/* * eeh_cache.c * PCI address cache; allows the lookup of PCI devices based on I/O address * * Copyright (C) 2004 Linas Vepstas IBM Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #undef DEBUG /** * The pci address cache subsystem. This subsystem places * PCI device address resources into a red-black tree, sorted * according to the address range, so that given only an i/o * address, the corresponding PCI device can be **quickly** * found. It is safe to perform an address lookup in an interrupt * context; this ability is an important feature. * * Currently, the only customer of this code is the EEH subsystem; * thus, this code has been somewhat tailored to suit EEH better. * In particular, the cache does *not* hold the addresses of devices * for which EEH is not enabled. * * (Implementation Note: The RB tree seems to be better/faster * than any hash algo I could think of for this problem, even * with the penalty of slow pointer chases for d-cache misses). */ struct pci_io_addr_range { struct rb_node rb_node; unsigned long addr_lo; unsigned long addr_hi; struct pci_dev *pcidev; unsigned int flags; }; static struct pci_io_addr_cache { struct rb_root rb_root; spinlock_t piar_lock; } pci_io_addr_cache_root; static inline struct pci_dev *__pci_get_device_by_addr(unsigned long addr) { struct rb_node *n = pci_io_addr_cache_root.rb_root.rb_node; while (n) { struct pci_io_addr_range *piar; piar = rb_entry(n, struct pci_io_addr_range, rb_node); if (addr < piar->addr_lo) { n = n->rb_left; } else { if (addr > piar->addr_hi) { n = n->rb_right; } else { pci_dev_get(piar->pcidev); return piar->pcidev; } } } return NULL; } /** * pci_get_device_by_addr - Get device, given only address * @addr: mmio (PIO) phys address or i/o port number * * Given an mmio phys address, or a port number, find a pci device * that implements this address. Be sure to pci_dev_put the device * when finished. I/O port numbers are assumed to be offset * from zero (that is, they do *not* have pci_io_addr added in). * It is safe to call this function within an interrupt. */ struct pci_dev *pci_get_device_by_addr(unsigned long addr) { struct pci_dev *dev; unsigned long flags; spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags); dev = __pci_get_device_by_addr(addr); spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags); return dev; } #ifdef DEBUG /* * Handy-dandy debug print routine, does nothing more * than print out the contents of our addr cache. */ static void pci_addr_cache_print(struct pci_io_addr_cache *cache) { struct rb_node *n; int cnt = 0; n = rb_first(&cache->rb_root); while (n) { struct pci_io_addr_range *piar; piar = rb_entry(n, struct pci_io_addr_range, rb_node); printk(KERN_DEBUG "PCI: %s addr range %d [%lx-%lx]: %s\n", (piar->flags & IORESOURCE_IO) ? "i/o" : "mem", cnt, piar->addr_lo, piar->addr_hi, pci_name(piar->pcidev)); cnt++; n = rb_next(n); } } #endif /* Insert address range into the rb tree. */ static struct pci_io_addr_range * pci_addr_cache_insert(struct pci_dev *dev, unsigned long alo, unsigned long ahi, unsigned int flags) { struct rb_node **p = &pci_io_addr_cache_root.rb_root.rb_node; struct rb_node *parent = NULL; struct pci_io_addr_range *piar; /* Walk tree, find a place to insert into tree */ while (*p) { parent = *p; piar = rb_entry(parent, struct pci_io_addr_range, rb_node); if (ahi < piar->addr_lo) { p = &parent->rb_left; } else if (alo > piar->addr_hi) { p = &parent->rb_right; } else { if (dev != piar->pcidev || alo != piar->addr_lo || ahi != piar->addr_hi) { printk(KERN_WARNING "PIAR: overlapping address range\n"); } return piar; } } piar = kmalloc(sizeof(struct pci_io_addr_range), GFP_ATOMIC); if (!piar) return NULL; pci_dev_get(dev); piar->addr_lo = alo; piar->addr_hi = ahi; piar->pcidev = dev; piar->flags = flags; #ifdef DEBUG printk(KERN_DEBUG "PIAR: insert range=[%lx:%lx] dev=%s\n", alo, ahi, pci_name (dev)); #endif rb_link_node(&piar->rb_node, parent, p); rb_insert_color(&piar->rb_node, &pci_io_addr_cache_root.rb_root); return piar; } static void __pci_addr_cache_insert_device(struct pci_dev *dev) { struct device_node *dn; struct pci_dn *pdn; int i; dn = pci_device_to_OF_node(dev); if (!dn) { printk(KERN_WARNING "PCI: no pci dn found for dev=%s\n", pci_name(dev)); return; } /* Skip any devices for which EEH is not enabled. */ pdn = PCI_DN(dn); if (!(pdn->eeh_mode & EEH_MODE_SUPPORTED) || pdn->eeh_mode & EEH_MODE_NOCHECK) { #ifdef DEBUG printk(KERN_INFO "PCI: skip building address cache for=%s - %s\n", pci_name(dev), pdn->node->full_name); #endif return; } /* Walk resources on this device, poke them into the tree */ for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) { unsigned long start = pci_resource_start(dev,i); unsigned long end = pci_resource_end(dev,i); unsigned int flags = pci_resource_flags(dev,i); /* We are interested only bus addresses, not dma or other stuff */ if (0 == (flags & (IORESOURCE_IO | IORESOURCE_MEM))) continue; if (start == 0 || ~start == 0 || end == 0 || ~end == 0) continue; pci_addr_cache_insert(dev, start, end, flags); } } /** * pci_addr_cache_insert_device - Add a device to the address cache * @dev: PCI device whose I/O addresses we are interested in. * * In order to support the fast lookup of devices based on addresses, * we maintain a cache of devices that can be quickly searched. * This routine adds a device to that cache. */ void pci_addr_cache_insert_device(struct pci_dev *dev) { unsigned long flags; spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags); __pci_addr_cache_insert_device(dev); spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags); } static inline void __pci_addr_cache_remove_device(struct pci_dev *dev) { struct rb_node *n; restart: n = rb_first(&pci_io_addr_cache_root.rb_root); while (n) { struct pci_io_addr_range *piar; piar = rb_entry(n, struct pci_io_addr_range, rb_node); if (piar->pcidev == dev) { rb_erase(n, &pci_io_addr_cache_root.rb_root); pci_dev_put(piar->pcidev); kfree(piar); goto restart; } n = rb_next(n); } } /** * pci_addr_cache_remove_device - remove pci device from addr cache * @dev: device to remove * * Remove a device from the addr-cache tree. * This is potentially expensive, since it will walk * the tree multiple times (once per resource). * But so what; device removal doesn't need to be that fast. */ void pci_addr_cache_remove_device(struct pci_dev *dev) { unsigned long flags; spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags); __pci_addr_cache_remove_device(dev); spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags); } /** * pci_addr_cache_build - Build a cache of I/O addresses * * Build a cache of pci i/o addresses. This cache will be used to * find the pci device that corresponds to a given address. * This routine scans all pci busses to build the cache. * Must be run late in boot process, after the pci controllers * have been scanned for devices (after all device resources are known). */ void __init pci_addr_cache_build(void) { struct device_node *dn; struct pci_dev *dev = NULL; spin_lock_init(&pci_io_addr_cache_root.piar_lock); while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) { /* Ignore PCI bridges */ if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE) continue; pci_addr_cache_insert_device(dev); dn = pci_device_to_OF_node(dev); if (!dn) continue; pci_dev_get (dev); /* matching put is in eeh_remove_device() */ PCI_DN(dn)->pcidev = dev; } #ifdef DEBUG /* Verify tree built up above, echo back the list of addrs. */ pci_addr_cache_print(&pci_io_addr_cache_root); #endif }