drivers/pci/bus.c

   1 /*
   2  *      drivers/pci/bus.c
   3  *
   4  * From setup-res.c, by:
   5  *      Dave Rusling (david.rusling@reo.mts.dec.com)
   6  *      David Mosberger (davidm@cs.arizona.edu)
   7  *      David Miller (davem@redhat.com)
   8  *      Ivan Kokshaysky (ink@jurassic.park.msu.ru)
   9  */
  10 #include <linux/module.h>
  11 #include <linux/kernel.h>
  12 #include <linux/pci.h>
  13 #include <linux/errno.h>
  14 #include <linux/ioport.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/init.h>
  17 #include <linux/slab.h>
  18
  19 #include "pci.h"
  20
  21 void pci_bus_add_resource(struct pci_bus *bus, struct resource *res,
  22                           unsigned int flags)
  23 {
  24         struct pci_bus_resource *bus_res;
  25
  26         bus_res = kzalloc(sizeof(struct pci_bus_resource), GFP_KERNEL);
  27         if (!bus_res) {
  28                 dev_err(&bus->dev, "can't add %pR resource\n", res);
  29                 return;
  30         }
  31
  32         bus_res->res = res;
  33         bus_res->flags = flags;
  34         list_add_tail(&bus_res->list, &bus->resources);
  35 }
  36
  37 struct resource *pci_bus_resource_n(const struct pci_bus *bus, int n)
  38 {
  39         struct pci_bus_resource *bus_res;
  40
  41         if (n < PCI_BRIDGE_RESOURCE_NUM)
  42                 return bus->resource[n];
  43
  44         n -= PCI_BRIDGE_RESOURCE_NUM;
  45         list_for_each_entry(bus_res, &bus->resources, list) {
  46                 if (n-- == 0)
  47                         return bus_res->res;
  48         }
  49         return NULL;
  50 }
  51 EXPORT_SYMBOL_GPL(pci_bus_resource_n);
  52
  53 void pci_bus_remove_resources(struct pci_bus *bus)
  54 {
  55         struct pci_bus_resource *bus_res, *tmp;
  56         int i;
  57
  58         for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
  59                 bus->resource[i] = NULL;
  60
  61         list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
  62                 list_del(&bus_res->list);
  63                 kfree(bus_res);
  64         }
  65 }
  66
  67 static bool pci_bus_resource_better(struct resource *res1, bool pos1,
  68                                     struct resource *res2, bool pos2)
  69 {
  70         /* If exactly one is positive decode, always prefer that one */
  71         if (pos1 != pos2)
  72                 return pos1 ? true : false;
  73
  74         /* Prefer the one that contains the highest address */
  75         if (res1->end != res2->end)
  76                 return (res1->end > res2->end) ? true : false;
  77
  78         /* Otherwise, prefer the one with highest "center of gravity" */
  79         if (res1->start != res2->start)
  80                 return (res1->start > res2->start) ? true : false;
  81
  82         /* Otherwise, choose one arbitrarily (but consistently) */
  83         return (res1 > res2) ? true : false;
  84 }
  85
  86 static bool pci_bus_resource_positive(struct pci_bus *bus, struct resource *res)
  87 {
  88         struct pci_bus_resource *bus_res;
  89
  90         /*
  91          * This relies on the fact that pci_bus.resource[] refers to P2P or
  92          * CardBus bridge base/limit registers, which are always positively
  93          * decoded.  The pci_bus.resources list contains host bridge or
  94          * subtractively decoded resources.
  95          */
  96         list_for_each_entry(bus_res, &bus->resources, list) {
  97                 if (bus_res->res == res)
  98                         return (bus_res->flags & PCI_SUBTRACTIVE_DECODE) ?
  99                                 false : true;
 100         }
 101         return true;
 102 }
 103
 104 /*
 105  * Find the next-best bus resource after the cursor "res".  If the cursor is
 106  * NULL, return the best resource.  "Best" means that we prefer positive
 107  * decode regions over subtractive decode, then those at higher addresses.
 108  */
 109 static struct resource *pci_bus_find_resource_prev(struct pci_bus *bus,
 110                                                    unsigned int type,
 111                                                    struct resource *res)
 112 {
 113         bool res_pos, r_pos, prev_pos = false;
 114         struct resource *r, *prev = NULL;
 115         int i;
 116
 117         res_pos = pci_bus_resource_positive(bus, res);
 118         pci_bus_for_each_resource(bus, r, i) {
 119                 if (!r)
 120                         continue;
 121
 122                 if ((r->flags & IORESOURCE_TYPE_BITS) != type)
 123                         continue;
 124
 125                 r_pos = pci_bus_resource_positive(bus, r);
 126                 if (!res || pci_bus_resource_better(res, res_pos, r, r_pos)) {
 127                         if (!prev || pci_bus_resource_better(r, r_pos,
 128                                                              prev, prev_pos)) {
 129                                 prev = r;
 130                                 prev_pos = r_pos;
 131                         }
 132                 }
 133         }
 134
 135         return prev;
 136 }
 137
 138 /**
 139  * pci_bus_alloc_resource - allocate a resource from a parent bus
 140  * @bus: PCI bus
 141  * @res: resource to allocate
 142  * @size: size of resource to allocate
 143  * @align: alignment of resource to allocate
 144  * @min: minimum /proc/iomem address to allocate
 145  * @type_mask: IORESOURCE_* type flags
 146  * @alignf: resource alignment function
 147  * @alignf_data: data argument for resource alignment function
 148  *
 149  * Given the PCI bus a device resides on, the size, minimum address,
 150  * alignment and type, try to find an acceptable resource allocation
 151  * for a specific device resource.
 152  */
 153 int
 154 pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
 155                 resource_size_t size, resource_size_t align,
 156                 resource_size_t min, unsigned int type_mask,
 157                 resource_size_t (*alignf)(void *,
 158                                           const struct resource *,
 159                                           resource_size_t,
 160                                           resource_size_t),
 161                 void *alignf_data)
 162 {
 163         int ret = -ENOMEM;
 164         struct resource *r;
 165         resource_size_t max = -1;
 166         unsigned int type = res->flags & IORESOURCE_TYPE_BITS;
 167
 168         type_mask |= IORESOURCE_IO | IORESOURCE_MEM;
 169
 170         /* don't allocate too high if the pref mem doesn't support 64bit*/
 171         if (!(res->flags & IORESOURCE_MEM_64))
 172                 max = PCIBIOS_MAX_MEM_32;
 173
 174         /* Look for space at highest addresses first */
 175         r = pci_bus_find_resource_prev(bus, type, NULL);
 176         for ( ; r; r = pci_bus_find_resource_prev(bus, type, r)) {
 177                 /* type_mask must match */
 178                 if ((res->flags ^ r->flags) & type_mask)
 179                         continue;
 180
 181                 /* We cannot allocate a non-prefetching resource
 182                    from a pre-fetching area */
 183                 if ((r->flags & IORESOURCE_PREFETCH) &&
 184                     !(res->flags & IORESOURCE_PREFETCH))
 185                         continue;
 186
 187                 /* Ok, try it out.. */
 188                 ret = allocate_resource(r, res, size,
 189                                         r->start ? : min,
 190                                         max, align,
 191                                         alignf, alignf_data);
 192                 if (ret == 0)
 193                         break;
 194         }
 195         return ret;
 196 }
 197
 198 /**
 199  * pci_bus_add_device - add a single device
 200  * @dev: device to add
 201  *
 202  * This adds a single pci device to the global
 203  * device list and adds sysfs and procfs entries
 204  */
 205 int pci_bus_add_device(struct pci_dev *dev)
 206 {
 207         int retval;
 208         retval = device_add(&dev->dev);
 209         if (retval)
 210                 return retval;
 211
 212         dev->is_added = 1;
 213         pci_proc_attach_device(dev);
 214         pci_create_sysfs_dev_files(dev);
 215         return 0;
 216 }
 217
 218 /**
 219  * pci_bus_add_child - add a child bus
 220  * @bus: bus to add
 221  *
 222  * This adds sysfs entries for a single bus
 223  */
 224 int pci_bus_add_child(struct pci_bus *bus)
 225 {
 226         int retval;
 227
 228         if (bus->bridge)
 229                 bus->dev.parent = bus->bridge;
 230
 231         retval = device_register(&bus->dev);
 232         if (retval)
 233                 return retval;
 234
 235         bus->is_added = 1;
 236
 237         retval = device_create_file(&bus->dev, &dev_attr_cpuaffinity);
 238         if (retval)
 239                 return retval;
 240
 241         retval = device_create_file(&bus->dev, &dev_attr_cpulistaffinity);
 242
 243         /* Create legacy_io and legacy_mem files for this bus */
 244         pci_create_legacy_files(bus);
 245
 246         return retval;
 247 }
 248
 249 /**
 250  * pci_bus_add_devices - insert newly discovered PCI devices
 251  * @bus: bus to check for new devices
 252  *
 253  * Add newly discovered PCI devices (which are on the bus->devices
 254  * list) to the global PCI device list, add the sysfs and procfs
 255  * entries.  Where a bridge is found, add the discovered bus to
 256  * the parents list of child buses, and recurse (breadth-first
 257  * to be compatible with 2.4)
 258  *
 259  * Call hotplug for each new devices.
 260  */
 261 void pci_bus_add_devices(const struct pci_bus *bus)
 262 {
 263         struct pci_dev *dev;
 264         struct pci_bus *child;
 265         int retval;
 266
 267         list_for_each_entry(dev, &bus->devices, bus_list) {
 268                 /* Skip already-added devices */
 269                 if (dev->is_added)
 270                         continue;
 271                 retval = pci_bus_add_device(dev);
 272                 if (retval)
 273                         dev_err(&dev->dev, "Error adding device, continuing\n");
 274         }
 275
 276         list_for_each_entry(dev, &bus->devices, bus_list) {
 277                 BUG_ON(!dev->is_added);
 278
 279                 child = dev->subordinate;
 280                 /*
 281                  * If there is an unattached subordinate bus, attach
 282                  * it and then scan for unattached PCI devices.
 283                  */
 284                 if (!child)
 285                         continue;
 286                 if (list_empty(&child->node)) {
 287                         down_write(&pci_bus_sem);
 288                         list_add_tail(&child->node, &dev->bus->children);
 289                         up_write(&pci_bus_sem);
 290                 }
 291                 pci_bus_add_devices(child);
 292
 293                 /*
 294                  * register the bus with sysfs as the parent is now
 295                  * properly registered.
 296                  */
 297                 if (child->is_added)
 298                         continue;
 299                 retval = pci_bus_add_child(child);
 300                 if (retval)
 301                         dev_err(&dev->dev, "Error adding bus, continuing\n");
 302         }
 303 }
 304
 305 void pci_enable_bridges(struct pci_bus *bus)
 306 {
 307         struct pci_dev *dev;
 308         int retval;
 309
 310         list_for_each_entry(dev, &bus->devices, bus_list) {
 311                 if (dev->subordinate) {
 312                         if (!pci_is_enabled(dev)) {
 313                                 retval = pci_enable_device(dev);
 314                                 if (retval)
 315                                         dev_err(&dev->dev, "Error enabling bridge (%d), continuing\n", retval);
 316                                 pci_set_master(dev);
 317                         }
 318                         pci_enable_bridges(dev->subordinate);
 319                 }
 320         }
 321 }
 322
 323 /** pci_walk_bus - walk devices on/under bus, calling callback.
 324  *  @top      bus whose devices should be walked
 325  *  @cb       callback to be called for each device found
 326  *  @userdata arbitrary pointer to be passed to callback.
 327  *
 328  *  Walk the given bus, including any bridged devices
 329  *  on buses under this bus.  Call the provided callback
 330  *  on each device found.
 331  *
 332  *  We check the return of @cb each time. If it returns anything
 333  *  other than 0, we break out.
 334  *
 335  */
 336 void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
 337                   void *userdata)
 338 {
 339         struct pci_dev *dev;
 340         struct pci_bus *bus;
 341         struct list_head *next;
 342         int retval;
 343
 344         bus = top;
 345         down_read(&pci_bus_sem);
 346         next = top->devices.next;
 347         for (;;) {
 348                 if (next == &bus->devices) {
 349                         /* end of this bus, go up or finish */
 350                         if (bus == top)
 351                                 break;
 352                         next = bus->self->bus_list.next;
 353                         bus = bus->self->bus;
 354                         continue;
 355                 }
 356                 dev = list_entry(next, struct pci_dev, bus_list);
 357                 if (dev->subordinate) {
 358                         /* this is a pci-pci bridge, do its devices next */
 359                         next = dev->subordinate->devices.next;
 360                         bus = dev->subordinate;
 361                 } else
 362                         next = dev->bus_list.next;
 363
 364                 /* Run device routines with the device locked */
 365                 device_lock(&dev->dev);
 366                 retval = cb(dev, userdata);
 367                 device_unlock(&dev->dev);
 368                 if (retval)
 369                         break;
 370         }
 371         up_read(&pci_bus_sem);
 372 }
 373 EXPORT_SYMBOL_GPL(pci_walk_bus);
 374
 375 EXPORT_SYMBOL(pci_bus_alloc_resource);
 376 EXPORT_SYMBOL_GPL(pci_bus_add_device);
 377 EXPORT_SYMBOL(pci_bus_add_devices);
 378 EXPORT_SYMBOL(pci_enable_bridges);