1 /*
2 * The PCI Library -- Capabilities
3 *
4 * Copyright (c) 2008 Martin Mares <[email protected]>
5 *
6 * Can be freely distributed and used under the terms of the GNU GPL v2+.
7 *
8 * SPDX-License-Identifier: GPL-2.0-or-later
9 */
10
11 #include <string.h>
12
13 #include "internal.h"
14
15 static void
pci_add_cap(struct pci_dev * d,unsigned int addr,unsigned int id,unsigned int type)16 pci_add_cap(struct pci_dev *d, unsigned int addr, unsigned int id, unsigned int type)
17 {
18 struct pci_cap *cap = pci_malloc(d->access, sizeof(*cap));
19
20 if (d->last_cap)
21 d->last_cap->next = cap;
22 else
23 d->first_cap = cap;
24 d->last_cap = cap;
25 cap->next = NULL;
26 cap->addr = addr;
27 cap->id = id;
28 cap->type = type;
29 d->access->debug("%04x:%02x:%02x.%d: Found capability %04x of type %d at %04x\n",
30 d->domain, d->bus, d->dev, d->func, id, type, addr);
31 }
32
33 static void
pci_scan_trad_caps(struct pci_dev * d)34 pci_scan_trad_caps(struct pci_dev *d)
35 {
36 word status = pci_read_word(d, PCI_STATUS);
37 byte been_there[256];
38 int where;
39
40 if (!(status & PCI_STATUS_CAP_LIST))
41 return;
42
43 memset(been_there, 0, 256);
44 where = pci_read_byte(d, PCI_CAPABILITY_LIST) & ~3;
45 while (where)
46 {
47 byte id = pci_read_byte(d, where + PCI_CAP_LIST_ID);
48 byte next = pci_read_byte(d, where + PCI_CAP_LIST_NEXT) & ~3;
49 if (been_there[where]++)
50 break;
51 if (id == 0xff)
52 break;
53 pci_add_cap(d, where, id, PCI_CAP_NORMAL);
54 where = next;
55 }
56 }
57
58 static void
pci_scan_ext_caps(struct pci_dev * d)59 pci_scan_ext_caps(struct pci_dev *d)
60 {
61 byte been_there[0x1000];
62 int where = 0x100;
63
64 if (!pci_find_cap(d, PCI_CAP_ID_EXP, PCI_CAP_NORMAL))
65 return;
66
67 memset(been_there, 0, 0x1000);
68 do
69 {
70 u32 header;
71 int id;
72
73 header = pci_read_long(d, where);
74 if (!header || header == 0xffffffff)
75 break;
76 id = header & 0xffff;
77 if (been_there[where]++)
78 break;
79 pci_add_cap(d, where, id, PCI_CAP_EXTENDED);
80 where = (header >> 20) & ~3;
81 }
82 while (where);
83 }
84
85 void
pci_scan_caps(struct pci_dev * d,unsigned int want_fields)86 pci_scan_caps(struct pci_dev *d, unsigned int want_fields)
87 {
88 if (want_fields & PCI_FILL_EXT_CAPS)
89 want_fields |= PCI_FILL_CAPS;
90
91 if (want_fill(d, want_fields, PCI_FILL_CAPS))
92 pci_scan_trad_caps(d);
93 if (want_fill(d, want_fields, PCI_FILL_EXT_CAPS))
94 pci_scan_ext_caps(d);
95 }
96
97 void
pci_free_caps(struct pci_dev * d)98 pci_free_caps(struct pci_dev *d)
99 {
100 struct pci_cap *cap;
101
102 while (cap = d->first_cap)
103 {
104 d->first_cap = cap->next;
105 pci_mfree(cap);
106 }
107 }
108
109 struct pci_cap *
pci_find_cap(struct pci_dev * d,unsigned int id,unsigned int type)110 pci_find_cap(struct pci_dev *d, unsigned int id, unsigned int type)
111 {
112 return pci_find_cap_nr(d, id, type, NULL);
113 }
114
115 /**
116 * Finds a particular capability of a device
117 *
118 * To select one capability if there are more than one with the same id, you
119 * can provide a pointer to an unsigned int that contains the index which you
120 * want as cap_number. If you don't care and are fine with the first one you
121 * can supply NULL. The cap_number will be replaced by the actual number
122 * of capabilities with that id.
123 */
124 struct pci_cap *
pci_find_cap_nr(struct pci_dev * d,unsigned int id,unsigned int type,unsigned int * cap_number)125 pci_find_cap_nr(struct pci_dev *d, unsigned int id, unsigned int type,
126 unsigned int *cap_number)
127 {
128 struct pci_cap *c;
129 struct pci_cap *found = NULL;
130 unsigned int target = (cap_number ? *cap_number : 0);
131 unsigned int index = 0;
132
133 pci_fill_info_v313(d, ((type == PCI_CAP_NORMAL) ? PCI_FILL_CAPS : PCI_FILL_EXT_CAPS));
134
135 for (c=d->first_cap; c; c=c->next)
136 {
137 if (c->type == type && c->id == id)
138 {
139 if (target == index)
140 found = c;
141 index++;
142 }
143 }
144
145 if (cap_number)
146 *cap_number = index;
147 return found;
148 }
149