xref: /linux/drivers/pnp/pnpbios/core.c (revision 0be3ff0c) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * pnpbios -- PnP BIOS driver
4  *
5  * This driver provides access to Plug-'n'-Play services provided by
6  * the PnP BIOS firmware, described in the following documents:
7  *   Plug and Play BIOS Specification, Version 1.0A, 5 May 1994
8  *   Plug and Play BIOS Clarification Paper, 6 October 1994
9  *     Compaq Computer Corporation, Phoenix Technologies Ltd., Intel Corp.
10  *
11  * Originally (C) 1998 Christian Schmidt <schmidt@digadd.de>
12  * Modifications (C) 1998 Tom Lees <tom@lpsg.demon.co.uk>
13  * Minor reorganizations by David Hinds <dahinds@users.sourceforge.net>
14  * Further modifications (C) 2001, 2002 by:
15  *   Alan Cox <alan@redhat.com>
16  *   Thomas Hood
17  *   Brian Gerst <bgerst@didntduck.org>
18  *
19  * Ported to the PnP Layer and several additional improvements (C) 2002
20  * by Adam Belay <ambx1@neo.rr.com>
21  */
22 
23 /* Change Log
24  *
25  * Adam Belay - <ambx1@neo.rr.com> - March 16, 2003
26  * rev 1.01	Only call pnp_bios_dev_node_info once
27  *		Added pnpbios_print_status
28  *		Added several new error messages and info messages
29  *		Added pnpbios_interface_attach_device
30  *		integrated core and proc init system
31  *		Introduced PNPMODE flags
32  *		Removed some useless includes
33  */
34 
35 #include <linux/types.h>
36 #include <linux/init.h>
37 #include <linux/linkage.h>
38 #include <linux/kernel.h>
39 #include <linux/device.h>
40 #include <linux/pnp.h>
41 #include <linux/mm.h>
42 #include <linux/smp.h>
43 #include <linux/slab.h>
44 #include <linux/completion.h>
45 #include <linux/spinlock.h>
46 #include <linux/dmi.h>
47 #include <linux/delay.h>
48 #include <linux/acpi.h>
49 #include <linux/freezer.h>
50 #include <linux/kmod.h>
51 #include <linux/kthread.h>
52 
53 #include <asm/page.h>
54 #include <asm/desc.h>
55 #include <asm/byteorder.h>
56 
57 #include "../base.h"
58 #include "pnpbios.h"
59 
60 /*
61  *
62  * PnP BIOS INTERFACE
63  *
64  */
65 
66 static union pnp_bios_install_struct *pnp_bios_install = NULL;
67 
68 int pnp_bios_present(void)
69 {
70 	return (pnp_bios_install != NULL);
71 }
72 
73 struct pnp_dev_node_info node_info;
74 
75 /*
76  *
77  * DOCKING FUNCTIONS
78  *
79  */
80 
81 static struct completion unload_sem;
82 
83 /*
84  * (Much of this belongs in a shared routine somewhere)
85  */
86 static int pnp_dock_event(int dock, struct pnp_docking_station_info *info)
87 {
88 	static char const sbin_pnpbios[] = "/sbin/pnpbios";
89 	char *argv[3], **envp, *buf, *scratch;
90 	int i = 0, value;
91 
92 	if (!(envp = kcalloc(20, sizeof(char *), GFP_KERNEL)))
93 		return -ENOMEM;
94 	if (!(buf = kzalloc(256, GFP_KERNEL))) {
95 		kfree(envp);
96 		return -ENOMEM;
97 	}
98 
99 	/* FIXME: if there are actual users of this, it should be
100 	 * integrated into the driver core and use the usual infrastructure
101 	 * like sysfs and uevents
102 	 */
103 	argv[0] = (char *)sbin_pnpbios;
104 	argv[1] = "dock";
105 	argv[2] = NULL;
106 
107 	/* minimal command environment */
108 	envp[i++] = "HOME=/";
109 	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
110 
111 #ifdef	DEBUG
112 	/* hint that policy agent should enter no-stdout debug mode */
113 	envp[i++] = "DEBUG=kernel";
114 #endif
115 	/* extensible set of named bus-specific parameters,
116 	 * supporting multiple driver selection algorithms.
117 	 */
118 	scratch = buf;
119 
120 	/* action:  add, remove */
121 	envp[i++] = scratch;
122 	scratch += sprintf(scratch, "ACTION=%s", dock ? "add" : "remove") + 1;
123 
124 	/* Report the ident for the dock */
125 	envp[i++] = scratch;
126 	scratch += sprintf(scratch, "DOCK=%x/%x/%x",
127 			   info->location_id, info->serial, info->capabilities);
128 	envp[i] = NULL;
129 
130 	value = call_usermodehelper(sbin_pnpbios, argv, envp, UMH_WAIT_EXEC);
131 	kfree(buf);
132 	kfree(envp);
133 	return 0;
134 }
135 
136 /*
137  * Poll the PnP docking at regular intervals
138  */
139 static int pnp_dock_thread(void *unused)
140 {
141 	static struct pnp_docking_station_info now;
142 	int docked = -1, d = 0;
143 
144 	set_freezable();
145 	while (1) {
146 		int status;
147 
148 		/*
149 		 * Poll every 2 seconds
150 		 */
151 		msleep_interruptible(2000);
152 
153 		if (try_to_freeze())
154 			continue;
155 
156 		status = pnp_bios_dock_station_info(&now);
157 
158 		switch (status) {
159 			/*
160 			 * No dock to manage
161 			 */
162 		case PNP_FUNCTION_NOT_SUPPORTED:
163 			kthread_complete_and_exit(&unload_sem, 0);
164 		case PNP_SYSTEM_NOT_DOCKED:
165 			d = 0;
166 			break;
167 		case PNP_SUCCESS:
168 			d = 1;
169 			break;
170 		default:
171 			pnpbios_print_status("pnp_dock_thread", status);
172 			printk(KERN_WARNING "PnPBIOS: disabling dock monitoring.\n");
173 			kthread_complete_and_exit(&unload_sem, 0);
174 		}
175 		if (d != docked) {
176 			if (pnp_dock_event(d, &now) == 0) {
177 				docked = d;
178 #if 0
179 				printk(KERN_INFO
180 				       "PnPBIOS: Docking station %stached\n",
181 				       docked ? "at" : "de");
182 #endif
183 			}
184 		}
185 	}
186 	kthread_complete_and_exit(&unload_sem, 0);
187 }
188 
189 static int pnpbios_get_resources(struct pnp_dev *dev)
190 {
191 	u8 nodenum = dev->number;
192 	struct pnp_bios_node *node;
193 
194 	if (!pnpbios_is_dynamic(dev))
195 		return -EPERM;
196 
197 	pnp_dbg(&dev->dev, "get resources\n");
198 	node = kzalloc(node_info.max_node_size, GFP_KERNEL);
199 	if (!node)
200 		return -1;
201 	if (pnp_bios_get_dev_node(&nodenum, (char)PNPMODE_DYNAMIC, node)) {
202 		kfree(node);
203 		return -ENODEV;
204 	}
205 	pnpbios_read_resources_from_node(dev, node);
206 	dev->active = pnp_is_active(dev);
207 	kfree(node);
208 	return 0;
209 }
210 
211 static int pnpbios_set_resources(struct pnp_dev *dev)
212 {
213 	u8 nodenum = dev->number;
214 	struct pnp_bios_node *node;
215 	int ret;
216 
217 	if (!pnpbios_is_dynamic(dev))
218 		return -EPERM;
219 
220 	pnp_dbg(&dev->dev, "set resources\n");
221 	node = kzalloc(node_info.max_node_size, GFP_KERNEL);
222 	if (!node)
223 		return -1;
224 	if (pnp_bios_get_dev_node(&nodenum, (char)PNPMODE_DYNAMIC, node)) {
225 		kfree(node);
226 		return -ENODEV;
227 	}
228 	if (pnpbios_write_resources_to_node(dev, node) < 0) {
229 		kfree(node);
230 		return -1;
231 	}
232 	ret = pnp_bios_set_dev_node(node->handle, (char)PNPMODE_DYNAMIC, node);
233 	kfree(node);
234 	if (ret > 0)
235 		ret = -1;
236 	return ret;
237 }
238 
239 static void pnpbios_zero_data_stream(struct pnp_bios_node *node)
240 {
241 	unsigned char *p = (char *)node->data;
242 	unsigned char *end = (char *)(node->data + node->size);
243 	unsigned int len;
244 	int i;
245 
246 	while ((char *)p < (char *)end) {
247 		if (p[0] & 0x80) {	/* large tag */
248 			len = (p[2] << 8) | p[1];
249 			p += 3;
250 		} else {
251 			if (((p[0] >> 3) & 0x0f) == 0x0f)
252 				return;
253 			len = p[0] & 0x07;
254 			p += 1;
255 		}
256 		for (i = 0; i < len; i++)
257 			p[i] = 0;
258 		p += len;
259 	}
260 	printk(KERN_ERR
261 	       "PnPBIOS: Resource structure did not contain an end tag.\n");
262 }
263 
264 static int pnpbios_disable_resources(struct pnp_dev *dev)
265 {
266 	struct pnp_bios_node *node;
267 	u8 nodenum = dev->number;
268 	int ret;
269 
270 	if (dev->flags & PNPBIOS_NO_DISABLE || !pnpbios_is_dynamic(dev))
271 		return -EPERM;
272 
273 	node = kzalloc(node_info.max_node_size, GFP_KERNEL);
274 	if (!node)
275 		return -ENOMEM;
276 
277 	if (pnp_bios_get_dev_node(&nodenum, (char)PNPMODE_DYNAMIC, node)) {
278 		kfree(node);
279 		return -ENODEV;
280 	}
281 	pnpbios_zero_data_stream(node);
282 
283 	ret = pnp_bios_set_dev_node(dev->number, (char)PNPMODE_DYNAMIC, node);
284 	kfree(node);
285 	if (ret > 0)
286 		ret = -1;
287 	return ret;
288 }
289 
290 /* PnP Layer support */
291 
292 struct pnp_protocol pnpbios_protocol = {
293 	.name = "Plug and Play BIOS",
294 	.get = pnpbios_get_resources,
295 	.set = pnpbios_set_resources,
296 	.disable = pnpbios_disable_resources,
297 };
298 
299 static int __init insert_device(struct pnp_bios_node *node)
300 {
301 	struct pnp_dev *dev;
302 	char id[8];
303 	int error;
304 
305 	/* check if the device is already added */
306 	list_for_each_entry(dev, &pnpbios_protocol.devices, protocol_list) {
307 		if (dev->number == node->handle)
308 			return -EEXIST;
309 	}
310 
311 	pnp_eisa_id_to_string(node->eisa_id & PNP_EISA_ID_MASK, id);
312 	dev = pnp_alloc_dev(&pnpbios_protocol, node->handle, id);
313 	if (!dev)
314 		return -ENOMEM;
315 
316 	pnpbios_parse_data_stream(dev, node);
317 	dev->active = pnp_is_active(dev);
318 	dev->flags = node->flags;
319 	if (!(dev->flags & PNPBIOS_NO_CONFIG))
320 		dev->capabilities |= PNP_CONFIGURABLE;
321 	if (!(dev->flags & PNPBIOS_NO_DISABLE) && pnpbios_is_dynamic(dev))
322 		dev->capabilities |= PNP_DISABLE;
323 	dev->capabilities |= PNP_READ;
324 	if (pnpbios_is_dynamic(dev))
325 		dev->capabilities |= PNP_WRITE;
326 	if (dev->flags & PNPBIOS_REMOVABLE)
327 		dev->capabilities |= PNP_REMOVABLE;
328 
329 	/* clear out the damaged flags */
330 	if (!dev->active)
331 		pnp_init_resources(dev);
332 
333 	error = pnp_add_device(dev);
334 	if (error) {
335 		put_device(&dev->dev);
336 		return error;
337 	}
338 
339 	pnpbios_interface_attach_device(node);
340 
341 	return 0;
342 }
343 
344 static void __init build_devlist(void)
345 {
346 	u8 nodenum;
347 	unsigned int nodes_got = 0;
348 	unsigned int devs = 0;
349 	struct pnp_bios_node *node;
350 
351 	node = kzalloc(node_info.max_node_size, GFP_KERNEL);
352 	if (!node)
353 		return;
354 
355 	for (nodenum = 0; nodenum < 0xff;) {
356 		u8 thisnodenum = nodenum;
357 		/* eventually we will want to use PNPMODE_STATIC here but for now
358 		 * dynamic will help us catch buggy bioses to add to the blacklist.
359 		 */
360 		if (!pnpbios_dont_use_current_config) {
361 			if (pnp_bios_get_dev_node
362 			    (&nodenum, (char)PNPMODE_DYNAMIC, node))
363 				break;
364 		} else {
365 			if (pnp_bios_get_dev_node
366 			    (&nodenum, (char)PNPMODE_STATIC, node))
367 				break;
368 		}
369 		nodes_got++;
370 		if (insert_device(node) == 0)
371 			devs++;
372 		if (nodenum <= thisnodenum) {
373 			printk(KERN_ERR
374 			       "PnPBIOS: build_devlist: Node number 0x%x is out of sequence following node 0x%x. Aborting.\n",
375 			       (unsigned int)nodenum,
376 			       (unsigned int)thisnodenum);
377 			break;
378 		}
379 	}
380 	kfree(node);
381 
382 	printk(KERN_INFO
383 	       "PnPBIOS: %i node%s reported by PnP BIOS; %i recorded by driver\n",
384 	       nodes_got, nodes_got != 1 ? "s" : "", devs);
385 }
386 
387 /*
388  *
389  * INIT AND EXIT
390  *
391  */
392 
393 static int pnpbios_disabled;
394 int pnpbios_dont_use_current_config;
395 
396 static int __init pnpbios_setup(char *str)
397 {
398 	int invert;
399 
400 	while ((str != NULL) && (*str != '\0')) {
401 		if (strncmp(str, "off", 3) == 0)
402 			pnpbios_disabled = 1;
403 		if (strncmp(str, "on", 2) == 0)
404 			pnpbios_disabled = 0;
405 		invert = (strncmp(str, "no-", 3) == 0);
406 		if (invert)
407 			str += 3;
408 		if (strncmp(str, "curr", 4) == 0)
409 			pnpbios_dont_use_current_config = invert;
410 		str = strchr(str, ',');
411 		if (str != NULL)
412 			str += strspn(str, ", \t");
413 	}
414 
415 	return 1;
416 }
417 
418 __setup("pnpbios=", pnpbios_setup);
419 
420 /* PnP BIOS signature: "$PnP" */
421 #define PNP_SIGNATURE   (('$' << 0) + ('P' << 8) + ('n' << 16) + ('P' << 24))
422 
423 static int __init pnpbios_probe_system(void)
424 {
425 	union pnp_bios_install_struct *check;
426 	u8 sum;
427 	int length, i;
428 
429 	printk(KERN_INFO "PnPBIOS: Scanning system for PnP BIOS support...\n");
430 
431 	/*
432 	 * Search the defined area (0xf0000-0xffff0) for a valid PnP BIOS
433 	 * structure and, if one is found, sets up the selectors and
434 	 * entry points
435 	 */
436 	for (check = (union pnp_bios_install_struct *)__va(0xf0000);
437 	     check < (union pnp_bios_install_struct *)__va(0xffff0);
438 	     check = (void *)check + 16) {
439 		if (check->fields.signature != PNP_SIGNATURE)
440 			continue;
441 		printk(KERN_INFO
442 		       "PnPBIOS: Found PnP BIOS installation structure at 0x%p\n",
443 		       check);
444 		length = check->fields.length;
445 		if (!length) {
446 			printk(KERN_ERR
447 			       "PnPBIOS: installation structure is invalid, skipping\n");
448 			continue;
449 		}
450 		for (sum = 0, i = 0; i < length; i++)
451 			sum += check->chars[i];
452 		if (sum) {
453 			printk(KERN_ERR
454 			       "PnPBIOS: installation structure is corrupted, skipping\n");
455 			continue;
456 		}
457 		if (check->fields.version < 0x10) {
458 			printk(KERN_WARNING
459 			       "PnPBIOS: PnP BIOS version %d.%d is not supported\n",
460 			       check->fields.version >> 4,
461 			       check->fields.version & 15);
462 			continue;
463 		}
464 		printk(KERN_INFO
465 		       "PnPBIOS: PnP BIOS version %d.%d, entry 0x%x:0x%x, dseg 0x%x\n",
466 		       check->fields.version >> 4, check->fields.version & 15,
467 		       check->fields.pm16cseg, check->fields.pm16offset,
468 		       check->fields.pm16dseg);
469 		pnp_bios_install = check;
470 		return 1;
471 	}
472 
473 	printk(KERN_INFO "PnPBIOS: PnP BIOS support was not detected.\n");
474 	return 0;
475 }
476 
477 static int __init exploding_pnp_bios(const struct dmi_system_id *d)
478 {
479 	printk(KERN_WARNING "%s detected. Disabling PnPBIOS\n", d->ident);
480 	return 0;
481 }
482 
483 static const struct dmi_system_id pnpbios_dmi_table[] __initconst = {
484 	{			/* PnPBIOS GPF on boot */
485 	 .callback = exploding_pnp_bios,
486 	 .ident = "Higraded P14H",
487 	 .matches = {
488 		     DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
489 		     DMI_MATCH(DMI_BIOS_VERSION, "07.00T"),
490 		     DMI_MATCH(DMI_SYS_VENDOR, "Higraded"),
491 		     DMI_MATCH(DMI_PRODUCT_NAME, "P14H"),
492 		     },
493 	 },
494 	{			/* PnPBIOS GPF on boot */
495 	 .callback = exploding_pnp_bios,
496 	 .ident = "ASUS P4P800",
497 	 .matches = {
498 		     DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc."),
499 		     DMI_MATCH(DMI_BOARD_NAME, "P4P800"),
500 		     },
501 	 },
502 	{}
503 };
504 
505 static int __init pnpbios_init(void)
506 {
507 	int ret;
508 
509 	if (pnpbios_disabled || dmi_check_system(pnpbios_dmi_table) ||
510 	    arch_pnpbios_disabled()) {
511 		printk(KERN_INFO "PnPBIOS: Disabled\n");
512 		return -ENODEV;
513 	}
514 
515 #ifdef CONFIG_PNPACPI
516 	if (!acpi_disabled && !pnpacpi_disabled) {
517 		pnpbios_disabled = 1;
518 		printk(KERN_INFO "PnPBIOS: Disabled by ACPI PNP\n");
519 		return -ENODEV;
520 	}
521 #endif				/* CONFIG_ACPI */
522 
523 	/* scan the system for pnpbios support */
524 	if (!pnpbios_probe_system())
525 		return -ENODEV;
526 
527 	/* make preparations for bios calls */
528 	pnpbios_calls_init(pnp_bios_install);
529 
530 	/* read the node info */
531 	ret = pnp_bios_dev_node_info(&node_info);
532 	if (ret) {
533 		printk(KERN_ERR
534 		       "PnPBIOS: Unable to get node info.  Aborting.\n");
535 		return ret;
536 	}
537 
538 	/* register with the pnp layer */
539 	ret = pnp_register_protocol(&pnpbios_protocol);
540 	if (ret) {
541 		printk(KERN_ERR
542 		       "PnPBIOS: Unable to register driver.  Aborting.\n");
543 		return ret;
544 	}
545 
546 	/* start the proc interface */
547 	ret = pnpbios_proc_init();
548 	if (ret)
549 		printk(KERN_ERR "PnPBIOS: Failed to create proc interface.\n");
550 
551 	/* scan for pnpbios devices */
552 	build_devlist();
553 
554 	pnp_platform_devices = 1;
555 	return 0;
556 }
557 
558 fs_initcall(pnpbios_init);
559 
560 static int __init pnpbios_thread_init(void)
561 {
562 	struct task_struct *task;
563 
564 	if (pnpbios_disabled)
565 		return 0;
566 
567 	init_completion(&unload_sem);
568 	task = kthread_run(pnp_dock_thread, NULL, "kpnpbiosd");
569 	return PTR_ERR_OR_ZERO(task);
570 }
571 
572 /* Start the kernel thread later: */
573 device_initcall(pnpbios_thread_init);
574 
575 EXPORT_SYMBOL(pnpbios_protocol);
576