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Diffstat (limited to 'arch/powerpc/kernel/eeh_cache.c')
| -rw-r--r-- | arch/powerpc/kernel/eeh_cache.c | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/eeh_cache.c b/arch/powerpc/kernel/eeh_cache.c new file mode 100644 index 000000000..2f9dbf8ad --- /dev/null +++ b/arch/powerpc/kernel/eeh_cache.c @@ -0,0 +1,288 @@ +// 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 <linux/debugfs.h> +#include <asm/pci-bridge.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; + + eeh_edev_dbg(piar->edev, "PIAR: insert range=[%pap:%pap]\n", + &alo, &ahi); + + 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 eeh_dev *edev; + int i; + + edev = pci_dev_to_eeh_dev(dev); + 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) { + eeh_edev_dbg(piar->edev, "PIAR: remove range=[%pap:%pap]\n", + &piar->addr_lo, &piar->addr_hi); + 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_init - Initialize a cache of I/O addresses + * + * Initialize a cache of pci i/o addresses. This cache will be used to + * find the pci device that corresponds to a given address. + */ +void eeh_addr_cache_init(void) +{ + spin_lock_init(&pci_io_addr_cache_root.piar_lock); +} + +static int eeh_addr_cache_show(struct seq_file *s, void *v) +{ + struct pci_io_addr_range *piar; + struct rb_node *n; + unsigned long flags; + + spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags); + 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_irqrestore(&pci_io_addr_cache_root.piar_lock, flags); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(eeh_addr_cache); + +void __init eeh_cache_debugfs_init(void) +{ + debugfs_create_file_unsafe("eeh_address_cache", 0400, + arch_debugfs_dir, NULL, + &eeh_addr_cache_fops); +} |