drm/nouveau: import initial work on vbios performance table parsing

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

drivers/gpu/drm/nouveau/Makefile

@@ -10,6 +10,7 @@ nouveau-y := nouveau_drv.o nouveau_state.o nouveau_channel.o nouveau_mem.o \
              nouveau_hw.o nouveau_calc.o nouveau_bios.o nouveau_i2c.o \
              nouveau_display.o nouveau_connector.o nouveau_fbcon.o \
              nouveau_dp.o nouveau_ramht.o \
+	     nouveau_pm.o nouveau_volt.o nouveau_perf.o \
              nv04_timer.o \
              nv04_mc.o nv40_mc.o nv50_mc.o \
              nv04_fb.o nv10_fb.o nv30_fb.o nv40_fb.o nv50_fb.o nvc0_fb.o \

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -359,6 +359,51 @@ struct nouveau_gpio_engine {
 	void (*irq_enable)(struct drm_device *, enum dcb_gpio_tag, bool on);
 };
 
+struct nouveau_pm_voltage_level {
+	u8 voltage;
+	u8 vid;
+};
+
+struct nouveau_pm_voltage {
+	bool supported;
+	u8 vid_mask;
+
+	struct nouveau_pm_voltage_level *level;
+	int nr_level;
+};
+
+#define NOUVEAU_PM_MAX_LEVEL 8
+struct nouveau_pm_level {
+	struct device_attribute dev_attr;
+	char name[32];
+	int id;
+
+	u32 core;
+	u32 memory;
+	u32 shader;
+	u32 unk05;
+
+	u8 voltage;
+	u8 fanspeed;
+};
+
+struct nouveau_pm_engine {
+	struct nouveau_pm_voltage voltage;
+	struct nouveau_pm_level perflvl[NOUVEAU_PM_MAX_LEVEL];
+	int nr_perflvl;
+
+	struct nouveau_pm_level boot;
+	struct nouveau_pm_level *cur;
+
+	int (*clock_get)(struct drm_device *, u32 id);
+	void *(*clock_pre)(struct drm_device *, u32 id, int khz);
+	void (*clock_set)(struct drm_device *, void *);
+	int (*voltage_get)(struct drm_device *);
+	int (*voltage_set)(struct drm_device *, int voltage);
+	int (*fanspeed_get)(struct drm_device *);
+	int (*fanspeed_set)(struct drm_device *, int fanspeed);
+};
+
 struct nouveau_engine {
 	struct nouveau_instmem_engine instmem;
 	struct nouveau_mc_engine      mc;
@@ -368,6 +413,7 @@ struct nouveau_engine {
 	struct nouveau_fifo_engine    fifo;
 	struct nouveau_display_engine display;
 	struct nouveau_gpio_engine    gpio;
+	struct nouveau_pm_engine      pm;
 };
 
 struct nouveau_pll_vals {

drivers/gpu/drm/nouveau/nouveau_perf.c

@@ -0,0 +1,159 @@
+/*
+ * 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 "nouveau_drv.h"
+#include "nouveau_pm.h"
+
+void
+nouveau_perf_init(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_engine *pm = &dev_priv->engine.pm;
+	struct nvbios *bios = &dev_priv->vbios;
+	struct bit_entry P;
+	u8 version, headerlen, recordlen, entries;
+	u8 *perf, *entry;
+	int vid, i;
+
+	if (bios->type == NVBIOS_BIT) {
+		if (bit_table(dev, 'P', &P))
+			return;
+
+		if (P.version != 1 && P.version != 2) {
+			NV_WARN(dev, "unknown perf for BIT P %d\n", P.version);
+			return;
+		}
+
+		perf = ROMPTR(bios, P.data[0]);
+		version   = perf[0];
+		headerlen = perf[1];
+		if (version < 0x40) {
+			recordlen = perf[3] + (perf[4] * perf[5]);
+			entries   = perf[2];
+		} else {
+			recordlen = perf[2] + (perf[3] * perf[4]);
+			entries   = perf[5];
+		}
+	} else {
+		if (bios->data[bios->offset + 6] < 0x27) {
+			NV_DEBUG(dev, "BMP version too old for perf\n");
+			return;
+		}
+
+		perf = ROMPTR(bios, bios->data[bios->offset + 0x94]);
+		if (!perf) {
+			NV_DEBUG(dev, "perf table pointer invalid\n");
+			return;
+		}
+
+		version   = perf[1];
+		headerlen = perf[0];
+		recordlen = perf[3];
+		entries   = perf[2];
+	}
+
+	entry = perf + headerlen;
+	for (i = 0; i < entries; i++) {
+		struct nouveau_pm_level *perflvl = &pm->perflvl[pm->nr_perflvl];
+
+		if (entry[0] == 0xff) {
+			entry += recordlen;
+			continue;
+		}
+
+		switch (version) {
+		case 0x12:
+		case 0x13:
+		case 0x15:
+			perflvl->fanspeed = entry[55];
+			perflvl->voltage = entry[56];
+			perflvl->core = ROM32(entry[1]) / 100;
+			perflvl->memory = ROM32(entry[5]) / 100;
+			break;
+		case 0x21:
+		case 0x23:
+		case 0x24:
+			perflvl->fanspeed = entry[4];
+			perflvl->voltage = entry[5];
+			perflvl->core = ROM16(entry[6]);
+			perflvl->memory = ROM16(entry[11]);
+			break;
+		case 0x25:
+			perflvl->fanspeed = entry[4];
+			perflvl->voltage = entry[5];
+			perflvl->core = ROM16(entry[6]);
+			perflvl->shader = ROM16(entry[10]);
+			perflvl->memory = ROM16(entry[12]);
+			break;
+		case 0x30:
+		case 0x35:
+			perflvl->fanspeed = entry[6];
+			perflvl->voltage = entry[7];
+			perflvl->core = ROM16(entry[8]);
+			perflvl->shader = ROM16(entry[10]);
+			perflvl->memory = ROM16(entry[12]);
+			/*XXX: confirm on 0x35 */
+			perflvl->unk05 = ROM16(entry[16]);
+			break;
+		case 0x40:
+#define subent(n) entry[perf[2] + ((n) * perf[3])]
+			perflvl->fanspeed = 0; /*XXX*/
+			perflvl->voltage = 0; /*XXX: entry[2] */;
+			perflvl->core = ROM16(subent(0)) & 0xfff;
+			perflvl->shader = ROM16(subent(1)) & 0xfff;
+			perflvl->memory = ROM16(subent(2)) & 0xfff;
+			break;
+		}
+
+		/* convert MHz -> KHz, it's more convenient */
+		perflvl->core *= 1000;
+		perflvl->memory *= 1000;
+		perflvl->shader *= 1000;
+		perflvl->unk05 *= 1000;
+
+		/* make sure vid is valid */
+		if (pm->voltage.supported && perflvl->voltage) {
+			vid = nouveau_volt_vid_lookup(dev, perflvl->voltage);
+			if (vid < 0) {
+				NV_DEBUG(dev, "drop perflvl %d, bad vid\n", i);
+				entry += recordlen;
+				continue;
+			}
+		}
+
+		snprintf(perflvl->name, sizeof(perflvl->name),
+			 "performance_level_%d", i);
+		perflvl->id = i;
+		pm->nr_perflvl++;
+
+		entry += recordlen;
+	}
+}
+
+void
+nouveau_perf_fini(struct drm_device *dev)
+{
+}

drivers/gpu/drm/nouveau/nouveau_pm.c

@@ -0,0 +1,214 @@
+/*
+ * 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 "nouveau_drv.h"
+#include "nouveau_pm.h"
+
+static int
+nouveau_pm_perflvl_get(struct drm_device *dev, struct nouveau_pm_level *perflvl)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_engine *pm = &dev_priv->engine.pm;
+	int ret;
+
+	if (!pm->clock_get)
+		return -EINVAL;
+
+	memset(perflvl, 0, sizeof(*perflvl));
+
+	ret = pm->clock_get(dev, PLL_CORE);
+	if (ret > 0)
+		perflvl->core = ret;
+
+	ret = pm->clock_get(dev, PLL_MEMORY);
+	if (ret > 0)
+		perflvl->memory = ret;
+
+	ret = pm->clock_get(dev, PLL_SHADER);
+	if (ret > 0)
+		perflvl->shader = ret;
+
+	ret = pm->clock_get(dev, PLL_UNK05);
+	if (ret > 0)
+		perflvl->unk05 = ret;
+
+	if (pm->voltage.supported && pm->voltage_get) {
+		ret = pm->voltage_get(dev);
+		if (ret > 0)
+			perflvl->voltage = ret;
+	}
+
+	return 0;
+}
+
+static void
+nouveau_pm_perflvl_info(struct nouveau_pm_level *perflvl, char *ptr, int len)
+{
+	char s[16], v[16], f[16];
+
+	s[0] = '\0';
+	if (perflvl->shader)
+		snprintf(s, sizeof(s), " shader %dMHz", perflvl->shader / 1000);
+
+	v[0] = '\0';
+	if (perflvl->voltage)
+		snprintf(v, sizeof(v), " voltage %dmV", perflvl->voltage * 10);
+
+	f[0] = '\0';
+	if (perflvl->fanspeed)
+		snprintf(f, sizeof(f), " fanspeed %d%%", perflvl->fanspeed);
+
+	snprintf(ptr, len, "core %dMHz memory %dMHz%s%s%s\n",
+		 perflvl->core / 1000, perflvl->memory / 1000, s, v, f);
+}
+
+static ssize_t
+nouveau_pm_get_perflvl_info(struct device *d,
+			    struct device_attribute *a, char *buf)
+{
+	struct nouveau_pm_level *perflvl = (struct nouveau_pm_level *)a;
+	char *ptr = buf;
+	int len = PAGE_SIZE;
+
+	snprintf(ptr, len, "%d: ", perflvl->id);
+	ptr += strlen(buf);
+	len -= strlen(buf);
+
+	nouveau_pm_perflvl_info(perflvl, ptr, len);
+	return strlen(buf);
+}
+
+static ssize_t
+nouveau_pm_get_perflvl(struct device *d, struct device_attribute *a, char *buf)
+{
+        struct drm_device *dev = pci_get_drvdata(to_pci_dev(d));
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_engine *pm = &dev_priv->engine.pm;
+	struct nouveau_pm_level cur;
+	int len = PAGE_SIZE, ret;
+	char *ptr = buf;
+
+	if (!pm->cur)
+		snprintf(ptr, len, "setting: boot\n");
+	else if (pm->cur == &pm->boot)
+		snprintf(ptr, len, "setting: boot\nc: ");
+	else
+		snprintf(ptr, len, "setting: static %d\nc: ", pm->cur->id);
+	ptr += strlen(buf);
+	len -= strlen(buf);
+
+	ret = nouveau_pm_perflvl_get(dev, &cur);
+	if (ret == 0)
+		nouveau_pm_perflvl_info(&cur, ptr, len);
+	return strlen(buf);
+}
+
+static ssize_t
+nouveau_pm_set_perflvl(struct device *d, struct device_attribute *a,
+		       const char *buf, size_t count)
+{
+	return -EPERM;
+}
+
+DEVICE_ATTR(performance_level, S_IRUGO | S_IWUSR,
+	    nouveau_pm_get_perflvl, nouveau_pm_set_perflvl);
+
+int
+nouveau_pm_init(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_engine *pm = &dev_priv->engine.pm;
+	struct device *d = &dev->pdev->dev;
+	char info[256];
+	int ret, i;
+
+	nouveau_volt_init(dev);
+	nouveau_perf_init(dev);
+
+	NV_INFO(dev, "%d available performance level(s)\n", pm->nr_perflvl);
+	for (i = 0; i < pm->nr_perflvl; i++) {
+		nouveau_pm_perflvl_info(&pm->perflvl[i], info, sizeof(info));
+		NV_INFO(dev, "%d: %s", pm->perflvl[i].id, info);
+	}
+
+	/* determine current ("boot") performance level */
+	ret = nouveau_pm_perflvl_get(dev, &pm->boot);
+	if (ret == 0) {
+		pm->cur = &pm->boot;
+
+		nouveau_pm_perflvl_info(&pm->boot, info, sizeof(info));
+		NV_INFO(dev, "c: %s", info);
+	}
+
+	/* initialise sysfs */
+	ret = device_create_file(d, &dev_attr_performance_level);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < pm->nr_perflvl; i++) {
+		struct nouveau_pm_level *perflvl = &pm->perflvl[i];
+
+		perflvl->dev_attr.attr.name = perflvl->name;
+		perflvl->dev_attr.attr.mode = S_IRUGO;
+		perflvl->dev_attr.show = nouveau_pm_get_perflvl_info;
+		perflvl->dev_attr.store = NULL;
+		sysfs_attr_init(&perflvl->dev_attr.attr);
+
+		ret = device_create_file(d, &perflvl->dev_attr);
+		if (ret) {
+			NV_ERROR(dev, "failed pervlvl %d sysfs: %d\n",
+				 perflvl->id, i);
+			perflvl->dev_attr.attr.name = NULL;
+			nouveau_pm_fini(dev);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+void
+nouveau_pm_fini(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_engine *pm = &dev_priv->engine.pm;
+	struct device *d = &dev->pdev->dev;
+	int i;
+
+	device_remove_file(d, &dev_attr_performance_level);
+	for (i = 0; i < pm->nr_perflvl; i++) {
+		struct nouveau_pm_level *pl = &pm->perflvl[i];
+
+		if (!pl->dev_attr.attr.name)
+			break;
+
+		device_remove_file(d, &pl->dev_attr);
+	}
+
+	nouveau_perf_fini(dev);
+	nouveau_volt_fini(dev);
+}
+

drivers/gpu/drm/nouveau/nouveau_pm.h

@@ -0,0 +1,44 @@
+/*
+ * 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
+ */
+
+#ifndef __NOUVEAU_PM_H__
+#define __NOUVEAU_PM_H__
+
+/* nouveau_pm.c */
+int  nouveau_pm_init(struct drm_device *dev);
+void nouveau_pm_fini(struct drm_device *dev);
+
+/* nouveau_volt.c */
+void nouveau_volt_init(struct drm_device *);
+void nouveau_volt_fini(struct drm_device *);
+int  nouveau_volt_vid_lookup(struct drm_device *, int voltage);
+int  nouveau_volt_lvl_lookup(struct drm_device *, int vid);
+int  nouveau_voltage_gpio_get(struct drm_device *);
+int  nouveau_voltage_gpio_set(struct drm_device *, int voltage);
+
+/* nouveau_perf.c */
+void nouveau_perf_init(struct drm_device *);
+void nouveau_perf_fini(struct drm_device *);
+
+#endif

drivers/gpu/drm/nouveau/nouveau_state.c

@@ -36,6 +36,7 @@
 #include "nouveau_drm.h"
 #include "nouveau_fbcon.h"
 #include "nouveau_ramht.h"
+#include "nouveau_pm.h"
 #include "nv50_display.h"
 
 static void nouveau_stub_takedown(struct drm_device *dev) {}
@@ -527,6 +528,8 @@ nouveau_card_init(struct drm_device *dev)
 	if (ret)
 		goto out_display_early;
 
+	nouveau_pm_init(dev);
+
 	ret = nouveau_mem_vram_init(dev);
 	if (ret)
 		goto out_bios;
@@ -635,6 +638,7 @@ out_gpuobj:
 out_vram:
 	nouveau_mem_vram_fini(dev);
 out_bios:
+	nouveau_pm_fini(dev);
 	nouveau_bios_takedown(dev);
 out_display_early:
 	engine->display.late_takedown(dev);
@@ -677,6 +681,7 @@ static void nouveau_card_takedown(struct drm_device *dev)
 
 	drm_irq_uninstall(dev);
 
+	nouveau_pm_fini(dev);
 	nouveau_bios_takedown(dev);
 
 	vga_client_register(dev->pdev, NULL, NULL, NULL);

drivers/gpu/drm/nouveau/nouveau_volt.c

@@ -0,0 +1,209 @@
+/*
+ * 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 "nouveau_drv.h"
+#include "nouveau_pm.h"
+
+static const enum dcb_gpio_tag vidtag[] = { 0x04, 0x05, 0x06, 0x1a };
+static int nr_vidtag = sizeof(vidtag) / sizeof(vidtag[0]);
+
+int
+nouveau_voltage_gpio_get(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_gpio_engine *gpio = &dev_priv->engine.gpio;
+	struct nouveau_pm_voltage *volt = &dev_priv->engine.pm.voltage;
+	u8 vid = 0;
+	int i;
+
+	for (i = 0; i < nr_vidtag; i++) {
+		if (!(volt->vid_mask & (1 << i)))
+			continue;
+
+		vid |= gpio->get(dev, vidtag[i]) << i;
+	}
+
+	return nouveau_volt_lvl_lookup(dev, vid);
+}
+
+int
+nouveau_voltage_gpio_set(struct drm_device *dev, int voltage)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_gpio_engine *gpio = &dev_priv->engine.gpio;
+	struct nouveau_pm_voltage *volt = &dev_priv->engine.pm.voltage;
+	int vid, i;
+
+	vid = nouveau_volt_vid_lookup(dev, voltage);
+	if (vid < 0)
+		return vid;
+
+	for (i = 0; i < nr_vidtag; i++) {
+		if (!(volt->vid_mask & (1 << i)))
+			continue;
+
+		gpio->set(dev, vidtag[i], !!(vid & (1 << i)));
+	}
+
+	return 0;
+}
+
+int
+nouveau_volt_vid_lookup(struct drm_device *dev, int voltage)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_voltage *volt = &dev_priv->engine.pm.voltage;
+	int i;
+
+	for (i = 0; i < volt->nr_level; i++) {
+		if (volt->level[i].voltage == voltage)
+			return volt->level[i].vid;
+	}
+
+	return -ENOENT;
+}
+
+int
+nouveau_volt_lvl_lookup(struct drm_device *dev, int vid)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_voltage *volt = &dev_priv->engine.pm.voltage;
+	int i;
+
+	for (i = 0; i < volt->nr_level; i++) {
+		if (volt->level[i].vid == vid)
+			return volt->level[i].voltage;
+	}
+
+	return -ENOENT;
+}
+
+void
+nouveau_volt_init(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_engine *pm = &dev_priv->engine.pm;
+	struct nouveau_pm_voltage *voltage = &pm->voltage;
+	struct nvbios *bios = &dev_priv->vbios;
+	struct bit_entry P;
+	u8 *volt = NULL, *entry;
+	int i, recordlen, entries, vidmask, vidshift;
+
+	if (bios->type == NVBIOS_BIT) {
+		if (bit_table(dev, 'P', &P))
+			return;
+
+		if (P.version == 1)
+			volt = ROMPTR(bios, P.data[16]);
+		else
+		if (P.version == 2)
+			volt = ROMPTR(bios, P.data[12]);
+		else {
+			NV_WARN(dev, "unknown volt for BIT P %d\n", P.version);
+		}
+	} else {
+		if (bios->data[bios->offset + 6] < 0x27) {
+			NV_DEBUG(dev, "BMP version too old for voltage\n");
+			return;
+		}
+
+		volt = ROMPTR(bios, bios->data[bios->offset + 0x98]);
+	}
+
+	if (!volt) {
+		NV_DEBUG(dev, "voltage table pointer invalid\n");
+		return;
+	}
+
+	switch (volt[0]) {
+	case 0x10:
+	case 0x11:
+	case 0x12:
+		recordlen = 5;
+		entries   = volt[2];
+		vidshift  = 0;
+		vidmask   = volt[4];
+		break;
+	case 0x20:
+		recordlen = volt[3];
+		entries   = volt[2];
+		vidshift  = 0; /* could be vidshift like 0x30? */
+		vidmask   = volt[5];
+		break;
+	case 0x30:
+		recordlen = volt[2];
+		entries   = volt[3];
+		vidshift  = hweight8(volt[5]);
+		vidmask   = volt[4];
+		break;
+	default:
+		NV_WARN(dev, "voltage table 0x%02x unknown\n", volt[0]);
+		return;
+	}
+
+	/* validate vid mask */
+	voltage->vid_mask = vidmask;
+	if (!voltage->vid_mask)
+		return;
+
+	i = 0;
+	while (vidmask) {
+		if (i > nr_vidtag) {
+			NV_DEBUG(dev, "vid bit %d unknown\n", i);
+			return;
+		}
+
+		if (!nouveau_bios_gpio_entry(dev, vidtag[i])) {
+			NV_DEBUG(dev, "vid bit %d has no gpio tag\n", i);
+			return;
+		}
+
+		vidmask >>= 1;
+		i++;
+	}
+
+	/* parse vbios entries into common format */
+	voltage->level = kcalloc(entries, sizeof(*voltage->level), GFP_KERNEL);
+	if (!voltage->level)
+		return;
+
+	entry = volt + volt[1];
+	for (i = 0; i < entries; i++, entry += recordlen) {
+		voltage->level[i].voltage = entry[0];
+		voltage->level[i].vid     = entry[1] >> vidshift;
+	}
+	voltage->nr_level  = entries;
+	voltage->supported = true;
+}
+
+void
+nouveau_volt_fini(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_pm_voltage *volt = &dev_priv->engine.pm.voltage;
+
+	kfree(volt->level);
+}