1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * PCI address cache; allows the lookup of PCI devices based on I/O address
5 * Copyright IBM Corporation 2004
6 * Copyright Linas Vepstas <linas@austin.ibm.com> 2004
9 #include <linux/list.h>
10 #include <linux/pci.h>
11 #include <linux/rbtree.h>
12 #include <linux/slab.h>
13 #include <linux/spinlock.h>
14 #include <linux/atomic.h>
15 #include <asm/pci-bridge.h>
16 #include <asm/debugfs.h>
17 #include <asm/ppc-pci.h>
23 * The pci address cache subsystem. This subsystem places
24 * PCI device address resources into a red-black tree, sorted
25 * according to the address range, so that given only an i/o
26 * address, the corresponding PCI device can be **quickly**
27 * found. It is safe to perform an address lookup in an interrupt
28 * context; this ability is an important feature.
30 * Currently, the only customer of this code is the EEH subsystem;
31 * thus, this code has been somewhat tailored to suit EEH better.
32 * In particular, the cache does *not* hold the addresses of devices
33 * for which EEH is not enabled.
35 * (Implementation Note: The RB tree seems to be better/faster
36 * than any hash algo I could think of for this problem, even
37 * with the penalty of slow pointer chases for d-cache misses).
40 struct pci_io_addr_range
{
41 struct rb_node rb_node
;
42 resource_size_t addr_lo
;
43 resource_size_t addr_hi
;
45 struct pci_dev
*pcidev
;
49 static struct pci_io_addr_cache
{
50 struct rb_root rb_root
;
52 } pci_io_addr_cache_root
;
54 static inline struct eeh_dev
*__eeh_addr_cache_get_device(unsigned long addr
)
56 struct rb_node
*n
= pci_io_addr_cache_root
.rb_root
.rb_node
;
59 struct pci_io_addr_range
*piar
;
60 piar
= rb_entry(n
, struct pci_io_addr_range
, rb_node
);
62 if (addr
< piar
->addr_lo
)
64 else if (addr
> piar
->addr_hi
)
74 * eeh_addr_cache_get_dev - Get device, given only address
75 * @addr: mmio (PIO) phys address or i/o port number
77 * Given an mmio phys address, or a port number, find a pci device
78 * that implements this address. I/O port numbers are assumed to be offset
79 * from zero (that is, they do *not* have pci_io_addr added in).
80 * It is safe to call this function within an interrupt.
82 struct eeh_dev
*eeh_addr_cache_get_dev(unsigned long addr
)
87 spin_lock_irqsave(&pci_io_addr_cache_root
.piar_lock
, flags
);
88 edev
= __eeh_addr_cache_get_device(addr
);
89 spin_unlock_irqrestore(&pci_io_addr_cache_root
.piar_lock
, flags
);
95 * Handy-dandy debug print routine, does nothing more
96 * than print out the contents of our addr cache.
98 static void eeh_addr_cache_print(struct pci_io_addr_cache
*cache
)
103 n
= rb_first(&cache
->rb_root
);
105 struct pci_io_addr_range
*piar
;
106 piar
= rb_entry(n
, struct pci_io_addr_range
, rb_node
);
107 pr_info("PCI: %s addr range %d [%pap-%pap]: %s\n",
108 (piar
->flags
& IORESOURCE_IO
) ? "i/o" : "mem", cnt
,
109 &piar
->addr_lo
, &piar
->addr_hi
, pci_name(piar
->pcidev
));
116 /* Insert address range into the rb tree. */
117 static struct pci_io_addr_range
*
118 eeh_addr_cache_insert(struct pci_dev
*dev
, resource_size_t alo
,
119 resource_size_t ahi
, unsigned long flags
)
121 struct rb_node
**p
= &pci_io_addr_cache_root
.rb_root
.rb_node
;
122 struct rb_node
*parent
= NULL
;
123 struct pci_io_addr_range
*piar
;
125 /* Walk tree, find a place to insert into tree */
128 piar
= rb_entry(parent
, struct pci_io_addr_range
, rb_node
);
129 if (ahi
< piar
->addr_lo
) {
130 p
= &parent
->rb_left
;
131 } else if (alo
> piar
->addr_hi
) {
132 p
= &parent
->rb_right
;
134 if (dev
!= piar
->pcidev
||
135 alo
!= piar
->addr_lo
|| ahi
!= piar
->addr_hi
) {
136 pr_warn("PIAR: overlapping address range\n");
141 piar
= kzalloc(sizeof(struct pci_io_addr_range
), GFP_ATOMIC
);
147 piar
->edev
= pci_dev_to_eeh_dev(dev
);
151 eeh_edev_dbg(piar
->edev
, "PIAR: insert range=[%pap:%pap]\n",
154 rb_link_node(&piar
->rb_node
, parent
, p
);
155 rb_insert_color(&piar
->rb_node
, &pci_io_addr_cache_root
.rb_root
);
160 static void __eeh_addr_cache_insert_dev(struct pci_dev
*dev
)
162 struct eeh_dev
*edev
;
165 edev
= pci_dev_to_eeh_dev(dev
);
167 pr_warn("PCI: no EEH dev found for %s\n",
172 /* Skip any devices for which EEH is not enabled. */
174 dev_dbg(&dev
->dev
, "EEH: Skip building address cache\n");
179 * Walk resources on this device, poke the first 7 (6 normal BAR and 1
180 * ROM BAR) into the tree.
182 for (i
= 0; i
<= PCI_ROM_RESOURCE
; i
++) {
183 resource_size_t start
= pci_resource_start(dev
,i
);
184 resource_size_t end
= pci_resource_end(dev
,i
);
185 unsigned long flags
= pci_resource_flags(dev
,i
);
187 /* We are interested only bus addresses, not dma or other stuff */
188 if (0 == (flags
& (IORESOURCE_IO
| IORESOURCE_MEM
)))
190 if (start
== 0 || ~start
== 0 || end
== 0 || ~end
== 0)
192 eeh_addr_cache_insert(dev
, start
, end
, flags
);
197 * eeh_addr_cache_insert_dev - Add a device to the address cache
198 * @dev: PCI device whose I/O addresses we are interested in.
200 * In order to support the fast lookup of devices based on addresses,
201 * we maintain a cache of devices that can be quickly searched.
202 * This routine adds a device to that cache.
204 void eeh_addr_cache_insert_dev(struct pci_dev
*dev
)
208 spin_lock_irqsave(&pci_io_addr_cache_root
.piar_lock
, flags
);
209 __eeh_addr_cache_insert_dev(dev
);
210 spin_unlock_irqrestore(&pci_io_addr_cache_root
.piar_lock
, flags
);
213 static inline void __eeh_addr_cache_rmv_dev(struct pci_dev
*dev
)
218 n
= rb_first(&pci_io_addr_cache_root
.rb_root
);
220 struct pci_io_addr_range
*piar
;
221 piar
= rb_entry(n
, struct pci_io_addr_range
, rb_node
);
223 if (piar
->pcidev
== dev
) {
224 eeh_edev_dbg(piar
->edev
, "PIAR: remove range=[%pap:%pap]\n",
225 &piar
->addr_lo
, &piar
->addr_hi
);
226 rb_erase(n
, &pci_io_addr_cache_root
.rb_root
);
235 * eeh_addr_cache_rmv_dev - remove pci device from addr cache
236 * @dev: device to remove
238 * Remove a device from the addr-cache tree.
239 * This is potentially expensive, since it will walk
240 * the tree multiple times (once per resource).
241 * But so what; device removal doesn't need to be that fast.
243 void eeh_addr_cache_rmv_dev(struct pci_dev
*dev
)
247 spin_lock_irqsave(&pci_io_addr_cache_root
.piar_lock
, flags
);
248 __eeh_addr_cache_rmv_dev(dev
);
249 spin_unlock_irqrestore(&pci_io_addr_cache_root
.piar_lock
, flags
);
253 * eeh_addr_cache_init - Initialize a cache of I/O addresses
255 * Initialize a cache of pci i/o addresses. This cache will be used to
256 * find the pci device that corresponds to a given address.
258 void eeh_addr_cache_init(void)
260 spin_lock_init(&pci_io_addr_cache_root
.piar_lock
);
263 static int eeh_addr_cache_show(struct seq_file
*s
, void *v
)
265 struct pci_io_addr_range
*piar
;
268 spin_lock(&pci_io_addr_cache_root
.piar_lock
);
269 for (n
= rb_first(&pci_io_addr_cache_root
.rb_root
); n
; n
= rb_next(n
)) {
270 piar
= rb_entry(n
, struct pci_io_addr_range
, rb_node
);
272 seq_printf(s
, "%s addr range [%pap-%pap]: %s\n",
273 (piar
->flags
& IORESOURCE_IO
) ? "i/o" : "mem",
274 &piar
->addr_lo
, &piar
->addr_hi
, pci_name(piar
->pcidev
));
276 spin_unlock(&pci_io_addr_cache_root
.piar_lock
);
280 DEFINE_SHOW_ATTRIBUTE(eeh_addr_cache
);
282 void eeh_cache_debugfs_init(void)
284 debugfs_create_file_unsafe("eeh_address_cache", 0400,
285 powerpc_debugfs_root
, NULL
,
286 &eeh_addr_cache_fops
);