linux/arch/powerpc/kernel/eeh_cache.c
Gavin Shan 0ba178888b powerpc/eeh: Remove reference to PCI device
We will rely on pcibios_release_device() to remove the EEH cache
and unbind EEH device for the specific PCI device. So we shouldn't
hold the reference to the PCI device from EEH cache and EEH device.
Otherwise, pcibios_release_device() won't be called as we expected.
The patch removes the reference to the PCI device in EEH core.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-07-24 14:18:46 +10:00

311 lines
8.6 KiB
C

/*
* 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
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;
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 (!eeh_probe_mode_dev() && !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);
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 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) {
dn = pci_device_to_OF_node(dev);
if (!dn)
continue;
edev = of_node_to_eeh_dev(dn);
if (!edev)
continue;
dev->dev.archdata.edev = edev;
edev->pdev = dev;
eeh_addr_cache_insert_dev(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
}