drm/nouveau: allow static performance level setting

Guarded by a module parameter for the moment, read the code for the
magic value which enables it.

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

drivers/gpu/drm/nouveau/nouveau_bios.c

@@ -4832,8 +4832,11 @@ int get_pll_limits(struct drm_device *dev, uint32_t limit_match, struct pll_lims
 	 */
 	if (limit_match > PLL_MAX)
 		pll_lim->reg = limit_match;
-	else
+	else {
 		pll_lim->reg = get_pll_register(dev, limit_match);
+		if (!pll_lim->reg)
+			return -ENOENT;
+	}
 
 	if (pll_lim_ver == 0x10 || pll_lim_ver == 0x11) {
 		uint8_t *pll_rec = &bios->data[bios->pll_limit_tbl_ptr + headerlen + recordlen * pllindex];

drivers/gpu/drm/nouveau/nouveau_drv.c

@@ -102,6 +102,14 @@ MODULE_PARM_DESC(reg_debug, "Register access debug bitmask:\n"
 int nouveau_reg_debug;
 module_param_named(reg_debug, nouveau_reg_debug, int, 0600);
 
+MODULE_PARM_DESC(perflvl, "Performance level (default: boot)\n");
+char *nouveau_perflvl;
+module_param_named(perflvl, nouveau_perflvl, charp, 0400);
+
+MODULE_PARM_DESC(perflvl_wr, "Allow perflvl changes (warning: dangerous!)\n");
+int nouveau_perflvl_wr;
+module_param_named(perflvl_wr, nouveau_perflvl_wr, int, 0400);
+
 int nouveau_fbpercrtc;
 #if 0
 module_param_named(fbpercrtc, nouveau_fbpercrtc, int, 0400);

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -716,6 +716,8 @@ extern int nouveau_ignorelid;
 extern int nouveau_nofbaccel;
 extern int nouveau_noaccel;
 extern int nouveau_override_conntype;
+extern char *nouveau_perflvl;
+extern int nouveau_perflvl_wr;
 
 extern int nouveau_pci_suspend(struct pci_dev *pdev, pm_message_t pm_state);
 extern int nouveau_pci_resume(struct pci_dev *pdev);

drivers/gpu/drm/nouveau/nouveau_pm.c

@@ -27,6 +27,78 @@
 #include "nouveau_drv.h"
 #include "nouveau_pm.h"
 
+static int
+nouveau_pm_clock_set(struct drm_device *dev, u8 id, u32 khz)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_engine *pm = &dev_priv->engine.pm;
+	void *pre_state;
+
+	if (khz == 0)
+		return 0;
+
+	pre_state = pm->clock_pre(dev, id, khz);
+	if (IS_ERR(pre_state))
+		return PTR_ERR(pre_state);
+
+	if (pre_state)
+		pm->clock_set(dev, pre_state);
+	return 0;
+}
+
+static int
+nouveau_pm_profile_set(struct drm_device *dev, const char *profile)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_engine *pm = &dev_priv->engine.pm;
+	struct nouveau_pm_level *perflvl = NULL;
+	int ret;
+
+	/* safety precaution, for now */
+	if (nouveau_perflvl_wr != 7777)
+		return -EPERM;
+
+	if (!pm->clock_set)
+		return -EINVAL;
+
+	if (!strncmp(profile, "boot", 4))
+		perflvl = &pm->boot;
+	else {
+		int pl = simple_strtol(profile, NULL, 10);
+		int i;
+
+		for (i = 0; i < pm->nr_perflvl; i++) {
+			if (pm->perflvl[i].id == pl) {
+				perflvl = &pm->perflvl[i];
+				break;
+			}
+		}
+
+		if (!perflvl)
+			return -EINVAL;
+	}
+
+	if (perflvl == pm->cur)
+		return 0;
+
+	NV_INFO(dev, "setting performance level: %s\n", profile);
+	if (pm->voltage.supported && pm->voltage_set && perflvl->voltage) {
+		ret = pm->voltage_set(dev, perflvl->voltage);
+		if (ret) {
+			NV_ERROR(dev, "voltage_set %d failed: %d\n",
+				 perflvl->voltage, ret);
+		}
+	}
+
+	nouveau_pm_clock_set(dev, PLL_CORE, perflvl->core);
+	nouveau_pm_clock_set(dev, PLL_SHADER, perflvl->shader);
+	nouveau_pm_clock_set(dev, PLL_MEMORY, perflvl->memory);
+	nouveau_pm_clock_set(dev, PLL_UNK05, perflvl->unk05);
+
+	pm->cur = perflvl;
+	return 0;
+}
+
 static int
 nouveau_pm_perflvl_get(struct drm_device *dev, struct nouveau_pm_level *perflvl)
 {
@@ -130,7 +202,13 @@ static ssize_t
 nouveau_pm_set_perflvl(struct device *d, struct device_attribute *a,
 		       const char *buf, size_t count)
 {
-	return -EPERM;
+        struct drm_device *dev = pci_get_drvdata(to_pci_dev(d));
+	int ret;
+
+	ret = nouveau_pm_profile_set(dev, buf);
+	if (ret)
+		return ret;
+	return strlen(buf);
 }
 
 DEVICE_ATTR(performance_level, S_IRUGO | S_IWUSR,
@@ -163,6 +241,15 @@ nouveau_pm_init(struct drm_device *dev)
 		NV_INFO(dev, "c: %s", info);
 	}
 
+	/* switch performance levels now if requested */
+	if (nouveau_perflvl != NULL) {
+		ret = nouveau_pm_profile_set(dev, nouveau_perflvl);
+		if (ret) {
+			NV_ERROR(dev, "error setting perflvl \"%s\": %d\n",
+				 nouveau_perflvl, ret);
+		}
+	}
+
 	/* initialise sysfs */
 	ret = device_create_file(d, &dev_attr_performance_level);
 	if (ret)

drivers/gpu/drm/nouveau/nv04_pm.c

@@ -50,7 +50,7 @@ nv04_pm_clock_pre(struct drm_device *dev, u32 id, int khz)
 	ret = get_pll_limits(dev, id, &state->pll);
 	if (ret) {
 		kfree(state);
-		return ERR_PTR(ret);
+		return (ret == -ENOENT) ? NULL : ERR_PTR(ret);
 	}
 
 	ret = nouveau_calc_pll_mnp(dev, &state->pll, khz, &state->calc);

drivers/gpu/drm/nouveau/nv50_pm.c

@@ -80,7 +80,7 @@ nv50_pm_clock_pre(struct drm_device *dev, u32 id, int khz)
 	ret = get_pll_limits(dev, id, &state->pll);
 	if (ret < 0) {
 		kfree(state);
-		return ERR_PTR(ret);
+		return (ret == -ENOENT) ? NULL : ERR_PTR(ret);
 	}
 
 	ret = nv50_calc_pll(dev, &state->pll, khz, &state->N, &state->M,