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