1 /*
2 * direct.c - Low-level direct PCI config space access
3 */
4
5 #include <linux/pci.h>
6 #include <linux/init.h>
7 #include <linux/dmi.h>
8 #include "pci.h"
9
10 /*
11 * Functions for accessing PCI configuration space with type 1 accesses
12 */
13
14 #define PCI_CONF1_ADDRESS(bus, devfn, reg) \
15 (0x80000000 | (bus << 16) | (devfn << 8) | (reg & ~3))
16
17 static int pci_conf1_read(unsigned int seg, unsigned int bus,
18 unsigned int devfn, int reg, int len, u32 *value)
19 {
20 unsigned long flags;
21
22 if ((bus > 255) || (devfn > 255) || (reg > 255)) {
23 *value = -1;
24 return -EINVAL;
25 }
26
27 spin_lock_irqsave(&pci_config_lock, flags);
28
29 outl(PCI_CONF1_ADDRESS(bus, devfn, reg), 0xCF8);
30
31 switch (len) {
32 case 1:
33 *value = inb(0xCFC + (reg & 3));
34 break;
35 case 2:
36 *value = inw(0xCFC + (reg & 2));
37 break;
38 case 4:
39 *value = inl(0xCFC);
40 break;
41 }
42
43 spin_unlock_irqrestore(&pci_config_lock, flags);
44
45 return 0;
46 }
47
48 static int pci_conf1_write(unsigned int seg, unsigned int bus,
49 unsigned int devfn, int reg, int len, u32 value)
50 {
51 unsigned long flags;
52
53 if ((bus > 255) || (devfn > 255) || (reg > 255))
54 return -EINVAL;
55
56 spin_lock_irqsave(&pci_config_lock, flags);
57
58 outl(PCI_CONF1_ADDRESS(bus, devfn, reg), 0xCF8);
59
60 switch (len) {
61 case 1:
62 outb((u8)value, 0xCFC + (reg & 3));
63 break;
64 case 2:
65 outw((u16)value, 0xCFC + (reg & 2));
66 break;
67 case 4:
68 outl((u32)value, 0xCFC);
69 break;
70 }
71
72 spin_unlock_irqrestore(&pci_config_lock, flags);
73
74 return 0;
75 }
76
77 #undef PCI_CONF1_ADDRESS
78
79 struct pci_raw_ops pci_direct_conf1 = {
80 .read = pci_conf1_read,
81 .write = pci_conf1_write,
82 };
83
84
85 /*
86 * Functions for accessing PCI configuration space with type 2 accesses
87 */
88
89 #define PCI_CONF2_ADDRESS(dev, reg) (u16)(0xC000 | (dev << 8) | reg)
90
91 static int pci_conf2_read(unsigned int seg, unsigned int bus,
92 unsigned int devfn, int reg, int len, u32 *value)
93 {
94 unsigned long flags;
95 int dev, fn;
96
97 if ((bus > 255) || (devfn > 255) || (reg > 255)) {
98 *value = -1;
99 return -EINVAL;
100 }
101
102 dev = PCI_SLOT(devfn);
103 fn = PCI_FUNC(devfn);
104
105 if (dev & 0x10)
106 return PCIBIOS_DEVICE_NOT_FOUND;
107
108 spin_lock_irqsave(&pci_config_lock, flags);
109
110 outb((u8)(0xF0 | (fn << 1)), 0xCF8);
111 outb((u8)bus, 0xCFA);
112
113 switch (len) {
114 case 1:
115 *value = inb(PCI_CONF2_ADDRESS(dev, reg));
116 break;
117 case 2:
118 *value = inw(PCI_CONF2_ADDRESS(dev, reg));
119 break;
120 case 4:
121 *value = inl(PCI_CONF2_ADDRESS(dev, reg));
122 break;
123 }
124
125 outb(0, 0xCF8);
126
127 spin_unlock_irqrestore(&pci_config_lock, flags);
128
129 return 0;
130 }
131
132 static int pci_conf2_write(unsigned int seg, unsigned int bus,
133 unsigned int devfn, int reg, int len, u32 value)
134 {
135 unsigned long flags;
136 int dev, fn;
137
138 if ((bus > 255) || (devfn > 255) || (reg > 255))
139 return -EINVAL;
140
141 dev = PCI_SLOT(devfn);
142 fn = PCI_FUNC(devfn);
143
144 if (dev & 0x10)
145 return PCIBIOS_DEVICE_NOT_FOUND;
146
147 spin_lock_irqsave(&pci_config_lock, flags);
148
149 outb((u8)(0xF0 | (fn << 1)), 0xCF8);
150 outb((u8)bus, 0xCFA);
151
152 switch (len) {
153 case 1:
154 outb((u8)value, PCI_CONF2_ADDRESS(dev, reg));
155 break;
156 case 2:
157 outw((u16)value, PCI_CONF2_ADDRESS(dev, reg));
158 break;
159 case 4:
160 outl((u32)value, PCI_CONF2_ADDRESS(dev, reg));
161 break;
162 }
163
164 outb(0, 0xCF8);
165
166 spin_unlock_irqrestore(&pci_config_lock, flags);
167
168 return 0;
169 }
170
171 #undef PCI_CONF2_ADDRESS
172
173 static struct pci_raw_ops pci_direct_conf2 = {
174 .read = pci_conf2_read,
175 .write = pci_conf2_write,
176 };
177
178
179 /*
180 * Before we decide to use direct hardware access mechanisms, we try to do some
181 * trivial checks to ensure it at least _seems_ to be working -- we just test
182 * whether bus 00 contains a host bridge (this is similar to checking
183 * techniques used in XFree86, but ours should be more reliable since we
184 * attempt to make use of direct access hints provided by the PCI BIOS).
185 *
186 * This should be close to trivial, but it isn't, because there are buggy
187 * chipsets (yes, you guessed it, by Intel and Compaq) that have no class ID.
188 */
189 static int __init pci_sanity_check(struct pci_raw_ops *o)
190 {
191 u32 x = 0;
192 int devfn;
193
194 if (pci_probe & PCI_NO_CHECKS)
195 return 1;
196 /* Assume Type 1 works for newer systems.
197 This handles machines that don't have anything on PCI Bus 0. */
198 if (dmi_get_year(DMI_BIOS_DATE) >= 2001)
199 return 1;
200
201 for (devfn = 0; devfn < 0x100; devfn++) {
202 if (o->read(0, 0, devfn, PCI_CLASS_DEVICE, 2, &x))
203 continue;
204 if (x == PCI_CLASS_BRIDGE_HOST || x == PCI_CLASS_DISPLAY_VGA)
205 return 1;
206
207 if (o->read(0, 0, devfn, PCI_VENDOR_ID, 2, &x))
208 continue;
209 if (x == PCI_VENDOR_ID_INTEL || x == PCI_VENDOR_ID_COMPAQ)
210 return 1;
211 }
212
213 DBG(KERN_WARNING "PCI: Sanity check failed\n");
214 return 0;
215 }
216
217 static int __init pci_check_type1(void)
218 {
219 unsigned long flags;
220 unsigned int tmp;
221 int works = 0;
222
223 spin_lock_irqsave(&pci_config_lock, flags);
224
225 outb(0x01, 0xCFB);
226 tmp = inl(0xCF8);
227 outl(0x80000000, 0xCF8);
228
229 if (inl(0xCF8) == 0x80000000) {
230 spin_unlock_irqrestore(&pci_config_lock, flags);
231
232 if (pci_sanity_check(&pci_direct_conf1))
233 works = 1;
234
235 spin_lock_irqsave(&pci_config_lock, flags);
236 }
237 outl(tmp, 0xCF8);
238
239 spin_unlock_irqrestore(&pci_config_lock, flags);
240
241 return works;
242 }
243
244 static int __init pci_check_type2(void)
245 {
246 unsigned long flags;
247 int works = 0;
248
249 spin_lock_irqsave(&pci_config_lock, flags);
250
251 outb(0x00, 0xCFB);
252 outb(0x00, 0xCF8);
253 outb(0x00, 0xCFA);
254
255 if (inb(0xCF8) == 0x00 && inb(0xCFA) == 0x00) {
256 spin_unlock_irqrestore(&pci_config_lock, flags);
257
258 if (pci_sanity_check(&pci_direct_conf2))
259 works = 1;
260 } else
261 spin_unlock_irqrestore(&pci_config_lock, flags);
262
263 return works;
264 }
265
266 void __init pci_direct_init(int type)
267 {
268 if (type == 0)
269 return;
270 printk(KERN_INFO "PCI: Using configuration type %d\n", type);
271 if (type == 1)
272 raw_pci_ops = &pci_direct_conf1;
273 else
274 raw_pci_ops = &pci_direct_conf2;
275 }
276
277 int __init pci_direct_probe(void)
278 {
279 struct resource *region, *region2;
280
281 if ((pci_probe & PCI_PROBE_CONF1) == 0)
282 goto type2;
283 region = request_region(0xCF8, 8, "PCI conf1");
284 if (!region)
285 goto type2;
286
287 if (pci_check_type1())
288 return 1;
289 release_resource(region);
290
291 type2:
292 if ((pci_probe & PCI_PROBE_CONF2) == 0)
293 return 0;
294 region = request_region(0xCF8, 4, "PCI conf2");
295 if (!region)
296 return 0;
297 region2 = request_region(0xC000, 0x1000, "PCI conf2");
298 if (!region2)
299 goto fail2;
300
301 if (pci_check_type2()) {
302 printk(KERN_INFO "PCI: Using configuration type 2\n");
303 raw_pci_ops = &pci_direct_conf2;
304 return 2;
305 }
306
307 release_resource(region2);
308 fail2:
309 release_resource(region);
310 return 0;
311 }
312
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