Changelog v1:
When gem allocation is requested, kernel space mapping isn't needed.
But if need, such as console framebuffer, the physical pages would be
mapped with kernel space though vmap function.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: remove 'pages' and 'page_size' elements in exynos gem buffer

Changelog v2:

Removed redundant check for invalid sgl.
Added check for valid page_offset in the beginning of exynos_drm_gem_map_buf.

Changelog v1:

The 'pages' structure is not required since we can use the 'sgt'. Even for
CONTIG buffers, a SGT is created (which will have just one sgl). This SGT
can be used during mmap instead of 'pages'. The 'page_size' element of the
structure is also not used anywhere and is removed.
This patch also fixes a memory leak where the 'pages' structure was being
allocated during gem buffer allocation but not being freed during deallocate.

Signed-off-by: Prathyush K <prathyush.k@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: add userptr feature for g2d module

This patch adds userptr feautre for G2D module.

The userptr means user space address allocated by malloc().
And the purpose of this feature is to make G2D's dma able
to access the user space region.

To user this feature, user should flag G2D_BUF_USRPTR to
offset variable of struct drm_exynos_g2d_cmd and fill
struct drm_exynos_g2d_userptr with user space address
and size for it and then should set a pointer to
drm_exynos_g2d_userptr object to data variable of struct
drm_exynos_g2d_cmd. The last bit of offset variable is used
to check if the cmdlist's buffer type is userptr or not.
If userptr, the g2d driver gets user space address and size
and then gets pages through get_user_pages().
(another case is counted as gem handle)

Below is sample codes:

static void set_cmd(struct drm_exynos_g2d_cmd *cmd,
unsigned long offset, unsigned long data)
{
cmd->offset = offset;
cmd->data = data;
}

static int solid_fill_test(int x, int y, unsigned long userptr)
{
struct drm_exynos_g2d_cmd cmd_gem[5];
struct drm_exynos_g2d_userptr g2d_userptr;
unsigned int gem_nr = 0;
...

g2d_userptr.userptr = userptr;
g2d_userptr.size = x * y * 4;

set_cmd(&cmd_gem[gem_nr++], DST_BASE_ADDR_REG |
G2D_BUF_USERPTR,
(unsigned long)&g2d_userptr);
...
}

int main(int argc, char **argv)
{
unsigned long addr;
...

addr = malloc(x * y * 4);
...

solid_fill_test(x, y, addr);
...
}

And next, the pages are mapped with iommu table and the device
address is set to cmdlist so that G2D's dma can access it.
As you may know, the pages from get_user_pages() are pinned.
In other words, they CAN NOT be migrated and also swapped out.
So the dma access would be safe.

But the use of userptr feature has performance overhead so
this patch also has memory pool to the userptr feature.
Please, assume that user sends cmdlist filled with userptr
and size every time to g2d driver, and the get_user_pages
funcion will be called every time.

The memory pool has maximum 64MB size and the userptr that
user had ever sent, is holded in the memory pool.
This meaning is that if the userptr from user is same as one
in the memory pool, device address to the userptr in the memory
pool is set to cmdlist.

And last, the pages from get_user_pages() will be freed once
user calls free() and the dma access is completed. Actually,
get_user_pages() takes 2 reference counts if the user process
has never accessed user region allocated by malloc(). Then, if
the user calls free(), the page reference count becomes 1 and
becomes 0 with put_page() call. And the reverse holds as well.
This means how the pages backed are used by dma and freed.

This patch is based on "drm/exynos: add iommu support for g2d",
https://patchwork.kernel.org/patch/1629481/

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: add iommu support for g2d

Chagelog v2:
removed unnecessary structure, struct g2d_gem_node.

Chagelog v1:
This patch adds iommu support for g2d driver. For this, it
adds subdrv_probe/remove callback to enable or disable
g2d iommu. And with this patch, in case of using g2d iommu,
we can get or put device address to a gem handle from user
through exynos_drm_gem_get/put_dma_addr(). Actually, these
functions take a reference to a gem handle so that the gem
object used by g2d dma is released properly.

And runqueue_node has a pointer to drm_file object of current
process to manage gem handles to owner.

This patch is based on the below patch set, "drm/exynos: add
iommu support for -next".
http://www.spinics.net/lists/dri-devel/msg29041.html

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: add iommu support for exynos drm framework

Changelog v4:
- fix condition to drm_iommu_detach_device funtion.

Changelog v3:
- add dma_parms->max_segment_size setting of drm_device->dev.
- use devm_kzalloc instead of kzalloc.

Changelog v2:
- fix iommu attach condition.
. check archdata.dma_ops of drm device instead of
subdrv device's one.
- code clean to exynos_drm_iommu.c file.
. remove '#ifdef CONFIG_ARM_DMA_USE_IOMMU' from exynos_drm_iommu.c
and add it to driver/gpu/drm/exynos/Kconfig.

Changelog v1:
This patch adds iommu support for exynos drm framework with dma mapping
api. In this patch, we used dma mapping api to allocate physical memory
and maps it with iommu table and removed some existing codes and added
new some codes for iommu support.

GEM allocation requires one device object to use dma mapping api so
this patch uses one iommu mapping for all sub drivers. In other words,
all sub drivers have same iommu mapping.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: fixed a comment to gem size.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: added a feature to get gem buffer information.

this patch adds a feature to get a gem buffer information and user application
can get the gem buffer information simply in runtime through gem handle.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: added drm prime feature.

this patch adds exynos specific codes for DRM Prime feature.
with this patch, user application can get file descriptor
from gem handle through DRM_IOCTL_PRIME_HANDLE_TO_FD ioctl
command(export) and also gem handle from file descriptor
through DRM_IOCTL_PRIME_FD_TO_HANLDE(import) ioctl command.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: fixed page align and code clean.

1M section, 64k page count also should be rounded up so this patch
rounds up them and caculates page count of them properly and also
checks memory flags from user.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: added new funtion to get/put dma address.

this function would be used for drm based 2d acceleration driver
to get/put dma address through gem handle.
when exynos_drm_get_dma_address is called reference count of
gem object would be increased not to be released by gem close and
when exynos_drm_put_dma_address is called the reference count of
this gem object would be decreased to be released.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drm/exynos: update gem and buffer framework.

with this patch, we can allocate physically continuous or non-continuous
memory and also it creates scatterlist for iommu support so allocated
memory region can be mapped to iommu page table using scatterlist.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drm/exynos: Split creation of gem object and gem handle

exynos_drm_gem_create function created gem object with gem handle but it
can be called externally without gem handle creation through this patch.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: gem code cleanup

This cleans codes of exynos gem - indents and order function and so on.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: changed buffer structure.

the purpose of this patch is to consider IOMMU support in the future.
EXYNOS4 SoC supports IOMMU also so the address for DMA could be
physical address with IOMMU or device address with IOMMU.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drm/exynos: use gem create function generically

this patch addes exynos_drm_gem_init() creating and initialzing a gem.
allocation functions could use this function to create new gem and
it changes size type of exynos_drm_gem_create structure to 64bit
and also corrects comments to exynos_drm_gem_create structure.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

DRM: add DRM Driver for Samsung SoC EXYNOS4210.

This patch is a DRM Driver for Samsung SoC Exynos4210 and now enables
only FIMD yet but we will add HDMI support also in the future.

this patch is based on git repository below:
git://people.freedesktop.org/~airlied/linux.git
branch name: drm-next
commit-id: 88ef4e3f4f616462b78a7838eb3ffc3818d30f67

you can refer to our working repository below:
http://git.infradead.org/users/kmpark/linux-2.6-samsung
branch name: samsung-drm

We tried to re-use lowlevel codes of the FIMD driver(s3c-fb.c
based on Linux framebuffer) but couldn't so because lowlevel codes
of s3c-fb.c are included internally and so FIMD module of this driver has
its own lowlevel codes.

We used GEM framework for buffer management and DMA APIs(dma_alloc_*)
for buffer allocation so we can allocate physically continuous memory
for DMA through it and also we could use CMA later if CMA is applied to
mainline.

Refer to this link for CMA(Continuous Memory Allocator):
http://lkml.org/lkml/2011/7/20/45

this driver supports only physically continuous memory(non-iommu).

Links to previous versions of the patchset:
v1: < https://lwn.net/Articles/454380/ >
v2: < http://www.spinics.net/lists/kernel/msg1224275.html >
v3: < http://www.spinics.net/lists/dri-devel/msg13755.html >
v4: < http://permalink.gmane.org/gmane.comp.video.dri.devel/60439 >
v5: < http://comments.gmane.org/gmane.comp.video.dri.devel/60802 >

Changelog v2:
DRM: add DRM_IOCTL_SAMSUNG_GEM_MMAP ioctl command.

this feature maps user address space to physical memory region
once user application requests DRM_IOCTL_SAMSUNG_GEM_MMAP ioctl.

DRM: code clean and add exception codes.

Changelog v3:
DRM: Support multiple irq.

FIMD and HDMI have their own irq handler but DRM Framework can regiter
only one irq handler this patch supports mutiple irq for Samsung SoC.

DRM: Consider modularization.

each DRM, FIMD could be built as a module.

DRM: Have indenpendent crtc object.

crtc isn't specific to SoC Platform so this patch gets a crtc
to be used as common object.
created crtc could be attached to any encoder object.

DRM: code clean and add exception codes.

Changelog v4:
DRM: remove is_defult from samsung_fb.

is_default isn't used for default framebuffer.

DRM: code refactoring to fimd module.
this patch is be considered with multiple display objects and
would use its own request_irq() to register a irq handler instead of
drm framework's one.

DRM: remove find_samsung_drm_gem_object()

DRM: move kernel private data structures and definitions to driver folder.

samsung_drm.h would contain only public information for userspace
ioctl interface.

DRM: code refactoring to gem modules.
buffer module isn't dependent of gem module anymore.

DRM: fixed security issue.

DRM: remove encoder porinter from specific connector.

samsung connector doesn't need to have generic encoder.

DRM: code clean and add exception codes.

Changelog v5:
DRM: updated fimd(display controller) driver.
added various pixel formats, color key and pixel blending features.

DRM: removed end_buf_off from samsung_drm_overlay structure.
this variable isn't used and end buffer address would be
calculated by each sub driver.

DRM: use generic function for mmap_offset.
replaced samsung_drm_gem_create_mmap_offset() and
samsung_drm_free_mmap_offset() with generic ones applied
to mainline recentrly.

DRM: removed unnecessary codes and added exception codes.

DRM: added comments and code clean.

Changelog v6:
DRM: added default config options.

DRM: added padding for 64-bit align.

DRM: changed prefix 'samsung' to 'exynos'

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>