1/*
2 * Purpose: Export the firmware instance and label associated with
3 * a pci device to sysfs
4 * Copyright (C) 2010 Dell Inc.
5 * by Narendra K <Narendra_K@dell.com>,
6 * Jordan Hargrave <Jordan_Hargrave@dell.com>
7 *
8 * PCI Firmware Specification Revision 3.1 section 4.6.7 (DSM for Naming a
9 * PCI or PCI Express Device Under Operating Systems) defines an instance
10 * number and string name. This code retrieves them and exports them to sysfs.
11 * If the system firmware does not provide the ACPI _DSM (Device Specific
12 * Method), then the SMBIOS type 41 instance number and string is exported to
13 * sysfs.
14 *
15 * SMBIOS defines type 41 for onboard pci devices. This code retrieves
16 * the instance number and string from the type 41 record and exports
17 * it to sysfs.
18 *
19 * Please see http://linux.dell.com/wiki/index.php/Oss/libnetdevname for more
20 * information.
21 */
22
23#include <linux/dmi.h>
24#include <linux/sysfs.h>
25#include <linux/pci.h>
26#include <linux/pci_ids.h>
27#include <linux/module.h>
28#include <linux/device.h>
29#include <linux/nls.h>
30#include <linux/acpi.h>
31#include <linux/pci-acpi.h>
32#include "pci.h"
33
34#ifdef CONFIG_DMI
35enum smbios_attr_enum {
36	SMBIOS_ATTR_NONE = 0,
37	SMBIOS_ATTR_LABEL_SHOW,
38	SMBIOS_ATTR_INSTANCE_SHOW,
39};
40
41static size_t find_smbios_instance_string(struct pci_dev *pdev, char *buf,
42					  enum smbios_attr_enum attribute)
43{
44	const struct dmi_device *dmi;
45	struct dmi_dev_onboard *donboard;
46	int bus;
47	int devfn;
48
49	bus = pdev->bus->number;
50	devfn = pdev->devfn;
51
52	dmi = NULL;
53	while ((dmi = dmi_find_device(DMI_DEV_TYPE_DEV_ONBOARD,
54				      NULL, dmi)) != NULL) {
55		donboard = dmi->device_data;
56		if (donboard && donboard->bus == bus &&
57					donboard->devfn == devfn) {
58			if (buf) {
59				if (attribute == SMBIOS_ATTR_INSTANCE_SHOW)
60					return scnprintf(buf, PAGE_SIZE,
61							 "%d\n",
62							 donboard->instance);
63				else if (attribute == SMBIOS_ATTR_LABEL_SHOW)
64					return scnprintf(buf, PAGE_SIZE,
65							 "%s\n",
66							 dmi->name);
67			}
68			return strlen(dmi->name);
69		}
70	}
71	return 0;
72}
73
74static umode_t smbios_instance_string_exist(struct kobject *kobj,
75					    struct attribute *attr, int n)
76{
77	struct device *dev;
78	struct pci_dev *pdev;
79
80	dev = container_of(kobj, struct device, kobj);
81	pdev = to_pci_dev(dev);
82
83	return find_smbios_instance_string(pdev, NULL, SMBIOS_ATTR_NONE) ?
84					   S_IRUGO : 0;
85}
86
87static ssize_t smbioslabel_show(struct device *dev,
88				struct device_attribute *attr, char *buf)
89{
90	struct pci_dev *pdev;
91	pdev = to_pci_dev(dev);
92
93	return find_smbios_instance_string(pdev, buf,
94					   SMBIOS_ATTR_LABEL_SHOW);
95}
96
97static ssize_t smbiosinstance_show(struct device *dev,
98				   struct device_attribute *attr, char *buf)
99{
100	struct pci_dev *pdev;
101	pdev = to_pci_dev(dev);
102
103	return find_smbios_instance_string(pdev, buf,
104					   SMBIOS_ATTR_INSTANCE_SHOW);
105}
106
107static struct device_attribute smbios_attr_label = {
108	.attr = {.name = "label", .mode = 0444},
109	.show = smbioslabel_show,
110};
111
112static struct device_attribute smbios_attr_instance = {
113	.attr = {.name = "index", .mode = 0444},
114	.show = smbiosinstance_show,
115};
116
117static struct attribute *smbios_attributes[] = {
118	&smbios_attr_label.attr,
119	&smbios_attr_instance.attr,
120	NULL,
121};
122
123static struct attribute_group smbios_attr_group = {
124	.attrs = smbios_attributes,
125	.is_visible = smbios_instance_string_exist,
126};
127
128static int pci_create_smbiosname_file(struct pci_dev *pdev)
129{
130	return sysfs_create_group(&pdev->dev.kobj, &smbios_attr_group);
131}
132
133static void pci_remove_smbiosname_file(struct pci_dev *pdev)
134{
135	sysfs_remove_group(&pdev->dev.kobj, &smbios_attr_group);
136}
137#else
138static inline int pci_create_smbiosname_file(struct pci_dev *pdev)
139{
140	return -1;
141}
142
143static inline void pci_remove_smbiosname_file(struct pci_dev *pdev)
144{
145}
146#endif
147
148#ifdef CONFIG_ACPI
149enum acpi_attr_enum {
150	ACPI_ATTR_LABEL_SHOW,
151	ACPI_ATTR_INDEX_SHOW,
152};
153
154static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf)
155{
156	int len;
157	len = utf16s_to_utf8s((const wchar_t *)obj->buffer.pointer,
158			      obj->buffer.length,
159			      UTF16_LITTLE_ENDIAN,
160			      buf, PAGE_SIZE);
161	buf[len] = '\n';
162}
163
164static int dsm_get_label(struct device *dev, char *buf,
165			 enum acpi_attr_enum attr)
166{
167	acpi_handle handle;
168	union acpi_object *obj, *tmp;
169	int len = -1;
170
171	handle = ACPI_HANDLE(dev);
172	if (!handle)
173		return -1;
174
175	obj = acpi_evaluate_dsm(handle, pci_acpi_dsm_uuid, 0x2,
176				DEVICE_LABEL_DSM, NULL);
177	if (!obj)
178		return -1;
179
180	tmp = obj->package.elements;
181	if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 &&
182	    tmp[0].type == ACPI_TYPE_INTEGER &&
183	    (tmp[1].type == ACPI_TYPE_STRING ||
184	     tmp[1].type == ACPI_TYPE_BUFFER)) {
185		/*
186		 * The second string element is optional even when
187		 * this _DSM is implemented; when not implemented,
188		 * this entry must return a null string.
189		 */
190		if (attr == ACPI_ATTR_INDEX_SHOW) {
191			scnprintf(buf, PAGE_SIZE, "%llu\n", tmp->integer.value);
192		} else if (attr == ACPI_ATTR_LABEL_SHOW) {
193			if (tmp[1].type == ACPI_TYPE_STRING)
194				scnprintf(buf, PAGE_SIZE, "%s\n",
195					  tmp[1].string.pointer);
196			else if (tmp[1].type == ACPI_TYPE_BUFFER)
197				dsm_label_utf16s_to_utf8s(tmp + 1, buf);
198		}
199		len = strlen(buf) > 0 ? strlen(buf) : -1;
200	}
201
202	ACPI_FREE(obj);
203
204	return len;
205}
206
207static bool device_has_dsm(struct device *dev)
208{
209	acpi_handle handle;
210
211	handle = ACPI_HANDLE(dev);
212	if (!handle)
213		return false;
214
215	return !!acpi_check_dsm(handle, pci_acpi_dsm_uuid, 0x2,
216				1 << DEVICE_LABEL_DSM);
217}
218
219static umode_t acpi_index_string_exist(struct kobject *kobj,
220				       struct attribute *attr, int n)
221{
222	struct device *dev;
223
224	dev = container_of(kobj, struct device, kobj);
225
226	if (device_has_dsm(dev))
227		return S_IRUGO;
228
229	return 0;
230}
231
232static ssize_t acpilabel_show(struct device *dev,
233			      struct device_attribute *attr, char *buf)
234{
235	return dsm_get_label(dev, buf, ACPI_ATTR_LABEL_SHOW);
236}
237
238static ssize_t acpiindex_show(struct device *dev,
239			      struct device_attribute *attr, char *buf)
240{
241	return dsm_get_label(dev, buf, ACPI_ATTR_INDEX_SHOW);
242}
243
244static struct device_attribute acpi_attr_label = {
245	.attr = {.name = "label", .mode = 0444},
246	.show = acpilabel_show,
247};
248
249static struct device_attribute acpi_attr_index = {
250	.attr = {.name = "acpi_index", .mode = 0444},
251	.show = acpiindex_show,
252};
253
254static struct attribute *acpi_attributes[] = {
255	&acpi_attr_label.attr,
256	&acpi_attr_index.attr,
257	NULL,
258};
259
260static struct attribute_group acpi_attr_group = {
261	.attrs = acpi_attributes,
262	.is_visible = acpi_index_string_exist,
263};
264
265static int pci_create_acpi_index_label_files(struct pci_dev *pdev)
266{
267	return sysfs_create_group(&pdev->dev.kobj, &acpi_attr_group);
268}
269
270static int pci_remove_acpi_index_label_files(struct pci_dev *pdev)
271{
272	sysfs_remove_group(&pdev->dev.kobj, &acpi_attr_group);
273	return 0;
274}
275#else
276static inline int pci_create_acpi_index_label_files(struct pci_dev *pdev)
277{
278	return -1;
279}
280
281static inline int pci_remove_acpi_index_label_files(struct pci_dev *pdev)
282{
283	return -1;
284}
285
286static inline bool device_has_dsm(struct device *dev)
287{
288	return false;
289}
290#endif
291
292void pci_create_firmware_label_files(struct pci_dev *pdev)
293{
294	if (device_has_dsm(&pdev->dev))
295		pci_create_acpi_index_label_files(pdev);
296	else
297		pci_create_smbiosname_file(pdev);
298}
299
300void pci_remove_firmware_label_files(struct pci_dev *pdev)
301{
302	if (device_has_dsm(&pdev->dev))
303		pci_remove_acpi_index_label_files(pdev);
304	else
305		pci_remove_smbiosname_file(pdev);
306}
307