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