Merge airlied/drm-next into drm-intel-next-queued
[linux-2.6-microblaze.git] / drivers / xen / xen-pciback / conf_space.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * PCI Backend - Functions for creating a virtual configuration space for
4  *               exported PCI Devices.
5  *               It's dangerous to allow PCI Driver Domains to change their
6  *               device's resources (memory, i/o ports, interrupts). We need to
7  *               restrict changes to certain PCI Configuration registers:
8  *               BARs, INTERRUPT_PIN, most registers in the header...
9  *
10  * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
11  */
12
13 #include <linux/kernel.h>
14 #include <linux/moduleparam.h>
15 #include <linux/pci.h>
16 #include "pciback.h"
17 #include "conf_space.h"
18 #include "conf_space_quirks.h"
19
20 bool xen_pcibk_permissive;
21 module_param_named(permissive, xen_pcibk_permissive, bool, 0644);
22
23 /* This is where xen_pcibk_read_config_byte, xen_pcibk_read_config_word,
24  * xen_pcibk_write_config_word, and xen_pcibk_write_config_byte are created. */
25 #define DEFINE_PCI_CONFIG(op, size, type)                       \
26 int xen_pcibk_##op##_config_##size                              \
27 (struct pci_dev *dev, int offset, type value, void *data)       \
28 {                                                               \
29         return pci_##op##_config_##size(dev, offset, value);    \
30 }
31
32 DEFINE_PCI_CONFIG(read, byte, u8 *)
33 DEFINE_PCI_CONFIG(read, word, u16 *)
34 DEFINE_PCI_CONFIG(read, dword, u32 *)
35
36 DEFINE_PCI_CONFIG(write, byte, u8)
37 DEFINE_PCI_CONFIG(write, word, u16)
38 DEFINE_PCI_CONFIG(write, dword, u32)
39
40 static int conf_space_read(struct pci_dev *dev,
41                            const struct config_field_entry *entry,
42                            int offset, u32 *value)
43 {
44         int ret = 0;
45         const struct config_field *field = entry->field;
46
47         *value = 0;
48
49         switch (field->size) {
50         case 1:
51                 if (field->u.b.read)
52                         ret = field->u.b.read(dev, offset, (u8 *) value,
53                                               entry->data);
54                 break;
55         case 2:
56                 if (field->u.w.read)
57                         ret = field->u.w.read(dev, offset, (u16 *) value,
58                                               entry->data);
59                 break;
60         case 4:
61                 if (field->u.dw.read)
62                         ret = field->u.dw.read(dev, offset, value, entry->data);
63                 break;
64         }
65         return ret;
66 }
67
68 static int conf_space_write(struct pci_dev *dev,
69                             const struct config_field_entry *entry,
70                             int offset, u32 value)
71 {
72         int ret = 0;
73         const struct config_field *field = entry->field;
74
75         switch (field->size) {
76         case 1:
77                 if (field->u.b.write)
78                         ret = field->u.b.write(dev, offset, (u8) value,
79                                                entry->data);
80                 break;
81         case 2:
82                 if (field->u.w.write)
83                         ret = field->u.w.write(dev, offset, (u16) value,
84                                                entry->data);
85                 break;
86         case 4:
87                 if (field->u.dw.write)
88                         ret = field->u.dw.write(dev, offset, value,
89                                                 entry->data);
90                 break;
91         }
92         return ret;
93 }
94
95 static inline u32 get_mask(int size)
96 {
97         if (size == 1)
98                 return 0xff;
99         else if (size == 2)
100                 return 0xffff;
101         else
102                 return 0xffffffff;
103 }
104
105 static inline int valid_request(int offset, int size)
106 {
107         /* Validate request (no un-aligned requests) */
108         if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0)
109                 return 1;
110         return 0;
111 }
112
113 static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask,
114                               int offset)
115 {
116         if (offset >= 0) {
117                 new_val_mask <<= (offset * 8);
118                 new_val <<= (offset * 8);
119         } else {
120                 new_val_mask >>= (offset * -8);
121                 new_val >>= (offset * -8);
122         }
123         val = (val & ~new_val_mask) | (new_val & new_val_mask);
124
125         return val;
126 }
127
128 static int xen_pcibios_err_to_errno(int err)
129 {
130         switch (err) {
131         case PCIBIOS_SUCCESSFUL:
132                 return XEN_PCI_ERR_success;
133         case PCIBIOS_DEVICE_NOT_FOUND:
134                 return XEN_PCI_ERR_dev_not_found;
135         case PCIBIOS_BAD_REGISTER_NUMBER:
136                 return XEN_PCI_ERR_invalid_offset;
137         case PCIBIOS_FUNC_NOT_SUPPORTED:
138                 return XEN_PCI_ERR_not_implemented;
139         case PCIBIOS_SET_FAILED:
140                 return XEN_PCI_ERR_access_denied;
141         }
142         return err;
143 }
144
145 int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
146                           u32 *ret_val)
147 {
148         int err = 0;
149         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
150         const struct config_field_entry *cfg_entry;
151         const struct config_field *field;
152         int field_start, field_end;
153         /* if read fails for any reason, return 0
154          * (as if device didn't respond) */
155         u32 value = 0, tmp_val;
156
157         if (unlikely(verbose_request))
158                 printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x\n",
159                        pci_name(dev), size, offset);
160
161         if (!valid_request(offset, size)) {
162                 err = XEN_PCI_ERR_invalid_offset;
163                 goto out;
164         }
165
166         /* Get the real value first, then modify as appropriate */
167         switch (size) {
168         case 1:
169                 err = pci_read_config_byte(dev, offset, (u8 *) &value);
170                 break;
171         case 2:
172                 err = pci_read_config_word(dev, offset, (u16 *) &value);
173                 break;
174         case 4:
175                 err = pci_read_config_dword(dev, offset, &value);
176                 break;
177         }
178
179         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
180                 field = cfg_entry->field;
181
182                 field_start = OFFSET(cfg_entry);
183                 field_end = OFFSET(cfg_entry) + field->size;
184
185                 if (offset + size > field_start && field_end > offset) {
186                         err = conf_space_read(dev, cfg_entry, field_start,
187                                               &tmp_val);
188                         if (err)
189                                 goto out;
190
191                         value = merge_value(value, tmp_val,
192                                             get_mask(field->size),
193                                             field_start - offset);
194                 }
195         }
196
197 out:
198         if (unlikely(verbose_request))
199                 printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x = %x\n",
200                        pci_name(dev), size, offset, value);
201
202         *ret_val = value;
203         return xen_pcibios_err_to_errno(err);
204 }
205
206 int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
207 {
208         int err = 0, handled = 0;
209         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
210         const struct config_field_entry *cfg_entry;
211         const struct config_field *field;
212         u32 tmp_val;
213         int field_start, field_end;
214
215         if (unlikely(verbose_request))
216                 printk(KERN_DEBUG
217                        DRV_NAME ": %s: write request %d bytes at 0x%x = %x\n",
218                        pci_name(dev), size, offset, value);
219
220         if (!valid_request(offset, size))
221                 return XEN_PCI_ERR_invalid_offset;
222
223         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
224                 field = cfg_entry->field;
225
226                 field_start = OFFSET(cfg_entry);
227                 field_end = OFFSET(cfg_entry) + field->size;
228
229                 if (offset + size > field_start && field_end > offset) {
230                         err = conf_space_read(dev, cfg_entry, field_start,
231                                               &tmp_val);
232                         if (err)
233                                 break;
234
235                         tmp_val = merge_value(tmp_val, value, get_mask(size),
236                                               offset - field_start);
237
238                         err = conf_space_write(dev, cfg_entry, field_start,
239                                                tmp_val);
240
241                         /* handled is set true here, but not every byte
242                          * may have been written! Properly detecting if
243                          * every byte is handled is unnecessary as the
244                          * flag is used to detect devices that need
245                          * special helpers to work correctly.
246                          */
247                         handled = 1;
248                 }
249         }
250
251         if (!handled && !err) {
252                 /* By default, anything not specificially handled above is
253                  * read-only. The permissive flag changes this behavior so
254                  * that anything not specifically handled above is writable.
255                  * This means that some fields may still be read-only because
256                  * they have entries in the config_field list that intercept
257                  * the write and do nothing. */
258                 if (dev_data->permissive || xen_pcibk_permissive) {
259                         switch (size) {
260                         case 1:
261                                 err = pci_write_config_byte(dev, offset,
262                                                             (u8) value);
263                                 break;
264                         case 2:
265                                 err = pci_write_config_word(dev, offset,
266                                                             (u16) value);
267                                 break;
268                         case 4:
269                                 err = pci_write_config_dword(dev, offset,
270                                                              (u32) value);
271                                 break;
272                         }
273                 } else if (!dev_data->warned_on_write) {
274                         dev_data->warned_on_write = 1;
275                         dev_warn(&dev->dev, "Driver tried to write to a "
276                                  "read-only configuration space field at offset"
277                                  " 0x%x, size %d. This may be harmless, but if "
278                                  "you have problems with your device:\n"
279                                  "1) see permissive attribute in sysfs\n"
280                                  "2) report problems to the xen-devel "
281                                  "mailing list along with details of your "
282                                  "device obtained from lspci.\n", offset, size);
283                 }
284         }
285
286         return xen_pcibios_err_to_errno(err);
287 }
288
289 void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)
290 {
291         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
292         struct config_field_entry *cfg_entry, *t;
293         const struct config_field *field;
294
295         dev_dbg(&dev->dev, "free-ing dynamically allocated virtual "
296                            "configuration space fields\n");
297         if (!dev_data)
298                 return;
299
300         list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
301                 field = cfg_entry->field;
302
303                 if (field->clean) {
304                         field->clean((struct config_field *)field);
305
306                         kfree(cfg_entry->data);
307
308                         list_del(&cfg_entry->list);
309                         kfree(cfg_entry);
310                 }
311
312         }
313 }
314
315 void xen_pcibk_config_reset_dev(struct pci_dev *dev)
316 {
317         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
318         const struct config_field_entry *cfg_entry;
319         const struct config_field *field;
320
321         dev_dbg(&dev->dev, "resetting virtual configuration space\n");
322         if (!dev_data)
323                 return;
324
325         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
326                 field = cfg_entry->field;
327
328                 if (field->reset)
329                         field->reset(dev, OFFSET(cfg_entry), cfg_entry->data);
330         }
331 }
332
333 void xen_pcibk_config_free_dev(struct pci_dev *dev)
334 {
335         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
336         struct config_field_entry *cfg_entry, *t;
337         const struct config_field *field;
338
339         dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n");
340         if (!dev_data)
341                 return;
342
343         list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
344                 list_del(&cfg_entry->list);
345
346                 field = cfg_entry->field;
347
348                 if (field->release)
349                         field->release(dev, OFFSET(cfg_entry), cfg_entry->data);
350
351                 kfree(cfg_entry);
352         }
353 }
354
355 int xen_pcibk_config_add_field_offset(struct pci_dev *dev,
356                                     const struct config_field *field,
357                                     unsigned int base_offset)
358 {
359         int err = 0;
360         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
361         struct config_field_entry *cfg_entry;
362         void *tmp;
363
364         cfg_entry = kmalloc(sizeof(*cfg_entry), GFP_KERNEL);
365         if (!cfg_entry) {
366                 err = -ENOMEM;
367                 goto out;
368         }
369
370         cfg_entry->data = NULL;
371         cfg_entry->field = field;
372         cfg_entry->base_offset = base_offset;
373
374         /* silently ignore duplicate fields */
375         err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry));
376         if (err)
377                 goto out;
378
379         if (field->init) {
380                 tmp = field->init(dev, OFFSET(cfg_entry));
381
382                 if (IS_ERR(tmp)) {
383                         err = PTR_ERR(tmp);
384                         goto out;
385                 }
386
387                 cfg_entry->data = tmp;
388         }
389
390         dev_dbg(&dev->dev, "added config field at offset 0x%02x\n",
391                 OFFSET(cfg_entry));
392         list_add_tail(&cfg_entry->list, &dev_data->config_fields);
393
394 out:
395         if (err)
396                 kfree(cfg_entry);
397
398         return err;
399 }
400
401 /* This sets up the device's virtual configuration space to keep track of
402  * certain registers (like the base address registers (BARs) so that we can
403  * keep the client from manipulating them directly.
404  */
405 int xen_pcibk_config_init_dev(struct pci_dev *dev)
406 {
407         int err = 0;
408         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
409
410         dev_dbg(&dev->dev, "initializing virtual configuration space\n");
411
412         INIT_LIST_HEAD(&dev_data->config_fields);
413
414         err = xen_pcibk_config_header_add_fields(dev);
415         if (err)
416                 goto out;
417
418         err = xen_pcibk_config_capability_add_fields(dev);
419         if (err)
420                 goto out;
421
422         err = xen_pcibk_config_quirks_init(dev);
423
424 out:
425         return err;
426 }
427
428 int xen_pcibk_config_init(void)
429 {
430         return xen_pcibk_config_capability_init();
431 }