[mirror_ubuntu-artful-kernel.git] / arch / powerpc / platforms / pseries / eeh_cache.c

/*
 * eeh_cache.c
 * PCI address cache; allows the lookup of PCI devices based on I/O address
 *
 * Copyright (C) 2004 Linas Vepstas <linas@austin.ibm.com> IBM Corporation
 *
 * 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/spinlock.h>
#include <asm/atomic.h>
#include <asm/pci-bridge.h>
#include <asm/ppc-pci.h>

#undef DEBUG

/**
 * 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 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 pci_dev *__pci_get_device_by_addr(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->pcidev;
			}
		}
	}

	return NULL;
}

/**
 * pci_get_device_by_addr - 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 pci_dev *pci_get_device_by_addr(unsigned long addr)
{
	struct pci_dev *dev;
	unsigned long flags;

	spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
	dev = __pci_get_device_by_addr(addr);
	spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
	return dev;
}

#ifdef DEBUG
/*
 * Handy-dandy debug print routine, does nothing more
 * than print out the contents of our addr cache.
 */
static void pci_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);
		printk(KERN_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 *
pci_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) {
				printk(KERN_WARNING "PIAR: overlapping address range\n");
			}
			return piar;
		}
	}
	piar = kmalloc(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->pcidev = dev;
	piar->flags = flags;

#ifdef DEBUG
	printk(KERN_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 __pci_addr_cache_insert_device(struct pci_dev *dev)
{
	struct device_node *dn;
	struct pci_dn *pdn;
	int i;

	dn = pci_device_to_OF_node(dev);
	if (!dn) {
		printk(KERN_WARNING "PCI: no pci dn found for dev=%s\n", pci_name(dev));
		return;
	}

	/* Skip any devices for which EEH is not enabled. */
	pdn = PCI_DN(dn);
	if (!(pdn->eeh_mode & EEH_MODE_SUPPORTED) ||
	    pdn->eeh_mode & EEH_MODE_NOCHECK) {
#ifdef DEBUG
		printk(KERN_INFO "PCI: skip building address cache for=%s - %s\n",
		       pci_name(dev), pdn->node->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;
		pci_addr_cache_insert(dev, start, end, flags);
	}
}

/**
 * pci_addr_cache_insert_device - 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 pci_addr_cache_insert_device(struct pci_dev *dev)
{
	unsigned long flags;

	spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
	__pci_addr_cache_insert_device(dev);
	spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
}

static inline void __pci_addr_cache_remove_device(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);
	}
}

/**
 * pci_addr_cache_remove_device - 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 pci_addr_cache_remove_device(struct pci_dev *dev)
{
	unsigned long flags;

	spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
	__pci_addr_cache_remove_device(dev);
	spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
}

/**
 * pci_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 pci_addr_cache_build(void)
{
	struct device_node *dn;
	struct pci_dev *dev = NULL;

	spin_lock_init(&pci_io_addr_cache_root.piar_lock);

	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
		/* Ignore PCI bridges */
		if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE)
			continue;

		pci_addr_cache_insert_device(dev);

		dn = pci_device_to_OF_node(dev);
		if (!dn)
			continue;
		pci_dev_get (dev);  /* matching put is in eeh_remove_device() */
		PCI_DN(dn)->pcidev = dev;
	}

#ifdef DEBUG
	/* Verify tree built up above, echo back the list of addrs. */
	pci_addr_cache_print(&pci_io_addr_cache_root);
#endif
}
Commit	Line	Data
5d5a0936 LV	1	/*
	2	* eeh_cache.c
	3	* PCI address cache; allows the lookup of PCI devices based on I/O address
	4	*
	5	* Copyright (C) 2004 Linas Vepstas <linas@austin.ibm.com> IBM Corporation
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*/
	21
	22	#include <linux/list.h>
	23	#include <linux/pci.h>
	24	#include <linux/rbtree.h>
	25	#include <linux/spinlock.h>
	26	#include <asm/atomic.h>
	27	#include <asm/pci-bridge.h>
	28	#include <asm/ppc-pci.h>
5d5a0936 LV	29
	30	#undef DEBUG
	31
	32	/**
	33	* The pci address cache subsystem. This subsystem places
	34	* PCI device address resources into a red-black tree, sorted
	35	* according to the address range, so that given only an i/o
	36	* address, the corresponding PCI device can be quickly
	37	* found. It is safe to perform an address lookup in an interrupt
	38	* context; this ability is an important feature.
	39	*
	40	* Currently, the only customer of this code is the EEH subsystem;
	41	* thus, this code has been somewhat tailored to suit EEH better.
	42	* In particular, the cache does not hold the addresses of devices
	43	* for which EEH is not enabled.
	44	*
	45	* (Implementation Note: The RB tree seems to be better/faster
	46	* than any hash algo I could think of for this problem, even
	47	* with the penalty of slow pointer chases for d-cache misses).
	48	*/
	49	struct pci_io_addr_range
	50	{
	51	struct rb_node rb_node;
	52	unsigned long addr_lo;
	53	unsigned long addr_hi;
	54	struct pci_dev *pcidev;
	55	unsigned int flags;
	56	};
	57
	58	static struct pci_io_addr_cache
	59	{
	60	struct rb_root rb_root;
	61	spinlock_t piar_lock;
	62	} pci_io_addr_cache_root;
	63
	64	static inline struct pci_dev *__pci_get_device_by_addr(unsigned long addr)
	65	{
	66	struct rb_node *n = pci_io_addr_cache_root.rb_root.rb_node;
	67
	68	while (n) {
	69	struct pci_io_addr_range *piar;
	70	piar = rb_entry(n, struct pci_io_addr_range, rb_node);
	71
	72	if (addr < piar->addr_lo) {
	73	n = n->rb_left;
	74	} else {
	75	if (addr > piar->addr_hi) {
	76	n = n->rb_right;
	77	} else {
	78	pci_dev_get(piar->pcidev);
	79	return piar->pcidev;
	80	}
	81	}
	82	}
	83
	84	return NULL;
	85	}
	86
	87	/**
	88	* pci_get_device_by_addr - Get device, given only address
	89	* @addr: mmio (PIO) phys address or i/o port number
	90	*
	91	* Given an mmio phys address, or a port number, find a pci device
	92	* that implements this address. Be sure to pci_dev_put the device
93	* when finished. I/O port numbers are assumed to be offset
94	* from zero (that is, they do not have pci_io_addr added in).
95	* It is safe to call this function within an interrupt.
96	*/
97	struct pci_dev *pci_get_device_by_addr(unsigned long addr)
98	{
99	struct pci_dev *dev;
100	unsigned long flags;
101
102	spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
103	dev = __pci_get_device_by_addr(addr);
104	spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
105	return dev;
106	}
107
108	#ifdef DEBUG
109	/*
110	* Handy-dandy debug print routine, does nothing more
111	* than print out the contents of our addr cache.
112	*/
113	static void pci_addr_cache_print(struct pci_io_addr_cache *cache)
114	{
115	struct rb_node *n;
116	int cnt = 0;
117
118	n = rb_first(&cache->rb_root);
119	while (n) {
120	struct pci_io_addr_range *piar;
121	piar = rb_entry(n, struct pci_io_addr_range, rb_node);
122	printk(KERN_DEBUG "PCI: %s addr range %d [%lx-%lx]: %s\n",
123	(piar->flags & IORESOURCE_IO) ? "i/o" : "mem", cnt,
124	piar->addr_lo, piar->addr_hi, pci_name(piar->pcidev));
125	cnt++;
126	n = rb_next(n);
127	}
128	}
129	#endif
130
131	/* Insert address range into the rb tree. */
132	static struct pci_io_addr_range *
133	pci_addr_cache_insert(struct pci_dev *dev, unsigned long alo,
134	unsigned long ahi, unsigned int flags)
135	{
136	struct rb_node **p = &pci_io_addr_cache_root.rb_root.rb_node;
137	struct rb_node *parent = NULL;
138	struct pci_io_addr_range *piar;
139
140	/* Walk tree, find a place to insert into tree */
141	while (*p) {
142	parent = *p;
143	piar = rb_entry(parent, struct pci_io_addr_range, rb_node);
144	if (ahi < piar->addr_lo) {
145	p = &parent->rb_left;
146	} else if (alo > piar->addr_hi) {
147	p = &parent->rb_right;
148	} else {
149	if (dev != piar->pcidev \|\|
150	alo != piar->addr_lo \|\| ahi != piar->addr_hi) {
151	printk(KERN_WARNING "PIAR: overlapping address range\n");
152	}
153	return piar;
154	}
155	}
5cbded58	156	piar = kmalloc(sizeof(struct pci_io_addr_range), GFP_ATOMIC);
5d5a0936 LV	157	if (!piar)
	158	return NULL;
	159
af525592	160	pci_dev_get(dev);
5d5a0936 LV	161	piar->addr_lo = alo;
	162	piar->addr_hi = ahi;
	163	piar->pcidev = dev;
	164	piar->flags = flags;
	165
	166	#ifdef DEBUG
	167	printk(KERN_DEBUG "PIAR: insert range=[%lx:%lx] dev=%s\n",
	168	alo, ahi, pci_name (dev));
	169	#endif
	170
	171	rb_link_node(&piar->rb_node, parent, p);
	172	rb_insert_color(&piar->rb_node, &pci_io_addr_cache_root.rb_root);
	173
	174	return piar;
	175	}
	176
	177	static void __pci_addr_cache_insert_device(struct pci_dev *dev)
	178	{
	179	struct device_node *dn;
	180	struct pci_dn *pdn;
	181	int i;
5d5a0936 LV	182
	183	dn = pci_device_to_OF_node(dev);
	184	if (!dn) {
	185	printk(KERN_WARNING "PCI: no pci dn found for dev=%s\n", pci_name(dev));
	186	return;
	187	}
	188
	189	/* Skip any devices for which EEH is not enabled. */
	190	pdn = PCI_DN(dn);
	191	if (!(pdn->eeh_mode & EEH_MODE_SUPPORTED) \|\|
	192	pdn->eeh_mode & EEH_MODE_NOCHECK) {
	193	#ifdef DEBUG
	194	printk(KERN_INFO "PCI: skip building address cache for=%s - %s\n",
	195	pci_name(dev), pdn->node->full_name);
	196	#endif
	197	return;
	198	}
	199
5d5a0936 LV	200	/* Walk resources on this device, poke them into the tree */
	201	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
	202	unsigned long start = pci_resource_start(dev,i);
	203	unsigned long end = pci_resource_end(dev,i);
	204	unsigned int flags = pci_resource_flags(dev,i);
	205
	206	/* We are interested only bus addresses, not dma or other stuff */
	207	if (0 == (flags & (IORESOURCE_IO \| IORESOURCE_MEM)))
	208	continue;
	209	if (start == 0 \|\| ~start == 0 \|\| end == 0 \|\| ~end == 0)
	210	continue;
	211	pci_addr_cache_insert(dev, start, end, flags);
5d5a0936	212	}
5d5a0936 LV	213	}
	214
	215	/**
	216	* pci_addr_cache_insert_device - Add a device to the address cache
	217	* @dev: PCI device whose I/O addresses we are interested in.
	218	*
	219	* In order to support the fast lookup of devices based on addresses,
	220	* we maintain a cache of devices that can be quickly searched.
	221	* This routine adds a device to that cache.
	222	*/
	223	void pci_addr_cache_insert_device(struct pci_dev *dev)
	224	{
	225	unsigned long flags;
	226
	227	spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
	228	__pci_addr_cache_insert_device(dev);
	229	spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
	230	}
	231
	232	static inline void __pci_addr_cache_remove_device(struct pci_dev *dev)
	233	{
	234	struct rb_node *n;
5d5a0936 LV	235
	236	restart:
	237	n = rb_first(&pci_io_addr_cache_root.rb_root);
	238	while (n) {
	239	struct pci_io_addr_range *piar;
	240	piar = rb_entry(n, struct pci_io_addr_range, rb_node);
	241
	242	if (piar->pcidev == dev) {
	243	rb_erase(n, &pci_io_addr_cache_root.rb_root);
af525592	244	pci_dev_put(piar->pcidev);
5d5a0936 LV	245	kfree(piar);
	246	goto restart;
	247	}
	248	n = rb_next(n);
	249	}
5d5a0936 LV	250	}
	251
	252	/**
	253	* pci_addr_cache_remove_device - remove pci device from addr cache
	254	* @dev: device to remove
	255	*
	256	* Remove a device from the addr-cache tree.
	257	* This is potentially expensive, since it will walk
	258	* the tree multiple times (once per resource).
	259	* But so what; device removal doesn't need to be that fast.
	260	*/
	261	void pci_addr_cache_remove_device(struct pci_dev *dev)
	262	{
	263	unsigned long flags;
	264
	265	spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
	266	__pci_addr_cache_remove_device(dev);
	267	spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
	268	}
	269
	270	/**
	271	* pci_addr_cache_build - Build a cache of I/O addresses
	272	*
	273	* Build a cache of pci i/o addresses. This cache will be used to
	274	* find the pci device that corresponds to a given address.
	275	* This routine scans all pci busses to build the cache.
	276	* Must be run late in boot process, after the pci controllers
d6e05edc	277	* have been scanned for devices (after all device resources are known).
5d5a0936 LV	278	*/
	279	void __init pci_addr_cache_build(void)
	280	{
	281	struct device_node *dn;
	282	struct pci_dev *dev = NULL;
	283
	284	spin_lock_init(&pci_io_addr_cache_root.piar_lock);
	285
	286	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
	287	/* Ignore PCI bridges */
	288	if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE)
	289	continue;
	290
	291	pci_addr_cache_insert_device(dev);
	292
5d5a0936	293	dn = pci_device_to_OF_node(dev);
ccba051c NL	294	if (!dn)
ccba051c NL	295	continue;
821b537f LV	296	pci_dev_get (dev); /* matching put is in eeh_remove_device() */
821b537f LV	297	PCI_DN(dn)->pcidev = dev;
5d5a0936 LV	298	}
	299
	300	#ifdef DEBUG
	301	/* Verify tree built up above, echo back the list of addrs. */
	302	pci_addr_cache_print(&pci_io_addr_cache_root);
	303	#endif
	304	}
	305