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Diffstat (limited to 'arch/powerpc/kernel/eeh_cache.c')
| -rw-r--r-- | arch/powerpc/kernel/eeh_cache.c | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/eeh_cache.c b/arch/powerpc/kernel/eeh_cache.c new file mode 100644 index 000000000000..1d5d9a6ba740 --- /dev/null +++ b/arch/powerpc/kernel/eeh_cache.c @@ -0,0 +1,318 @@ +/* + * PCI address cache; allows the lookup of PCI devices based on I/O address + * + * Copyright IBM Corporation 2004 + * Copyright Linas Vepstas <linas@austin.ibm.com> 2004 + * + * 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 <linux/list.h> +#include <linux/pci.h> +#include <linux/rbtree.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/atomic.h> +#include <asm/pci-bridge.h> +#include <asm/ppc-pci.h> + + +/** + * 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 eeh_dev *edev; + 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 eeh_dev *__eeh_addr_cache_get_device(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->edev; + } + } + } + + return NULL; +} + +/** + * eeh_addr_cache_get_dev - 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 eeh_dev *eeh_addr_cache_get_dev(unsigned long addr) +{ + struct eeh_dev *edev; + unsigned long flags; + + spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags); + edev = __eeh_addr_cache_get_device(addr); + spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags); + return edev; +} + +#ifdef DEBUG +/* + * Handy-dandy debug print routine, does nothing more + * than print out the contents of our addr cache. + */ +static void eeh_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); + pr_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 * +eeh_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) { + pr_warning("PIAR: overlapping address range\n"); + } + return piar; + } + } + piar = kzalloc(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->edev = pci_dev_to_eeh_dev(dev); + piar->pcidev = dev; + piar->flags = flags; + +#ifdef DEBUG + pr_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 __eeh_addr_cache_insert_dev(struct pci_dev *dev) +{ + struct device_node *dn; + struct eeh_dev *edev; + int i; + + dn = pci_device_to_OF_node(dev); + if (!dn) { + pr_warning("PCI: no pci dn found for dev=%s\n", pci_name(dev)); + return; + } + + edev = of_node_to_eeh_dev(dn); + if (!edev) { + pr_warning("PCI: no EEH dev found for dn=%s\n", + dn->full_name); + return; + } + + /* Skip any devices for which EEH is not enabled. */ + if (!edev->pe) { +#ifdef DEBUG + pr_info("PCI: skip building address cache for=%s - %s\n", + pci_name(dev), dn->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; + eeh_addr_cache_insert(dev, start, end, flags); + } +} + +/** + * eeh_addr_cache_insert_dev - 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 eeh_addr_cache_insert_dev(struct pci_dev *dev) +{ + unsigned long flags; + + /* Ignore PCI bridges */ + if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE) + return; + + spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags); + __eeh_addr_cache_insert_dev(dev); + spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags); +} + +static inline void __eeh_addr_cache_rmv_dev(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); + } +} + +/** + * eeh_addr_cache_rmv_dev - 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 eeh_addr_cache_rmv_dev(struct pci_dev *dev) +{ + unsigned long flags; + + spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags); + __eeh_addr_cache_rmv_dev(dev); + spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags); +} + +/** + * eeh_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 eeh_addr_cache_build(void) +{ + struct device_node *dn; + struct eeh_dev *edev; + struct pci_dev *dev = NULL; + + spin_lock_init(&pci_io_addr_cache_root.piar_lock); + + for_each_pci_dev(dev) { + eeh_addr_cache_insert_dev(dev); + + dn = pci_device_to_OF_node(dev); + if (!dn) + continue; + + edev = of_node_to_eeh_dev(dn); + if (!edev) + continue; + + pci_dev_get(dev); /* matching put is in eeh_remove_device() */ + dev->dev.archdata.edev = edev; + edev->pdev = dev; + + eeh_sysfs_add_device(dev); + } + +#ifdef DEBUG + /* Verify tree built up above, echo back the list of addrs. */ + eeh_addr_cache_print(&pci_io_addr_cache_root); +#endif +} |