// SPDX-License-Identifier: GPL-2.0-or-later/* * 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 */ #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/debugfs.h>#include <asm/ppc-pci.h>  /** * DOC: Overview * * 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.  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_info("PCI: %s addr range %d [%pap-%pap]: %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; 	pr_debug("PIAR: insert range=[%pap:%pap] dev=%s\n",		 &alo, &ahi, pci_name(dev)); 	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) {			pr_debug("PIAR: remove range=[%pap:%pap] dev=%s\n",				 &piar->addr_lo, &piar->addr_hi, pci_name(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);	}} static int eeh_addr_cache_show(struct seq_file *s, void *v){	struct pci_io_addr_range *piar;	struct rb_node *n; 	spin_lock(&pci_io_addr_cache_root.piar_lock);	for (n = rb_first(&pci_io_addr_cache_root.rb_root); n; n = rb_next(n)) {		piar = rb_entry(n, struct pci_io_addr_range, rb_node); 		seq_printf(s, "%s addr range [%pap-%pap]: %s\n",		       (piar->flags & IORESOURCE_IO) ? "i/o" : "mem",		       &piar->addr_lo, &piar->addr_hi, pci_name(piar->pcidev));	}	spin_unlock(&pci_io_addr_cache_root.piar_lock); 	return 0;}DEFINE_SHOW_ATTRIBUTE(eeh_addr_cache); void eeh_cache_debugfs_init(void){	debugfs_create_file_unsafe("eeh_address_cache", 0400,			powerpc_debugfs_root, NULL,			&eeh_addr_cache_fops);}