1 /*
2 * Setup routines for AGP 3.5 compliant bridges.
3 */
4
5 #include <linux/list.h>
6 #include <linux/pci.h>
7 #include <linux/agp_backend.h>
8 #include <linux/module.h>
9 #include <linux/slab.h>
10
11 #include "agp.h"
12
13 /* Generic AGP 3.5 enabling routines */
14
15 struct agp_3_5_dev {
16 struct list_head list;
17 u8 capndx;
18 u32 maxbw;
19 struct pci_dev *dev;
20 };
21
agp_3_5_dev_list_insert(struct list_head * head,struct list_head * new)22 static void agp_3_5_dev_list_insert(struct list_head *head, struct list_head *new)
23 {
24 struct agp_3_5_dev *cur, *n = list_entry(new, struct agp_3_5_dev, list);
25 struct list_head *pos;
26
27 list_for_each(pos, head) {
28 cur = list_entry(pos, struct agp_3_5_dev, list);
29 if (cur->maxbw > n->maxbw)
30 break;
31 }
32 list_add_tail(new, pos);
33 }
34
agp_3_5_dev_list_sort(struct agp_3_5_dev * list,unsigned int ndevs)35 static void agp_3_5_dev_list_sort(struct agp_3_5_dev *list, unsigned int ndevs)
36 {
37 struct agp_3_5_dev *cur;
38 struct pci_dev *dev;
39 struct list_head *pos, *tmp, *head = &list->list, *start = head->next;
40 u32 nistat;
41
42 INIT_LIST_HEAD(head);
43
44 for (pos=start; pos!=head; ) {
45 cur = list_entry(pos, struct agp_3_5_dev, list);
46 dev = cur->dev;
47
48 pci_read_config_dword(dev, cur->capndx+AGPNISTAT, &nistat);
49 cur->maxbw = (nistat >> 16) & 0xff;
50
51 tmp = pos;
52 pos = pos->next;
53 agp_3_5_dev_list_insert(head, tmp);
54 }
55 }
56
57 /*
58 * Initialize all isochronous transfer parameters for an AGP 3.0
59 * node (i.e. a host bridge in combination with the adapters
60 * lying behind it...)
61 */
62
agp_3_5_isochronous_node_enable(struct agp_bridge_data * bridge,struct agp_3_5_dev * dev_list,unsigned int ndevs)63 static int agp_3_5_isochronous_node_enable(struct agp_bridge_data *bridge,
64 struct agp_3_5_dev *dev_list, unsigned int ndevs)
65 {
66 /*
67 * Convenience structure to make the calculations clearer
68 * here. The field names come straight from the AGP 3.0 spec.
69 */
70 struct isoch_data {
71 u32 maxbw;
72 u32 n;
73 u32 y;
74 u32 l;
75 u32 rq;
76 struct agp_3_5_dev *dev;
77 };
78
79 struct pci_dev *td = bridge->dev, *dev;
80 struct list_head *head = &dev_list->list, *pos;
81 struct agp_3_5_dev *cur;
82 struct isoch_data *master, target;
83 unsigned int cdev = 0;
84 u32 mnistat, tnistat, tstatus, mcmd;
85 u16 tnicmd, mnicmd;
86 u8 mcapndx;
87 u32 tot_bw = 0, tot_n = 0, tot_rq = 0, y_max, rq_isoch, rq_async;
88 u32 step, rem, rem_isoch, rem_async;
89 int ret = 0;
90
91 /*
92 * We'll work with an array of isoch_data's (one for each
93 * device in dev_list) throughout this function.
94 */
95 if ((master = kmalloc(ndevs * sizeof(*master), GFP_KERNEL)) == NULL) {
96 ret = -ENOMEM;
97 goto get_out;
98 }
99
100 /*
101 * Sort the device list by maxbw. We need to do this because the
102 * spec suggests that the devices with the smallest requirements
103 * have their resources allocated first, with all remaining resources
104 * falling to the device with the largest requirement.
105 *
106 * We don't exactly do this, we divide target resources by ndevs
107 * and split them amongst the AGP 3.0 devices. The remainder of such
108 * division operations are dropped on the last device, sort of like
109 * the spec mentions it should be done.
110 *
111 * We can't do this sort when we initially construct the dev_list
112 * because we don't know until this function whether isochronous
113 * transfers are enabled and consequently whether maxbw will mean
114 * anything.
115 */
116 agp_3_5_dev_list_sort(dev_list, ndevs);
117
118 pci_read_config_dword(td, bridge->capndx+AGPNISTAT, &tnistat);
119 pci_read_config_dword(td, bridge->capndx+AGPSTAT, &tstatus);
120
121 /* Extract power-on defaults from the target */
122 target.maxbw = (tnistat >> 16) & 0xff;
123 target.n = (tnistat >> 8) & 0xff;
124 target.y = (tnistat >> 6) & 0x3;
125 target.l = (tnistat >> 3) & 0x7;
126 target.rq = (tstatus >> 24) & 0xff;
127
128 y_max = target.y;
129
130 /*
131 * Extract power-on defaults for each device in dev_list. Along
132 * the way, calculate the total isochronous bandwidth required
133 * by these devices and the largest requested payload size.
134 */
135 list_for_each(pos, head) {
136 cur = list_entry(pos, struct agp_3_5_dev, list);
137 dev = cur->dev;
138
139 mcapndx = cur->capndx;
140
141 pci_read_config_dword(dev, cur->capndx+AGPNISTAT, &mnistat);
142
143 master[cdev].maxbw = (mnistat >> 16) & 0xff;
144 master[cdev].n = (mnistat >> 8) & 0xff;
145 master[cdev].y = (mnistat >> 6) & 0x3;
146 master[cdev].dev = cur;
147
148 tot_bw += master[cdev].maxbw;
149 y_max = max(y_max, master[cdev].y);
150
151 cdev++;
152 }
153
154 /* Check if this configuration has any chance of working */
155 if (tot_bw > target.maxbw) {
156 dev_err(&td->dev, "isochronous bandwidth required "
157 "by AGP 3.0 devices exceeds that which is supported by "
158 "the AGP 3.0 bridge!\n");
159 ret = -ENODEV;
160 goto free_and_exit;
161 }
162
163 target.y = y_max;
164
165 /*
166 * Write the calculated payload size into the target's NICMD
167 * register. Doing this directly effects the ISOCH_N value
168 * in the target's NISTAT register, so we need to do this now
169 * to get an accurate value for ISOCH_N later.
170 */
171 pci_read_config_word(td, bridge->capndx+AGPNICMD, &tnicmd);
172 tnicmd &= ~(0x3 << 6);
173 tnicmd |= target.y << 6;
174 pci_write_config_word(td, bridge->capndx+AGPNICMD, tnicmd);
175
176 /* Reread the target's ISOCH_N */
177 pci_read_config_dword(td, bridge->capndx+AGPNISTAT, &tnistat);
178 target.n = (tnistat >> 8) & 0xff;
179
180 /* Calculate the minimum ISOCH_N needed by each master */
181 for (cdev=0; cdev<ndevs; cdev++) {
182 master[cdev].y = target.y;
183 master[cdev].n = master[cdev].maxbw / (master[cdev].y + 1);
184
185 tot_n += master[cdev].n;
186 }
187
188 /* Exit if the minimal ISOCH_N allocation among the masters is more
189 * than the target can handle. */
190 if (tot_n > target.n) {
191 dev_err(&td->dev, "number of isochronous "
192 "transactions per period required by AGP 3.0 devices "
193 "exceeds that which is supported by the AGP 3.0 "
194 "bridge!\n");
195 ret = -ENODEV;
196 goto free_and_exit;
197 }
198
199 /* Calculate left over ISOCH_N capability in the target. We'll give
200 * this to the hungriest device (as per the spec) */
201 rem = target.n - tot_n;
202
203 /*
204 * Calculate the minimum isochronous RQ depth needed by each master.
205 * Along the way, distribute the extra ISOCH_N capability calculated
206 * above.
207 */
208 for (cdev=0; cdev<ndevs; cdev++) {
209 /*
210 * This is a little subtle. If ISOCH_Y > 64B, then ISOCH_Y
211 * byte isochronous writes will be broken into 64B pieces.
212 * This means we need to budget more RQ depth to account for
213 * these kind of writes (each isochronous write is actually
214 * many writes on the AGP bus).
215 */
216 master[cdev].rq = master[cdev].n;
217 if (master[cdev].y > 0x1)
218 master[cdev].rq *= (1 << (master[cdev].y - 1));
219
220 tot_rq += master[cdev].rq;
221 }
222 master[ndevs-1].n += rem;
223
224 /* Figure the number of isochronous and asynchronous RQ slots the
225 * target is providing. */
226 rq_isoch = (target.y > 0x1) ? target.n * (1 << (target.y - 1)) : target.n;
227 rq_async = target.rq - rq_isoch;
228
229 /* Exit if the minimal RQ needs of the masters exceeds what the target
230 * can provide. */
231 if (tot_rq > rq_isoch) {
232 dev_err(&td->dev, "number of request queue slots "
233 "required by the isochronous bandwidth requested by "
234 "AGP 3.0 devices exceeds the number provided by the "
235 "AGP 3.0 bridge!\n");
236 ret = -ENODEV;
237 goto free_and_exit;
238 }
239
240 /* Calculate asynchronous RQ capability in the target (per master) as
241 * well as the total number of leftover isochronous RQ slots. */
242 step = rq_async / ndevs;
243 rem_async = step + (rq_async % ndevs);
244 rem_isoch = rq_isoch - tot_rq;
245
246 /* Distribute the extra RQ slots calculated above and write our
247 * isochronous settings out to the actual devices. */
248 for (cdev=0; cdev<ndevs; cdev++) {
249 cur = master[cdev].dev;
250 dev = cur->dev;
251
252 mcapndx = cur->capndx;
253
254 master[cdev].rq += (cdev == ndevs - 1)
255 ? (rem_async + rem_isoch) : step;
256
257 pci_read_config_word(dev, cur->capndx+AGPNICMD, &mnicmd);
258 pci_read_config_dword(dev, cur->capndx+AGPCMD, &mcmd);
259
260 mnicmd &= ~(0xff << 8);
261 mnicmd &= ~(0x3 << 6);
262 mcmd &= ~(0xff << 24);
263
264 mnicmd |= master[cdev].n << 8;
265 mnicmd |= master[cdev].y << 6;
266 mcmd |= master[cdev].rq << 24;
267
268 pci_write_config_dword(dev, cur->capndx+AGPCMD, mcmd);
269 pci_write_config_word(dev, cur->capndx+AGPNICMD, mnicmd);
270 }
271
272 free_and_exit:
273 kfree(master);
274
275 get_out:
276 return ret;
277 }
278
279 /*
280 * This function basically allocates request queue slots among the
281 * AGP 3.0 systems in nonisochronous nodes. The algorithm is
282 * pretty stupid, divide the total number of RQ slots provided by the
283 * target by ndevs. Distribute this many slots to each AGP 3.0 device,
284 * giving any left over slots to the last device in dev_list.
285 */
agp_3_5_nonisochronous_node_enable(struct agp_bridge_data * bridge,struct agp_3_5_dev * dev_list,unsigned int ndevs)286 static void agp_3_5_nonisochronous_node_enable(struct agp_bridge_data *bridge,
287 struct agp_3_5_dev *dev_list, unsigned int ndevs)
288 {
289 struct agp_3_5_dev *cur;
290 struct list_head *head = &dev_list->list, *pos;
291 u32 tstatus, mcmd;
292 u32 trq, mrq, rem;
293 unsigned int cdev = 0;
294
295 pci_read_config_dword(bridge->dev, bridge->capndx+AGPSTAT, &tstatus);
296
297 trq = (tstatus >> 24) & 0xff;
298 mrq = trq / ndevs;
299
300 rem = mrq + (trq % ndevs);
301
302 for (pos=head->next; cdev<ndevs; cdev++, pos=pos->next) {
303 cur = list_entry(pos, struct agp_3_5_dev, list);
304
305 pci_read_config_dword(cur->dev, cur->capndx+AGPCMD, &mcmd);
306 mcmd &= ~(0xff << 24);
307 mcmd |= ((cdev == ndevs - 1) ? rem : mrq) << 24;
308 pci_write_config_dword(cur->dev, cur->capndx+AGPCMD, mcmd);
309 }
310 }
311
312 /*
313 * Fully configure and enable an AGP 3.0 host bridge and all the devices
314 * lying behind it.
315 */
agp_3_5_enable(struct agp_bridge_data * bridge)316 int agp_3_5_enable(struct agp_bridge_data *bridge)
317 {
318 struct pci_dev *td = bridge->dev, *dev = NULL;
319 u8 mcapndx;
320 u32 isoch, arqsz;
321 u32 tstatus, mstatus, ncapid;
322 u32 mmajor;
323 u16 mpstat;
324 struct agp_3_5_dev *dev_list, *cur;
325 struct list_head *head, *pos;
326 unsigned int ndevs = 0;
327 int ret = 0;
328
329 /* Extract some power-on defaults from the target */
330 pci_read_config_dword(td, bridge->capndx+AGPSTAT, &tstatus);
331 isoch = (tstatus >> 17) & 0x1;
332 if (isoch == 0) /* isoch xfers not available, bail out. */
333 return -ENODEV;
334
335 arqsz = (tstatus >> 13) & 0x7;
336
337 /*
338 * Allocate a head for our AGP 3.5 device list
339 * (multiple AGP v3 devices are allowed behind a single bridge).
340 */
341 if ((dev_list = kmalloc(sizeof(*dev_list), GFP_KERNEL)) == NULL) {
342 ret = -ENOMEM;
343 goto get_out;
344 }
345 head = &dev_list->list;
346 INIT_LIST_HEAD(head);
347
348 /* Find all AGP devices, and add them to dev_list. */
349 for_each_pci_dev(dev) {
350 mcapndx = pci_find_capability(dev, PCI_CAP_ID_AGP);
351 if (mcapndx == 0)
352 continue;
353
354 switch ((dev->class >>8) & 0xff00) {
355 case 0x0600: /* Bridge */
356 /* Skip bridges. We should call this function for each one. */
357 continue;
358
359 case 0x0001: /* Unclassified device */
360 /* Don't know what this is, but log it for investigation. */
361 if (mcapndx != 0) {
362 dev_info(&td->dev, "wacky, found unclassified AGP device %s [%04x/%04x]\n",
363 pci_name(dev),
364 dev->vendor, dev->device);
365 }
366 continue;
367
368 case 0x0300: /* Display controller */
369 case 0x0400: /* Multimedia controller */
370 if ((cur = kmalloc(sizeof(*cur), GFP_KERNEL)) == NULL) {
371 ret = -ENOMEM;
372 goto free_and_exit;
373 }
374 cur->dev = dev;
375
376 pos = &cur->list;
377 list_add(pos, head);
378 ndevs++;
379 continue;
380
381 default:
382 continue;
383 }
384 }
385
386 /*
387 * Take an initial pass through the devices lying behind our host
388 * bridge. Make sure each one is actually an AGP 3.0 device, otherwise
389 * exit with an error message. Along the way store the AGP 3.0
390 * cap_ptr for each device
391 */
392 list_for_each(pos, head) {
393 cur = list_entry(pos, struct agp_3_5_dev, list);
394 dev = cur->dev;
395
396 pci_read_config_word(dev, PCI_STATUS, &mpstat);
397 if ((mpstat & PCI_STATUS_CAP_LIST) == 0)
398 continue;
399
400 pci_read_config_byte(dev, PCI_CAPABILITY_LIST, &mcapndx);
401 if (mcapndx != 0) {
402 do {
403 pci_read_config_dword(dev, mcapndx, &ncapid);
404 if ((ncapid & 0xff) != 2)
405 mcapndx = (ncapid >> 8) & 0xff;
406 }
407 while (((ncapid & 0xff) != 2) && (mcapndx != 0));
408 }
409
410 if (mcapndx == 0) {
411 dev_err(&td->dev, "woah! Non-AGP device %s on "
412 "secondary bus of AGP 3.5 bridge!\n",
413 pci_name(dev));
414 ret = -ENODEV;
415 goto free_and_exit;
416 }
417
418 mmajor = (ncapid >> AGP_MAJOR_VERSION_SHIFT) & 0xf;
419 if (mmajor < 3) {
420 dev_err(&td->dev, "woah! AGP 2.0 device %s on "
421 "secondary bus of AGP 3.5 bridge operating "
422 "with AGP 3.0 electricals!\n", pci_name(dev));
423 ret = -ENODEV;
424 goto free_and_exit;
425 }
426
427 cur->capndx = mcapndx;
428
429 pci_read_config_dword(dev, cur->capndx+AGPSTAT, &mstatus);
430
431 if (((mstatus >> 3) & 0x1) == 0) {
432 dev_err(&td->dev, "woah! AGP 3.x device %s not "
433 "operating in AGP 3.x mode on secondary bus "
434 "of AGP 3.5 bridge operating with AGP 3.0 "
435 "electricals!\n", pci_name(dev));
436 ret = -ENODEV;
437 goto free_and_exit;
438 }
439 }
440
441 /*
442 * Call functions to divide target resources amongst the AGP 3.0
443 * masters. This process is dramatically different depending on
444 * whether isochronous transfers are supported.
445 */
446 if (isoch) {
447 ret = agp_3_5_isochronous_node_enable(bridge, dev_list, ndevs);
448 if (ret) {
449 dev_info(&td->dev, "something bad happened setting "
450 "up isochronous xfers; falling back to "
451 "non-isochronous xfer mode\n");
452 } else {
453 goto free_and_exit;
454 }
455 }
456 agp_3_5_nonisochronous_node_enable(bridge, dev_list, ndevs);
457
458 free_and_exit:
459 /* Be sure to free the dev_list */
460 for (pos=head->next; pos!=head; ) {
461 cur = list_entry(pos, struct agp_3_5_dev, list);
462
463 pos = pos->next;
464 kfree(cur);
465 }
466 kfree(dev_list);
467
468 get_out:
469 return ret;
470 }
471