drm/i915: Calculate max watermark levels for ILK+

There are quite a few variables we need to take into account to
determine the maximum watermark levels, so it feels a bit cleaner
to calculate those rather than just have a bunch of what look like
magic numbers.

v2: s/pipes_active/num_pipes_active
    s/othwewise/otherwise

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index d7bb61e..a4c3c54 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2270,6 +2270,104 @@ static uint32_t ilk_compute_fbc_wm(struct hsw_pipe_wm_parameters *params,
                          params->pri_bytes_per_pixel);
 }
 
+static unsigned int ilk_display_fifo_size(const struct drm_device *dev)
+{
+       if (INTEL_INFO(dev)->gen >= 7)
+               return 768;
+       else
+               return 512;
+}
+
+/* Calculate the maximum primary/sprite plane watermark */
+static unsigned int ilk_plane_wm_max(const struct drm_device *dev,
+                                    int level,
+                                    unsigned int num_pipes_active,
+                                    bool sprite_enabled,
+                                    enum intel_ddb_partitioning ddb_partitioning,
+                                    bool is_sprite)
+{
+       unsigned int fifo_size = ilk_display_fifo_size(dev);
+       unsigned int max;
+
+       /* if sprites aren't enabled, sprites get nothing */
+       if (is_sprite && !sprite_enabled)
+               return 0;
+
+       /* HSW allows LP1+ watermarks even with multiple pipes */
+       if (level == 0 || num_pipes_active > 1) {
+               fifo_size /= INTEL_INFO(dev)->num_pipes;
+
+               /*
+                * For some reason the non self refresh
+                * FIFO size is only half of the self
+                * refresh FIFO size on ILK/SNB.
+                */
+               if (INTEL_INFO(dev)->gen <= 6)
+                       fifo_size /= 2;
+       }
+
+       if (sprite_enabled) {
+               /* level 0 is always calculated with 1:1 split */
+               if (level > 0 && ddb_partitioning == INTEL_DDB_PART_5_6) {
+                       if (is_sprite)
+                               fifo_size *= 5;
+                       fifo_size /= 6;
+               } else {
+                       fifo_size /= 2;
+               }
+       }
+
+       /* clamp to max that the registers can hold */
+       if (INTEL_INFO(dev)->gen >= 7)
+               /* IVB/HSW primary/sprite plane watermarks */
+               max = level == 0 ? 127 : 1023;
+       else if (!is_sprite)
+               /* ILK/SNB primary plane watermarks */
+               max = level == 0 ? 127 : 511;
+       else
+               /* ILK/SNB sprite plane watermarks */
+               max = level == 0 ? 63 : 255;
+
+       return min(fifo_size, max);
+}
+
+/* Calculate the maximum cursor plane watermark */
+static unsigned int ilk_cursor_wm_max(const struct drm_device *dev,
+                                     int level, unsigned int num_pipes_active)
+{
+       /* HSW LP1+ watermarks w/ multiple pipes */
+       if (level > 0 && num_pipes_active > 1)
+               return 64;
+
+       /* otherwise just report max that registers can hold */
+       if (INTEL_INFO(dev)->gen >= 7)
+               return level == 0 ? 63 : 255;
+       else
+               return level == 0 ? 31 : 63;
+}
+
+/* Calculate the maximum FBC watermark */
+static unsigned int ilk_fbc_wm_max(void)
+{
+       /* max that registers can hold */
+       return 15;
+}
+
+static void ilk_wm_max(struct drm_device *dev,
+                      int level,
+                      unsigned int num_pipes_active,
+                      bool sprite_enabled,
+                      enum intel_ddb_partitioning ddb_partitioning,
+                      struct hsw_wm_maximums *max)
+{
+       max->pri = ilk_plane_wm_max(dev, level, num_pipes_active,
+                                   sprite_enabled, ddb_partitioning, false);
+       max->spr = ilk_plane_wm_max(dev, level, num_pipes_active,
+                                   sprite_enabled, ddb_partitioning, true);
+       max->cur = ilk_cursor_wm_max(dev, level, num_pipes_active);
+       max->fbc = ilk_fbc_wm_max();
+}
+
 static bool ilk_check_wm(int level,
                         const struct hsw_wm_maximums *max,
                         struct intel_wm_level *result)
@@ -2555,18 +2653,15 @@ static void hsw_compute_wm_parameters(struct drm_device *dev,
                        sprites_enabled++;
        }
 
-       if (pipes_active > 1) {
-               lp_max_1_2->pri = lp_max_5_6->pri = sprites_enabled ? 128 : 256;
-               lp_max_1_2->spr = lp_max_5_6->spr = 128;
-               lp_max_1_2->cur = lp_max_5_6->cur = 64;
-       } else {
-               lp_max_1_2->pri = sprites_enabled ? 384 : 768;
-               lp_max_5_6->pri = sprites_enabled ? 128 : 768;
-               lp_max_1_2->spr = 384;
-               lp_max_5_6->spr = 640;
-               lp_max_1_2->cur = lp_max_5_6->cur = 255;
-       }
-       lp_max_1_2->fbc = lp_max_5_6->fbc = 15;
+       ilk_wm_max(dev, 1, pipes_active, sprites_enabled,
+                  INTEL_DDB_PART_1_2, lp_max_1_2);
+
+       /* 5/6 split only in single pipe config on IVB+ */
+       if (INTEL_INFO(dev)->gen >= 7 && pipes_active <= 1)
+               ilk_wm_max(dev, 1, pipes_active, sprites_enabled,
+                          INTEL_DDB_PART_5_6, lp_max_5_6);
+       else
+               *lp_max_5_6 = *lp_max_1_2;
 }
 
 static void hsw_compute_wm_results(struct drm_device *dev,