drm/radeon/kms: add new pll algo for avivo asics

Based on the vbios code.  This should hopefully
fix the pll problems on a number of avivo asics
once it's enabled.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_display.c

@@ -780,6 +780,115 @@ static int radeon_ddc_dump(struct drm_connector *connector)
 	return ret;
 }
 
+/* avivo */
+static void avivo_get_fb_div(struct radeon_pll *pll,
+			     u32 target_clock,
+			     u32 post_div,
+			     u32 ref_div,
+			     u32 *fb_div,
+			     u32 *frac_fb_div)
+{
+	u32 tmp = post_div * ref_div;
+
+	tmp *= target_clock;
+	*fb_div = tmp / pll->reference_freq;
+	*frac_fb_div = tmp % pll->reference_freq;
+}
+
+static u32 avivo_get_post_div(struct radeon_pll *pll,
+			      u32 target_clock)
+{
+	u32 vco, post_div, tmp;
+
+	if (pll->flags & RADEON_PLL_USE_POST_DIV)
+		return pll->post_div;
+
+	if (pll->flags & RADEON_PLL_PREFER_MINM_OVER_MAXP) {
+		if (pll->flags & RADEON_PLL_IS_LCD)
+			vco = pll->lcd_pll_out_min;
+		else
+			vco = pll->pll_out_min;
+	} else {
+		if (pll->flags & RADEON_PLL_IS_LCD)
+			vco = pll->lcd_pll_out_max;
+		else
+			vco = pll->pll_out_max;
+	}
+
+	post_div = vco / target_clock;
+	tmp = vco % target_clock;
+
+	if (pll->flags & RADEON_PLL_PREFER_MINM_OVER_MAXP) {
+		if (tmp)
+			post_div++;
+	} else {
+		if (!tmp)
+			post_div--;
+	}
+
+	return post_div;
+}
+
+#define MAX_TOLERANCE 10
+
+void radeon_compute_pll_avivo(struct radeon_pll *pll,
+			      u32 freq,
+			      u32 *dot_clock_p,
+			      u32 *fb_div_p,
+			      u32 *frac_fb_div_p,
+			      u32 *ref_div_p,
+			      u32 *post_div_p)
+{
+	u32 target_clock = freq / 10;
+	u32 post_div = avivo_get_post_div(pll, target_clock);
+	u32 ref_div = pll->min_ref_div;
+	u32 fb_div = 0, frac_fb_div = 0, tmp;
+
+	if (pll->flags & RADEON_PLL_USE_REF_DIV)
+		ref_div = pll->reference_div;
+
+	if (pll->flags & RADEON_PLL_USE_FRAC_FB_DIV) {
+		avivo_get_fb_div(pll, target_clock, post_div, ref_div, &fb_div, &frac_fb_div);
+		frac_fb_div = (100 * frac_fb_div) / pll->reference_freq;
+		if (frac_fb_div >= 5) {
+			frac_fb_div -= 5;
+			frac_fb_div = frac_fb_div / 10;
+			frac_fb_div++;
+		}
+		if (frac_fb_div >= 10) {
+			fb_div++;
+			frac_fb_div = 0;
+		}
+	} else {
+		while (ref_div <= pll->max_ref_div) {
+			avivo_get_fb_div(pll, target_clock, post_div, ref_div,
+					 &fb_div, &frac_fb_div);
+			if (frac_fb_div >= (pll->reference_freq / 2))
+				fb_div++;
+			frac_fb_div = 0;
+			tmp = (pll->reference_freq * fb_div) / (post_div * ref_div);
+			tmp = (tmp * 10000) / target_clock;
+
+			if (tmp > (10000 + MAX_TOLERANCE))
+				ref_div++;
+			else if (tmp >= (10000 - MAX_TOLERANCE))
+				break;
+			else
+				ref_div++;
+		}
+	}
+
+	*dot_clock_p = ((pll->reference_freq * fb_div * 10) + (pll->reference_freq * frac_fb_div)) /
+		(ref_div * post_div * 10);
+	*fb_div_p = fb_div;
+	*frac_fb_div_p = frac_fb_div;
+	*ref_div_p = ref_div;
+	*post_div_p = post_div;
+	DRM_DEBUG_KMS("%d, pll dividers - fb: %d.%d ref: %d, post %d\n",
+		      *dot_clock_p, fb_div, frac_fb_div, ref_div, post_div);
+}
+
+/* pre-avivo */
 static inline uint32_t radeon_div(uint64_t n, uint32_t d)
 {
 	uint64_t mod;
@@ -790,13 +899,13 @@ static inline uint32_t radeon_div(uint64_t n, uint32_t d)
 	return n;
 }
 
-void radeon_compute_pll(struct radeon_pll *pll,
-			uint64_t freq,
-			uint32_t *dot_clock_p,
-			uint32_t *fb_div_p,
-			uint32_t *frac_fb_div_p,
-			uint32_t *ref_div_p,
-			uint32_t *post_div_p)
+void radeon_compute_pll_legacy(struct radeon_pll *pll,
+			       uint64_t freq,
+			       uint32_t *dot_clock_p,
+			       uint32_t *fb_div_p,
+			       uint32_t *frac_fb_div_p,
+			       uint32_t *ref_div_p,
+			       uint32_t *post_div_p)
 {
 	uint32_t min_ref_div = pll->min_ref_div;
 	uint32_t max_ref_div = pll->max_ref_div;