Re: [PATCH 4/7] drm/meson: plane: add support for AFBC mode for OSD1 plane

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Oct 10, 2019 at 7:32 PM Ayan Halder <Ayan.Halder@arm.com> wrote:
>
> On Thu, Oct 10, 2019 at 03:41:15PM +0200, Neil Armstrong wrote:
> > Hi Ayan,
> >
> > On 10/10/2019 15:26, Ayan Halder wrote:
> > > On Thu, Oct 10, 2019 at 11:25:23AM +0200, Neil Armstrong wrote:
> > >> This adds all the OSD configuration plumbing to support the AFBC decoders
> > >> path to display of the OSD1 plane.
> > >>
> > >> The Amlogic GXM and G12A AFBC decoders are integrated very differently.
> > >>
> > >> The Amlogic GXM has a direct output path to the OSD1 VIU pixel input,
> > >> because the GXM AFBC decoder seem to be a custom IP developed by Amlogic.
> > >>
> > >> On the other side, the Amlogic G12A AFBC decoder seems to be an external
> > >> IP that emit pixels on an AXI master hooked to a "Mali Unpack" block
> > >> feeding the OSD1 VIU pixel input.
> > >> This uses a weird "0x1000000" internal HW physical address on both
> > >> sides to transfer the pixels.
> > >>
> > >> For Amlogic GXM, the supported pixel formats are the same as the normal
> > >> linear OSD1 mode.
> > >>
> > >> On the other side, Amlogic added support for all AFBC v1.2 formats for
> > >> the G12A AFBC integration.
> > >>
> > >> For simplicity, we stick to the already supported formats for now.
> > >>
> > >> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> > >> ---
> > >>  drivers/gpu/drm/meson/meson_crtc.c  |   2 +
> > >>  drivers/gpu/drm/meson/meson_drv.h   |   4 +
> > >>  drivers/gpu/drm/meson/meson_plane.c | 215 ++++++++++++++++++++++++----
> > >>  3 files changed, 190 insertions(+), 31 deletions(-)
> > >>
> > >> diff --git a/drivers/gpu/drm/meson/meson_crtc.c b/drivers/gpu/drm/meson/meson_crtc.c
> > >> index 57ae1c13d1e6..d478fa232951 100644
> > >> --- a/drivers/gpu/drm/meson/meson_crtc.c
> > >> +++ b/drivers/gpu/drm/meson/meson_crtc.c
> > >> @@ -281,6 +281,8 @@ void meson_crtc_irq(struct meson_drm *priv)
> > >>    if (priv->viu.osd1_enabled && priv->viu.osd1_commit) {
> > >>            writel_relaxed(priv->viu.osd1_ctrl_stat,
> > >>                            priv->io_base + _REG(VIU_OSD1_CTRL_STAT));
> > >> +          writel_relaxed(priv->viu.osd1_ctrl_stat2,
> > >> +                          priv->io_base + _REG(VIU_OSD1_CTRL_STAT2));
> > >>            writel_relaxed(priv->viu.osd1_blk0_cfg[0],
> > >>                            priv->io_base + _REG(VIU_OSD1_BLK0_CFG_W0));
> > >>            writel_relaxed(priv->viu.osd1_blk0_cfg[1],
> > >> diff --git a/drivers/gpu/drm/meson/meson_drv.h b/drivers/gpu/drm/meson/meson_drv.h
> > >> index 60f13c6f34e5..de25349be8aa 100644
> > >> --- a/drivers/gpu/drm/meson/meson_drv.h
> > >> +++ b/drivers/gpu/drm/meson/meson_drv.h
> > >> @@ -53,8 +53,12 @@ struct meson_drm {
> > >>            bool osd1_enabled;
> > >>            bool osd1_interlace;
> > >>            bool osd1_commit;
> > >> +          bool osd1_afbcd;
> > >>            uint32_t osd1_ctrl_stat;
> > >> +          uint32_t osd1_ctrl_stat2;
> > >>            uint32_t osd1_blk0_cfg[5];
> > >> +          uint32_t osd1_blk1_cfg4;
> > >> +          uint32_t osd1_blk2_cfg4;
> > >>            uint32_t osd1_addr;
> > >>            uint32_t osd1_stride;
> > >>            uint32_t osd1_height;
> > >> diff --git a/drivers/gpu/drm/meson/meson_plane.c b/drivers/gpu/drm/meson/meson_plane.c
> > >> index 5e798c276037..412941aa8402 100644
> > >> --- a/drivers/gpu/drm/meson/meson_plane.c
> > >> +++ b/drivers/gpu/drm/meson/meson_plane.c
> > >> @@ -23,6 +23,7 @@
> > >>  #include "meson_plane.h"
> > >>  #include "meson_registers.h"
> > >>  #include "meson_viu.h"
> > >> +#include "meson_osd_afbcd.h"
> > >>
> > >>  /* OSD_SCI_WH_M1 */
> > >>  #define SCI_WH_M1_W(w)                    FIELD_PREP(GENMASK(28, 16), w)
> > >> @@ -92,12 +93,38 @@ static int meson_plane_atomic_check(struct drm_plane *plane,
> > >>                                               false, true);
> > >>  }
> > >>
> > >> +#define MESON_MOD_AFBC_VALID_BITS (AFBC_FORMAT_MOD_BLOCK_SIZE_16x16 |     \
> > >> +                             AFBC_FORMAT_MOD_BLOCK_SIZE_32x8 |    \
> > >> +                             AFBC_FORMAT_MOD_YTR |                \
> > >> +                             AFBC_FORMAT_MOD_SPARSE |             \
> > >> +                             AFBC_FORMAT_MOD_SPLIT)
> > >> +
> > >>  /* Takes a fixed 16.16 number and converts it to integer. */
> > >>  static inline int64_t fixed16_to_int(int64_t value)
> > >>  {
> > >>    return value >> 16;
> > >>  }
> > >>
> > >> +static u32 meson_g12a_afbcd_line_stride(struct meson_drm *priv)
> > >> +{
> > >> +  u32 line_stride = 0;
> > >> +
> > >> +  switch (priv->afbcd.format) {
> > >> +  case DRM_FORMAT_RGB565:
> > >> +          line_stride = ((priv->viu.osd1_width << 4) + 127) >> 7;
> > >> +          break;
> > >> +  case DRM_FORMAT_RGB888:
> > >> +  case DRM_FORMAT_XRGB8888:
> > >> +  case DRM_FORMAT_ARGB8888:
> > >> +  case DRM_FORMAT_XBGR8888:
> > >> +  case DRM_FORMAT_ABGR8888:
> > > Please have a look at
> > > https://www.kernel.org/doc/html/latest/gpu/afbc.html for our
> > > recommendation. We suggest that *X* formats are avoided.
> > >
> > > Also, for interoperability and maximum compression efficiency (with
> > > AFBC_FORMAT_MOD_YTR), we suggest the following order :-
> > >
> > >         Component 0: R
> > >         Component 1: G
> > >         Component 2: B
> > >         Component 3: A (if available)
> >
> >
> > Sorry I don't understand, you ask me to limit AFBC to ABGR8888 ?
>
> Apologies for the confusion, as per the link, the formats which are
> suggested with AFBC_FORMAT_MOD_YTR are the BGR/ABGR formats (as
> listed in the 'AFBC formats' table)
>
> Thus, any other permutation of the components might make it incompatible
> with some other AFBC producers/consumers.

Uh, that's not how this is supposed to be used. Drivers are meant to
expose _everything_ they support (bonus if you roughly sort it in
preference order). Userspace then computes the intersection of
modifiers/formats supported by all devices it needs to share a buffer
with. Allowing that was the entire point of modifiers, if we
artificially limit to the common denominator we're back "only linear
works everywhere".
-Daniel

>
> >
> > But why if the HW (GPU and DPU) is capable of ?
> >
> > Isn't it an userspace choice ? I understand XRGB8888 is a waste
> > of memory space and compression efficiency, but this is not the
> > kernel driver's to decide this, right ?
> It is a reccomendation by the AFBC spec. As far as I understand, it
> depends upon the implementor of the AFBC spec(ie dpu, gpu, vpu, etc)
> to allow/disallow *X* formats for AFBC encoding/decoding.
>
> >
> > For interoperability I'll understand recommending a minimal set
> > of modifiers and formats. But here, each platform is also limited
> > by it's GPU capabilites aswell.
> Agreed
>
> >
> > Limiting to ABGR8888 would discard like every non-Android renderers,
> > using AFBC, I'm not sure it's the kernels driver's responsibility.
> I am not familiar with non-Android renderers.
> >
> > >
> > > Thus, DRM_FORMAT_ABGR, DRM_FORMAT_BGR should only be allowed.
> > >> +          line_stride = ((priv->viu.osd1_width << 5) + 127) >> 7;
> > >> +          break;
> > >> +  }
> > >> +
> > >> +  return ((line_stride + 1) >> 1) << 1;
> > >> +}
> > >> +
> > >>  static void meson_plane_atomic_update(struct drm_plane *plane,
> > >>                                  struct drm_plane_state *old_state)
> > >>  {
> >
> > [...]
> >
> > >>
> > >> +static bool meson_plane_format_mod_supported(struct drm_plane *plane,
> > >> +                                       u32 format, u64 modifier)
> > >> +{
> > >> +  struct meson_plane *meson_plane = to_meson_plane(plane);
> > >> +  struct meson_drm *priv = meson_plane->priv;
> > >> +  int i;
> > >> +
> > >> +  if (modifier == DRM_FORMAT_MOD_INVALID)
> > >> +          return false;
> > >> +
> > >> +  if (modifier == DRM_FORMAT_MOD_LINEAR)
> > >> +          return true;
> > >> +
> > >> +  if (!meson_vpu_is_compatible(priv, VPU_COMPATIBLE_GXM) &&
> > >> +      !meson_vpu_is_compatible(priv, VPU_COMPATIBLE_G12A))
> > >> +          return false;
> > >> +
> > >> +  if (modifier & ~DRM_FORMAT_MOD_ARM_AFBC(MESON_MOD_AFBC_VALID_BITS))
> > >> +          return false;
> > >> +
> > >> +  for (i = 0 ; i < plane->modifier_count ; ++i)
> > >> +          if (plane->modifiers[i] == modifier)
> > >> +                  break;
> > >> +
> > >> +  if (i == plane->modifier_count) {
> > >> +          DRM_DEBUG_KMS("Unsupported modifier\n");
> > >> +          return false;
> > >> +  }
> >
> > I can add a warn_once here, would it be enough ?
> >
> > >> +
> > >> +  if (priv->afbcd.ops && priv->afbcd.ops->supported_fmt)
> > >> +          return priv->afbcd.ops->supported_fmt(modifier, format);
> > >> +
> > >> +  DRM_DEBUG_KMS("AFBC Unsupported\n");
> > >> +  return false;
> > >> +}
> > >> +
> > >>  static const struct drm_plane_funcs meson_plane_funcs = {
> > >>    .update_plane           = drm_atomic_helper_update_plane,
> > >>    .disable_plane          = drm_atomic_helper_disable_plane,
> > >> @@ -353,6 +457,7 @@ static const struct drm_plane_funcs meson_plane_funcs = {
> > >>    .reset                  = drm_atomic_helper_plane_reset,
> > >>    .atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
> > >>    .atomic_destroy_state   = drm_atomic_helper_plane_destroy_state,
> > >> +  .format_mod_supported   = meson_plane_format_mod_supported,
> > >>  };
> > >>
> > >>  static const uint32_t supported_drm_formats[] = {
> > >> @@ -364,10 +469,53 @@ static const uint32_t supported_drm_formats[] = {
> > >>    DRM_FORMAT_RGB565,
> > >>  };
> > >>
> > >> +static const uint64_t format_modifiers_afbc_gxm[] = {
> > >> +  DRM_FORMAT_MOD_ARM_AFBC(AFBC_FORMAT_MOD_BLOCK_SIZE_16x16 |
> > >> +                          AFBC_FORMAT_MOD_SPARSE |
> > >> +                          AFBC_FORMAT_MOD_YTR),
> > >> +  /* SPLIT mandates SPARSE, RGB modes mandates YTR */
> > >> +  DRM_FORMAT_MOD_ARM_AFBC(AFBC_FORMAT_MOD_BLOCK_SIZE_16x16 |
> > >> +                          AFBC_FORMAT_MOD_YTR |
> > >> +                          AFBC_FORMAT_MOD_SPARSE |
> > >> +                          AFBC_FORMAT_MOD_SPLIT),
> > >> +  DRM_FORMAT_MOD_LINEAR,
> > >> +  DRM_FORMAT_MOD_INVALID,
> > >> +};
> > >> +
> > >> +static const uint64_t format_modifiers_afbc_g12a[] = {
> > >> +  /*
> > >> +   * - TOFIX Support AFBC modifiers for YUV formats (16x16 + TILED)
> > >> +   * - AFBC_FORMAT_MOD_YTR is mandatory since we only support RGB
> > >> +   * - SPLIT is mandatory for performances reasons when in 16x16
> > >> +   *   block size
> > >> +   * - 32x8 block size + SPLIT is mandatory with 4K frame size
> > >> +   *   for performances reasons
> > >> +   */
> > >> +  DRM_FORMAT_MOD_ARM_AFBC(AFBC_FORMAT_MOD_BLOCK_SIZE_16x16 |
> > >> +                          AFBC_FORMAT_MOD_YTR |
> > >> +                          AFBC_FORMAT_MOD_SPARSE |
> > >> +                          AFBC_FORMAT_MOD_SPLIT),
> > >> +  DRM_FORMAT_MOD_ARM_AFBC(AFBC_FORMAT_MOD_BLOCK_SIZE_32x8 |
> > >> +                          AFBC_FORMAT_MOD_YTR |
> > >> +                          AFBC_FORMAT_MOD_SPARSE),
> > >> +  DRM_FORMAT_MOD_ARM_AFBC(AFBC_FORMAT_MOD_BLOCK_SIZE_32x8 |
> > >> +                          AFBC_FORMAT_MOD_YTR |
> > >> +                          AFBC_FORMAT_MOD_SPARSE |
> > >> +                          AFBC_FORMAT_MOD_SPLIT),
> > >> +  DRM_FORMAT_MOD_LINEAR,
> > >> +  DRM_FORMAT_MOD_INVALID,
> > >> +};
> > >> +
> > >> +static const uint64_t format_modifiers_default[] = {
> > >> +  DRM_FORMAT_MOD_LINEAR,
> > >> +  DRM_FORMAT_MOD_INVALID,
> > >> +};
> > >> +
> > >>  int meson_plane_create(struct meson_drm *priv)
> > >>  {
> > >>    struct meson_plane *meson_plane;
> > >>    struct drm_plane *plane;
> > >> +  const uint64_t *format_modifiers = format_modifiers_default;
> > >>
> > >>    meson_plane = devm_kzalloc(priv->drm->dev, sizeof(*meson_plane),
> > >>                               GFP_KERNEL);
> > >> @@ -377,11 +525,16 @@ int meson_plane_create(struct meson_drm *priv)
> > >>    meson_plane->priv = priv;
> > >>    plane = &meson_plane->base;
> > >>
> > >> +  if (meson_vpu_is_compatible(priv, VPU_COMPATIBLE_GXM))
> > >> +          format_modifiers = format_modifiers_afbc_gxm;
> > >> +  else if (meson_vpu_is_compatible(priv, VPU_COMPATIBLE_G12A))
> > >> +          format_modifiers = format_modifiers_afbc_g12a;
> > >> +
> > >>    drm_universal_plane_init(priv->drm, plane, 0xFF,
> > >>                             &meson_plane_funcs,
> > >>                             supported_drm_formats,
> > >>                             ARRAY_SIZE(supported_drm_formats),
> > >> -                           NULL,
> > >> +                           format_modifiers,
> > >>                             DRM_PLANE_TYPE_PRIMARY, "meson_primary_plane");
> > >>
> > >>    drm_plane_helper_add(plane, &meson_plane_helper_funcs);
> > >> --
> > >> 2.22.0
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

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