xref: /openbmc/linux/drivers/gpu/vga/vga_switcheroo.c (revision 4800cd83)
1 /*
2  * Copyright (c) 2010 Red Hat Inc.
3  * Author : Dave Airlie <airlied@redhat.com>
4  *
5  *
6  * Licensed under GPLv2
7  *
8  * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
9 
10  Switcher interface - methods require for ATPX and DCM
11  - switchto - this throws the output MUX switch
12  - discrete_set_power - sets the power state for the discrete card
13 
14  GPU driver interface
15  - set_gpu_state - this should do the equiv of s/r for the card
16 		  - this should *not* set the discrete power state
17  - switch_check  - check if the device is in a position to switch now
18  */
19 
20 #include <linux/module.h>
21 #include <linux/dmi.h>
22 #include <linux/seq_file.h>
23 #include <linux/uaccess.h>
24 #include <linux/fs.h>
25 #include <linux/debugfs.h>
26 #include <linux/fb.h>
27 
28 #include <linux/pci.h>
29 #include <linux/vga_switcheroo.h>
30 
31 struct vga_switcheroo_client {
32 	struct pci_dev *pdev;
33 	struct fb_info *fb_info;
34 	int pwr_state;
35 	void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state);
36 	void (*reprobe)(struct pci_dev *pdev);
37 	bool (*can_switch)(struct pci_dev *pdev);
38 	int id;
39 	bool active;
40 };
41 
42 static DEFINE_MUTEX(vgasr_mutex);
43 
44 struct vgasr_priv {
45 
46 	bool active;
47 	bool delayed_switch_active;
48 	enum vga_switcheroo_client_id delayed_client_id;
49 
50 	struct dentry *debugfs_root;
51 	struct dentry *switch_file;
52 
53 	int registered_clients;
54 	struct vga_switcheroo_client clients[VGA_SWITCHEROO_MAX_CLIENTS];
55 
56 	struct vga_switcheroo_handler *handler;
57 };
58 
59 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
60 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
61 
62 /* only one switcheroo per system */
63 static struct vgasr_priv vgasr_priv;
64 
65 int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
66 {
67 	mutex_lock(&vgasr_mutex);
68 	if (vgasr_priv.handler) {
69 		mutex_unlock(&vgasr_mutex);
70 		return -EINVAL;
71 	}
72 
73 	vgasr_priv.handler = handler;
74 	mutex_unlock(&vgasr_mutex);
75 	return 0;
76 }
77 EXPORT_SYMBOL(vga_switcheroo_register_handler);
78 
79 void vga_switcheroo_unregister_handler(void)
80 {
81 	mutex_lock(&vgasr_mutex);
82 	vgasr_priv.handler = NULL;
83 	mutex_unlock(&vgasr_mutex);
84 }
85 EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
86 
87 static void vga_switcheroo_enable(void)
88 {
89 	int i;
90 	int ret;
91 	/* call the handler to init */
92 	vgasr_priv.handler->init();
93 
94 	for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
95 		ret = vgasr_priv.handler->get_client_id(vgasr_priv.clients[i].pdev);
96 		if (ret < 0)
97 			return;
98 
99 		vgasr_priv.clients[i].id = ret;
100 	}
101 	vga_switcheroo_debugfs_init(&vgasr_priv);
102 	vgasr_priv.active = true;
103 }
104 
105 int vga_switcheroo_register_client(struct pci_dev *pdev,
106 				   void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state),
107 				   void (*reprobe)(struct pci_dev *pdev),
108 				   bool (*can_switch)(struct pci_dev *pdev))
109 {
110 	int index;
111 
112 	mutex_lock(&vgasr_mutex);
113 	/* don't do IGD vs DIS here */
114 	if (vgasr_priv.registered_clients & 1)
115 		index = 1;
116 	else
117 		index = 0;
118 
119 	vgasr_priv.clients[index].pwr_state = VGA_SWITCHEROO_ON;
120 	vgasr_priv.clients[index].pdev = pdev;
121 	vgasr_priv.clients[index].set_gpu_state = set_gpu_state;
122 	vgasr_priv.clients[index].reprobe = reprobe;
123 	vgasr_priv.clients[index].can_switch = can_switch;
124 	vgasr_priv.clients[index].id = -1;
125 	if (pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW)
126 		vgasr_priv.clients[index].active = true;
127 
128 	vgasr_priv.registered_clients |= (1 << index);
129 
130 	/* if we get two clients + handler */
131 	if (vgasr_priv.registered_clients == 0x3 && vgasr_priv.handler) {
132 		printk(KERN_INFO "vga_switcheroo: enabled\n");
133 		vga_switcheroo_enable();
134 	}
135 	mutex_unlock(&vgasr_mutex);
136 	return 0;
137 }
138 EXPORT_SYMBOL(vga_switcheroo_register_client);
139 
140 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
141 {
142 	int i;
143 
144 	mutex_lock(&vgasr_mutex);
145 	for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
146 		if (vgasr_priv.clients[i].pdev == pdev) {
147 			vgasr_priv.registered_clients &= ~(1 << i);
148 			break;
149 		}
150 	}
151 
152 	printk(KERN_INFO "vga_switcheroo: disabled\n");
153 	vga_switcheroo_debugfs_fini(&vgasr_priv);
154 	vgasr_priv.active = false;
155 	mutex_unlock(&vgasr_mutex);
156 }
157 EXPORT_SYMBOL(vga_switcheroo_unregister_client);
158 
159 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
160 				 struct fb_info *info)
161 {
162 	int i;
163 
164 	mutex_lock(&vgasr_mutex);
165 	for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
166 		if (vgasr_priv.clients[i].pdev == pdev) {
167 			vgasr_priv.clients[i].fb_info = info;
168 			break;
169 		}
170 	}
171 	mutex_unlock(&vgasr_mutex);
172 }
173 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
174 
175 static int vga_switcheroo_show(struct seq_file *m, void *v)
176 {
177 	int i;
178 	mutex_lock(&vgasr_mutex);
179 	for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
180 		seq_printf(m, "%d:%s:%c:%s:%s\n", i,
181 			   vgasr_priv.clients[i].id == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
182 			   vgasr_priv.clients[i].active ? '+' : ' ',
183 			   vgasr_priv.clients[i].pwr_state ? "Pwr" : "Off",
184 			   pci_name(vgasr_priv.clients[i].pdev));
185 	}
186 	mutex_unlock(&vgasr_mutex);
187 	return 0;
188 }
189 
190 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
191 {
192 	return single_open(file, vga_switcheroo_show, NULL);
193 }
194 
195 static int vga_switchon(struct vga_switcheroo_client *client)
196 {
197 	if (vgasr_priv.handler->power_state)
198 		vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
199 	/* call the driver callback to turn on device */
200 	client->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
201 	client->pwr_state = VGA_SWITCHEROO_ON;
202 	return 0;
203 }
204 
205 static int vga_switchoff(struct vga_switcheroo_client *client)
206 {
207 	/* call the driver callback to turn off device */
208 	client->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
209 	if (vgasr_priv.handler->power_state)
210 		vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
211 	client->pwr_state = VGA_SWITCHEROO_OFF;
212 	return 0;
213 }
214 
215 /* stage one happens before delay */
216 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
217 {
218 	int ret;
219 	int i;
220 	struct vga_switcheroo_client *active = NULL;
221 
222 	if (new_client->active == true)
223 		return 0;
224 
225 	for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
226 		if (vgasr_priv.clients[i].active == true) {
227 			active = &vgasr_priv.clients[i];
228 			break;
229 		}
230 	}
231 	if (!active)
232 		return 0;
233 
234 	/* power up the first device */
235 	ret = pci_enable_device(new_client->pdev);
236 	if (ret)
237 		return ret;
238 
239 	if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
240 		vga_switchon(new_client);
241 
242 	/* swap shadow resource to denote boot VGA device has changed so X starts on new device */
243 	active->pdev->resource[PCI_ROM_RESOURCE].flags &= ~IORESOURCE_ROM_SHADOW;
244 	new_client->pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;
245 	return 0;
246 }
247 
248 /* post delay */
249 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
250 {
251 	int ret;
252 	int i;
253 	struct vga_switcheroo_client *active = NULL;
254 
255 	for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
256 		if (vgasr_priv.clients[i].active == true) {
257 			active = &vgasr_priv.clients[i];
258 			break;
259 		}
260 	}
261 	if (!active)
262 		return 0;
263 
264 	active->active = false;
265 
266 	if (new_client->fb_info) {
267 		struct fb_event event;
268 		event.info = new_client->fb_info;
269 		fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
270 	}
271 
272 	ret = vgasr_priv.handler->switchto(new_client->id);
273 	if (ret)
274 		return ret;
275 
276 	if (new_client->reprobe)
277 		new_client->reprobe(new_client->pdev);
278 
279 	if (active->pwr_state == VGA_SWITCHEROO_ON)
280 		vga_switchoff(active);
281 
282 	new_client->active = true;
283 	return 0;
284 }
285 
286 static ssize_t
287 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
288 			     size_t cnt, loff_t *ppos)
289 {
290 	char usercmd[64];
291 	const char *pdev_name;
292 	int i, ret;
293 	bool delay = false, can_switch;
294 	bool just_mux = false;
295 	int client_id = -1;
296 	struct vga_switcheroo_client *client = NULL;
297 
298 	if (cnt > 63)
299 		cnt = 63;
300 
301 	if (copy_from_user(usercmd, ubuf, cnt))
302 		return -EFAULT;
303 
304 	mutex_lock(&vgasr_mutex);
305 
306 	if (!vgasr_priv.active) {
307 		cnt = -EINVAL;
308 		goto out;
309 	}
310 
311 	/* pwr off the device not in use */
312 	if (strncmp(usercmd, "OFF", 3) == 0) {
313 		for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
314 			if (vgasr_priv.clients[i].active)
315 				continue;
316 			if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_ON)
317 				vga_switchoff(&vgasr_priv.clients[i]);
318 		}
319 		goto out;
320 	}
321 	/* pwr on the device not in use */
322 	if (strncmp(usercmd, "ON", 2) == 0) {
323 		for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
324 			if (vgasr_priv.clients[i].active)
325 				continue;
326 			if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_OFF)
327 				vga_switchon(&vgasr_priv.clients[i]);
328 		}
329 		goto out;
330 	}
331 
332 	/* request a delayed switch - test can we switch now */
333 	if (strncmp(usercmd, "DIGD", 4) == 0) {
334 		client_id = VGA_SWITCHEROO_IGD;
335 		delay = true;
336 	}
337 
338 	if (strncmp(usercmd, "DDIS", 4) == 0) {
339 		client_id = VGA_SWITCHEROO_DIS;
340 		delay = true;
341 	}
342 
343 	if (strncmp(usercmd, "IGD", 3) == 0)
344 		client_id = VGA_SWITCHEROO_IGD;
345 
346 	if (strncmp(usercmd, "DIS", 3) == 0)
347 		client_id = VGA_SWITCHEROO_DIS;
348 
349 	if (strncmp(usercmd, "MIGD", 4) == 0) {
350 		just_mux = true;
351 		client_id = VGA_SWITCHEROO_IGD;
352 	}
353 	if (strncmp(usercmd, "MDIS", 4) == 0) {
354 		just_mux = true;
355 		client_id = VGA_SWITCHEROO_DIS;
356 	}
357 
358 	if (client_id == -1)
359 		goto out;
360 
361 	for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
362 		if (vgasr_priv.clients[i].id == client_id) {
363 			client = &vgasr_priv.clients[i];
364 			break;
365 		}
366 	}
367 
368 	vgasr_priv.delayed_switch_active = false;
369 
370 	if (just_mux) {
371 		ret = vgasr_priv.handler->switchto(client_id);
372 		goto out;
373 	}
374 
375 	/* okay we want a switch - test if devices are willing to switch */
376 	can_switch = true;
377 	for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
378 		can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
379 		if (can_switch == false) {
380 			printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
381 			break;
382 		}
383 	}
384 
385 	if (can_switch == false && delay == false)
386 		goto out;
387 
388 	if (can_switch == true) {
389 		pdev_name = pci_name(client->pdev);
390 		ret = vga_switchto_stage1(client);
391 		if (ret)
392 			printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
393 
394 		ret = vga_switchto_stage2(client);
395 		if (ret)
396 			printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
397 
398 	} else {
399 		printk(KERN_INFO "vga_switcheroo: setting delayed switch to client %d\n", client->id);
400 		vgasr_priv.delayed_switch_active = true;
401 		vgasr_priv.delayed_client_id = client_id;
402 
403 		ret = vga_switchto_stage1(client);
404 		if (ret)
405 			printk(KERN_ERR "vga_switcheroo: delayed switching stage 1 failed %d\n", ret);
406 	}
407 
408 out:
409 	mutex_unlock(&vgasr_mutex);
410 	return cnt;
411 }
412 
413 static const struct file_operations vga_switcheroo_debugfs_fops = {
414 	.owner = THIS_MODULE,
415 	.open = vga_switcheroo_debugfs_open,
416 	.write = vga_switcheroo_debugfs_write,
417 	.read = seq_read,
418 	.llseek = seq_lseek,
419 	.release = single_release,
420 };
421 
422 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
423 {
424 	if (priv->switch_file) {
425 		debugfs_remove(priv->switch_file);
426 		priv->switch_file = NULL;
427 	}
428 	if (priv->debugfs_root) {
429 		debugfs_remove(priv->debugfs_root);
430 		priv->debugfs_root = NULL;
431 	}
432 }
433 
434 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
435 {
436 	/* already initialised */
437 	if (priv->debugfs_root)
438 		return 0;
439 	priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
440 
441 	if (!priv->debugfs_root) {
442 		printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
443 		goto fail;
444 	}
445 
446 	priv->switch_file = debugfs_create_file("switch", 0644,
447 						priv->debugfs_root, NULL, &vga_switcheroo_debugfs_fops);
448 	if (!priv->switch_file) {
449 		printk(KERN_ERR "vga_switcheroo: cannot create /sys/kernel/debug/vgaswitcheroo/switch\n");
450 		goto fail;
451 	}
452 	return 0;
453 fail:
454 	vga_switcheroo_debugfs_fini(priv);
455 	return -1;
456 }
457 
458 int vga_switcheroo_process_delayed_switch(void)
459 {
460 	struct vga_switcheroo_client *client = NULL;
461 	const char *pdev_name;
462 	bool can_switch = true;
463 	int i;
464 	int ret;
465 	int err = -EINVAL;
466 
467 	mutex_lock(&vgasr_mutex);
468 	if (!vgasr_priv.delayed_switch_active)
469 		goto err;
470 
471 	printk(KERN_INFO "vga_switcheroo: processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
472 
473 	for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
474 		if (vgasr_priv.clients[i].id == vgasr_priv.delayed_client_id)
475 			client = &vgasr_priv.clients[i];
476 		can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
477 		if (can_switch == false) {
478 			printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
479 			break;
480 		}
481 	}
482 
483 	if (can_switch == false || client == NULL)
484 		goto err;
485 
486 	pdev_name = pci_name(client->pdev);
487 	ret = vga_switchto_stage2(client);
488 	if (ret)
489 		printk(KERN_ERR "vga_switcheroo: delayed switching failed stage 2 %d\n", ret);
490 
491 	vgasr_priv.delayed_switch_active = false;
492 	err = 0;
493 err:
494 	mutex_unlock(&vgasr_mutex);
495 	return err;
496 }
497 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
498 
499