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/seq_file.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/fs.h>
  24 #include <linux/debugfs.h>
  25 #include <linux/fb.h>
  26
  27 #include <linux/pci.h>
  28 #include <linux/console.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         if (vgasr_priv.handler->init)
  87                 vgasr_priv.handler->init();
  88
  89         list_for_each_entry(client, &vgasr_priv.clients, list) {
  90                 if (client->id != -1)
  91                         continue;
  92                 ret = vgasr_priv.handler->get_client_id(client->pdev);
  93                 if (ret < 0)
  94                         return;
  95
  96                 client->id = ret;
  97         }
  98         vga_switcheroo_debugfs_init(&vgasr_priv);
  99         vgasr_priv.active = true;
 100 }
 101
 102 int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
 103 {
 104         mutex_lock(&vgasr_mutex);
 105         if (vgasr_priv.handler) {
 106                 mutex_unlock(&vgasr_mutex);
 107                 return -EINVAL;
 108         }
 109
 110         vgasr_priv.handler = handler;
 111         if (vga_switcheroo_ready()) {
 112                 printk(KERN_INFO "vga_switcheroo: enabled\n");
 113                 vga_switcheroo_enable();
 114         }
 115         mutex_unlock(&vgasr_mutex);
 116         return 0;
 117 }
 118 EXPORT_SYMBOL(vga_switcheroo_register_handler);
 119
 120 void vga_switcheroo_unregister_handler(void)
 121 {
 122         mutex_lock(&vgasr_mutex);
 123         vgasr_priv.handler = NULL;
 124         if (vgasr_priv.active) {
 125                 pr_info("vga_switcheroo: disabled\n");
 126                 vga_switcheroo_debugfs_fini(&vgasr_priv);
 127                 vgasr_priv.active = false;
 128         }
 129         mutex_unlock(&vgasr_mutex);
 130 }
 131 EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
 132
 133 static int register_client(struct pci_dev *pdev,
 134                            const struct vga_switcheroo_client_ops *ops,
 135                            int id, bool active)
 136 {
 137         struct vga_switcheroo_client *client;
 138
 139         client = kzalloc(sizeof(*client), GFP_KERNEL);
 140         if (!client)
 141                 return -ENOMEM;
 142
 143         client->pwr_state = VGA_SWITCHEROO_ON;
 144         client->pdev = pdev;
 145         client->ops = ops;
 146         client->id = id;
 147         client->active = active;
 148
 149         mutex_lock(&vgasr_mutex);
 150         list_add_tail(&client->list, &vgasr_priv.clients);
 151         if (client_is_vga(client))
 152                 vgasr_priv.registered_clients++;
 153
 154         if (vga_switcheroo_ready()) {
 155                 printk(KERN_INFO "vga_switcheroo: enabled\n");
 156                 vga_switcheroo_enable();
 157         }
 158         mutex_unlock(&vgasr_mutex);
 159         return 0;
 160 }
 161
 162 int vga_switcheroo_register_client(struct pci_dev *pdev,
 163                                    const struct vga_switcheroo_client_ops *ops)
 164 {
 165         return register_client(pdev, ops, -1,
 166                                pdev == vga_default_device());
 167 }
 168 EXPORT_SYMBOL(vga_switcheroo_register_client);
 169
 170 int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
 171                                          const struct vga_switcheroo_client_ops *ops,
 172                                          int id, bool active)
 173 {
 174         return register_client(pdev, ops, id | ID_BIT_AUDIO, active);
 175 }
 176 EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
 177
 178 static struct vga_switcheroo_client *
 179 find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
 180 {
 181         struct vga_switcheroo_client *client;
 182         list_for_each_entry(client, head, list)
 183                 if (client->pdev == pdev)
 184                         return client;
 185         return NULL;
 186 }
 187
 188 static struct vga_switcheroo_client *
 189 find_client_from_id(struct list_head *head, int client_id)
 190 {
 191         struct vga_switcheroo_client *client;
 192         list_for_each_entry(client, head, list)
 193                 if (client->id == client_id)
 194                         return client;
 195         return NULL;
 196 }
 197
 198 static struct vga_switcheroo_client *
 199 find_active_client(struct list_head *head)
 200 {
 201         struct vga_switcheroo_client *client;
 202         list_for_each_entry(client, head, list)
 203                 if (client->active && client_is_vga(client))
 204                         return client;
 205         return NULL;
 206 }
 207
 208 int vga_switcheroo_get_client_state(struct pci_dev *pdev)
 209 {
 210         struct vga_switcheroo_client *client;
 211
 212         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 213         if (!client)
 214                 return VGA_SWITCHEROO_NOT_FOUND;
 215         if (!vgasr_priv.active)
 216                 return VGA_SWITCHEROO_INIT;
 217         return client->pwr_state;
 218 }
 219 EXPORT_SYMBOL(vga_switcheroo_get_client_state);
 220
 221 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
 222 {
 223         struct vga_switcheroo_client *client;
 224
 225         mutex_lock(&vgasr_mutex);
 226         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 227         if (client) {
 228                 if (client_is_vga(client))
 229                         vgasr_priv.registered_clients--;
 230                 list_del(&client->list);
 231                 kfree(client);
 232         }
 233         if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
 234                 printk(KERN_INFO "vga_switcheroo: disabled\n");
 235                 vga_switcheroo_debugfs_fini(&vgasr_priv);
 236                 vgasr_priv.active = false;
 237         }
 238         mutex_unlock(&vgasr_mutex);
 239 }
 240 EXPORT_SYMBOL(vga_switcheroo_unregister_client);
 241
 242 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
 243                                  struct fb_info *info)
 244 {
 245         struct vga_switcheroo_client *client;
 246
 247         mutex_lock(&vgasr_mutex);
 248         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 249         if (client)
 250                 client->fb_info = info;
 251         mutex_unlock(&vgasr_mutex);
 252 }
 253 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
 254
 255 static int vga_switcheroo_show(struct seq_file *m, void *v)
 256 {
 257         struct vga_switcheroo_client *client;
 258         int i = 0;
 259         mutex_lock(&vgasr_mutex);
 260         list_for_each_entry(client, &vgasr_priv.clients, list) {
 261                 seq_printf(m, "%d:%s%s:%c:%s:%s\n", i,
 262                            client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
 263                            client_is_vga(client) ? "" : "-Audio",
 264                            client->active ? '+' : ' ',
 265                            client->pwr_state ? "Pwr" : "Off",
 266                            pci_name(client->pdev));
 267                 i++;
 268         }
 269         mutex_unlock(&vgasr_mutex);
 270         return 0;
 271 }
 272
 273 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
 274 {
 275         return single_open(file, vga_switcheroo_show, NULL);
 276 }
 277
 278 static int vga_switchon(struct vga_switcheroo_client *client)
 279 {
 280         if (vgasr_priv.handler->power_state)
 281                 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
 282         /* call the driver callback to turn on device */
 283         client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
 284         client->pwr_state = VGA_SWITCHEROO_ON;
 285         return 0;
 286 }
 287
 288 static int vga_switchoff(struct vga_switcheroo_client *client)
 289 {
 290         /* call the driver callback to turn off device */
 291         client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
 292         if (vgasr_priv.handler->power_state)
 293                 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
 294         client->pwr_state = VGA_SWITCHEROO_OFF;
 295         return 0;
 296 }
 297
 298 static void set_audio_state(int id, int state)
 299 {
 300         struct vga_switcheroo_client *client;
 301
 302         client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
 303         if (client && client->pwr_state != state) {
 304                 client->ops->set_gpu_state(client->pdev, state);
 305                 client->pwr_state = state;
 306         }
 307 }
 308
 309 /* stage one happens before delay */
 310 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
 311 {
 312         struct vga_switcheroo_client *active;
 313
 314         active = find_active_client(&vgasr_priv.clients);
 315         if (!active)
 316                 return 0;
 317
 318         if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
 319                 vga_switchon(new_client);
 320
 321         vga_set_default_device(new_client->pdev);
 322         return 0;
 323 }
 324
 325 /* post delay */
 326 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
 327 {
 328         int ret;
 329         struct vga_switcheroo_client *active;
 330
 331         active = find_active_client(&vgasr_priv.clients);
 332         if (!active)
 333                 return 0;
 334
 335         active->active = false;
 336
 337         set_audio_state(active->id, VGA_SWITCHEROO_OFF);
 338
 339         if (new_client->fb_info) {
 340                 struct fb_event event;
 341                 console_lock();
 342                 event.info = new_client->fb_info;
 343                 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
 344                 console_unlock();
 345         }
 346
 347         ret = vgasr_priv.handler->switchto(new_client->id);
 348         if (ret)
 349                 return ret;
 350
 351         if (new_client->ops->reprobe)
 352                 new_client->ops->reprobe(new_client->pdev);
 353
 354         if (active->pwr_state == VGA_SWITCHEROO_ON)
 355                 vga_switchoff(active);
 356
 357         set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
 358
 359         new_client->active = true;
 360         return 0;
 361 }
 362
 363 static bool check_can_switch(void)
 364 {
 365         struct vga_switcheroo_client *client;
 366
 367         list_for_each_entry(client, &vgasr_priv.clients, list) {
 368                 if (!client->ops->can_switch(client->pdev)) {
 369                         printk(KERN_ERR "vga_switcheroo: client %x refused switch\n", client->id);
 370                         return false;
 371                 }
 372         }
 373         return true;
 374 }
 375
 376 static ssize_t
 377 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
 378                              size_t cnt, loff_t *ppos)
 379 {
 380         char usercmd[64];
 381         int ret;
 382         bool delay = false, can_switch;
 383         bool just_mux = false;
 384         int client_id = -1;
 385         struct vga_switcheroo_client *client = NULL;
 386
 387         if (cnt > 63)
 388                 cnt = 63;
 389
 390         if (copy_from_user(usercmd, ubuf, cnt))
 391                 return -EFAULT;
 392
 393         mutex_lock(&vgasr_mutex);
 394
 395         if (!vgasr_priv.active) {
 396                 cnt = -EINVAL;
 397                 goto out;
 398         }
 399
 400         /* pwr off the device not in use */
 401         if (strncmp(usercmd, "OFF", 3) == 0) {
 402                 list_for_each_entry(client, &vgasr_priv.clients, list) {
 403                         if (client->active || client_is_audio(client))
 404                                 continue;
 405                         set_audio_state(client->id, VGA_SWITCHEROO_OFF);
 406                         if (client->pwr_state == VGA_SWITCHEROO_ON)
 407                                 vga_switchoff(client);
 408                 }
 409                 goto out;
 410         }
 411         /* pwr on the device not in use */
 412         if (strncmp(usercmd, "ON", 2) == 0) {
 413                 list_for_each_entry(client, &vgasr_priv.clients, list) {
 414                         if (client->active || client_is_audio(client))
 415                                 continue;
 416                         if (client->pwr_state == VGA_SWITCHEROO_OFF)
 417                                 vga_switchon(client);
 418                         set_audio_state(client->id, VGA_SWITCHEROO_ON);
 419                 }
 420                 goto out;
 421         }
 422
 423         /* request a delayed switch - test can we switch now */
 424         if (strncmp(usercmd, "DIGD", 4) == 0) {
 425                 client_id = VGA_SWITCHEROO_IGD;
 426                 delay = true;
 427         }
 428
 429         if (strncmp(usercmd, "DDIS", 4) == 0) {
 430                 client_id = VGA_SWITCHEROO_DIS;
 431                 delay = true;
 432         }
 433
 434         if (strncmp(usercmd, "IGD", 3) == 0)
 435                 client_id = VGA_SWITCHEROO_IGD;
 436
 437         if (strncmp(usercmd, "DIS", 3) == 0)
 438                 client_id = VGA_SWITCHEROO_DIS;
 439
 440         if (strncmp(usercmd, "MIGD", 4) == 0) {
 441                 just_mux = true;
 442                 client_id = VGA_SWITCHEROO_IGD;
 443         }
 444         if (strncmp(usercmd, "MDIS", 4) == 0) {
 445                 just_mux = true;
 446                 client_id = VGA_SWITCHEROO_DIS;
 447         }
 448
 449         if (client_id == -1)
 450                 goto out;
 451         client = find_client_from_id(&vgasr_priv.clients, client_id);
 452         if (!client)
 453                 goto out;
 454
 455         vgasr_priv.delayed_switch_active = false;
 456
 457         if (just_mux) {
 458                 ret = vgasr_priv.handler->switchto(client_id);
 459                 goto out;
 460         }
 461
 462         if (client->active)
 463                 goto out;
 464
 465         /* okay we want a switch - test if devices are willing to switch */
 466         can_switch = check_can_switch();
 467
 468         if (can_switch == false && delay == false)
 469                 goto out;
 470
 471         if (can_switch) {
 472                 ret = vga_switchto_stage1(client);
 473                 if (ret)
 474                         printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
 475
 476                 ret = vga_switchto_stage2(client);
 477                 if (ret)
 478                         printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
 479
 480         } else {
 481                 printk(KERN_INFO "vga_switcheroo: setting delayed switch to client %d\n", client->id);
 482                 vgasr_priv.delayed_switch_active = true;
 483                 vgasr_priv.delayed_client_id = client_id;
 484
 485                 ret = vga_switchto_stage1(client);
 486                 if (ret)
 487                         printk(KERN_ERR "vga_switcheroo: delayed switching stage 1 failed %d\n", ret);
 488         }
 489
 490 out:
 491         mutex_unlock(&vgasr_mutex);
 492         return cnt;
 493 }
 494
 495 static const struct file_operations vga_switcheroo_debugfs_fops = {
 496         .owner = THIS_MODULE,
 497         .open = vga_switcheroo_debugfs_open,
 498         .write = vga_switcheroo_debugfs_write,
 499         .read = seq_read,
 500         .llseek = seq_lseek,
 501         .release = single_release,
 502 };
 503
 504 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
 505 {
 506         if (priv->switch_file) {
 507                 debugfs_remove(priv->switch_file);
 508                 priv->switch_file = NULL;
 509         }
 510         if (priv->debugfs_root) {
 511                 debugfs_remove(priv->debugfs_root);
 512                 priv->debugfs_root = NULL;
 513         }
 514 }
 515
 516 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
 517 {
 518         /* already initialised */
 519         if (priv->debugfs_root)
 520                 return 0;
 521         priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
 522
 523         if (!priv->debugfs_root) {
 524                 printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
 525                 goto fail;
 526         }
 527
 528         priv->switch_file = debugfs_create_file("switch", 0644,
 529                                                 priv->debugfs_root, NULL, &vga_switcheroo_debugfs_fops);
 530         if (!priv->switch_file) {
 531                 printk(KERN_ERR "vga_switcheroo: cannot create /sys/kernel/debug/vgaswitcheroo/switch\n");
 532                 goto fail;
 533         }
 534         return 0;
 535 fail:
 536         vga_switcheroo_debugfs_fini(priv);
 537         return -1;
 538 }
 539
 540 int vga_switcheroo_process_delayed_switch(void)
 541 {
 542         struct vga_switcheroo_client *client;
 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         ret = vga_switchto_stage2(client);
 558         if (ret)
 559                 printk(KERN_ERR "vga_switcheroo: delayed switching failed stage 2 %d\n", ret);
 560
 561         vgasr_priv.delayed_switch_active = false;
 562         err = 0;
 563 err:
 564         mutex_unlock(&vgasr_mutex);
 565         return err;
 566 }
 567 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);