drm/i915/display: Fix the 12 BPC bits for PIPE_MISC reg

Till DISPLAY12 the PIPE_MISC bits 5-7 are used to set the
Dithering BPC, with valid values of 6, 8, 10 BPC.
For ADLP+ these bits are used to set the PORT OUTPUT BPC, with valid
values of: 6, 8, 10, 12 BPC, and need to be programmed whether
dithering is enabled or not.

This patch:
-corrects the bits 5-7 for PIPE MISC register for 12 BPC.
-renames the bits and mask to have generic names for these bits for
dithering bpc and port output bpc.

v3: Added a note for MIPI DSI which uses the PIPE_MISC for readout
for pipe_bpp. (Uma Shankar)

v2: Added 'display' to the subject and fixes tag. (Uma Shankar)

Fixes: 756f85cffef2 ("drm/i915/bdw: Broadwell has PIPEMISC")
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com> (v1)
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v3.13+
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210811051857.109723-1-ankit.k.nautiyal@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 122f091e0a1e1e2b855656f653fc0f79197b2c5f..58f51854bb79396ca679b60fc6f9b2be0548cbb5 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -5835,16 +5835,18 @@ static void bdw_set_pipemisc(const struct intel_crtc_state *crtc_state)
 
        switch (crtc_state->pipe_bpp) {
        case 18:
-               val |= PIPEMISC_DITHER_6_BPC;
+               val |= PIPEMISC_6_BPC;
                break;
        case 24:
-               val |= PIPEMISC_DITHER_8_BPC;
+               val |= PIPEMISC_8_BPC;
                break;
        case 30:
-               val |= PIPEMISC_DITHER_10_BPC;
+               val |= PIPEMISC_10_BPC;
                break;
        case 36:
-               val |= PIPEMISC_DITHER_12_BPC;
+               /* Port output 12BPC defined for ADLP+ */
+               if (DISPLAY_VER(dev_priv) > 12)
+                       val |= PIPEMISC_12_BPC_ADLP;
                break;
        default:
                MISSING_CASE(crtc_state->pipe_bpp);
@@ -5897,15 +5899,27 @@ int bdw_get_pipemisc_bpp(struct intel_crtc *crtc)
 
        tmp = intel_de_read(dev_priv, PIPEMISC(crtc->pipe));
 
-       switch (tmp & PIPEMISC_DITHER_BPC_MASK) {
-       case PIPEMISC_DITHER_6_BPC:
+       switch (tmp & PIPEMISC_BPC_MASK) {
+       case PIPEMISC_6_BPC:
                return 18;
-       case PIPEMISC_DITHER_8_BPC:
+       case PIPEMISC_8_BPC:
                return 24;
-       case PIPEMISC_DITHER_10_BPC:
+       case PIPEMISC_10_BPC:
                return 30;
-       case PIPEMISC_DITHER_12_BPC:
-               return 36;
+       /*
+        * PORT OUTPUT 12 BPC defined for ADLP+.
+        *
+        * TODO:
+        * For previous platforms with DSI interface, bits 5:7
+        * are used for storing pipe_bpp irrespective of dithering.
+        * Since the value of 12 BPC is not defined for these bits
+        * on older platforms, need to find a workaround for 12 BPC
+        * MIPI DSI HW readout.
+        */
+       case PIPEMISC_12_BPC_ADLP:
+               if (DISPLAY_VER(dev_priv) > 12)
+                       return 36;
+               fallthrough;
        default:
                MISSING_CASE(tmp);
                return 0;

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 680acccef26bdcdedf345fdbb9508bbe6f681baa..c9a62a248e49a0c025656f785ea28c49dca612e4 100644 (file)
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6163,11 +6163,17 @@ enum {
 #define   PIPEMISC_HDR_MODE_PRECISION  (1 << 23) /* icl+ */
 #define   PIPEMISC_OUTPUT_COLORSPACE_YUV  (1 << 11)
 #define   PIPEMISC_PIXEL_ROUNDING_TRUNC        REG_BIT(8) /* tgl+ */
-#define   PIPEMISC_DITHER_BPC_MASK     (7 << 5)
-#define   PIPEMISC_DITHER_8_BPC                (0 << 5)
-#define   PIPEMISC_DITHER_10_BPC       (1 << 5)
-#define   PIPEMISC_DITHER_6_BPC                (2 << 5)
-#define   PIPEMISC_DITHER_12_BPC       (3 << 5)
+/*
+ * For Display < 13, Bits 5-7 of PIPE MISC represent DITHER BPC with
+ * valid values of: 6, 8, 10 BPC.
+ * ADLP+, the bits 5-7 represent PORT OUTPUT BPC with valid values of:
+ * 6, 8, 10, 12 BPC.
+ */
+#define   PIPEMISC_BPC_MASK            (7 << 5)
+#define   PIPEMISC_8_BPC               (0 << 5)
+#define   PIPEMISC_10_BPC              (1 << 5)
+#define   PIPEMISC_6_BPC               (2 << 5)
+#define   PIPEMISC_12_BPC_ADLP         (4 << 5) /* adlp+ */
 #define   PIPEMISC_DITHER_ENABLE       (1 << 4)
 #define   PIPEMISC_DITHER_TYPE_MASK    (3 << 2)
 #define   PIPEMISC_DITHER_TYPE_SP      (0 << 2)