drm/nv50: support fractional feedback divider on newer chips

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/Makefile

@@ -22,7 +22,8 @@ nouveau-y := nouveau_drv.o nouveau_state.o nouveau_channel.o nouveau_mem.o \
              nv50_cursor.o nv50_display.o nv50_fbcon.o \
              nv04_dac.o nv04_dfp.o nv04_tv.o nv17_tv.o nv17_tv_modes.o \
              nv04_crtc.o nv04_display.o nv04_cursor.o nv04_fbcon.o \
-             nv17_gpio.o nv50_gpio.o
+             nv17_gpio.o nv50_gpio.o \
+	     nv50_calc.o
 
 nouveau-$(CONFIG_DRM_NOUVEAU_DEBUG) += nouveau_debugfs.o
 nouveau-$(CONFIG_COMPAT) += nouveau_ioc32.o

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -1170,6 +1170,12 @@ int nv17_gpio_set(struct drm_device *dev, enum dcb_gpio_tag tag, int state);
 int nv50_gpio_get(struct drm_device *dev, enum dcb_gpio_tag tag);
 int nv50_gpio_set(struct drm_device *dev, enum dcb_gpio_tag tag, int state);
 
+/* nv50_calc. */
+int nv50_calc_pll(struct drm_device *, struct pll_lims *, int clk,
+		  int *N1, int *M1, int *N2, int *M2, int *P);
+int nv50_calc_pll2(struct drm_device *, struct pll_lims *,
+		   int clk, int *N, int *fN, int *M, int *P);
+
 #ifndef ioread32_native
 #ifdef __BIG_ENDIAN
 #define ioread16_native ioread16be

drivers/gpu/drm/nouveau/nv50_calc.c

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2010 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: Ben Skeggs
+ */
+
+#include "drmP.h"
+#include "drm_fixed.h"
+#include "nouveau_drv.h"
+#include "nouveau_hw.h"
+
+int
+nv50_calc_pll(struct drm_device *dev, struct pll_lims *pll, int clk,
+	      int *N1, int *M1, int *N2, int *M2, int *P)
+{
+	struct nouveau_pll_vals pll_vals;
+	int ret;
+
+	ret = nouveau_calc_pll_mnp(dev, pll, clk, &pll_vals);
+	if (ret <= 0)
+		return ret;
+
+	*N1 = pll_vals.N1;
+	*M1 = pll_vals.M1;
+	*N2 = pll_vals.N2;
+	*M2 = pll_vals.M2;
+	*P = pll_vals.log2P;
+	return ret;
+}
+
+int
+nv50_calc_pll2(struct drm_device *dev, struct pll_lims *pll, int clk,
+	       int *N, int *fN, int *M, int *P)
+{
+	fixed20_12 fb_div, a, b;
+
+	*P = pll->vco1.maxfreq / clk;
+	if (*P > pll->max_p)
+		*P = pll->max_p;
+	if (*P < pll->min_p)
+		*P = pll->min_p;
+
+	/* *M = ceil(refclk / pll->vco.max_inputfreq); */
+	a.full = dfixed_const(pll->refclk);
+	b.full = dfixed_const(pll->vco1.max_inputfreq);
+	a.full = dfixed_div(a, b);
+	a.full = dfixed_ceil(a);
+	*M = dfixed_trunc(a);
+
+	/* fb_div = (vco * *M) / refclk; */
+	fb_div.full = dfixed_const(clk * *P);
+	fb_div.full = dfixed_mul(fb_div, a);
+	a.full = dfixed_const(pll->refclk);
+	fb_div.full = dfixed_div(fb_div, a);
+
+	/* *N = floor(fb_div); */
+	a.full = dfixed_floor(fb_div);
+	*N = dfixed_trunc(fb_div);
+
+	/* *fN = (fmod(fb_div, 1.0) * 8192) - 4096; */
+	b.full = dfixed_const(8192);
+	a.full = dfixed_mul(a, b);
+	fb_div.full = dfixed_mul(fb_div, b);
+	fb_div.full = fb_div.full - a.full;
+	*fN = dfixed_trunc(fb_div) - 4096;
+	*fN &= 0xffff;
+
+	return clk;
+}

drivers/gpu/drm/nouveau/nv50_crtc.c

@@ -264,38 +264,40 @@ nv50_crtc_set_scale(struct nouveau_crtc *nv_crtc, int scaling_mode, bool update)
 int
 nv50_crtc_set_clock(struct drm_device *dev, int head, int pclk)
 {
-	uint32_t pll_reg = NV50_PDISPLAY_CRTC_CLK_CTRL1(head);
-	struct nouveau_pll_vals pll;
-	struct pll_lims limits;
+	uint32_t reg = NV50_PDISPLAY_CRTC_CLK_CTRL1(head);
+	struct pll_lims pll;
 	uint32_t reg1, reg2;
-	int ret;
+	int ret, N1, M1, N2, M2, P;
 
-	ret = get_pll_limits(dev, pll_reg, &limits);
+	ret = get_pll_limits(dev, reg, &pll);
 	if (ret)
 		return ret;
 
-	ret = nouveau_calc_pll_mnp(dev, &limits, pclk, &pll);
-	if (ret <= 0)
-		return ret;
+	if (pll.vco2.maxfreq) {
+		ret = nv50_calc_pll(dev, &pll, pclk, &N1, &M1, &N2, &M2, &P);
+		if (ret <= 0)
+			return 0;
 
-	if (limits.vco2.maxfreq) {
 		NV_DEBUG(dev, "pclk %d out %d NM1 %d %d NM2 %d %d P %d\n",
-			 pclk, ret, pll.N1, pll.M1, pll.N2, pll.M2, pll.log2P);
-
-		reg1 = nv_rd32(dev, pll_reg + 4) & 0xff00ff00;
-		reg2 = nv_rd32(dev, pll_reg + 8) & 0x8000ff00;
-		nv_wr32(dev, pll_reg, 0x10000611);
-		nv_wr32(dev, pll_reg + 4, reg1 | (pll.M1 << 16) | pll.N1);
-		nv_wr32(dev, pll_reg + 8,
-			reg2 | (pll.log2P << 28) | (pll.M2 << 16) | pll.N2);
+			 pclk, ret, N1, M1, N2, M2, P);
+
+		reg1 = nv_rd32(dev, reg + 4) & 0xff00ff00;
+		reg2 = nv_rd32(dev, reg + 8) & 0x8000ff00;
+		nv_wr32(dev, reg, 0x10000611);
+		nv_wr32(dev, reg + 4, reg1 | (M1 << 16) | N1);
+		nv_wr32(dev, reg + 8, reg2 | (P << 28) | (M2 << 16) | N2);
 	} else {
-		NV_DEBUG(dev, "pclk %d out %d NM %d %d P %d\n",
-			 pclk, ret, pll.N1, pll.M1, pll.log2P);
+		ret = nv50_calc_pll2(dev, &pll, pclk, &N1, &N2, &M1, &P);
+		if (ret <= 0)
+			return 0;
+
+		NV_DEBUG(dev, "pclk %d out %d N %d fN 0x%04x M %d P %d\n",
+			 pclk, ret, N1, N2, M1, P);
 
-		reg1 = nv_rd32(dev, pll_reg + 4) & 0xffc00000;
-		nv_wr32(dev, pll_reg, 0x50000610);
-		nv_wr32(dev, pll_reg + 4, reg1 |
-			(pll.log2P << 16) | (pll.M1 << 8) | pll.N1);
+		reg1 = nv_rd32(dev, reg + 4) & 0xffc00000;
+		nv_wr32(dev, reg, 0x50000610);
+		nv_wr32(dev, reg + 4, reg1 | (P << 16) | (M1 << 8) | N1);
+		nv_wr32(dev, reg + 8, N2);
 	}
 
 	return 0;