Root/drivers/pci/pci-label.c

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 <acpi/acpi_bus.h>
33#include "pci.h"
34
35#define DEVICE_LABEL_DSM 0x07
36
37#ifndef CONFIG_DMI
38
39static inline int
40pci_create_smbiosname_file(struct pci_dev *pdev)
41{
42    return -1;
43}
44
45static inline void
46pci_remove_smbiosname_file(struct pci_dev *pdev)
47{
48}
49
50#else
51
52enum smbios_attr_enum {
53    SMBIOS_ATTR_NONE = 0,
54    SMBIOS_ATTR_LABEL_SHOW,
55    SMBIOS_ATTR_INSTANCE_SHOW,
56};
57
58static size_t
59find_smbios_instance_string(struct pci_dev *pdev, char *buf,
60                enum smbios_attr_enum attribute)
61{
62    const struct dmi_device *dmi;
63    struct dmi_dev_onboard *donboard;
64    int bus;
65    int devfn;
66
67    bus = pdev->bus->number;
68    devfn = pdev->devfn;
69
70    dmi = NULL;
71    while ((dmi = dmi_find_device(DMI_DEV_TYPE_DEV_ONBOARD,
72                      NULL, dmi)) != NULL) {
73        donboard = dmi->device_data;
74        if (donboard && donboard->bus == bus &&
75                    donboard->devfn == devfn) {
76            if (buf) {
77                if (attribute == SMBIOS_ATTR_INSTANCE_SHOW)
78                    return scnprintf(buf, PAGE_SIZE,
79                             "%d\n",
80                             donboard->instance);
81                else if (attribute == SMBIOS_ATTR_LABEL_SHOW)
82                    return scnprintf(buf, PAGE_SIZE,
83                             "%s\n",
84                             dmi->name);
85            }
86            return strlen(dmi->name);
87        }
88    }
89    return 0;
90}
91
92static umode_t
93smbios_instance_string_exist(struct kobject *kobj, struct attribute *attr,
94                 int n)
95{
96    struct device *dev;
97    struct pci_dev *pdev;
98
99    dev = container_of(kobj, struct device, kobj);
100    pdev = to_pci_dev(dev);
101
102    return find_smbios_instance_string(pdev, NULL, SMBIOS_ATTR_NONE) ?
103                       S_IRUGO : 0;
104}
105
106static ssize_t
107smbioslabel_show(struct device *dev, struct device_attribute *attr, char *buf)
108{
109    struct pci_dev *pdev;
110    pdev = to_pci_dev(dev);
111
112    return find_smbios_instance_string(pdev, buf,
113                       SMBIOS_ATTR_LABEL_SHOW);
114}
115
116static ssize_t
117smbiosinstance_show(struct device *dev,
118            struct device_attribute *attr, char *buf)
119{
120    struct pci_dev *pdev;
121    pdev = to_pci_dev(dev);
122
123    return find_smbios_instance_string(pdev, buf,
124                       SMBIOS_ATTR_INSTANCE_SHOW);
125}
126
127static struct device_attribute smbios_attr_label = {
128    .attr = {.name = "label", .mode = 0444},
129    .show = smbioslabel_show,
130};
131
132static struct device_attribute smbios_attr_instance = {
133    .attr = {.name = "index", .mode = 0444},
134    .show = smbiosinstance_show,
135};
136
137static struct attribute *smbios_attributes[] = {
138    &smbios_attr_label.attr,
139    &smbios_attr_instance.attr,
140    NULL,
141};
142
143static struct attribute_group smbios_attr_group = {
144    .attrs = smbios_attributes,
145    .is_visible = smbios_instance_string_exist,
146};
147
148static int
149pci_create_smbiosname_file(struct pci_dev *pdev)
150{
151    return sysfs_create_group(&pdev->dev.kobj, &smbios_attr_group);
152}
153
154static void
155pci_remove_smbiosname_file(struct pci_dev *pdev)
156{
157    sysfs_remove_group(&pdev->dev.kobj, &smbios_attr_group);
158}
159
160#endif
161
162#ifndef CONFIG_ACPI
163
164static inline int
165pci_create_acpi_index_label_files(struct pci_dev *pdev)
166{
167    return -1;
168}
169
170static inline int
171pci_remove_acpi_index_label_files(struct pci_dev *pdev)
172{
173    return -1;
174}
175
176static inline bool
177device_has_dsm(struct device *dev)
178{
179    return false;
180}
181
182#else
183
184static const char device_label_dsm_uuid[] = {
185    0xD0, 0x37, 0xC9, 0xE5, 0x53, 0x35, 0x7A, 0x4D,
186    0x91, 0x17, 0xEA, 0x4D, 0x19, 0xC3, 0x43, 0x4D
187};
188
189enum acpi_attr_enum {
190    ACPI_ATTR_NONE = 0,
191    ACPI_ATTR_LABEL_SHOW,
192    ACPI_ATTR_INDEX_SHOW,
193};
194
195static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf)
196{
197    int len;
198    len = utf16s_to_utf8s((const wchar_t *)obj->
199                  package.elements[1].string.pointer,
200                  obj->package.elements[1].string.length,
201                  UTF16_LITTLE_ENDIAN,
202                  buf, PAGE_SIZE);
203    buf[len] = '\n';
204}
205
206static int
207dsm_get_label(acpi_handle handle, int func,
208          struct acpi_buffer *output,
209          char *buf, enum acpi_attr_enum attribute)
210{
211    struct acpi_object_list input;
212    union acpi_object params[4];
213    union acpi_object *obj;
214    int len = 0;
215
216    int err;
217
218    input.count = 4;
219    input.pointer = params;
220    params[0].type = ACPI_TYPE_BUFFER;
221    params[0].buffer.length = sizeof(device_label_dsm_uuid);
222    params[0].buffer.pointer = (char *)device_label_dsm_uuid;
223    params[1].type = ACPI_TYPE_INTEGER;
224    params[1].integer.value = 0x02;
225    params[2].type = ACPI_TYPE_INTEGER;
226    params[2].integer.value = func;
227    params[3].type = ACPI_TYPE_PACKAGE;
228    params[3].package.count = 0;
229    params[3].package.elements = NULL;
230
231    err = acpi_evaluate_object(handle, "_DSM", &input, output);
232    if (err)
233        return -1;
234
235    obj = (union acpi_object *)output->pointer;
236
237    switch (obj->type) {
238    case ACPI_TYPE_PACKAGE:
239        if (obj->package.count != 2)
240            break;
241        len = obj->package.elements[0].integer.value;
242        if (buf) {
243            if (attribute == ACPI_ATTR_INDEX_SHOW)
244                scnprintf(buf, PAGE_SIZE, "%llu\n",
245                obj->package.elements[0].integer.value);
246            else if (attribute == ACPI_ATTR_LABEL_SHOW)
247                dsm_label_utf16s_to_utf8s(obj, buf);
248            kfree(output->pointer);
249            return strlen(buf);
250        }
251        kfree(output->pointer);
252        return len;
253    break;
254    default:
255        kfree(output->pointer);
256    }
257    return -1;
258}
259
260static bool
261device_has_dsm(struct device *dev)
262{
263    acpi_handle handle;
264    struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
265
266    handle = DEVICE_ACPI_HANDLE(dev);
267
268    if (!handle)
269        return FALSE;
270
271    if (dsm_get_label(handle, DEVICE_LABEL_DSM, &output, NULL,
272              ACPI_ATTR_NONE) > 0)
273        return TRUE;
274
275    return FALSE;
276}
277
278static umode_t
279acpi_index_string_exist(struct kobject *kobj, struct attribute *attr, int n)
280{
281    struct device *dev;
282
283    dev = container_of(kobj, struct device, kobj);
284
285    if (device_has_dsm(dev))
286        return S_IRUGO;
287
288    return 0;
289}
290
291static ssize_t
292acpilabel_show(struct device *dev, struct device_attribute *attr, char *buf)
293{
294    struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
295    acpi_handle handle;
296    int length;
297
298    handle = DEVICE_ACPI_HANDLE(dev);
299
300    if (!handle)
301        return -1;
302
303    length = dsm_get_label(handle, DEVICE_LABEL_DSM,
304                   &output, buf, ACPI_ATTR_LABEL_SHOW);
305
306    if (length < 1)
307        return -1;
308
309    return length;
310}
311
312static ssize_t
313acpiindex_show(struct device *dev, struct device_attribute *attr, char *buf)
314{
315    struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
316    acpi_handle handle;
317    int length;
318
319    handle = DEVICE_ACPI_HANDLE(dev);
320
321    if (!handle)
322        return -1;
323
324    length = dsm_get_label(handle, DEVICE_LABEL_DSM,
325                   &output, buf, ACPI_ATTR_INDEX_SHOW);
326
327    if (length < 0)
328        return -1;
329
330    return length;
331
332}
333
334static struct device_attribute acpi_attr_label = {
335    .attr = {.name = "label", .mode = 0444},
336    .show = acpilabel_show,
337};
338
339static struct device_attribute acpi_attr_index = {
340    .attr = {.name = "acpi_index", .mode = 0444},
341    .show = acpiindex_show,
342};
343
344static struct attribute *acpi_attributes[] = {
345    &acpi_attr_label.attr,
346    &acpi_attr_index.attr,
347    NULL,
348};
349
350static struct attribute_group acpi_attr_group = {
351    .attrs = acpi_attributes,
352    .is_visible = acpi_index_string_exist,
353};
354
355static int
356pci_create_acpi_index_label_files(struct pci_dev *pdev)
357{
358    return sysfs_create_group(&pdev->dev.kobj, &acpi_attr_group);
359}
360
361static int
362pci_remove_acpi_index_label_files(struct pci_dev *pdev)
363{
364    sysfs_remove_group(&pdev->dev.kobj, &acpi_attr_group);
365    return 0;
366}
367#endif
368
369void pci_create_firmware_label_files(struct pci_dev *pdev)
370{
371    if (device_has_dsm(&pdev->dev))
372        pci_create_acpi_index_label_files(pdev);
373    else
374        pci_create_smbiosname_file(pdev);
375}
376
377void pci_remove_firmware_label_files(struct pci_dev *pdev)
378{
379    if (device_has_dsm(&pdev->dev))
380        pci_remove_acpi_index_label_files(pdev);
381    else
382        pci_remove_smbiosname_file(pdev);
383}
384

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