eeh_cache.c

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/*
 * PCI address cache; allows the lookup of PCI devices based on I/O address
 *
 * Copyright IBM Corporation 2004
 * Copyright Linas Vepstas <[email protected]> 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>


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;
}

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);
    }
}

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);
    }
}

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);
}

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
}