DSS2: Check fclk limits when configuring video planes

Check that the currect functional clock is fast enough to support
the requested scaling ratios. Also check if 5-tap filtering can be
used even though the downscaling ratio is less than 1:2 since the
functional clock rate required for 5-tap filtering can be less than
the requirement for 3-tap filtering, and 5-tap filtering should look
better.

Signed-off-by: Ville Syrjälä <ville.syrjala@nokia.com>

diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index 41734f3..61861d8 100644 (file)
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -1026,11 +1026,11 @@ static void _dispc_set_vid_accu1(enum omap_plane plane, int haccu, int vaccu)
 static void _dispc_set_scaling(enum omap_plane plane,
                u16 orig_width, u16 orig_height,
                u16 out_width, u16 out_height,
-               bool ilace)
+               bool ilace, bool five_taps)
 {
        int fir_hinc;
        int fir_vinc;
-       int hscaleup, vscaleup, five_taps;
+       int hscaleup, vscaleup;
        int fieldmode = 0;
        int accu0 = 0;
        int accu1 = 0;
@@ -1040,7 +1040,6 @@ static void _dispc_set_scaling(enum omap_plane plane,
 
        hscaleup = orig_width <= out_width;
        vscaleup = orig_height <= out_height;
-       five_taps = orig_height > out_height * 2;
 
        _dispc_set_scale_coef(plane, hscaleup, vscaleup, five_taps);
 
@@ -1283,6 +1282,73 @@ static void calc_rotation_offset(u8 rotation, bool mirror,
        }
 }
 
+static unsigned long calc_fclk_five_taps(u16 width, u16 height,
+               u16 out_width, u16 out_height, enum omap_color_mode color_mode)
+{
+       u32 fclk = 0;
+       /* FIXME venc pclk? */
+       u64 tmp, pclk = dispc_pclk_rate();
+
+       if (height > out_height) {
+               /* FIXME get real display PPL */
+               unsigned int ppl = 800;
+
+               tmp = pclk * height * out_width;
+               do_div(tmp, 2 * out_height * ppl);
+               fclk = tmp;
+
+               if (height > 2 * out_height) {
+                       tmp = pclk * (height - 2 * out_height) * out_width;
+                       do_div(tmp, 2 * out_height * (ppl - out_width));
+                       fclk = max(fclk, (u32) tmp);
+               }
+       }
+
+       if (width > out_width) {
+               tmp = pclk * width;
+               do_div(tmp, out_width);
+               fclk = max(fclk, (u32) tmp);
+
+               if (color_mode == OMAP_DSS_COLOR_RGB24U)
+                       fclk <<= 1;
+       }
+
+       return fclk;
+}
+
+static unsigned long calc_fclk(u16 width, u16 height,
+               u16 out_width, u16 out_height,
+               enum omap_color_mode color_mode, bool five_taps)
+{
+       unsigned int hf, vf;
+
+       if (five_taps)
+               return calc_fclk_five_taps(width, height,
+                               out_width, out_height, color_mode);
+
+       /*
+        * FIXME how to determine the 'A' factor
+        * for the no downscaling case ?
+        */
+
+       if (width > 3 * out_width)
+               hf = 4;
+       else if (width > 2 * out_width)
+               hf = 3;
+       else if (width > out_width)
+               hf = 2;
+       else
+               hf = 1;
+
+       if (height > out_height)
+               vf = 2;
+       else
+               vf = 1;
+
+       /* FIXME venc pclk? */
+       return dispc_pclk_rate() * vf * hf;
+}
+
 static int _dispc_setup_plane(enum omap_plane plane,
                enum omap_channel channel_out,
                u32 paddr, u16 screen_width,
@@ -1294,7 +1360,7 @@ static int _dispc_setup_plane(enum omap_plane plane,
                u8 rotation, int mirror)
 {
        const int maxdownscale = cpu_is_omap34xx() ? 4 : 2;
-       bool five_taps = height > out_height * 2;
+       bool five_taps = 0;
        bool fieldmode = 0;
        int cconv = 0;
        unsigned offset0, offset1;
@@ -1323,8 +1389,8 @@ static int _dispc_setup_plane(enum omap_plane plane,
                }
        } else {
                /* video plane */
-               if (width > (2048 >> five_taps))
-                       return -EINVAL;
+
+               unsigned long fclk;
 
                if (out_width < width / maxdownscale ||
                   out_width > width * 8)
@@ -1356,6 +1422,30 @@ static int _dispc_setup_plane(enum omap_plane plane,
                default:
                        return -EINVAL;
                }
+
+               /* Must use 5-tap filter? */
+               five_taps = height > out_height * 2;
+
+               /* Try to use 5-tap filter whenever possible. */
+               if (cpu_is_omap34xx() && !five_taps &&
+                   height > out_height && width <= 1024) {
+                       fclk = calc_fclk_five_taps(width, height,
+                                       out_width, out_height, color_mode);
+                       if (fclk <= dispc_fclk_rate())
+                               five_taps = true;
+               }
+
+               if (width > (2048 >> five_taps))
+                       return -EINVAL;
+
+               fclk = calc_fclk(width, height, out_width, out_height,
+                               color_mode, five_taps);
+
+               DSSDBG("required fclk rate = %lu Hz\n", fclk);
+               DSSDBG("current fclk rate = %lu Hz\n", dispc_fclk_rate());
+
+               if (fclk > dispc_fclk_rate())
+                       return -EINVAL;
        }
 
        if (ilace && height >= out_height)
@@ -1399,7 +1489,7 @@ static int _dispc_setup_plane(enum omap_plane plane,
        if (plane != OMAP_DSS_GFX) {
                _dispc_set_scaling(plane, width, height,
                                   out_width, out_height,
-                                  ilace);
+                                  ilace, five_taps);
                _dispc_set_vid_size(plane, out_width, out_height);
                _dispc_set_vid_color_conv(plane, cconv);
        }