drm/nvc0/pm: initial engine reclocking

Signed-off-by: Ben Skeggs <[e-mail]>

drivers/gpu/drm/nouveau/nouveau_pm.h

···
 
 /* nvc0_pm.c */
 int nvc0_pm_clocks_get(struct drm_device *, struct nouveau_pm_level *);
+void *nvc0_pm_clocks_pre(struct drm_device *, struct nouveau_pm_level *);
+int nvc0_pm_clocks_set(struct drm_device *, void *);
 
 /* nouveau_temp.c */
 void nouveau_temp_init(struct drm_device *dev);

drivers/gpu/drm/nouveau/nouveau_state.c

···
 		engine->vram.flags_valid	= nvc0_vram_flags_valid;
 		engine->pm.temp_get		= nv84_temp_get;
 		engine->pm.clocks_get		= nvc0_pm_clocks_get;
+		engine->pm.clocks_pre		= nvc0_pm_clocks_pre;
+		engine->pm.clocks_set		= nvc0_pm_clocks_set;
 		engine->pm.voltage_get		= nouveau_voltage_gpio_get;
 		engine->pm.voltage_set		= nouveau_voltage_gpio_set;
 		engine->pm.pwm_get		= nv50_pm_pwm_get;
···
 		engine->vram.flags_valid	= nvc0_vram_flags_valid;
 		engine->pm.temp_get		= nv84_temp_get;
 		engine->pm.clocks_get		= nvc0_pm_clocks_get;
+		engine->pm.clocks_pre		= nvc0_pm_clocks_pre;
+		engine->pm.clocks_set		= nvc0_pm_clocks_set;
 		engine->pm.voltage_get		= nouveau_voltage_gpio_get;
 		engine->pm.voltage_set		= nouveau_voltage_gpio_set;
 		break;

drivers/gpu/drm/nouveau/nvc0_pm.c

···
 	perflvl->vdec   = read_clk(dev, 0x0e);
 	return 0;
 }
+
+struct nvc0_pm_clock {
+	u32 freq;
+	u32 ssel;
+	u32 mdiv;
+	u32 dsrc;
+	u32 ddiv;
+	u32 coef;
+};
+
+struct nvc0_pm_state {
+	struct nvc0_pm_clock eng[16];
+};
+
+static u32
+calc_div(struct drm_device *dev, int clk, u32 ref, u32 freq, u32 *ddiv)
+{
+	u32 div = min((ref * 2) / freq, (u32)65);
+	if (div < 2)
+		div = 2;
+
+	*ddiv = div - 2;
+	return (ref * 2) / div;
+}
+
+static u32
+calc_src(struct drm_device *dev, int clk, u32 freq, u32 *dsrc, u32 *ddiv)
+{
+	u32 sclk;
+
+	/* use one of the fixed frequencies if possible */
+	*ddiv = 0x00000000;
+	switch (freq) {
+	case  27000:
+	case 108000:
+		*dsrc = 0x00000000;
+		if (freq == 108000)
+			*dsrc |= 0x00030000;
+		return freq;
+	case 100000:
+		*dsrc = 0x00000002;
+		return freq;
+	default:
+		*dsrc = 0x00000003;
+		break;
+	}
+
+	/* otherwise, calculate the closest divider */
+	sclk = read_vco(dev, clk);
+	if (clk < 7)
+		sclk = calc_div(dev, clk, sclk, freq, ddiv);
+	return sclk;
+}
+
+static u32
+calc_pll(struct drm_device *dev, int clk, u32 freq, u32 *coef)
+{
+	struct pll_lims limits;
+	int N, M, P, ret;
+
+	ret = get_pll_limits(dev, 0x137000 + (clk * 0x20), &limits);
+	if (ret)
+		return 0;
+
+	limits.refclk = read_div(dev, clk, 0x137120, 0x137140);
+	if (!limits.refclk)
+		return 0;
+
+	ret = nva3_calc_pll(dev, &limits, freq, &N, NULL, &M, &P);
+	if (ret <= 0)
+		return 0;
+
+	*coef = (P << 16) | (N << 8) | M;
+	return ret;
+}
+
+/* A (likely rather simplified and incomplete) view of the clock tree
+ *
+ * Key:
+ *
+ * S: source select
+ * D: divider
+ * P: pll
+ * F: switch
+ *
+ * Engine clocks:
+ *
+ * 137250(D) ---- 137100(F0) ---- 137160(S)/1371d0(D) ------------------- ref
+ *                      (F1) ---- 1370X0(P) ---- 137120(S)/137140(D) ---- ref
+ *
+ * Not all registers exist for all clocks.  For example: clocks >= 8 don't
+ * have their own PLL (all tied to clock 7's PLL when in PLL mode), nor do
+ * they have the divider at 1371d0, though the source selection at 137160
+ * still exists.  You must use the divider at 137250 for these instead.
+ *
+ * Memory clock:
+ *
+ * TBD, read_mem() above is likely very wrong...
+ *
+ */
+
+static int
+calc_clk(struct drm_device *dev, int clk, struct nvc0_pm_clock *info, u32 freq)
+{
+	u32 src0, div0, div1D, div1P = 0;
+	u32 clk0, clk1 = 0;
+
+	/* invalid clock domain */
+	if (!freq)
+		return 0;
+
+	/* first possible path, using only dividers */
+	clk0 = calc_src(dev, clk, freq, &src0, &div0);
+	clk0 = calc_div(dev, clk, clk0, freq, &div1D);
+
+	/* see if we can get any closer using PLLs */
+	if (clk0 != freq) {
+		if (clk < 7)
+			clk1 = calc_pll(dev, clk, freq, &info->coef);
+		else
+			clk1 = read_pll(dev, 0x1370e0);
+		clk1 = calc_div(dev, clk, clk1, freq, &div1P);
+	}
+
+	/* select the method which gets closest to target freq */
+	if (abs((int)freq - clk0) <= abs((int)freq - clk1)) {
+		info->dsrc = src0;
+		if (div0) {
+			info->ddiv |= 0x80000000;
+			info->ddiv |= div0 << 8;
+			info->ddiv |= div0;
+		}
+		if (div1D) {
+			info->mdiv |= 0x80000000;
+			info->mdiv |= div1D;
+		}
+		info->ssel = 0;
+		info->freq = clk0;
+	} else {
+		if (div1P) {
+			info->mdiv |= 0x80000000;
+			info->mdiv |= div1P << 8;
+		}
+		info->ssel = (1 << clk);
+		info->freq = clk1;
+	}
+
+	return 0;
+}
+
+void *
+nvc0_pm_clocks_pre(struct drm_device *dev, struct nouveau_pm_level *perflvl)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nvc0_pm_state *info;
+	int ret;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return ERR_PTR(-ENOMEM);
+
+	/* NFI why this is still in the performance table, the ROPCs appear
+	 * to get their clock from clock 2 ("hub07", actually hub05 on this
+	 * chip, but, anyway...) as well.  nvatiming confirms hub05 and ROP
+	 * are always the same freq with the binary driver even when the
+	 * performance table says they should differ.
+	 */
+	if (dev_priv->chipset == 0xd9)
+		perflvl->rop = 0;
+
+	if ((ret = calc_clk(dev, 0x00, &info->eng[0x00], perflvl->shader)) ||
+	    (ret = calc_clk(dev, 0x01, &info->eng[0x01], perflvl->rop)) ||
+	    (ret = calc_clk(dev, 0x02, &info->eng[0x02], perflvl->hub07)) ||
+	    (ret = calc_clk(dev, 0x07, &info->eng[0x07], perflvl->hub06)) ||
+	    (ret = calc_clk(dev, 0x08, &info->eng[0x08], perflvl->hub01)) ||
+	    (ret = calc_clk(dev, 0x09, &info->eng[0x09], perflvl->copy)) ||
+	    (ret = calc_clk(dev, 0x0c, &info->eng[0x0c], perflvl->daemon)) ||
+	    (ret = calc_clk(dev, 0x0e, &info->eng[0x0e], perflvl->vdec))) {
+		kfree(info);
+		return ERR_PTR(ret);
+	}
+
+	return info;
+}
+
+static void
+prog_clk(struct drm_device *dev, int clk, struct nvc0_pm_clock *info)
+{
+	/* program dividers at 137160/1371d0 first */
+	if (clk < 7 && !info->ssel) {
+		nv_mask(dev, 0x1371d0 + (clk * 0x04), 0x80003f3f, info->ddiv);
+		nv_wr32(dev, 0x137160 + (clk * 0x04), info->dsrc);
+	}
+
+	/* switch clock to non-pll mode */
+	nv_mask(dev, 0x137100, (1 << clk), 0x00000000);
+	nv_wait(dev, 0x137100, (1 << clk), 0x00000000);
+
+	/* reprogram pll */
+	if (clk < 7) {
+		/* make sure it's disabled first... */
+		u32 base = 0x137000 + (clk * 0x20);
+		u32 ctrl = nv_rd32(dev, base + 0x00);
+		if (ctrl & 0x00000001) {
+			nv_mask(dev, base + 0x00, 0x00000004, 0x00000000);
+			nv_mask(dev, base + 0x00, 0x00000001, 0x00000000);
+		}
+		/* program it to new values, if necessary */
+		if (info->ssel) {
+			nv_wr32(dev, base + 0x04, info->coef);
+			nv_mask(dev, base + 0x00, 0x00000001, 0x00000001);
+			nv_wait(dev, base + 0x00, 0x00020000, 0x00020000);
+			nv_mask(dev, base + 0x00, 0x00020004, 0x00000004);
+		}
+	}
+
+	/* select pll/non-pll mode, and program final clock divider */
+	nv_mask(dev, 0x137100, (1 << clk), info->ssel);
+	nv_wait(dev, 0x137100, (1 << clk), info->ssel);
+	nv_mask(dev, 0x137250 + (clk * 0x04), 0x00003f3f, info->mdiv);
+}
+
+int
+nvc0_pm_clocks_set(struct drm_device *dev, void *data)
+{
+	struct nvc0_pm_state *info = data;
+	int i;
+
+	for (i = 0; i < 16; i++) {
+		if (!info->eng[i].freq)
+			continue;
+		prog_clk(dev, i, &info->eng[i]);
+	}
+
+	kfree(info);
+	return 0;
+}