arch/powerpc/platforms/pseries/eeh_cache.c

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