drivers/gpu/vga/vga_switcheroo.c

   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 #include <linux/vgaarb.h>
  32
  33 struct vga_switcheroo_client {
  34         struct pci_dev *pdev;
  35         struct fb_info *fb_info;
  36         int pwr_state;
  37         const struct vga_switcheroo_client_ops *ops;
  38         int id;
  39         bool active;
  40         struct list_head list;
  41 };
  42
  43 static DEFINE_MUTEX(vgasr_mutex);
  44
  45 struct vgasr_priv {
  46
  47         bool active;
  48         bool delayed_switch_active;
  49         enum vga_switcheroo_client_id delayed_client_id;
  50
  51         struct dentry *debugfs_root;
  52         struct dentry *switch_file;
  53
  54         int registered_clients;
  55         struct list_head clients;
  56
  57         struct vga_switcheroo_handler *handler;
  58 };
  59
  60 #define ID_BIT_AUDIO            0x100
  61 #define client_is_audio(c)      ((c)->id & ID_BIT_AUDIO)
  62 #define client_is_vga(c)        ((c)->id == -1 || !client_is_audio(c))
  63 #define client_id(c)            ((c)->id & ~ID_BIT_AUDIO)
  64
  65 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
  66 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
  67
  68 /* only one switcheroo per system */
  69 static struct vgasr_priv vgasr_priv = {
  70         .clients = LIST_HEAD_INIT(vgasr_priv.clients),
  71 };
  72
  73 static bool vga_switcheroo_ready(void)
  74 {
  75         /* we're ready if we get two clients + handler */
  76         return !vgasr_priv.active &&
  77                vgasr_priv.registered_clients == 2 && vgasr_priv.handler;
  78 }
  79
  80 static void vga_switcheroo_enable(void)
  81 {
  82         int ret;
  83         struct vga_switcheroo_client *client;
  84
  85         /* call the handler to init */
  86         vgasr_priv.handler->init();
  87
  88         list_for_each_entry(client, &vgasr_priv.clients, list) {
  89                 if (client->id != -1)
  90                         continue;
  91                 ret = vgasr_priv.handler->get_client_id(client->pdev);
  92                 if (ret < 0)
  93                         return;
  94
  95                 client->id = ret;
  96         }
  97         vga_switcheroo_debugfs_init(&vgasr_priv);
  98         vgasr_priv.active = true;
  99 }
 100
 101 int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
 102 {
 103         mutex_lock(&vgasr_mutex);
 104         if (vgasr_priv.handler) {
 105                 mutex_unlock(&vgasr_mutex);
 106                 return -EINVAL;
 107         }
 108
 109         vgasr_priv.handler = handler;
 110         if (vga_switcheroo_ready()) {
 111                 printk(KERN_INFO "vga_switcheroo: enabled\n");
 112                 vga_switcheroo_enable();
 113         }
 114         mutex_unlock(&vgasr_mutex);
 115         return 0;
 116 }
 117 EXPORT_SYMBOL(vga_switcheroo_register_handler);
 118
 119 void vga_switcheroo_unregister_handler(void)
 120 {
 121         mutex_lock(&vgasr_mutex);
 122         vgasr_priv.handler = NULL;
 123         if (vgasr_priv.active) {
 124                 pr_info("vga_switcheroo: disabled\n");
 125                 vga_switcheroo_debugfs_fini(&vgasr_priv);
 126                 vgasr_priv.active = false;
 127         }
 128         mutex_unlock(&vgasr_mutex);
 129 }
 130 EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
 131
 132 static int register_client(struct pci_dev *pdev,
 133                            const struct vga_switcheroo_client_ops *ops,
 134                            int id, bool active)
 135 {
 136         struct vga_switcheroo_client *client;
 137
 138         client = kzalloc(sizeof(*client), GFP_KERNEL);
 139         if (!client)
 140                 return -ENOMEM;
 141
 142         client->pwr_state = VGA_SWITCHEROO_ON;
 143         client->pdev = pdev;
 144         client->ops = ops;
 145         client->id = id;
 146         client->active = active;
 147
 148         mutex_lock(&vgasr_mutex);
 149         list_add_tail(&client->list, &vgasr_priv.clients);
 150         if (client_is_vga(client))
 151                 vgasr_priv.registered_clients++;
 152
 153         if (vga_switcheroo_ready()) {
 154                 printk(KERN_INFO "vga_switcheroo: enabled\n");
 155                 vga_switcheroo_enable();
 156         }
 157         mutex_unlock(&vgasr_mutex);
 158         return 0;
 159 }
 160
 161 int vga_switcheroo_register_client(struct pci_dev *pdev,
 162                                    const struct vga_switcheroo_client_ops *ops)
 163 {
 164         return register_client(pdev, ops, -1,
 165                                pdev == vga_default_device());
 166 }
 167 EXPORT_SYMBOL(vga_switcheroo_register_client);
 168
 169 int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
 170                                          const struct vga_switcheroo_client_ops *ops,
 171                                          int id, bool active)
 172 {
 173         return register_client(pdev, ops, id | ID_BIT_AUDIO, active);
 174 }
 175 EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
 176
 177 static struct vga_switcheroo_client *
 178 find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
 179 {
 180         struct vga_switcheroo_client *client;
 181         list_for_each_entry(client, head, list)
 182                 if (client->pdev == pdev)
 183                         return client;
 184         return NULL;
 185 }
 186
 187 static struct vga_switcheroo_client *
 188 find_client_from_id(struct list_head *head, int client_id)
 189 {
 190         struct vga_switcheroo_client *client;
 191         list_for_each_entry(client, head, list)
 192                 if (client->id == client_id)
 193                         return client;
 194         return NULL;
 195 }
 196
 197 static struct vga_switcheroo_client *
 198 find_active_client(struct list_head *head)
 199 {
 200         struct vga_switcheroo_client *client;
 201         list_for_each_entry(client, head, list)
 202                 if (client->active && client_is_vga(client))
 203                         return client;
 204         return NULL;
 205 }
 206
 207 int vga_switcheroo_get_client_state(struct pci_dev *pdev)
 208 {
 209         struct vga_switcheroo_client *client;
 210
 211         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 212         if (!client)
 213                 return VGA_SWITCHEROO_NOT_FOUND;
 214         if (!vgasr_priv.active)
 215                 return VGA_SWITCHEROO_INIT;
 216         return client->pwr_state;
 217 }
 218 EXPORT_SYMBOL(vga_switcheroo_get_client_state);
 219
 220 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
 221 {
 222         struct vga_switcheroo_client *client;
 223
 224         mutex_lock(&vgasr_mutex);
 225         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 226         if (client) {
 227                 if (client_is_vga(client))
 228                         vgasr_priv.registered_clients--;
 229                 list_del(&client->list);
 230                 kfree(client);
 231         }
 232         if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
 233                 printk(KERN_INFO "vga_switcheroo: disabled\n");
 234                 vga_switcheroo_debugfs_fini(&vgasr_priv);
 235                 vgasr_priv.active = false;
 236         }
 237         mutex_unlock(&vgasr_mutex);
 238 }
 239 EXPORT_SYMBOL(vga_switcheroo_unregister_client);
 240
 241 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
 242                                  struct fb_info *info)
 243 {
 244         struct vga_switcheroo_client *client;
 245
 246         mutex_lock(&vgasr_mutex);
 247         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 248         if (client)
 249                 client->fb_info = info;
 250         mutex_unlock(&vgasr_mutex);
 251 }
 252 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
 253
 254 static int vga_switcheroo_show(struct seq_file *m, void *v)
 255 {
 256         struct vga_switcheroo_client *client;
 257         int i = 0;
 258         mutex_lock(&vgasr_mutex);
 259         list_for_each_entry(client, &vgasr_priv.clients, list) {
 260                 seq_printf(m, "%d:%s%s:%c:%s:%s\n", i,
 261                            client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
 262                            client_is_vga(client) ? "" : "-Audio",
 263                            client->active ? '+' : ' ',
 264                            client->pwr_state ? "Pwr" : "Off",
 265                            pci_name(client->pdev));
 266                 i++;
 267         }
 268         mutex_unlock(&vgasr_mutex);
 269         return 0;
 270 }
 271
 272 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
 273 {
 274         return single_open(file, vga_switcheroo_show, NULL);
 275 }
 276
 277 static int vga_switchon(struct vga_switcheroo_client *client)
 278 {
 279         if (vgasr_priv.handler->power_state)
 280                 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
 281         /* call the driver callback to turn on device */
 282         client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
 283         client->pwr_state = VGA_SWITCHEROO_ON;
 284         return 0;
 285 }
 286
 287 static int vga_switchoff(struct vga_switcheroo_client *client)
 288 {
 289         /* call the driver callback to turn off device */
 290         client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
 291         if (vgasr_priv.handler->power_state)
 292                 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
 293         client->pwr_state = VGA_SWITCHEROO_OFF;
 294         return 0;
 295 }
 296
 297 static void set_audio_state(int id, int state)
 298 {
 299         struct vga_switcheroo_client *client;
 300
 301         client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
 302         if (client && client->pwr_state != state) {
 303                 client->ops->set_gpu_state(client->pdev, state);
 304                 client->pwr_state = state;
 305         }
 306 }
 307
 308 /* stage one happens before delay */
 309 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
 310 {
 311         struct vga_switcheroo_client *active;
 312
 313         active = find_active_client(&vgasr_priv.clients);
 314         if (!active)
 315                 return 0;
 316
 317         if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
 318                 vga_switchon(new_client);
 319
 320         vga_set_default_device(new_client->pdev);
 321         return 0;
 322 }
 323
 324 /* post delay */
 325 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
 326 {
 327         int ret;
 328         struct vga_switcheroo_client *active;
 329
 330         active = find_active_client(&vgasr_priv.clients);
 331         if (!active)
 332                 return 0;
 333
 334         active->active = false;
 335
 336         set_audio_state(active->id, VGA_SWITCHEROO_OFF);
 337
 338         if (new_client->fb_info) {
 339                 struct fb_event event;
 340                 event.info = new_client->fb_info;
 341                 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
 342         }
 343
 344         ret = vgasr_priv.handler->switchto(new_client->id);
 345         if (ret)
 346                 return ret;
 347
 348         if (new_client->ops->reprobe)
 349                 new_client->ops->reprobe(new_client->pdev);
 350
 351         if (active->pwr_state == VGA_SWITCHEROO_ON)
 352                 vga_switchoff(active);
 353
 354         set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
 355
 356         new_client->active = true;
 357         return 0;
 358 }
 359
 360 static bool check_can_switch(void)
 361 {
 362         struct vga_switcheroo_client *client;
 363
 364         list_for_each_entry(client, &vgasr_priv.clients, list) {
 365                 if (!client->ops->can_switch(client->pdev)) {
 366                         printk(KERN_ERR "vga_switcheroo: client %x refused switch\n", client->id);
 367                         return false;
 368                 }
 369         }
 370         return true;
 371 }
 372
 373 static ssize_t
 374 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
 375                              size_t cnt, loff_t *ppos)
 376 {
 377         char usercmd[64];
 378         const char *pdev_name;
 379         int ret;
 380         bool delay = false, can_switch;
 381         bool just_mux = false;
 382         int client_id = -1;
 383         struct vga_switcheroo_client *client = NULL;
 384
 385         if (cnt > 63)
 386                 cnt = 63;
 387
 388         if (copy_from_user(usercmd, ubuf, cnt))
 389                 return -EFAULT;
 390
 391         mutex_lock(&vgasr_mutex);
 392
 393         if (!vgasr_priv.active) {
 394                 cnt = -EINVAL;
 395                 goto out;
 396         }
 397
 398         /* pwr off the device not in use */
 399         if (strncmp(usercmd, "OFF", 3) == 0) {
 400                 list_for_each_entry(client, &vgasr_priv.clients, list) {
 401                         if (client->active || client_is_audio(client))
 402                                 continue;
 403                         set_audio_state(client->id, VGA_SWITCHEROO_OFF);
 404                         if (client->pwr_state == VGA_SWITCHEROO_ON)
 405                                 vga_switchoff(client);
 406                 }
 407                 goto out;
 408         }
 409         /* pwr on the device not in use */
 410         if (strncmp(usercmd, "ON", 2) == 0) {
 411                 list_for_each_entry(client, &vgasr_priv.clients, list) {
 412                         if (client->active || client_is_audio(client))
 413                                 continue;
 414                         if (client->pwr_state == VGA_SWITCHEROO_OFF)
 415                                 vga_switchon(client);
 416                         set_audio_state(client->id, VGA_SWITCHEROO_ON);
 417                 }
 418                 goto out;
 419         }
 420
 421         /* request a delayed switch - test can we switch now */
 422         if (strncmp(usercmd, "DIGD", 4) == 0) {
 423                 client_id = VGA_SWITCHEROO_IGD;
 424                 delay = true;
 425         }
 426
 427         if (strncmp(usercmd, "DDIS", 4) == 0) {
 428                 client_id = VGA_SWITCHEROO_DIS;
 429                 delay = true;
 430         }
 431
 432         if (strncmp(usercmd, "IGD", 3) == 0)
 433                 client_id = VGA_SWITCHEROO_IGD;
 434
 435         if (strncmp(usercmd, "DIS", 3) == 0)
 436                 client_id = VGA_SWITCHEROO_DIS;
 437
 438         if (strncmp(usercmd, "MIGD", 4) == 0) {
 439                 just_mux = true;
 440                 client_id = VGA_SWITCHEROO_IGD;
 441         }
 442         if (strncmp(usercmd, "MDIS", 4) == 0) {
 443                 just_mux = true;
 444                 client_id = VGA_SWITCHEROO_DIS;
 445         }
 446
 447         if (client_id == -1)
 448                 goto out;
 449         client = find_client_from_id(&vgasr_priv.clients, client_id);
 450         if (!client)
 451                 goto out;
 452
 453         vgasr_priv.delayed_switch_active = false;
 454
 455         if (just_mux) {
 456                 ret = vgasr_priv.handler->switchto(client_id);
 457                 goto out;
 458         }
 459
 460         if (client->active)
 461                 goto out;
 462
 463         /* okay we want a switch - test if devices are willing to switch */
 464         can_switch = check_can_switch();
 465
 466         if (can_switch == false && delay == false)
 467                 goto out;
 468
 469         if (can_switch) {
 470                 pdev_name = pci_name(client->pdev);
 471                 ret = vga_switchto_stage1(client);
 472                 if (ret)
 473                         printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
 474
 475                 ret = vga_switchto_stage2(client);
 476                 if (ret)
 477                         printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
 478
 479         } else {
 480                 printk(KERN_INFO "vga_switcheroo: setting delayed switch to client %d\n", client->id);
 481                 vgasr_priv.delayed_switch_active = true;
 482                 vgasr_priv.delayed_client_id = client_id;
 483
 484                 ret = vga_switchto_stage1(client);
 485                 if (ret)
 486                         printk(KERN_ERR "vga_switcheroo: delayed switching stage 1 failed %d\n", ret);
 487         }
 488
 489 out:
 490         mutex_unlock(&vgasr_mutex);
 491         return cnt;
 492 }
 493
 494 static const struct file_operations vga_switcheroo_debugfs_fops = {
 495         .owner = THIS_MODULE,
 496         .open = vga_switcheroo_debugfs_open,
 497         .write = vga_switcheroo_debugfs_write,
 498         .read = seq_read,
 499         .llseek = seq_lseek,
 500         .release = single_release,
 501 };
 502
 503 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
 504 {
 505         if (priv->switch_file) {
 506                 debugfs_remove(priv->switch_file);
 507                 priv->switch_file = NULL;
 508         }
 509         if (priv->debugfs_root) {
 510                 debugfs_remove(priv->debugfs_root);
 511                 priv->debugfs_root = NULL;
 512         }
 513 }
 514
 515 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
 516 {
 517         /* already initialised */
 518         if (priv->debugfs_root)
 519                 return 0;
 520         priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
 521
 522         if (!priv->debugfs_root) {
 523                 printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
 524                 goto fail;
 525         }
 526
 527         priv->switch_file = debugfs_create_file("switch", 0644,
 528                                                 priv->debugfs_root, NULL, &vga_switcheroo_debugfs_fops);
 529         if (!priv->switch_file) {
 530                 printk(KERN_ERR "vga_switcheroo: cannot create /sys/kernel/debug/vgaswitcheroo/switch\n");
 531                 goto fail;
 532         }
 533         return 0;
 534 fail:
 535         vga_switcheroo_debugfs_fini(priv);
 536         return -1;
 537 }
 538
 539 int vga_switcheroo_process_delayed_switch(void)
 540 {
 541         struct vga_switcheroo_client *client;
 542         const char *pdev_name;
 543         int ret;
 544         int err = -EINVAL;
 545
 546         mutex_lock(&vgasr_mutex);
 547         if (!vgasr_priv.delayed_switch_active)
 548                 goto err;
 549
 550         printk(KERN_INFO "vga_switcheroo: processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
 551
 552         client = find_client_from_id(&vgasr_priv.clients,
 553                                      vgasr_priv.delayed_client_id);
 554         if (!client || !check_can_switch())
 555                 goto err;
 556
 557         pdev_name = pci_name(client->pdev);
 558         ret = vga_switchto_stage2(client);
 559         if (ret)
 560                 printk(KERN_ERR "vga_switcheroo: delayed switching failed stage 2 %d\n", ret);
 561
 562         vgasr_priv.delayed_switch_active = false;
 563         err = 0;
 564 err:
 565         mutex_unlock(&vgasr_mutex);
 566         return err;
 567 }
 568 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
 569