arch/powerpc/platforms/pseries/eeh_cache.c

   1 /*
   2  * PCI address cache; allows the lookup of PCI devices based on I/O address
   3  *
   4  * Copyright IBM Corporation 2004
   5  * Copyright Linas Vepstas <linas@austin.ibm.com> 2004
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  20  */
  21
  22 #include <linux/list.h>
  23 #include <linux/pci.h>
  24 #include <linux/rbtree.h>
  25 #include <linux/slab.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/atomic.h>
  28 #include <asm/pci-bridge.h>
  29 #include <asm/ppc-pci.h>
  30
  31
  32 /**
  33  * The pci address cache subsystem.  This subsystem places
  34  * PCI device address resources into a red-black tree, sorted
  35  * according to the address range, so that given only an i/o
  36  * address, the corresponding PCI device can be **quickly**
  37  * found. It is safe to perform an address lookup in an interrupt
  38  * context; this ability is an important feature.
  39  *
  40  * Currently, the only customer of this code is the EEH subsystem;
  41  * thus, this code has been somewhat tailored to suit EEH better.
  42  * In particular, the cache does *not* hold the addresses of devices
  43  * for which EEH is not enabled.
  44  *
  45  * (Implementation Note: The RB tree seems to be better/faster
  46  * than any hash algo I could think of for this problem, even
  47  * with the penalty of slow pointer chases for d-cache misses).
  48  */
  49 struct pci_io_addr_range {
  50         struct rb_node rb_node;
  51         unsigned long addr_lo;
  52         unsigned long addr_hi;
  53         struct pci_dev *pcidev;
  54         unsigned int flags;
  55 };
  56
  57 static struct pci_io_addr_cache {
  58         struct rb_root rb_root;
  59         spinlock_t piar_lock;
  60 } pci_io_addr_cache_root;
  61
  62 static inline struct pci_dev *__pci_addr_cache_get_device(unsigned long addr)
  63 {
  64         struct rb_node *n = pci_io_addr_cache_root.rb_root.rb_node;
  65
  66         while (n) {
  67                 struct pci_io_addr_range *piar;
  68                 piar = rb_entry(n, struct pci_io_addr_range, rb_node);
  69
  70                 if (addr < piar->addr_lo) {
  71                         n = n->rb_left;
  72                 } else {
  73                         if (addr > piar->addr_hi) {
  74                                 n = n->rb_right;
  75                         } else {
  76                                 pci_dev_get(piar->pcidev);
  77                                 return piar->pcidev;
  78                         }
  79                 }
  80         }
  81
  82         return NULL;
  83 }
  84
  85 /**
  86  * pci_addr_cache_get_device - Get device, given only address
  87  * @addr: mmio (PIO) phys address or i/o port number
  88  *
  89  * Given an mmio phys address, or a port number, find a pci device
  90  * that implements this address.  Be sure to pci_dev_put the device
  91  * when finished.  I/O port numbers are assumed to be offset
  92  * from zero (that is, they do *not* have pci_io_addr added in).
  93  * It is safe to call this function within an interrupt.
  94  */
  95 struct pci_dev *pci_addr_cache_get_device(unsigned long addr)
  96 {
  97         struct pci_dev *dev;
  98         unsigned long flags;
  99
 100         spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
 101         dev = __pci_addr_cache_get_device(addr);
 102         spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
 103         return dev;
 104 }
 105
 106 #ifdef DEBUG
 107 /*
 108  * Handy-dandy debug print routine, does nothing more
 109  * than print out the contents of our addr cache.
 110  */
 111 static void pci_addr_cache_print(struct pci_io_addr_cache *cache)
 112 {
 113         struct rb_node *n;
 114         int cnt = 0;
 115
 116         n = rb_first(&cache->rb_root);
 117         while (n) {
 118                 struct pci_io_addr_range *piar;
 119                 piar = rb_entry(n, struct pci_io_addr_range, rb_node);
 120                 printk(KERN_DEBUG "PCI: %s addr range %d [%lx-%lx]: %s\n",
 121                        (piar->flags & IORESOURCE_IO) ? "i/o" : "mem", cnt,
 122                        piar->addr_lo, piar->addr_hi, pci_name(piar->pcidev));
 123                 cnt++;
 124                 n = rb_next(n);
 125         }
 126 }
 127 #endif
 128
 129 /* Insert address range into the rb tree. */
 130 static struct pci_io_addr_range *
 131 pci_addr_cache_insert(struct pci_dev *dev, unsigned long alo,
 132                       unsigned long ahi, unsigned int flags)
 133 {
 134         struct rb_node **p = &pci_io_addr_cache_root.rb_root.rb_node;
 135         struct rb_node *parent = NULL;
 136         struct pci_io_addr_range *piar;
 137
 138         /* Walk tree, find a place to insert into tree */
 139         while (*p) {
 140                 parent = *p;
 141                 piar = rb_entry(parent, struct pci_io_addr_range, rb_node);
 142                 if (ahi < piar->addr_lo) {
 143                         p = &parent->rb_left;
 144                 } else if (alo > piar->addr_hi) {
 145                         p = &parent->rb_right;
 146                 } else {
 147                         if (dev != piar->pcidev ||
 148                             alo != piar->addr_lo || ahi != piar->addr_hi) {
 149                                 printk(KERN_WARNING "PIAR: overlapping address range\n");
 150                         }
 151                         return piar;
 152                 }
 153         }
 154         piar = kmalloc(sizeof(struct pci_io_addr_range), GFP_ATOMIC);
 155         if (!piar)
 156                 return NULL;
 157
 158         pci_dev_get(dev);
 159         piar->addr_lo = alo;
 160         piar->addr_hi = ahi;
 161         piar->pcidev = dev;
 162         piar->flags = flags;
 163
 164 #ifdef DEBUG
 165         printk(KERN_DEBUG "PIAR: insert range=[%lx:%lx] dev=%s\n",
 166                           alo, ahi, pci_name(dev));
 167 #endif
 168
 169         rb_link_node(&piar->rb_node, parent, p);
 170         rb_insert_color(&piar->rb_node, &pci_io_addr_cache_root.rb_root);
 171
 172         return piar;
 173 }
 174
 175 static void __pci_addr_cache_insert_device(struct pci_dev *dev)
 176 {
 177         struct device_node *dn;
 178         struct eeh_dev *edev;
 179         int i;
 180
 181         dn = pci_device_to_OF_node(dev);
 182         if (!dn) {
 183                 printk(KERN_WARNING "PCI: no pci dn found for dev=%s\n", pci_name(dev));
 184                 return;
 185         }
 186
 187         edev = of_node_to_eeh_dev(dn);
 188         if (!edev) {
 189                 pr_warning("PCI: no EEH dev found for dn=%s\n",
 190                         dn->full_name);
 191                 return;
 192         }
 193
 194         /* Skip any devices for which EEH is not enabled. */
 195         if (!(edev->mode & EEH_MODE_SUPPORTED) ||
 196             edev->mode & EEH_MODE_NOCHECK) {
 197 #ifdef DEBUG
 198                 pr_info("PCI: skip building address cache for=%s - %s\n",
 199                         pci_name(dev), dn->full_name);
 200 #endif
 201                 return;
 202         }
 203
 204         /* Walk resources on this device, poke them into the tree */
 205         for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
 206                 unsigned long start = pci_resource_start(dev,i);
 207                 unsigned long end = pci_resource_end(dev,i);
 208                 unsigned int flags = pci_resource_flags(dev,i);
 209
 210                 /* We are interested only bus addresses, not dma or other stuff */
 211                 if (0 == (flags & (IORESOURCE_IO | IORESOURCE_MEM)))
 212                         continue;
 213                 if (start == 0 || ~start == 0 || end == 0 || ~end == 0)
 214                          continue;
 215                 pci_addr_cache_insert(dev, start, end, flags);
 216         }
 217 }
 218
 219 /**
 220  * pci_addr_cache_insert_device - Add a device to the address cache
 221  * @dev: PCI device whose I/O addresses we are interested in.
 222  *
 223  * In order to support the fast lookup of devices based on addresses,
 224  * we maintain a cache of devices that can be quickly searched.
 225  * This routine adds a device to that cache.
 226  */
 227 void pci_addr_cache_insert_device(struct pci_dev *dev)
 228 {
 229         unsigned long flags;
 230
 231         /* Ignore PCI bridges */
 232         if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE)
 233                 return;
 234
 235         spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
 236         __pci_addr_cache_insert_device(dev);
 237         spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
 238 }
 239
 240 static inline void __pci_addr_cache_remove_device(struct pci_dev *dev)
 241 {
 242         struct rb_node *n;
 243
 244 restart:
 245         n = rb_first(&pci_io_addr_cache_root.rb_root);
 246         while (n) {
 247                 struct pci_io_addr_range *piar;
 248                 piar = rb_entry(n, struct pci_io_addr_range, rb_node);
 249
 250                 if (piar->pcidev == dev) {
 251                         rb_erase(n, &pci_io_addr_cache_root.rb_root);
 252                         pci_dev_put(piar->pcidev);
 253                         kfree(piar);
 254                         goto restart;
 255                 }
 256                 n = rb_next(n);
 257         }
 258 }
 259
 260 /**
 261  * pci_addr_cache_remove_device - remove pci device from addr cache
 262  * @dev: device to remove
 263  *
 264  * Remove a device from the addr-cache tree.
 265  * This is potentially expensive, since it will walk
 266  * the tree multiple times (once per resource).
 267  * But so what; device removal doesn't need to be that fast.
 268  */
 269 void pci_addr_cache_remove_device(struct pci_dev *dev)
 270 {
 271         unsigned long flags;
 272
 273         spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
 274         __pci_addr_cache_remove_device(dev);
 275         spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
 276 }
 277
 278 /**
 279  * pci_addr_cache_build - Build a cache of I/O addresses
 280  *
 281  * Build a cache of pci i/o addresses.  This cache will be used to
 282  * find the pci device that corresponds to a given address.
 283  * This routine scans all pci busses to build the cache.
 284  * Must be run late in boot process, after the pci controllers
 285  * have been scanned for devices (after all device resources are known).
 286  */
 287 void __init pci_addr_cache_build(void)
 288 {
 289         struct device_node *dn;
 290         struct eeh_dev *edev;
 291         struct pci_dev *dev = NULL;
 292
 293         spin_lock_init(&pci_io_addr_cache_root.piar_lock);
 294
 295         for_each_pci_dev(dev) {
 296                 pci_addr_cache_insert_device(dev);
 297
 298                 dn = pci_device_to_OF_node(dev);
 299                 if (!dn)
 300                         continue;
 301
 302                 edev = of_node_to_eeh_dev(dn);
 303                 if (!edev)
 304                         continue;
 305
 306                 pci_dev_get(dev);  /* matching put is in eeh_remove_device() */
 307                 dev->dev.archdata.edev = edev;
 308                 edev->pdev = dev;
 309
 310                 eeh_sysfs_add_device(dev);
 311         }
 312
 313 #ifdef DEBUG
 314         /* Verify tree built up above, echo back the list of addrs. */
 315         pci_addr_cache_print(&pci_io_addr_cache_root);
 316 #endif
 317 }
 318