aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/pci/pcbios.c
blob: 1c975cc9839e0617e3b08d245e91277ec10450e3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
/*
 * BIOS32 and PCI BIOS handling.
 */

#include <linux/pci.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <asm/pci_x86.h>
#include <asm/pci-functions.h>

/* BIOS32 signature: "_32_" */
#define BIOS32_SIGNATURE	(('_' << 0) + ('3' << 8) + ('2' << 16) + ('_' << 24))

/* PCI signature: "PCI " */
#define PCI_SIGNATURE		(('P' << 0) + ('C' << 8) + ('I' << 16) + (' ' << 24))

/* PCI service signature: "$PCI" */
#define PCI_SERVICE		(('$' << 0) + ('P' << 8) + ('C' << 16) + ('I' << 24))

/* PCI BIOS hardware mechanism flags */
#define PCIBIOS_HW_TYPE1		0x01
#define PCIBIOS_HW_TYPE2		0x02
#define PCIBIOS_HW_TYPE1_SPEC		0x10
#define PCIBIOS_HW_TYPE2_SPEC		0x20

/*
 * This is the standard structure used to identify the entry point
 * to the BIOS32 Service Directory, as documented in
 * 	Standard BIOS 32-bit Service Directory Proposal
 * 	Revision 0.4 May 24, 1993
 * 	Phoenix Technologies Ltd.
 *	Norwood, MA
 * and the PCI BIOS specification.
 */

union bios32 {
	struct {
		unsigned long signature;	/* _32_ */
		unsigned long entry;		/* 32 bit physical address */
		unsigned char revision;		/* Revision level, 0 */
		unsigned char length;		/* Length in paragraphs should be 01 */
		unsigned char checksum;		/* All bytes must add up to zero */
		unsigned char reserved[5]; 	/* Must be zero */
	} fields;
	char chars[16];
};

/*
 * Physical address of the service directory.  I don't know if we're
 * allowed to have more than one of these or not, so just in case
 * we'll make pcibios_present() take a memory start parameter and store
 * the array there.
 */

static struct {
	unsigned long address;
	unsigned short segment;
} bios32_indirect = { 0, __KERNEL_CS };

/*
 * Returns the entry point for the given service, NULL on error
 */

static unsigned long bios32_service(unsigned long service)
{
	unsigned char return_code;	/* %al */
	unsigned long address;		/* %ebx */
	unsigned long length;		/* %ecx */
	unsigned long entry;		/* %edx */
	unsigned long flags;

	local_irq_save(flags);
	__asm__("lcall *(%%edi); cld"
		: "=a" (return_code),
		  "=b" (address),
		  "=c" (length),
		  "=d" (entry)
		: "0" (service),
		  "1" (0),
		  "D" (&bios32_indirect));
	local_irq_restore(flags);

	switch (return_code) {
		case 0:
			return address + entry;
		case 0x80:	/* Not present */
			printk(KERN_WARNING "bios32_service(0x%lx): not present\n", service);
			return 0;
		default: /* Shouldn't happen */
			printk(KERN_WARNING "bios32_service(0x%lx): returned 0x%x -- BIOS bug!\n",
				service, return_code);
			return 0;
	}
}

static struct {
	unsigned long address;
	unsigned short segment;
} pci_indirect = { 0, __KERNEL_CS };

static int pci_bios_present;

static int __devinit check_pcibios(void)
{
	u32 signature, eax, ebx, ecx;
	u8 status, major_ver, minor_ver, hw_mech;
	unsigned long flags, pcibios_entry;

	if ((pcibios_entry = bios32_service(PCI_SERVICE))) {
		pci_indirect.address = pcibios_entry + PAGE_OFFSET;

		local_irq_save(flags);
		__asm__(
			"lcall *(%%edi); cld\n\t"
			"jc 1f\n\t"
			"xor %%ah, %%ah\n"
			"1:"
			: "=d" (signature),
			  "=a" (eax),
			  "=b" (ebx),
			  "=c" (ecx)
			: "1" (PCIBIOS_PCI_BIOS_PRESENT),
			  "D" (&pci_indirect)
			: "memory");
		local_irq_restore(flags);

		status = (eax >> 8) & 0xff;
		hw_mech = eax & 0xff;
		major_ver = (ebx >> 8) & 0xff;
		minor_ver = ebx & 0xff;
		if (pcibios_last_bus < 0)
			pcibios_last_bus = ecx & 0xff;
		DBG("PCI: BIOS probe returned s=%02x hw=%02x ver=%02x.%02x l=%02x\n",
			status, hw_mech, major_ver, minor_ver, pcibios_last_bus);
		if (status || signature != PCI_SIGNATURE) {
			printk (KERN_ERR "PCI: BIOS BUG #%x[%08x] found\n",
				status, signature);
			return 0;
		}
		printk(KERN_INFO "PCI: PCI BIOS revision %x.%02x entry at 0x%lx, last bus=%d\n",
			major_ver, minor_ver, pcibios_entry, pcibios_last_bus);
#ifdef CONFIG_PCI_DIRECT
		if (!(hw_mech & PCIBIOS_HW_TYPE1))
			pci_probe &= ~PCI_PROBE_CONF1;
		if (!(hw_mech & PCIBIOS_HW_TYPE2))
			pci_probe &= ~PCI_PROBE_CONF2;
#endif
		return 1;
	}
	return 0;
}

static int pci_bios_read(unsigned int seg, unsigned int bus,
			 unsigned int devfn, int reg, int len, u32 *value)
{
	unsigned long result = 0;
	unsigned long flags;
	unsigned long bx = (bus << 8) | devfn;

	if (!value || (bus > 255) || (devfn > 255) || (reg > 255))
		return -EINVAL;

	spin_lock_irqsave(&pci_config_lock, flags);

	switch (len) {
	case 1:
		__asm__("lcall *(%%esi); cld\n\t"
			"jc 1f\n\t"
			"xor %%ah, %%ah\n"
			"1:"
			: "=c" (*value),
			  "=a" (result)
			: "1" (PCIBIOS_READ_CONFIG_BYTE),
			  "b" (bx),
			  "D" ((long)reg),
			  "S" (&pci_indirect));
		/*
		 * Zero-extend the result beyond 8 bits, do not trust the
		 * BIOS having done it:
		 */
		*value &= 0xff;
		break;
	case 2:
		__asm__("lcall *(%%esi); cld\n\t"
			"jc 1f\n\t"
			"xor %%ah, %%ah\n"
			"1:"
			: "=c" (*value),
			  "=a" (result)
			: "1" (PCIBIOS_READ_CONFIG_WORD),
			  "b" (bx),
			  "D" ((long)reg),
			  "S" (&pci_indirect));
		/*
		 * Zero-extend the result beyond 16 bits, do not trust the
		 * BIOS having done it:
		 */
		*value &= 0xffff;
		break;
	case 4:
		__asm__("lcall *(%%esi); cld\n\t"
			"jc 1f\n\t"
			"xor %%ah, %%ah\n"
			"1:"
			: "=c" (*value),
			  "=a" (result)
			: "1" (PCIBIOS_READ_CONFIG_DWORD),
			  "b" (bx),
			  "D" ((long)reg),
			  "S" (&pci_indirect));
		break;
	}

	spin_unlock_irqrestore(&pci_config_lock, flags);

	return (int)((result & 0xff00) >> 8);
}

static int pci_bios_write(unsigned int seg, unsigned int bus,
			  unsigned int devfn, int reg, int len, u32 value)
{
	unsigned long result = 0;
	unsigned long flags;
	unsigned long bx = (bus << 8) | devfn;

	if ((bus > 255) || (devfn > 255) || (reg > 255)) 
		return -EINVAL;

	spin_lock_irqsave(&pci_config_lock, flags);

	switch (len) {
	case 1:
		__asm__("lcall *(%%esi); cld\n\t"
			"jc 1f\n\t"
			"xor %%ah, %%ah\n"
			"1:"
			: "=a" (result)
			: "0" (PCIBIOS_WRITE_CONFIG_BYTE),
			  "c" (value),
			  "b" (bx),
			  "D" ((long)reg),
			  "S" (&pci_indirect));
		break;
	case 2:
		__asm__("lcall *(%%esi); cld\n\t"
			"jc 1f\n\t"
			"xor %%ah, %%ah\n"
			"1:"
			: "=a" (result)
			: "0" (PCIBIOS_WRITE_CONFIG_WORD),
			  "c" (value),
			  "b" (bx),
			  "D" ((long)reg),
			  "S" (&pci_indirect));
		break;
	case 4:
		__asm__("lcall *(%%esi); cld\n\t"
			"jc 1f\n\t"
			"xor %%ah, %%ah\n"
			"1:"
			: "=a" (result)
			: "0" (PCIBIOS_WRITE_CONFIG_DWORD),
			  "c" (value),
			  "b" (bx),
			  "D" ((long)reg),
			  "S" (&pci_indirect));
		break;
	}

	spin_unlock_irqrestore(&pci_config_lock, flags);

	return (int)((result & 0xff00) >> 8);
}


/*
 * Function table for BIOS32 access
 */

static struct pci_raw_ops pci_bios_access = {
	.read =		pci_bios_read,
	.write =	pci_bios_write
};

/*
 * Try to find PCI BIOS.
 */

static struct pci_raw_ops * __devinit pci_find_bios(void)
{
	union bios32 *check;
	unsigned char sum;
	int i, length;

	/*
	 * Follow the standard procedure for locating the BIOS32 Service
	 * directory by scanning the permissible address range from
	 * 0xe0000 through 0xfffff for a valid BIOS32 structure.
	 */

	for (check = (union bios32 *) __va(0xe0000);
	     check <= (union bios32 *) __va(0xffff0);
	     ++check) {
		long sig;
		if (probe_kernel_address(&check->fields.signature, sig))
			continue;

		if (check->fields.signature != BIOS32_SIGNATURE)
			continue;
		length = check->fields.length * 16;
		if (!length)
			continue;
		sum = 0;
		for (i = 0; i < length ; ++i)
			sum += check->chars[i];
		if (sum != 0)
			continue;
		if (check->fields.revision != 0) {
			printk("PCI: unsupported BIOS32 revision %d at 0x%p\n",
				check->fields.revision, check);
			continue;
		}
		DBG("PCI: BIOS32 Service Directory structure at 0x%p\n", check);
		if (check->fields.entry >= 0x100000) {
			printk("PCI: BIOS32 entry (0x%p) in high memory, "
					"cannot use.\n", check);
			return NULL;
		} else {
			unsigned long bios32_entry = check->fields.entry;
			DBG("PCI: BIOS32 Service Directory entry at 0x%lx\n",
					bios32_entry);
			bios32_indirect.address = bios32_entry + PAGE_OFFSET;
			if (check_pcibios())
				return &pci_bios_access;
		}
		break;	/* Hopefully more than one BIOS32 cannot happen... */
	}

	return NULL;
}

/*
 *  BIOS Functions for IRQ Routing
 */

struct irq_routing_options {
	u16 size;
	struct irq_info *table;
	u16 segment;
} __attribute__((packed));

struct irq_routing_table * pcibios_get_irq_routing_table(void)
{
	struct irq_routing_options opt;
	struct irq_routing_table *rt = NULL;
	int ret, map;
	unsigned long page;

	if (!pci_bios_present)
		return NULL;
	page = __get_free_page(GFP_KERNEL);
	if (!page)
		return NULL;
	opt.table = (struct irq_info *) page;
	opt.size = PAGE_SIZE;
	opt.segment = __KERNEL_DS;

	DBG("PCI: Fetching IRQ routing table... ");
	__asm__("push %%es\n\t"
		"push %%ds\n\t"
		"pop  %%es\n\t"
		"lcall *(%%esi); cld\n\t"
		"pop %%es\n\t"
		"jc 1f\n\t"
		"xor %%ah, %%ah\n"
		"1:"
		: "=a" (ret),
		  "=b" (map),
		  "=m" (opt)
		: "0" (PCIBIOS_GET_ROUTING_OPTIONS),
		  "1" (0),
		  "D" ((long) &opt),
		  "S" (&pci_indirect),
		  "m" (opt)
		: "memory");
	DBG("OK  ret=%d, size=%d, map=%x\n", ret, opt.size, map);
	if (ret & 0xff00)
		printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", (ret >> 8) & 0xff);
	else if (opt.size) {
		rt = kmalloc(sizeof(struct irq_routing_table) + opt.size, GFP_KERNEL);
		if (rt) {
			memset(rt, 0, sizeof(struct irq_routing_table));
			rt->size = opt.size + sizeof(struct irq_routing_table);
			rt->exclusive_irqs = map;
			memcpy(rt->slots, (void *) page, opt.size);
			printk(KERN_INFO "PCI: Using BIOS Interrupt Routing Table\n");
		}
	}
	free_page(page);
	return rt;
}
EXPORT_SYMBOL(pcibios_get_irq_routing_table);

int pcibios_set_irq_routing(struct pci_dev *dev, int pin, int irq)
{
	int ret;

	__asm__("lcall *(%%esi); cld\n\t"
		"jc 1f\n\t"
		"xor %%ah, %%ah\n"
		"1:"
		: "=a" (ret)
		: "0" (PCIBIOS_SET_PCI_HW_INT),
		  "b" ((dev->bus->number << 8) | dev->devfn),
		  "c" ((irq << 8) | (pin + 10)),
		  "S" (&pci_indirect));
	return !(ret & 0xff00);
}
EXPORT_SYMBOL(pcibios_set_irq_routing);

void __init pci_pcbios_init(void)
{
	if ((pci_probe & PCI_PROBE_BIOS) 
		&& ((raw_pci_ops = pci_find_bios()))) {
		pci_bios_present = 1;
	}
}