1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * ACPI PCI Hot Plug IBM Extension
4  *
5  * Copyright (C) 2004 Vernon Mauery <vernux@us.ibm.com>
6  * Copyright (C) 2004 IBM Corp.
7  *
8  * All rights reserved.
9  *
10  * Send feedback to <vernux@us.ibm.com>
11  *
12  */
13 
14 #define pr_fmt(fmt) "acpiphp_ibm: " fmt
15 
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/module.h>
19 #include <linux/kernel.h>
20 #include <linux/sysfs.h>
21 #include <linux/kobject.h>
22 #include <linux/moduleparam.h>
23 #include <linux/pci.h>
24 #include <linux/uaccess.h>
25 
26 #include "acpiphp.h"
27 #include "../pci.h"
28 
29 #define DRIVER_VERSION	"1.0.1"
30 #define DRIVER_AUTHOR	"Irene Zubarev <zubarev@us.ibm.com>, Vernon Mauery <vernux@us.ibm.com>"
31 #define DRIVER_DESC	"ACPI Hot Plug PCI Controller Driver IBM extension"
32 
33 
34 MODULE_AUTHOR(DRIVER_AUTHOR);
35 MODULE_DESCRIPTION(DRIVER_DESC);
36 MODULE_LICENSE("GPL");
37 MODULE_VERSION(DRIVER_VERSION);
38 
39 #define FOUND_APCI 0x61504349
40 /* these are the names for the IBM ACPI pseudo-device */
41 #define IBM_HARDWARE_ID1 "IBM37D0"
42 #define IBM_HARDWARE_ID2 "IBM37D4"
43 
44 #define hpslot_to_sun(A) (to_slot(A)->sun)
45 
46 /* union apci_descriptor - allows access to the
47  * various device descriptors that are embedded in the
48  * aPCI table
49  */
50 union apci_descriptor {
51 	struct {
52 		char sig[4];
53 		u8   len;
54 	} header;
55 	struct {
56 		u8  type;
57 		u8  len;
58 		u16 slot_id;
59 		u8  bus_id;
60 		u8  dev_num;
61 		u8  slot_num;
62 		u8  slot_attr[2];
63 		u8  attn;
64 		u8  status[2];
65 		u8  sun;
66 		u8  res[3];
67 	} slot;
68 	struct {
69 		u8 type;
70 		u8 len;
71 	} generic;
72 };
73 
74 /* struct notification - keeps info about the device
75  * that cause the ACPI notification event
76  */
77 struct notification {
78 	struct acpi_device *device;
79 	u8                  event;
80 };
81 
82 static int ibm_set_attention_status(struct hotplug_slot *slot, u8 status);
83 static int ibm_get_attention_status(struct hotplug_slot *slot, u8 *status);
84 static void ibm_handle_events(acpi_handle handle, u32 event, void *context);
85 static int ibm_get_table_from_acpi(char **bufp);
86 static ssize_t ibm_read_apci_table(struct file *filp, struct kobject *kobj,
87 				   struct bin_attribute *bin_attr,
88 				   char *buffer, loff_t pos, size_t size);
89 static acpi_status __init ibm_find_acpi_device(acpi_handle handle,
90 		u32 lvl, void *context, void **rv);
91 static int __init ibm_acpiphp_init(void);
92 static void __exit ibm_acpiphp_exit(void);
93 
94 static acpi_handle ibm_acpi_handle;
95 static struct notification ibm_note;
96 static struct bin_attribute ibm_apci_table_attr __ro_after_init = {
97 	    .attr = {
98 		    .name = "apci_table",
99 		    .mode = S_IRUGO,
100 	    },
101 	    .read = ibm_read_apci_table,
102 	    .write = NULL,
103 };
104 static struct acpiphp_attention_info ibm_attention_info =
105 {
106 	.set_attn = ibm_set_attention_status,
107 	.get_attn = ibm_get_attention_status,
108 	.owner = THIS_MODULE,
109 };
110 
111 /**
112  * ibm_slot_from_id - workaround for bad ibm hardware
113  * @id: the slot number that linux refers to the slot by
114  *
115  * Description: This method returns the aCPI slot descriptor
116  * corresponding to the Linux slot number.  This descriptor
117  * has info about the aPCI slot id and attention status.
118  * This descriptor must be freed using kfree when done.
119  */
120 static union apci_descriptor *ibm_slot_from_id(int id)
121 {
122 	int ind = 0, size;
123 	union apci_descriptor *ret = NULL, *des;
124 	char *table;
125 
126 	size = ibm_get_table_from_acpi(&table);
127 	if (size < 0)
128 		return NULL;
129 	des = (union apci_descriptor *)table;
130 	if (memcmp(des->header.sig, "aPCI", 4) != 0)
131 		goto ibm_slot_done;
132 
133 	des = (union apci_descriptor *)&table[ind += des->header.len];
134 	while (ind < size && (des->generic.type != 0x82 ||
135 			des->slot.slot_num != id)) {
136 		des = (union apci_descriptor *)&table[ind += des->generic.len];
137 	}
138 
139 	if (ind < size && des->slot.slot_num == id)
140 		ret = des;
141 
142 ibm_slot_done:
143 	if (ret) {
144 		ret = kmalloc(sizeof(union apci_descriptor), GFP_KERNEL);
145 		if (ret)
146 			memcpy(ret, des, sizeof(union apci_descriptor));
147 	}
148 	kfree(table);
149 	return ret;
150 }
151 
152 /**
153  * ibm_set_attention_status - callback method to set the attention LED
154  * @slot: the hotplug_slot to work with
155  * @status: what to set the LED to (0 or 1)
156  *
157  * Description: This method is registered with the acpiphp module as a
158  * callback to do the device specific task of setting the LED status.
159  */
160 static int ibm_set_attention_status(struct hotplug_slot *slot, u8 status)
161 {
162 	union acpi_object args[2];
163 	struct acpi_object_list params = { .pointer = args, .count = 2 };
164 	acpi_status stat;
165 	unsigned long long rc;
166 	union apci_descriptor *ibm_slot;
167 	int id = hpslot_to_sun(slot);
168 
169 	ibm_slot = ibm_slot_from_id(id);
170 	if (!ibm_slot) {
171 		pr_err("APLS null ACPI descriptor for slot %d\n", id);
172 		return -ENODEV;
173 	}
174 
175 	pr_debug("%s: set slot %d (%d) attention status to %d\n", __func__,
176 			ibm_slot->slot.slot_num, ibm_slot->slot.slot_id,
177 			(status ? 1 : 0));
178 
179 	args[0].type = ACPI_TYPE_INTEGER;
180 	args[0].integer.value = ibm_slot->slot.slot_id;
181 	args[1].type = ACPI_TYPE_INTEGER;
182 	args[1].integer.value = (status) ? 1 : 0;
183 
184 	kfree(ibm_slot);
185 
186 	stat = acpi_evaluate_integer(ibm_acpi_handle, "APLS", &params, &rc);
187 	if (ACPI_FAILURE(stat)) {
188 		pr_err("APLS evaluation failed:  0x%08x\n", stat);
189 		return -ENODEV;
190 	} else if (!rc) {
191 		pr_err("APLS method failed:  0x%08llx\n", rc);
192 		return -ERANGE;
193 	}
194 	return 0;
195 }
196 
197 /**
198  * ibm_get_attention_status - callback method to get attention LED status
199  * @slot: the hotplug_slot to work with
200  * @status: returns what the LED is set to (0 or 1)
201  *
202  * Description: This method is registered with the acpiphp module as a
203  * callback to do the device specific task of getting the LED status.
204  *
205  * Because there is no direct method of getting the LED status directly
206  * from an ACPI call, we read the aPCI table and parse out our
207  * slot descriptor to read the status from that.
208  */
209 static int ibm_get_attention_status(struct hotplug_slot *slot, u8 *status)
210 {
211 	union apci_descriptor *ibm_slot;
212 	int id = hpslot_to_sun(slot);
213 
214 	ibm_slot = ibm_slot_from_id(id);
215 	if (!ibm_slot) {
216 		pr_err("APLS null ACPI descriptor for slot %d\n", id);
217 		return -ENODEV;
218 	}
219 
220 	if (ibm_slot->slot.attn & 0xa0 || ibm_slot->slot.status[1] & 0x08)
221 		*status = 1;
222 	else
223 		*status = 0;
224 
225 	pr_debug("%s: get slot %d (%d) attention status is %d\n", __func__,
226 			ibm_slot->slot.slot_num, ibm_slot->slot.slot_id,
227 			*status);
228 
229 	kfree(ibm_slot);
230 	return 0;
231 }
232 
233 /**
234  * ibm_handle_events - listens for ACPI events for the IBM37D0 device
235  * @handle: an ACPI handle to the device that caused the event
236  * @event: the event info (device specific)
237  * @context: passed context (our notification struct)
238  *
239  * Description: This method is registered as a callback with the ACPI
240  * subsystem it is called when this device has an event to notify the OS of.
241  *
242  * The events actually come from the device as two events that get
243  * synthesized into one event with data by this function.  The event
244  * ID comes first and then the slot number that caused it.  We report
245  * this as one event to the OS.
246  *
247  * From section 5.6.2.2 of the ACPI 2.0 spec, I understand that the OSPM will
248  * only re-enable the interrupt that causes this event AFTER this method
249  * has returned, thereby enforcing serial access for the notification struct.
250  */
251 static void ibm_handle_events(acpi_handle handle, u32 event, void *context)
252 {
253 	u8 detail = event & 0x0f;
254 	u8 subevent = event & 0xf0;
255 	struct notification *note = context;
256 
257 	pr_debug("%s: Received notification %02x\n", __func__, event);
258 
259 	if (subevent == 0x80) {
260 		pr_debug("%s: generating bus event\n", __func__);
261 		acpi_bus_generate_netlink_event(note->device->pnp.device_class,
262 						  dev_name(&note->device->dev),
263 						  note->event, detail);
264 	} else
265 		note->event = event;
266 }
267 
268 /**
269  * ibm_get_table_from_acpi - reads the APLS buffer from ACPI
270  * @bufp: address to pointer to allocate for the table
271  *
272  * Description: This method reads the APLS buffer in from ACPI and
273  * stores the "stripped" table into a single buffer
274  * it allocates and passes the address back in bufp.
275  *
276  * If NULL is passed in as buffer, this method only calculates
277  * the size of the table and returns that without filling
278  * in the buffer.
279  *
280  * Returns < 0 on error or the size of the table on success.
281  */
282 static int ibm_get_table_from_acpi(char **bufp)
283 {
284 	union acpi_object *package;
285 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
286 	acpi_status status;
287 	char *lbuf = NULL;
288 	int i, size = -EIO;
289 
290 	status = acpi_evaluate_object(ibm_acpi_handle, "APCI", NULL, &buffer);
291 	if (ACPI_FAILURE(status)) {
292 		pr_err("%s:  APCI evaluation failed\n", __func__);
293 		return -ENODEV;
294 	}
295 
296 	package = (union acpi_object *) buffer.pointer;
297 	if (!(package) ||
298 			(package->type != ACPI_TYPE_PACKAGE) ||
299 			!(package->package.elements)) {
300 		pr_err("%s:  Invalid APCI object\n", __func__);
301 		goto read_table_done;
302 	}
303 
304 	for (size = 0, i = 0; i < package->package.count; i++) {
305 		if (package->package.elements[i].type != ACPI_TYPE_BUFFER) {
306 			pr_err("%s:  Invalid APCI element %d\n", __func__, i);
307 			goto read_table_done;
308 		}
309 		size += package->package.elements[i].buffer.length;
310 	}
311 
312 	if (bufp == NULL)
313 		goto read_table_done;
314 
315 	lbuf = kzalloc(size, GFP_KERNEL);
316 	pr_debug("%s: element count: %i, ASL table size: %i, &table = 0x%p\n",
317 			__func__, package->package.count, size, lbuf);
318 
319 	if (lbuf) {
320 		*bufp = lbuf;
321 	} else {
322 		size = -ENOMEM;
323 		goto read_table_done;
324 	}
325 
326 	size = 0;
327 	for (i = 0; i < package->package.count; i++) {
328 		memcpy(&lbuf[size],
329 				package->package.elements[i].buffer.pointer,
330 				package->package.elements[i].buffer.length);
331 		size += package->package.elements[i].buffer.length;
332 	}
333 
334 read_table_done:
335 	kfree(buffer.pointer);
336 	return size;
337 }
338 
339 /**
340  * ibm_read_apci_table - callback for the sysfs apci_table file
341  * @filp: the open sysfs file
342  * @kobj: the kobject this binary attribute is a part of
343  * @bin_attr: struct bin_attribute for this file
344  * @buffer: the kernel space buffer to fill
345  * @pos: the offset into the file
346  * @size: the number of bytes requested
347  *
348  * Description: Gets registered with sysfs as the reader callback
349  * to be executed when /sys/bus/pci/slots/apci_table gets read.
350  *
351  * Since we don't get notified on open and close for this file,
352  * things get really tricky here...
353  * our solution is to only allow reading the table in all at once.
354  */
355 static ssize_t ibm_read_apci_table(struct file *filp, struct kobject *kobj,
356 				   struct bin_attribute *bin_attr,
357 				   char *buffer, loff_t pos, size_t size)
358 {
359 	int bytes_read = -EINVAL;
360 	char *table = NULL;
361 
362 	pr_debug("%s: pos = %d, size = %zd\n", __func__, (int)pos, size);
363 
364 	if (pos == 0) {
365 		bytes_read = ibm_get_table_from_acpi(&table);
366 		if (bytes_read > 0 && bytes_read <= size)
367 			memcpy(buffer, table, bytes_read);
368 		kfree(table);
369 	}
370 	return bytes_read;
371 }
372 
373 /**
374  * ibm_find_acpi_device - callback to find our ACPI device
375  * @handle: the ACPI handle of the device we are inspecting
376  * @lvl: depth into the namespace tree
377  * @context: a pointer to our handle to fill when we find the device
378  * @rv: a return value to fill if desired
379  *
380  * Description: Used as a callback when calling acpi_walk_namespace
381  * to find our device.  When this method returns non-zero
382  * acpi_walk_namespace quits its search and returns our value.
383  */
384 static acpi_status __init ibm_find_acpi_device(acpi_handle handle,
385 		u32 lvl, void *context, void **rv)
386 {
387 	acpi_handle *phandle = (acpi_handle *)context;
388 	unsigned long long current_status = 0;
389 	acpi_status status;
390 	struct acpi_device_info *info;
391 	int retval = 0;
392 
393 	status = acpi_get_object_info(handle, &info);
394 	if (ACPI_FAILURE(status)) {
395 		pr_err("%s:  Failed to get device information status=0x%x\n",
396 			__func__, status);
397 		return retval;
398 	}
399 
400 	acpi_bus_get_status_handle(handle, &current_status);
401 
402 	if (current_status && (info->valid & ACPI_VALID_HID) &&
403 			(!strcmp(info->hardware_id.string, IBM_HARDWARE_ID1) ||
404 			 !strcmp(info->hardware_id.string, IBM_HARDWARE_ID2))) {
405 		pr_debug("found hardware: %s, handle: %p\n",
406 			info->hardware_id.string, handle);
407 		*phandle = handle;
408 		/* returning non-zero causes the search to stop
409 		 * and returns this value to the caller of
410 		 * acpi_walk_namespace, but it also causes some warnings
411 		 * in the acpi debug code to print...
412 		 */
413 		retval = FOUND_APCI;
414 	}
415 	kfree(info);
416 	return retval;
417 }
418 
419 static int __init ibm_acpiphp_init(void)
420 {
421 	int retval = 0;
422 	acpi_status status;
423 	struct acpi_device *device;
424 	struct kobject *sysdir = &pci_slots_kset->kobj;
425 
426 	pr_debug("%s\n", __func__);
427 
428 	if (acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
429 			ACPI_UINT32_MAX, ibm_find_acpi_device, NULL,
430 			&ibm_acpi_handle, NULL) != FOUND_APCI) {
431 		pr_err("%s: acpi_walk_namespace failed\n", __func__);
432 		retval = -ENODEV;
433 		goto init_return;
434 	}
435 	pr_debug("%s: found IBM aPCI device\n", __func__);
436 	if (acpi_bus_get_device(ibm_acpi_handle, &device)) {
437 		pr_err("%s: acpi_bus_get_device failed\n", __func__);
438 		retval = -ENODEV;
439 		goto init_return;
440 	}
441 	if (acpiphp_register_attention(&ibm_attention_info)) {
442 		retval = -ENODEV;
443 		goto init_return;
444 	}
445 
446 	ibm_note.device = device;
447 	status = acpi_install_notify_handler(ibm_acpi_handle,
448 			ACPI_DEVICE_NOTIFY, ibm_handle_events,
449 			&ibm_note);
450 	if (ACPI_FAILURE(status)) {
451 		pr_err("%s: Failed to register notification handler\n",
452 				__func__);
453 		retval = -EBUSY;
454 		goto init_cleanup;
455 	}
456 
457 	ibm_apci_table_attr.size = ibm_get_table_from_acpi(NULL);
458 	retval = sysfs_create_bin_file(sysdir, &ibm_apci_table_attr);
459 
460 	return retval;
461 
462 init_cleanup:
463 	acpiphp_unregister_attention(&ibm_attention_info);
464 init_return:
465 	return retval;
466 }
467 
468 static void __exit ibm_acpiphp_exit(void)
469 {
470 	acpi_status status;
471 	struct kobject *sysdir = &pci_slots_kset->kobj;
472 
473 	pr_debug("%s\n", __func__);
474 
475 	if (acpiphp_unregister_attention(&ibm_attention_info))
476 		pr_err("%s: attention info deregistration failed", __func__);
477 
478 	status = acpi_remove_notify_handler(
479 			   ibm_acpi_handle,
480 			   ACPI_DEVICE_NOTIFY,
481 			   ibm_handle_events);
482 	if (ACPI_FAILURE(status))
483 		pr_err("%s: Notification handler removal failed\n", __func__);
484 	/* remove the /sys entries */
485 	sysfs_remove_bin_file(sysdir, &ibm_apci_table_attr);
486 }
487 
488 module_init(ibm_acpiphp_init);
489 module_exit(ibm_acpiphp_exit);
490