drm/i915/vlv: modeset_global_* for VLV v7

On VLV/BYT, we can adjust the CDclk frequency up or down based on the
max pixel clock we need to drive.  Lowering it can save power, while
raising it is necessary to support high resolution.

Add a new callback in modeset_affected_pipes and a
modeset_global_resources function to perform this adjustment as
necessary.

v2: use punit interface for 320 and 266 MHz CDclk adjustments (Ville)
v3: reset GMBUS dividers too, since we changed CDclk (Ville)
v4: jump to highest voltage when going to 400MHz CDclk (Jesse)
v5: drop duplicate define (Ville)
    use shifts by 1 for fixed point (Ville)
    drop new callback (Daniel)
v6: fixup adjusted_mode.clock -> adjusted_mode.crtc_clock again (Ville)
    document Bunit reg access better (Ville)
v7: pass modeset_pipes and pipe_config to global_pipes so we get the right
    clock data (Ville)

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 0de97ad..86a1ad8 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -360,9 +360,17 @@
 #define VLV_IOSF_DATA				(VLV_DISPLAY_BASE + 0x2104)
 #define VLV_IOSF_ADDR				(VLV_DISPLAY_BASE + 0x2108)
 
+/* See configdb bunit SB addr map */
+#define BUNIT_REG_BISOC				0x11
+
 #define PUNIT_OPCODE_REG_READ			6
 #define PUNIT_OPCODE_REG_WRITE			7
 
+#define PUNIT_REG_DSPFREQ			0x36
+#define   DSPFREQSTAT_SHIFT			30
+#define   DSPFREQSTAT_MASK			(0x3 << DSPFREQSTAT_SHIFT)
+#define   DSPFREQGUAR_SHIFT			14
+#define   DSPFREQGUAR_MASK			(0x3 << DSPFREQGUAR_SHIFT)
 #define PUNIT_REG_PWRGT_CTRL			0x60
 #define PUNIT_REG_PWRGT_STATUS			0x61
 #define	  PUNIT_CLK_GATE			1
@@ -425,6 +433,7 @@
 #define  DSI_PLL_N1_DIV_MASK			(3 << 16)
 #define  DSI_PLL_M1_DIV_SHIFT			0
 #define  DSI_PLL_M1_DIV_MASK			(0x1ff << 0)
+#define CCK_DISPLAY_CLOCK_CONTROL		0x6b
 
 /*
  * DPIO - a special bus for various display related registers to hide behind