drm/i915: Allow planes to declare their minimum acceptable cdclk

Various pixel formats and plane scaling impose additional constraints
on the cdclk frequency. Provide a new plane->min_cdclk() hook that
will be used to compute the minimum acceptable cdclk frequency for
each plane.

Annoyingly on some platforms the numer of active planes affects
this calculation so we must also toss in more planes into the
state when the number of active planes changes.

The sequence of state computation must also be changed:
1. check_plane() (updates plane's visibility etc.)
2. figure out if more planes now require update min_cdclk
   computaion
3. calculate the new min cdclk for each plane in the state
4. if the minimum of any plane now exceeds the current
   logical cdclk we recompute the cdclk
4. during cdclk computation take the planes' min_cdclk into
   accoutn
5. follow the normal cdclk programming to change the
   cdclk frequency. This may now require a modeset (except
   on bxt/glk in some cases), which either succeeds or
   fails depending on whether userspace has given
   us permission to perform a modeset or not.

v2: Fix plane id check in intel_crtc_add_planes_to_state()
    Only print the debug message when cdclk needs bumping
    Use dev_priv->cdclk... as the old state explicitly

Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191015193035.25982-5-ville.syrjala@linux.intel.com

1 files changed, 341 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c b/drivers/gpu/drm/i915/display/intel_sprite.c
index 5ae12ab3c5b7..469f79b01114 100644
--- a/drivers/gpu/drm/i915/display/intel_sprite.c
+++ b/drivers/gpu/drm/i915/display/intel_sprite.c
@@ -322,6 +322,55 @@ bool icl_is_hdr_plane(struct drm_i915_private *dev_priv, enum plane_id plane_id)
 		icl_hdr_plane_mask() & BIT(plane_id);
 }
 
+static void
+skl_plane_ratio(const struct intel_crtc_state *crtc_state,
+		const struct intel_plane_state *plane_state,
+		unsigned int *num, unsigned int *den)
+{
+	struct drm_i915_private *dev_priv = to_i915(plane_state->base.plane->dev);
+	const struct drm_framebuffer *fb = plane_state->base.fb;
+
+	if (fb->format->cpp[0] == 8) {
+		if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv)) {
+			*num = 10;
+			*den = 8;
+		} else {
+			*num = 9;
+			*den = 8;
+		}
+	} else {
+		*num = 1;
+		*den = 1;
+	}
+}
+
+static int skl_plane_min_cdclk(const struct intel_crtc_state *crtc_state,
+			       const struct intel_plane_state *plane_state)
+{
+	struct drm_i915_private *dev_priv = to_i915(plane_state->base.plane->dev);
+	unsigned int pixel_rate = crtc_state->pixel_rate;
+	unsigned int src_w, src_h, dst_w, dst_h;
+	unsigned int num, den;
+
+	skl_plane_ratio(crtc_state, plane_state, &num, &den);
+
+	/* two pixels per clock on glk+ */
+	if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv))
+		den *= 2;
+
+	src_w = drm_rect_width(&plane_state->base.src) >> 16;
+	src_h = drm_rect_height(&plane_state->base.src) >> 16;
+	dst_w = drm_rect_width(&plane_state->base.dst);
+	dst_h = drm_rect_height(&plane_state->base.dst);
+
+	/* Downscaling limits the maximum pixel rate */
+	dst_w = min(src_w, dst_w);
+	dst_h = min(src_h, dst_h);
+
+	return DIV64_U64_ROUND_UP(mul_u32_u32(pixel_rate * num, src_w * src_h),
+				  mul_u32_u32(den, dst_w * dst_h));
+}
+
 static unsigned int
 skl_plane_max_stride(struct intel_plane *plane,
 		     u32 pixel_format, u64 modifier,
@@ -811,6 +860,85 @@ vlv_update_clrc(const struct intel_plane_state *plane_state)
 		      SP_SH_SIN(sh_sin) | SP_SH_COS(sh_cos));
 }
 
+static void
+vlv_plane_ratio(const struct intel_crtc_state *crtc_state,
+		const struct intel_plane_state *plane_state,
+		unsigned int *num, unsigned int *den)
+{
+	u8 active_planes = crtc_state->active_planes & ~BIT(PLANE_CURSOR);
+	const struct drm_framebuffer *fb = plane_state->base.fb;
+	unsigned int cpp = fb->format->cpp[0];
+
+	/*
+	 * VLV bspec only considers cases where all three planes are
+	 * enabled, and cases where the primary and one sprite is enabled.
+	 * Let's assume the case with just two sprites enabled also
+	 * maps to the latter case.
+	 */
+	if (hweight8(active_planes) == 3) {
+		switch (cpp) {
+		case 8:
+			*num = 11;
+			*den = 8;
+			break;
+		case 4:
+			*num = 18;
+			*den = 16;
+			break;
+		default:
+			*num = 1;
+			*den = 1;
+			break;
+		}
+	} else if (hweight8(active_planes) == 2) {
+		switch (cpp) {
+		case 8:
+			*num = 10;
+			*den = 8;
+			break;
+		case 4:
+			*num = 17;
+			*den = 16;
+			break;
+		default:
+			*num = 1;
+			*den = 1;
+			break;
+		}
+	} else {
+		switch (cpp) {
+		case 8:
+			*num = 10;
+			*den = 8;
+			break;
+		default:
+			*num = 1;
+			*den = 1;
+			break;
+		}
+	}
+}
+
+int vlv_plane_min_cdclk(const struct intel_crtc_state *crtc_state,
+			const struct intel_plane_state *plane_state)
+{
+	unsigned int pixel_rate;
+	unsigned int num, den;
+
+	/*
+	 * Note that crtc_state->pixel_rate accounts for both
+	 * horizontal and vertical panel fitter downscaling factors.
+	 * Pre-HSW bspec tells us to only consider the horizontal
+	 * downscaling factor here. We ignore that and just consider
+	 * both for simplicity.
+	 */
+	pixel_rate = crtc_state->pixel_rate;
+
+	vlv_plane_ratio(crtc_state, plane_state, &num, &den);
+
+	return DIV_ROUND_UP(pixel_rate * num, den);
+}
+
 static u32 vlv_sprite_ctl_crtc(const struct intel_crtc_state *crtc_state)
 {
 	u32 sprctl = 0;
@@ -1017,6 +1145,164 @@ vlv_plane_get_hw_state(struct intel_plane *plane,
 	return ret;
 }
 
+static void ivb_plane_ratio(const struct intel_crtc_state *crtc_state,
+			    const struct intel_plane_state *plane_state,
+			    unsigned int *num, unsigned int *den)
+{
+	u8 active_planes = crtc_state->active_planes & ~BIT(PLANE_CURSOR);
+	const struct drm_framebuffer *fb = plane_state->base.fb;
+	unsigned int cpp = fb->format->cpp[0];
+
+	if (hweight8(active_planes) == 2) {
+		switch (cpp) {
+		case 8:
+			*num = 10;
+			*den = 8;
+			break;
+		case 4:
+			*num = 17;
+			*den = 16;
+			break;
+		default:
+			*num = 1;
+			*den = 1;
+			break;
+		}
+	} else {
+		switch (cpp) {
+		case 8:
+			*num = 9;
+			*den = 8;
+			break;
+		default:
+			*num = 1;
+			*den = 1;
+			break;
+		}
+	}
+}
+
+static void ivb_plane_ratio_scaling(const struct intel_crtc_state *crtc_state,
+				    const struct intel_plane_state *plane_state,
+				    unsigned int *num, unsigned int *den)
+{
+	const struct drm_framebuffer *fb = plane_state->base.fb;
+	unsigned int cpp = fb->format->cpp[0];
+
+	switch (cpp) {
+	case 8:
+		*num = 12;
+		*den = 8;
+		break;
+	case 4:
+		*num = 19;
+		*den = 16;
+		break;
+	case 2:
+		*num = 33;
+		*den = 32;
+		break;
+	default:
+		*num = 1;
+		*den = 1;
+		break;
+	}
+}
+
+int ivb_plane_min_cdclk(const struct intel_crtc_state *crtc_state,
+			const struct intel_plane_state *plane_state)
+{
+	unsigned int pixel_rate;
+	unsigned int num, den;
+
+	/*
+	 * Note that crtc_state->pixel_rate accounts for both
+	 * horizontal and vertical panel fitter downscaling factors.
+	 * Pre-HSW bspec tells us to only consider the horizontal
+	 * downscaling factor here. We ignore that and just consider
+	 * both for simplicity.
+	 */
+	pixel_rate = crtc_state->pixel_rate;
+
+	ivb_plane_ratio(crtc_state, plane_state, &num, &den);
+
+	return DIV_ROUND_UP(pixel_rate * num, den);
+}
+
+static int ivb_sprite_min_cdclk(const struct intel_crtc_state *crtc_state,
+				const struct intel_plane_state *plane_state)
+{
+	unsigned int src_w, dst_w, pixel_rate;
+	unsigned int num, den;
+
+	/*
+	 * Note that crtc_state->pixel_rate accounts for both
+	 * horizontal and vertical panel fitter downscaling factors.
+	 * Pre-HSW bspec tells us to only consider the horizontal
+	 * downscaling factor here. We ignore that and just consider
+	 * both for simplicity.
+	 */
+	pixel_rate = crtc_state->pixel_rate;
+
+	src_w = drm_rect_width(&plane_state->base.src) >> 16;
+	dst_w = drm_rect_width(&plane_state->base.dst);
+
+	if (src_w != dst_w)
+		ivb_plane_ratio_scaling(crtc_state, plane_state, &num, &den);
+	else
+		ivb_plane_ratio(crtc_state, plane_state, &num, &den);
+
+	/* Horizontal downscaling limits the maximum pixel rate */
+	dst_w = min(src_w, dst_w);
+
+	return DIV_ROUND_UP_ULL(mul_u32_u32(pixel_rate, num * src_w),
+				den * dst_w);
+}
+
+static void hsw_plane_ratio(const struct intel_crtc_state *crtc_state,
+			    const struct intel_plane_state *plane_state,
+			    unsigned int *num, unsigned int *den)
+{
+	u8 active_planes = crtc_state->active_planes & ~BIT(PLANE_CURSOR);
+	const struct drm_framebuffer *fb = plane_state->base.fb;
+	unsigned int cpp = fb->format->cpp[0];
+
+	if (hweight8(active_planes) == 2) {
+		switch (cpp) {
+		case 8:
+			*num = 10;
+			*den = 8;
+			break;
+		default:
+			*num = 1;
+			*den = 1;
+			break;
+		}
+	} else {
+		switch (cpp) {
+		case 8:
+			*num = 9;
+			*den = 8;
+			break;
+		default:
+			*num = 1;
+			*den = 1;
+			break;
+		}
+	}
+}
+
+int hsw_plane_min_cdclk(const struct intel_crtc_state *crtc_state,
+			const struct intel_plane_state *plane_state)
+{
+	unsigned int pixel_rate = crtc_state->pixel_rate;
+	unsigned int num, den;
+
+	hsw_plane_ratio(crtc_state, plane_state, &num, &den);
+
+	return DIV_ROUND_UP(pixel_rate * num, den);
+}
+
 static u32 ivb_sprite_ctl_crtc(const struct intel_crtc_state *crtc_state)
 {
 	u32 sprctl = 0;
@@ -1243,6 +1529,53 @@ ivb_plane_get_hw_state(struct intel_plane *plane,
 	return ret;
 }
 
+static int g4x_sprite_min_cdclk(const struct intel_crtc_state *crtc_state,
+				const struct intel_plane_state *plane_state)
+{
+	const struct drm_framebuffer *fb = plane_state->base.fb;
+	unsigned int hscale, pixel_rate;
+	unsigned int limit, decimate;
+
+	/*
+	 * Note that crtc_state->pixel_rate accounts for both
+	 * horizontal and vertical panel fitter downscaling factors.
+	 * Pre-HSW bspec tells us to only consider the horizontal
+	 * downscaling factor here. We ignore that and just consider
+	 * both for simplicity.
+	 */
+	pixel_rate = crtc_state->pixel_rate;
+
+	/* Horizontal downscaling limits the maximum pixel rate */
+	hscale = drm_rect_calc_hscale(&plane_state->base.src,
+				      &plane_state->base.dst,
+				      0, INT_MAX);
+	if (hscale < 0x10000)
+		return pixel_rate;
+
+	/* Decimation steps at 2x,4x,8x,16x */
+	decimate = ilog2(hscale >> 16);
+	hscale >>= decimate;
+
+	/* Starting limit is 90% of cdclk */
+	limit = 9;
+
+	/* -10% per decimation step */
+	limit -= decimate;
+
+	/* -10% for RGB */
+	if (fb->format->cpp[0] >= 4)
+		limit--; /* -10% for RGB */
+
+	/*
+	 * We should also do -10% if sprite scaling is enabled
+	 * on the other pipe, but we can't really check for that,
+	 * so we ignore it.
+	 */
+
+	return DIV_ROUND_UP_ULL(mul_u32_u32(pixel_rate, 10 * hscale),
+				limit << 16);
+}
+
 static unsigned int
 g4x_sprite_max_stride(struct intel_plane *plane,
 		      u32 pixel_format, u64 modifier,
@@ -2511,6 +2844,7 @@ skl_universal_plane_create(struct drm_i915_private *dev_priv,
 	plane->disable_plane = skl_disable_plane;
 	plane->get_hw_state = skl_plane_get_hw_state;
 	plane->check_plane = skl_plane_check;
+	plane->min_cdclk = skl_plane_min_cdclk;
 	if (icl_is_nv12_y_plane(plane_id))
 		plane->update_slave = icl_update_slave;
 
@@ -2618,6 +2952,7 @@ intel_sprite_plane_create(struct drm_i915_private *dev_priv,
 		plane->disable_plane = vlv_disable_plane;
 		plane->get_hw_state = vlv_plane_get_hw_state;
 		plane->check_plane = vlv_sprite_check;
+		plane->min_cdclk = vlv_plane_min_cdclk;
 
 		formats = vlv_plane_formats;
 		num_formats = ARRAY_SIZE(vlv_plane_formats);
@@ -2631,6 +2966,11 @@ intel_sprite_plane_create(struct drm_i915_private *dev_priv,
 		plane->get_hw_state = ivb_plane_get_hw_state;
 		plane->check_plane = g4x_sprite_check;
 
+		if (IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv))
+			plane->min_cdclk = hsw_plane_min_cdclk;
+		else
+			plane->min_cdclk = ivb_sprite_min_cdclk;
+
 		formats = snb_plane_formats;
 		num_formats = ARRAY_SIZE(snb_plane_formats);
 		modifiers = i9xx_plane_format_modifiers;
@@ -2642,6 +2982,7 @@ intel_sprite_plane_create(struct drm_i915_private *dev_priv,
 		plane->disable_plane = g4x_disable_plane;
 		plane->get_hw_state = g4x_plane_get_hw_state;
 		plane->check_plane = g4x_sprite_check;
+		plane->min_cdclk = g4x_sprite_min_cdclk;
 
 		modifiers = i9xx_plane_format_modifiers;
 		if (IS_GEN(dev_priv, 6)) {