Revert "drm/vkms: Fix race-condition between the hrtimer and the atomic commit"

This reverts commit a0e6a017ab56936c0405fe914a793b241ed25ee0.

Unlocking a mutex in the context of a hrtimer callback is violating mutex
locking rules, as mutex_unlock() from interrupt context is not permitted.

Link: https://lore.kernel.org/dri-devel/ZQLAc%2FFwkv%2FGiVoK@phenom.ffwll.local/T/#t
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230914102024.1789154-1-mcanal@igalia.com

drm/vkms: Fix race-condition between the hrtimer and the atomic commit

Currently, it is possible for the composer to be set as enabled and then
as disabled without a proper call for the vkms_vblank_simulate(). This
is problematic, because the driver would skip one CRC output, causing CRC
tests to fail. Therefore, we need to make sure that, for each time the
composer is set as enabled, a composer job is added to the queue.

In order to provide this guarantee, add a mutex that will lock before
the composer is set as enabled and will unlock only after the composer
job is added to the queue. This way, we can have a guarantee that the
driver won't skip a CRC entry.

This race-condition is affecting the IGT test "writeback-check-output",
making the test fail and also, leaking writeback framebuffers, as the
writeback job is queued, but it is not signaled. This patch avoids both
problems.

[v2]:
* Create a new mutex and keep the spinlock across the atomic commit in
order to avoid interrupts that could result in deadlocks.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Arthur Grillo <arthurgrillo@riseup.net>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230523123207.173976-1-mcanal@igalia.com

drm/vkms: Add support to 1D gamma LUT

Support a 1D gamma LUT with interpolation for each color channel on the
VKMS driver. Add a check for the LUT length by creating
vkms_atomic_check().

Enable VKMS to run the test igt@kms_plane@pixel-format.

Tested with:
igt@kms_color@gamma
igt@kms_color@legacy-gamma
igt@kms_color@invalid-gamma-lut-sizes

v2:
- Add interpolation between the values of the LUT (Simon Ser)

v3:
- s/ratio/delta (Pekka)
- s/color_channel/channel_value (Pekka)
- s/lut_area/lut_channel
- Store the `drm_color_lut`, `lut_length`, and
`channel_value2index_ratio` inside a struct called `vkms_lut`
(Pekka)
- Pre-compute some constants values used through the LUT procedure
(Pekka)
- Change the switch statement to a cast to __u16* (Pekka)
- Make the apply_lut_to_channel_value return the computation result
(Pekka)

v4:
- Add a comment explaining that `enum lut_area` depends on the
layout of `struct drm_color_lut` (Pekka)
- Remove unused variable (kernel test robot)

v5:
- Mention that this will make it possible to run the test
igt@kms_plane@pixel-format (Maíra)
- s/had/has (Maíra)

Signed-off-by: Arthur Grillo <arthurgrillo@riseup.net>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Maíra Canal <mairacanal@riseup.net>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230709013835.161004-1-arthurgrillo@riseup.net

drm/vkms: Use drmm_crtc_init_with_planes()

Use drmm_crtc_init_with_planes() instead of drm_crtc_init_with_planes()
to get rid of the explicit destroy hook in struct drm_crtc_funcs.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230116205800.1266227-1-mcanal@igalia.com

drm/vkms: fix misuse of WARN_ON

vkms_vblank_simulate() uses WARN_ON for timing-dependent condition
(timer overrun). This is a mis-use of WARN_ON, WARN_ON must be used
to denote kernel bugs. Use pr_warn() instead.

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: syzbot+4fc21a003c8332eb0bdd@syzkaller.appspotmail.com
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Melissa Wen <melissa.srw@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Melissa Wen <melissa.srw@gmail.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210320132840.1315853-1-dvyukov@google.com

drm/vkms: Annotate vblank timer

This is needed to signal the fences from page flips, annotate it
accordingly. We need to annotate entire timer callback since if we get
stuck anywhere in there, then the timer stops, and hence fences stop.
Just annotating the top part that does the vblank handling isn't
enough.

Tested-by: Melissa Wen <melissa.srw@gmail.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Cc: linux-rdma@vger.kernel.org
Cc: amd-gfx@lists.freedesktop.org
Cc: intel-gfx@lists.freedesktop.org
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210121152959.1725404-3-daniel.vetter@ffwll.ch

drm/atomic: Pass the full state to CRTC atomic begin and flush

The current atomic helpers have either their object state being passed as
an argument or the full atomic state.

The former is the pattern that was done at first, before switching to the
latter for new hooks or when it was needed.

Let's start convert all the remaining helpers to provide a consistent
interface, starting with the CRTC's atomic_begin and atomic_flush.

The conversion was done using the coccinelle script below, built tested on
all the drivers and actually tested on vc4.

virtual report

@@
struct drm_crtc_helper_funcs *FUNCS;
identifier old_crtc_state, old_state;
identifier crtc;
identifier f;
@@

f(struct drm_crtc_state *old_crtc_state)
{
...
struct drm_atomic_state *old_state = old_crtc_state->state;
<...
- FUNCS->atomic_begin(crtc, old_crtc_state);
+ FUNCS->atomic_begin(crtc, old_state);
...>
}

@@
struct drm_crtc_helper_funcs *FUNCS;
identifier old_crtc_state, old_state;
identifier crtc;
identifier f;
@@

f(struct drm_crtc_state *old_crtc_state)
{
...
struct drm_atomic_state *old_state = old_crtc_state->state;
<...
- FUNCS->atomic_flush(crtc, old_crtc_state);
+ FUNCS->atomic_flush(crtc, old_state);
...>
}

@@
struct drm_crtc_helper_funcs *FUNCS;
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
identifier dev, state;
identifier f;
@@

f(struct drm_device *dev, struct drm_atomic_state *state, ...)
{
<...
- FUNCS->atomic_begin(crtc, crtc_state);
+ FUNCS->atomic_begin(crtc, state);
...>
}

@@
struct drm_crtc_helper_funcs *FUNCS;
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
identifier dev, state;
identifier f;
@@

f(struct drm_device *dev, struct drm_atomic_state *state, ...)
{
<...
- FUNCS->atomic_flush(crtc, crtc_state);
+ FUNCS->atomic_flush(crtc, state);
...>
}

@@
identifier crtc, old_state;
@@

struct drm_crtc_helper_funcs {
...
- void (*atomic_begin)(struct drm_crtc *crtc, struct drm_crtc_state *old_state);
+ void (*atomic_begin)(struct drm_crtc *crtc, struct drm_atomic_state *state);
...
- void (*atomic_flush)(struct drm_crtc *crtc, struct drm_crtc_state *old_state);
+ void (*atomic_flush)(struct drm_crtc *crtc, struct drm_atomic_state *state);
...
}

@ crtc_atomic_func @
identifier helpers;
identifier func;
@@

(
static struct drm_crtc_helper_funcs helpers = {
...,
.atomic_begin = func,
...,
};
|
static struct drm_crtc_helper_funcs helpers = {
...,
.atomic_flush = func,
...,
};
)

@ ignores_old_state @
identifier crtc_atomic_func.func;
identifier crtc, old_state;
@@

void func(struct drm_crtc *crtc,
struct drm_crtc_state *old_state)
{
... when != old_state
}

@ adds_old_state depends on crtc_atomic_func && !ignores_old_state @
identifier crtc_atomic_func.func;
identifier crtc, old_state;
@@

void func(struct drm_crtc *crtc, struct drm_crtc_state *old_state)
{
+ struct drm_crtc_state *old_state = drm_atomic_get_old_crtc_state(state, crtc);
...
}

@ depends on crtc_atomic_func @
identifier crtc_atomic_func.func;
expression E;
type T;
@@

void func(...)
{
...
- T state = E;
+ T crtc_state = E;
<+...
- state
+ crtc_state
...+>

}

@ depends on crtc_atomic_func @
identifier crtc_atomic_func.func;
type T;
@@

void func(...)
{
...
- T state;
+ T crtc_state;
<+...
- state
+ crtc_state
...+>

}

@@
identifier old_state;
identifier crtc;
@@

void vc4_hvs_atomic_flush(struct drm_crtc *crtc,
- struct drm_crtc_state *old_state
+ struct drm_atomic_state *state
)
{
+ struct drm_crtc_state *old_state = drm_atomic_get_old_crtc_state(state, crtc);
...
}

@@
identifier old_state;
identifier crtc;
@@

void vc4_hvs_atomic_flush(struct drm_crtc *crtc,
- struct drm_crtc_state *old_state
+ struct drm_atomic_state *state
);

@@
identifier old_state;
identifier crtc;
@@

void vmw_du_crtc_atomic_begin(struct drm_crtc *crtc,
- struct drm_crtc_state *old_state
+ struct drm_atomic_state *state
)
{
...
}

@@
identifier old_state;
identifier crtc;
@@

void vmw_du_crtc_atomic_begin(struct drm_crtc *crtc,
- struct drm_crtc_state *old_state
+ struct drm_atomic_state *state
);

@@
identifier old_state;
identifier crtc;
@@

void vmw_du_crtc_atomic_flush(struct drm_crtc *crtc,
- struct drm_crtc_state *old_state
+ struct drm_atomic_state *state
)
{
...
}

@@
identifier old_state;
identifier crtc;
@@

void vmw_du_crtc_atomic_flush(struct drm_crtc *crtc,
- struct drm_crtc_state *old_state
+ struct drm_atomic_state *state
);

@ depends on crtc_atomic_func @
identifier crtc_atomic_func.func;
identifier old_state;
identifier crtc;
@@

void func(struct drm_crtc *crtc,
- struct drm_crtc_state *old_state
+ struct drm_atomic_state *state
)
{ ... }

@ include depends on adds_old_state @
@@

#include <drm/drm_atomic.h>

@ no_include depends on !include && adds_old_state @
@@

+ #include <drm/drm_atomic.h>
#include <drm/...>

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20201028123222.1732139-2-maxime@cerno.tech

drm/atomic: Pass the full state to CRTC atomic_check

The current atomic helpers have either their object state being passed as
an argument or the full atomic state.

The former is the pattern that was done at first, before switching to the
latter for new hooks or when it was needed.

Let's start convert all the remaining helpers to provide a consistent
interface, starting with the CRTC's atomic_check.

The conversion was done using the coccinelle script below,
built tested on all the drivers and actually tested on vc4.

virtual report

@@
struct drm_crtc_helper_funcs *FUNCS;
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
identifier dev, state;
identifier ret, f;
@@

f(struct drm_device *dev, struct drm_atomic_state *state)
{
<...
- ret = FUNCS->atomic_check(crtc, crtc_state);
+ ret = FUNCS->atomic_check(crtc, state);
...>
}

@@
identifier crtc, new_state;
@@

struct drm_crtc_helper_funcs {
...
- int (*atomic_check)(struct drm_crtc *crtc, struct drm_crtc_state *new_state);
+ int (*atomic_check)(struct drm_crtc *crtc, struct drm_atomic_state *state);
...
}

@ crtc_atomic_func @
identifier helpers;
identifier func;
@@

static struct drm_crtc_helper_funcs helpers = {
...,
.atomic_check = func,
...,
};

@ ignores_new_state @
identifier crtc_atomic_func.func;
identifier crtc, new_state;
@@

int func(struct drm_crtc *crtc,
struct drm_crtc_state *new_state)
{
... when != new_state
}

@ adds_new_state depends on crtc_atomic_func && !ignores_new_state @
identifier crtc_atomic_func.func;
identifier crtc, new_state;
@@

int func(struct drm_crtc *crtc, struct drm_crtc_state *new_state)
{
+ struct drm_crtc_state *new_state = drm_atomic_get_new_crtc_state(state, crtc);
...
}

@ depends on crtc_atomic_func @
identifier crtc_atomic_func.func;
expression E;
type T;
@@

int func(...)
{
...
- T state = E;
+ T crtc_state = E;
<+...
- state
+ crtc_state
...+>
}

@ depends on crtc_atomic_func @
identifier crtc_atomic_func.func;
type T;
@@

int func(...)
{
...
- T state;
+ T crtc_state;
<+...
- state
+ crtc_state
...+>
}

@ depends on crtc_atomic_func @
identifier crtc_atomic_func.func;
identifier new_state;
identifier crtc;
@@

int func(struct drm_crtc *crtc,
- struct drm_crtc_state *new_state
+ struct drm_atomic_state *state
)
{ ... }

@@
identifier new_state;
identifier crtc;
@@

int vmw_du_crtc_atomic_check(struct drm_crtc *crtc,
- struct drm_crtc_state *new_state
+ struct drm_atomic_state *state
)
{
+ struct drm_crtc_state *new_state = drm_atomic_get_new_crtc_state(state, crtc);
...
}

@@
identifier new_state;
identifier crtc;
@@

int vmw_du_crtc_atomic_check(struct drm_crtc *crtc,
- struct drm_crtc_state *new_state
+ struct drm_atomic_state *state
);

@ include depends on adds_new_state @
@@

#include <drm/drm_atomic.h>

@ no_include depends on !include && adds_new_state @
@@

+ #include <drm/drm_atomic.h>
#include <drm/...>

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20201028123222.1732139-1-maxime@cerno.tech

drm/atomic: Pass the full state to CRTC atomic enable/disable

If the CRTC driver ever needs to access the full DRM state, it can't do so
at atomic_enable / atomic_disable time since drm_atomic_helper_swap_state
will have cleared the pointer from the struct drm_crtc_state to the struct
drm_atomic_state before calling those hooks.

In order to allow that, let's pass the full DRM state to atomic_enable and
atomic_disable. The conversion was done using the coccinelle script below,
built tested on all the drivers and actually tested on vc4.

virtual report

@@
struct drm_crtc_helper_funcs *FUNCS;
identifier dev, state;
identifier crtc, crtc_state;
@@

disable_outputs(struct drm_device *dev, struct drm_atomic_state *state)
{
<...
- FUNCS->atomic_disable(crtc, crtc_state);
+ FUNCS->atomic_disable(crtc, state);
...>
}

@@
struct drm_crtc_helper_funcs *FUNCS;
identifier dev, state;
identifier crtc, crtc_state;
@@

drm_atomic_helper_commit_modeset_enables(struct drm_device *dev, struct drm_atomic_state *state)
{
<...
- FUNCS->atomic_enable(crtc, crtc_state);
+ FUNCS->atomic_enable(crtc, state);
...>
}

@@
identifier crtc, old_state;
@@

struct drm_crtc_helper_funcs {
...
- void (*atomic_enable)(struct drm_crtc *crtc, struct drm_crtc_state *old_state);
+ void (*atomic_enable)(struct drm_crtc *crtc, struct drm_atomic_state *state);
...
- void (*atomic_disable)(struct drm_crtc *crtc, struct drm_crtc_state *old_state);
+ void (*atomic_disable)(struct drm_crtc *crtc, struct drm_atomic_state *state);
...
}

@ crtc_atomic_func @
identifier helpers;
identifier func;
@@

(
static struct drm_crtc_helper_funcs helpers = {
...,
.atomic_enable = func,
...,
};
|
static struct drm_crtc_helper_funcs helpers = {
...,
.atomic_disable = func,
...,
};
)

@ ignores_old_state @
identifier crtc_atomic_func.func;
identifier crtc, old_state;
@@

void func(struct drm_crtc *crtc,
struct drm_crtc_state *old_state)
{
... when != old_state
}

@ adds_old_state depends on crtc_atomic_func && !ignores_old_state @
identifier crtc_atomic_func.func;
identifier crtc, old_state;
@@

void func(struct drm_crtc *crtc, struct drm_crtc_state *old_state)
{
+ struct drm_crtc_state *old_state = drm_atomic_get_old_crtc_state(state, crtc);
...
}

@ depends on crtc_atomic_func @
identifier crtc_atomic_func.func;
expression E;
type T;
@@

void func(...)
{
...
- T state = E;
+ T crtc_state = E;
<+...
- state
+ crtc_state
...+>

}

@ depends on crtc_atomic_func @
identifier crtc_atomic_func.func;
type T;
@@

void func(...)
{
...
- T state;
+ T crtc_state;
<+...
- state
+ crtc_state
...+>

}

@ depends on crtc_atomic_func @
identifier crtc_atomic_func.func;
identifier old_state;
identifier crtc;
@@

void func(struct drm_crtc *crtc,
- struct drm_crtc_state *old_state
+ struct drm_atomic_state *state
)
{ ... }

@ include depends on adds_old_state @
@@

#include <drm/drm_atomic.h>

@ no_include depends on !include && adds_old_state @
@@

+ #include <drm/drm_atomic.h>
#include <drm/...>

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/845aa10ef171fc0ea060495efef142a0c13f7870.1602161031.git-series.maxime@cerno.tech

drm/vkms: avoid warning in vkms_get_vblank_timestamp

This patch avoid the warning in vkms_get_vblank_timestamp when vblanks
aren't enabled. When running igt test kms_cursor_crc just after vkms
module, the warning raised like below. Initial value of vblank time is
zero and hrtimer.node.expires is also zero if vblank aren't enabled
before. vkms module isn't real hardware but just virtual hardware
module. so vkms can't generate a resonable timestamp when hrtimer is
off. it's best to grab the current time.

[106444.464503] [IGT] kms_cursor_crc: starting subtest pipe-A-cursor-size-change
[106444.471475] WARNING: CPU: 0 PID: 10109 at
vkms_get_vblank_timestamp+0x42/0x50 [vkms]
[106444.471511] CPU: 0 PID: 10109 Comm: kms_cursor_crc Tainted: G W OE
5.9.0-rc1+ #6
[106444.471514] RIP: 0010:vkms_get_vblank_timestamp+0x42/0x50 [vkms]
[106444.471528] Call Trace:
[106444.471551] drm_get_last_vbltimestamp+0xb9/0xd0 [drm]
[106444.471566] drm_reset_vblank_timestamp+0x63/0xe0 [drm]
[106444.471579] drm_crtc_vblank_on+0x85/0x150 [drm]
[106444.471582] vkms_crtc_atomic_enable+0xe/0x10 [vkms]
[106444.471592] drm_atomic_helper_commit_modeset_enables+0x1db/0x230
[drm_kms_helper]
[106444.471594] vkms_atomic_commit_tail+0x38/0xc0 [vkms]
[106444.471601] commit_tail+0x97/0x130 [drm_kms_helper]
[106444.471608] drm_atomic_helper_commit+0x117/0x140 [drm_kms_helper]
[106444.471622] drm_atomic_commit+0x4a/0x50 [drm]
[106444.471629] drm_atomic_helper_set_config+0x63/0xb0 [drm_kms_helper]
[106444.471642] drm_mode_setcrtc+0x1d9/0x7b0 [drm]
[106444.471654] ? drm_mode_getcrtc+0x1a0/0x1a0 [drm]
[106444.471666] drm_ioctl_kernel+0xb6/0x100 [drm]
[106444.471677] drm_ioctl+0x3ad/0x470 [drm]
[106444.471688] ? drm_mode_getcrtc+0x1a0/0x1a0 [drm]
[106444.471692] ? tomoyo_file_ioctl+0x19/0x20
[106444.471694] __x64_sys_ioctl+0x96/0xd0
[106444.471697] do_syscall_64+0x37/0x80
[106444.471699] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Melissa Wen <melissa.srw@gmail.com>

Signed-off-by: Sidong Yang <realwakka@gmail.com>
Reviewed-by: Melissa Wen <melissa.srw@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200828124553.2178-1-realwakka@gmail.com

drm/vkms: Convert to CRTC VBLANK callbacks

VBLANK callbacks in struct drm_driver are deprecated in favor of
their equivalents in struct drm_crtc_funcs. Convert vkms over.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueira@gmail.com>
Tested-by: Rodrigo Siqueira <rodrigosiqueira@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200123135943.24140-20-tzimmermann@suse.de

drm/vkms: Reduce critical section in vblank_simulate

We can reduce the critical section in vkms_vblank_simulate under
output->lock quite a lot:

- hrtimer_forward_now just needs to be ordered correctly wrt
drm_crtc_handle_vblank. We already access the hrtimer timestamp
without locks. While auditing that I noticed that we don't correctly
annotate the read there, so sprinkle a READ_ONCE to make sure the
compiler doesn't do anything foolish.

- drm_crtc_handle_vblank must stay under the lock to avoid races with
drm_crtc_arm_vblank_event.

- The access to vkms_ouptut->crc_state also must stay under the lock.

- next problem is making sure the output->state structure doesn't get
freed too early. First we rely on a given hrtimer being serialized:
If we call drm_crtc_handle_vblank, then we are guaranteed that the
previous call to vkms_vblank_simulate has completed. The other side
of the coin is that the atomic updates waits for the vblank to
happen before it releases the old state. Both taken together means
that by the time the atomic update releases the old state, the
hrtimer won't access it anymore (it might be accessing the new state
at the same time, but that's ok).

- state is invariant, except the few fields separate protected by
state->crc_lock. So no need to hold the lock for that.

- finally the queue_work. We need to make sure there's no races with
the flush_work, i.e. when we call flush_work we need to guarantee
that the hrtimer can't requeue the work again. This is guaranteed by
the same vblank/hrtimer ordering guarantees like the reasoning above
why state won't be freed too early: flush_work on the old state is
called after wait_for_flip_done in the atomic commit code.

Therefore we can also move everything after the output->crc_state out
of the critical section.

Motivated by suggestions from Rodrigo.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719152314.7706-3-daniel.vetter@ffwll.ch

drm/vkms: drop use of drmP.h

Drop use of the deprecated drmP.h header.
Replace it with the necessary includes in the individual .c files.
The header files was self-contained, and extra includes were not added
there.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Acked-by: Emil Velikov <emil.velikov@collabora.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Link: https://patchwork.freedesktop.org/patch/msgid/20190630061922.7254-13-sam@ravnborg.org

drm/vkms: Rename vkms_crc.c into vkms_composer.c

As a preparation work for introducing writeback to vkms, this patch
renames the file vkms_crc.c into vkms_composer.c. Accordingly, it also
adjusts the functions and data structures to match the changes.

No functional change.

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/dea62063077ebf5cc1dfce8876e56788d15367e6.1561491964.git.rodrigosiqueiramelo@gmail.com

drm/vkms: totally reworked crc data tracking

The crc computation worker needs to be able to get at some data
structures and framebuffer mappings, while potentially more atomic
updates are going on. The solution thus far is to copy relevant bits
around, but that's very tedious.

Here's a new approach, which tries to be more clever, but relies on a
few not-so-obvious things:
- crtc_state is always updated when a plane_state changes. Therefore
we can just stuff plane_state pointers into a crtc_state. That
solves the problem of easily getting at the needed plane_states.
- with the flushing changes from previous patches the above also holds
without races due to the next atomic update being a bit eager with
cleaning up pending work - we always wait for all crc work items to
complete before unmapping framebuffers.
- we also need to make sure that the hrtimer fires off the right
worker. Keep a new distinct crc_state pointer, under the
vkms_output->lock protection for this. Note that crtc->state is
updated very early in the atomic commit, way before we arm the
vblank event - the vblank event should always match the buffers we
use to compute the crc. This also solves an issue in the hrtimer,
where we've accessed drm_crtc->state without holding the right locks
(we held none - oops).
- in the worker itself we can then just access the plane states we
need, again solving a bunch of ordering and locking issues.
Accessing plane->state requires locks, accessing the private
vkms_crtc_state->active_planes pointer only requires that the memory
doesn't get freed too early.

The idea behind vkms_crtc_state->active_planes is that this would
contain all visible planes, in z-order, as a first step towards a more
generic blending implementation.

Note that this patch also fixes races between prepare_fb/cleanup_fb
and the crc worker accessing ->vaddr.

Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Tested-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190606222751.32567-10-daniel.vetter@ffwll.ch

drm/vkms: No _irqsave within spin_lock_irq needed

irqs are already off.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Tested-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190606222751.32567-9-daniel.vetter@ffwll.ch

drm/vkms: flush crc workers earlier in commit flow

Currently, we flush pending CRC workers very late in the commit flow,
when we destroy all the old crtc states. Unfortunately, at that point,
the framebuffers are already unpinned (and our vaddr possible gone), so
this isn't good. Also, the plane_states we need might also already be
cleaned up, since cleanup order of state structures isn't well defined.

Fix this by waiting for all CRC workers of the old state to complete
before we start any of the cleanup work. For correct ordering and
avoiding races, we can only flush_work after
drm_atomic_helper_wait_for_vblanks() since we know that all subsequent
queue_work will be for the new state. Only once that's done is
flush_work() useful, before that we might flush the work, and then right
after the hrtimer that simulates vblank queues it again. Every time you
have a flush_work before cleaning up the work structure, the following
sequence must be obeyed, or it can go wrong:

1. Make sure no one else can re-queue the work anymore (in our case
that's done by a combination of first updating output->crc_state and
then waiting for the vblank to pass to make sure the hrtimer has noticed
that change).
2. flush_work()
3. Actually clean up stuff (which isn't done here).

Doing the flush_work before we even completed the output->state update,
much less waited for the vblank to make sure that's happened, missed the
point.

Note that this is not yet race-free because of the hrtimer and crc
worker look at the wrong state pointers, but that will be fixed in
subsequent patches.

Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Tested-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190606222751.32567-7-daniel.vetter@ffwll.ch

drm/vkms: Rename vkms_output.state_lock to crc_lock

Plus add a comment about what it actually protects. It's very little.

Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Tested-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190606222751.32567-4-daniel.vetter@ffwll.ch

drm/vkms: Fix crc worker races

The issue we have is that the crc worker might fall behind. We've
tried to handle this by tracking both the earliest frame for which it
still needs to compute a crc, and the last one. Plus when the
crtc_state changes, we have a new work item, which are all run in
order due to the ordered workqueue we allocate for each vkms crtc.

Trouble is there's been a few small issues in the current code:
- we need to capture frame_end in the vblank hrtimer, not in the
worker. The worker might run much later, and then we generate a lot
of crc for which there's already a different worker queued up.
- frame number might be 0, so create a new crc_pending boolean to
track this without confusion.
- we need to atomically grab frame_start/end and clear it, so do that
all in one go. This is not going to create a new race, because if we
race with the hrtimer then our work will be re-run.
- only race that can happen is the following:
1. worker starts
2. hrtimer runs and updates frame_end
3. worker grabs frame_start/end, already reading the new frame_end,
and clears crc_pending
4. hrtimer calls queue_work()
5. worker completes
6. worker gets re-run, crc_pending is false
Explain this case a bit better by rewording the comment.

v2: Demote warning level output to debug when we fail to requeue, this
is expected under high load when the crc worker can't quite keep up.

Cc: Shayenne Moura <shayenneluzmoura@gmail.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Tested-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190606222751.32567-2-daniel.vetter@ffwll.ch

drm/vkms: add crc sources list

Other drivers are able to list crc sources when accessing
/sys/kernel/debug/dri/.../crtc-0/crc/control

Even though VKMS now supports only 'auto' mode, it is more consistent to
have the list available to the userspace.

Signed-off-by: Oleg Vasilev <oleg.vasilev@intel.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613121802.2193-3-oleg.vasilev@intel.com

drm/vkms: Forward timer right after drm_crtc_handle_vblank

In

commit def35e7c592616bc09be328de8795e5e624a3cf8
Author: Shayenne Moura <shayenneluzmoura@gmail.com>
Date: Wed Jan 30 14:06:36 2019 -0200

drm/vkms: Bugfix extra vblank frame

we fixed the vblank counter to give accurate results outside of
drm_crtc_handle_vblank, which fixed bugs around vblank timestamps
being off-by-one and causing the vblank counter to jump when it
shouldn't.

The trouble is that this completely broke crc generation. Shayenne and
Rodrigo tracked this down to the vblank timestamp going backwards in
time somehow. Which then resulted in an underflow in drm_vblank.c
code, which resulted in all kinds of things breaking really badly.

The reason for this is that once we've called drm_crtc_handle_vblank
and the hrtimer isn't forwarded yet, we're returning a vblank
timestamp in the past. This race is really hard to hit since it's
small, except when you enable crc generation: In that case there's a
call to drm_crtc_accurate_vblank right in-betwen, so we're guaranteed
to hit the bug.

The fix is to roll the hrtimer forward _before_ we do the vblank
processing (which has a side-effect of incrementing the vblank
counter), and we always subtract one frame from the hrtimer - since
now it's always one frame in the future.

To make sure we don't hit this again also add a WARN_ON checking for
whether our timestamp is somehow moving into the past, which is never
should.

This also aligns more with how real hw works:
1. first all registers are updated with the new timestamp/vblank
counter values.
2. then an interrupt is generated
3. kernel interrupt handler eventually fires.

So doing this aligns vkms closer with what drm_vblank.c expects.
Document this also in a comment.

Cc: Shayenne Moura <shayenneluzmoura@gmail.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Tested-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190606084404.12014-1-daniel.vetter@ffwll.ch

drm/vkms: Convert to using __drm_atomic_helper_crtc_reset() for reset.

Convert vkms to using __drm_atomic_helper_crtc_reset(), instead of
writing its own version. Instead of open coding destroy_state(),
call it directly for freeing the old state.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190301125627.7285-17-maarten.lankhorst@linux.intel.com
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>

drm: vkms: check status of alloc_ordered_workqueue

alloc_ordered_workqueue may fail and return NULL.
The fix returns ENOMEM when it fails to avoid potential NULL
pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190309043628.6078-1-kjlu@umn.edu

drm/vkms: Fix license inconsistent

Fixes license inconsistent related to the VKMS driver and remove the
redundant boilerplate comment.

Fixes: 854502fa0a38 ("drm/vkms: Add basic CRTC initialization")

Cc: stable@vger.kernel.org
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190206140116.7qvy2lpwbcd7wds6@smtp.gmail.com

drm/vkms: WARN when hrtimer_forward_now fails

Add a warn to verify the hrtimer_forward_now return and changes
ret_overrun from int to u64 to match the return value provided by
hrtimer_forward_now.

Signed-off-by: Shayenne Moura <shayenneluzmoura@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190206200813.d5w7gjpepoeeadiy@smtp.gmail.com

drm/vkms: Bugfix racing hrtimer vblank handle

When the vblank irq happens, kernel time subsystem executes
`vkms_vblank_simulate`. In parallel or not, it prepares all stuff
necessary to the next vblank with arm, and it must flush these stuff
before the next vblank irq. However, vblank counter is ahead when arm is
executed in parallel with handle vblank.

CPU 0: CPU 1:
| |
atomic_commit_tail is ongoing |
| |
| hrtimer: vkms_vblank_simulate()
| |
| drm_crtc_handle_vblank()
| |
drm_crtc_arm_vblank() |
| |
->get_vblank_timestamp() |
| |
| hrtimer_forward_now()

Then, we should guarantee that the vblank interval time is correct (not
changed) before finish the vblank handle.

Fix the bug including the call to `hrtimer_forward_now()` in the same
lock of `drm_crtc_handle_vblank()` to ensure that the timestamp update
is correct when finish the vblank handle.

Signed-off-by: Shayenne Moura <shayenneluzmoura@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e2e4b8f3a5cab7b2dba75bf1930f86b0a4ee08c9.1548856186.git.shayenneluzmoura@gmail.com

drm/vkms: Bugfix extra vblank frame

kms_flip tests are breaking on vkms when simulate vblank because vblank
event sequence count returns one extra frame after arm vblank event to
make a page flip.

When vblank interrupt happens, userspace processes the vblank event and
issues the next page flip command. Kernel calls queue_work to call
commit_planes and arm the new page flip. The next vblank picks up the
newly armed vblank event and vblank interrupt happens again.

The arm and vblank event are asynchronous, then, on the next vblank, we
receive x+2 from `get_vblank_timestamp`, instead x+1, although timestamp
and vblank seqno matches.

Function `get_vblank_timestamp` is reached by 2 ways:

- from `drm_mode_page_flip_ioctl`: driver is doing one atomic
operation to synchronize planes in the same output. There is no
vblank simulation, the `drm_crtc_arm_vblank_event` function adds 1
on vblank count, and the variable in_vblank_irq is false
- from `vkms_vblank_simulate`: since the driver is doing a vblank
simulation, the variable in_vblank_irq is true.

Fix this problem subtracting one vblank period from vblank_time when
`get_vblank_timestamp` is called from trace `drm_mode_page_flip_ioctl`,
i.e., is not a real vblank interrupt, and getting the timestamp and
vblank seqno when it is a real vblank interrupt.

The reason for all this is that get_vblank_timestamp always supplies the
timestamp for the next vblank event. The hrtimer is the vblank
simulator, and it needs the correct previous value to present the next
vblank. Since this is how hw timestamp registers work and what the
vblank core expects.

Signed-off-by: Shayenne Moura <shayenneluzmoura@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/171e6e1c239cbca0c3df7183ed8acdfeeace9cf4.1548856186.git.shayenneluzmoura@gmail.com

drm: Split out drm_probe_helper.h

Having the probe helper stuff (which pretty much everyone needs) in
the drm_crtc_helper.h file (which atomic drivers should never need) is
confusing. Split them out.

To make sure I actually achieved the goal here I went through all
drivers. And indeed, all atomic drivers are now free of
drm_crtc_helper.h includes.

v2: Make it compile. There was so much compile fail on arm drivers
that I figured I'll better not include any of the acks on v1.

v3: Massive rebase because i915 has lost a lot of drmP.h includes, but
not all: Through drm_crtc_helper.h > drm_modeset_helper.h -> drmP.h
there was still one, which this patch largely removes. Which means
rolling out lots more includes all over.

This will also conflict with ongoing drmP.h cleanup by others I
expect.

v3: Rebase on top of atomic bochs.

v4: Review from Laurent for bridge/rcar/omap/shmob/core bits:
- (re)move some of the added includes, use the better include files in
other places (all suggested from Laurent adopted unchanged).
- sort alphabetically

v5: Actually try to sort them, and while at it, sort all the ones I
touch.

v6: Rebase onto i915 changes.

v7: Rebase once more.

Acked-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Acked-by: CK Hu <ck.hu@mediatek.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: virtualization@lists.linux-foundation.org
Cc: etnaviv@lists.freedesktop.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: intel-gfx@lists.freedesktop.org
Cc: linux-mediatek@lists.infradead.org
Cc: linux-amlogic@lists.infradead.org
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: spice-devel@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-rockchip@lists.infradead.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Cc: linux-tegra@vger.kernel.org
Cc: xen-devel@lists.xen.org
Link: https://patchwork.freedesktop.org/patch/msgid/20190117210334.13234-1-daniel.vetter@ffwll.ch

drm/vkms: Fix flush_work() without INIT_WORK().

syzbot is hitting a lockdep warning [1] because flush_work() is called
without INIT_WORK() after kzalloc() at vkms_atomic_crtc_reset().

Commit 6c234fe37c57627a ("drm/vkms: Implement CRC debugfs API") added
INIT_WORK() to only vkms_atomic_crtc_duplicate_state() side. Assuming
that lifecycle of crc_work is appropriately managed, fix this problem
by adding INIT_WORK() to vkms_atomic_crtc_reset() side.

[1] https://syzkaller.appspot.com/bug?id=a5954455fcfa51c29ca2ab55b203076337e1c770

Reported-and-tested-by: syzbot <syzbot+12f1b031b6da017e34f8@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Shayenne Moura <shayenneluzmoura@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1547829823-9877-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp

drm/vkms: Fix race condition around accessing frame number

crtc_state is accessed by both vblank_handle() and the ordered
work_struct handle vkms_crc_work_handle() to retrieve and or update
the frame number for computed CRC.

Since work_struct can fail, add frame_end to account for missing frame
numbers.

Use (frame_[start/end]) for synchronization between hrtimer callback
and ordered work_struct handle.

This patch passes the following subtests from igt kms_pipe_crc_basic test:
bad-source, read-crc-pipe-A, read-crc-pipe-A-frame-sequence,
nonblocking-crc-pipe-A, nonblocking-crc-pipe-A-frame-sequence

Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180903211743.GA2773@haneenDRM

drm/vkms/crc: Implement verify_crc_source callback

This patch implements "verify_crc_source" callback function for
Virtual KMS drm driver.

Changes Since V1:
- update values_cnt in verify_crc_source
Changes Since V2:
- don't return early from set_crc_source to keep behavior same (Haneen)

Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Reviewed-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180821083858.26275-2-mahesh1.kumar@intel.com

drm/vkms: Implement CRC debugfs API

This patch implement the necessary functions to compute and add CRCs
entries:

- Implement the set_crc_source() callback.
- Compute CRC using crc32 on the visible part of the framebuffer.
- Use ordered workqueue per output to compute and add CRC at the end
of a vblank.
- Use appropriate synchronization methods since the CRC computation must
be atomic wrt the generated vblank event for a given atomic update, by
using spinlock across atomic_begin/atomic_flush to wrap the event
handling code completely and match the flip event with the CRC.

Since vkms_crc_work_handle() can sleep, spinlock can't be acquired
while accessing vkms_output->primary_crc to compute CRC.
To make sure the data is updated and released without conflict with
the vkms_crc_work_handle(), the work_struct is flushed @crtc_destroy
and the data is updated before scheduling the work handle again, as
follow:

* CRC data update:
1- store vkms_crc_data {fb, src} per plane_state
2- @plane_duplicate_state -> allocate vkms_crc_data
3- during atomic commit (@atomic_update) ->
a) copy {fb, src} to plane_state->crc_data
b) get reference to fb,
3- @plane_destroy_state -> a) if (fb refcount) remove reference to fb
b) deallocate crc_data

* Atomic Commit:
1- vkms_plane_atomic_check
2- vkms_prepare_fb -> vmap vkms_gem_obj->vaddr
3- atomic_begin -> hold crc spinlock
4- atomic_plane_update -> a) update vkms_output->primary_crc
b) get reference to fb
5- atomic_flush -> a) send vblank event while holding event_lock
b) release crc spinlock

* hrtimer regular callback:
1- hold crc spinlock
2- drm_crtc_handle_vblank()
3- queue vkms_crc_work_handle
4- release crc spinlock

* cleanup:
1- @cleanup_fb ->vunmap vkms_gem_obj->vaddr
2- @crtc_destroy -> flush work struct
3- @plane_destroy -> a) if (fb refcount) remove reference to fb
b) deallocate crc_data

Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
[seanpaul fixed typo in vkms_crtc s/vblamk/vblank/]
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/b948327f48c3e70ab232b4a0848ee6d033b26484.1533171495.git.hamohammed.sa@gmail.com

drm/vkms: subclass CRTC state

Subclass CRTC state struct to enable storing driver's private
state. This patch only adds the base drm_crtc_state struct and
the atomic functions that handle it.

Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1f3564a5a0a6c4410c5d383c86a572ddda4818a8.1532446182.git.hamohammed.sa@gmail.com

drm/vkms: Add vblank events simulated by hrtimers

This commit adds regular vblank events simulated through hrtimers, which
is a feature required by VKMS to mimic real hardware. Additionally, all
the vblank event send after pageflip is kept in the atomic_flush
function.

Changes since V1:
- Compute the vblank timer interval per interruption
Ville Syrjälä and Daniel Vetter:
- Removes hardcoded vblank interval to get it from user space

Changes since V2:
Chris Wilson
- Removes unnecessary algorithm to compute the next period
Daniel Vetter:
- Uses drm_calc_timestamping_constants to get the vblank interval
instead of calculating it manually
- Adds disable_vblank helper that turns of crtc
- Simplifies implementation by using drm_crtc_arm_vblank_event
- Replaces the code in atomic_begin to atomic_flush
- Removes unnecessary field in vkms_output

Changes since V3:
Daniel Vetter:
- Squash "drm/vkms: Add atomic helpers functions" into the commit that
handling vblank events simulated by hrtimers

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/7709bba40782ec06332d57fff337797b272581fc.1531359228.git.rodrigosiqueiramelo@gmail.com

drm/vkms: Add basic CRTC initialization

This commit adds the essential infrastructure for around CRTCs which
is composed of: a new data struct for output data information, a
function for creating planes, and a simple encoder attached to the
connector. Finally, due to the introduction of a new initialization
function, connectors were moved from vkms_drv.c to vkms_display.c.

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Reviewed-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b6e27bc6a54f5cb340658fa5969f7b48fbfbf1b7.1526514457.git.rodrigosiqueiramelo@gmail.com