arch/powerpc/kernel/eeh_cache.c - linux - Git at Google

 /*
  * 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;
 	resource_size_t addr_lo;
 	resource_size_t addr_hi;
 	struct eeh_dev *edev;
 	struct pci_dev *pcidev;
 	unsigned long 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, resource_size_t alo,
 		      resource_size_t ahi, unsigned long 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_warn("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 pci_dn *pdn;
 	struct eeh_dev *edev;
 	int i;

 	pdn = pci_get_pdn_by_devfn(dev->bus, dev->devfn);
 	if (!pdn) {
 		pr_warn("PCI: no pci dn found for dev=%s\n",
 			pci_name(dev));
 		return;
 	}

 	edev = pdn_to_eeh_dev(pdn);
 	if (!edev) {
 		pr_warn("PCI: no EEH dev found for %s\n",
 			pci_name(dev));
 		return;
 	}

 	/* Skip any devices for which EEH is not enabled. */
 	if (!edev->pe) {
 		dev_dbg(&dev->dev, "EEH: Skip building address cache\n");
 		return;
 	}

 	/*
 	 * Walk resources on this device, poke the first 7 (6 normal BAR and 1
 	 * ROM BAR) into the tree.
 	 */
 	for (i = 0; i <= PCI_ROM_RESOURCE; i++) {
 		resource_size_t start = pci_resource_start(dev,i);
 		resource_size_t end = pci_resource_end(dev,i);
 		unsigned long 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;

 	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 pci_dn *pdn;
 	struct eeh_dev *edev;
 	struct pci_dev *dev = NULL;

 	spin_lock_init(&pci_io_addr_cache_root.piar_lock);

 	for_each_pci_dev(dev) {
 		pdn = pci_get_pdn_by_devfn(dev->bus, dev->devfn);
 		if (!pdn)
 			continue;

 		edev = pdn_to_eeh_dev(pdn);
 		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
 }
	/*
	* 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;
	resource_size_t addr_lo;
	resource_size_t addr_hi;
	struct eeh_dev *edev;
	struct pci_dev *pcidev;
	unsigned long 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, resource_size_t alo,
	resource_size_t ahi, unsigned long 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_warn("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 pci_dn *pdn;
	struct eeh_dev *edev;
	int i;

	pdn = pci_get_pdn_by_devfn(dev->bus, dev->devfn);
	if (!pdn) {
	pr_warn("PCI: no pci dn found for dev=%s\n",
	pci_name(dev));
	return;
	}

	edev = pdn_to_eeh_dev(pdn);
	if (!edev) {
	pr_warn("PCI: no EEH dev found for %s\n",
	pci_name(dev));
	return;
	}

	/* Skip any devices for which EEH is not enabled. */
	if (!edev->pe) {
	dev_dbg(&dev->dev, "EEH: Skip building address cache\n");
	return;
	}

	/*
	* Walk resources on this device, poke the first 7 (6 normal BAR and 1
	* ROM BAR) into the tree.
	*/
	for (i = 0; i <= PCI_ROM_RESOURCE; i++) {
	resource_size_t start = pci_resource_start(dev,i);
	resource_size_t end = pci_resource_end(dev,i);
	unsigned long 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;

	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 pci_dn *pdn;
	struct eeh_dev *edev;
	struct pci_dev *dev = NULL;

	spin_lock_init(&pci_io_addr_cache_root.piar_lock);

	for_each_pci_dev(dev) {
	pdn = pci_get_pdn_by_devfn(dev->bus, dev->devfn);
	if (!pdn)
	continue;

	edev = pdn_to_eeh_dev(pdn);
	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
	}