drm/nv40/pm: implement first type of pwm fanspeed funcs

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

drivers/gpu/drm/nouveau/nouveau_pm.h

@@ -56,6 +56,8 @@ void nv04_pm_clock_set(struct drm_device *, void *);
 int nv40_pm_clocks_get(struct drm_device *, struct nouveau_pm_level *);
 void *nv40_pm_clocks_pre(struct drm_device *, struct nouveau_pm_level *);
 void nv40_pm_clocks_set(struct drm_device *, void *);
+int nv40_pm_fanspeed_get(struct drm_device *);
+int nv40_pm_fanspeed_set(struct drm_device *, int percent);
 
 /* nv50_pm.c */
 int nv50_pm_clock_get(struct drm_device *, u32 id);

drivers/gpu/drm/nouveau/nouveau_state.c

@@ -292,6 +292,15 @@ static int nouveau_init_engine_ptrs(struct drm_device *dev)
 		engine->pm.voltage_get		= nouveau_voltage_gpio_get;
 		engine->pm.voltage_set		= nouveau_voltage_gpio_set;
 		engine->pm.temp_get		= nv40_temp_get;
+		switch (dev_priv->chipset) {
+		case 0x40:
+		case 0x49:
+			engine->pm.fanspeed_get	= nv40_pm_fanspeed_get;
+			engine->pm.fanspeed_set	= nv40_pm_fanspeed_set;
+			break;
+		default:
+			break;
+		}
 		engine->vram.init		= nouveau_mem_detect;
 		engine->vram.takedown		= nouveau_stub_takedown;
 		engine->vram.flags_valid	= nouveau_mem_flags_valid;

drivers/gpu/drm/nouveau/nv40_pm.c

@@ -346,3 +346,29 @@ nv40_pm_clocks_set(struct drm_device *dev, void *pre_state)
 
 	kfree(info);
 }
+
+int
+nv40_pm_fanspeed_get(struct drm_device *dev)
+{
+	u32 reg = nv_rd32(dev, 0x0010f0);
+	if (reg & 0x80000000) {
+		u32 duty = (reg & 0x7fff0000) >> 16;
+		u32 divs = (reg & 0x00007fff);
+		if (divs && divs >= duty)
+			return ((divs - duty) * 100) / divs;
+	}
+
+	return 100;
+}
+
+int
+nv40_pm_fanspeed_set(struct drm_device *dev, int percent)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_engine *pm = &dev_priv->engine.pm;
+	u32 divs = pm->pwm_divisor;
+	u32 duty = ((100 - percent) * divs) / 100;
+
+	nv_wr32(dev, 0x0010f0, 0x80000000 | (duty << 16) | divs);
+	return 0;
+}