1 /*
2 * Copyright 2006 Jake Moilanen <moilanen@austin.ibm.com>, IBM Corp.
3 * Copyright 2006-2007 Michael Ellerman, IBM Corp.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; version 2 of the
8 * License.
9 *
10 */
11
12 #include <linux/device.h>
13 #include <linux/irq.h>
14 #include <linux/msi.h>
15
16 #include <asm/rtas.h>
17 #include <asm/hw_irq.h>
18 #include <asm/ppc-pci.h>
19 #include <asm/machdep.h>
20
21 #include "pseries.h"
22
23 static int query_token, change_token;
24
25 #define RTAS_QUERY_FN 0
26 #define RTAS_CHANGE_FN 1
27 #define RTAS_RESET_FN 2
28 #define RTAS_CHANGE_MSI_FN 3
29 #define RTAS_CHANGE_MSIX_FN 4
30 #define RTAS_CHANGE_32MSI_FN 5
31
32 /* RTAS Helpers */
33
rtas_change_msi(struct pci_dn * pdn,u32 func,u32 num_irqs)34 static int rtas_change_msi(struct pci_dn *pdn, u32 func, u32 num_irqs)
35 {
36 u32 addr, seq_num, rtas_ret[3];
37 unsigned long buid;
38 int rc;
39
40 addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
41 buid = pdn->phb->buid;
42
43 seq_num = 1;
44 do {
45 if (func == RTAS_CHANGE_MSI_FN || func == RTAS_CHANGE_MSIX_FN ||
46 func == RTAS_CHANGE_32MSI_FN)
47 rc = rtas_call(change_token, 6, 4, rtas_ret, addr,
48 BUID_HI(buid), BUID_LO(buid),
49 func, num_irqs, seq_num);
50 else
51 rc = rtas_call(change_token, 6, 3, rtas_ret, addr,
52 BUID_HI(buid), BUID_LO(buid),
53 func, num_irqs, seq_num);
54
55 seq_num = rtas_ret[1];
56 } while (rtas_busy_delay(rc));
57
58 /*
59 * If the RTAS call succeeded, return the number of irqs allocated.
60 * If not, make sure we return a negative error code.
61 */
62 if (rc == 0)
63 rc = rtas_ret[0];
64 else if (rc > 0)
65 rc = -rc;
66
67 pr_debug("rtas_msi: ibm,change_msi(func=%d,num=%d), got %d rc = %d\n",
68 func, num_irqs, rtas_ret[0], rc);
69
70 return rc;
71 }
72
rtas_disable_msi(struct pci_dev * pdev)73 static void rtas_disable_msi(struct pci_dev *pdev)
74 {
75 struct pci_dn *pdn;
76
77 pdn = pci_get_pdn(pdev);
78 if (!pdn)
79 return;
80
81 /*
82 * disabling MSI with the explicit interface also disables MSI-X
83 */
84 if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0) != 0) {
85 /*
86 * may have failed because explicit interface is not
87 * present
88 */
89 if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) {
90 pr_debug("rtas_msi: Setting MSIs to 0 failed!\n");
91 }
92 }
93 }
94
rtas_query_irq_number(struct pci_dn * pdn,int offset)95 static int rtas_query_irq_number(struct pci_dn *pdn, int offset)
96 {
97 u32 addr, rtas_ret[2];
98 unsigned long buid;
99 int rc;
100
101 addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
102 buid = pdn->phb->buid;
103
104 do {
105 rc = rtas_call(query_token, 4, 3, rtas_ret, addr,
106 BUID_HI(buid), BUID_LO(buid), offset);
107 } while (rtas_busy_delay(rc));
108
109 if (rc) {
110 pr_debug("rtas_msi: error (%d) querying source number\n", rc);
111 return rc;
112 }
113
114 return rtas_ret[0];
115 }
116
rtas_teardown_msi_irqs(struct pci_dev * pdev)117 static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
118 {
119 struct msi_desc *entry;
120
121 for_each_pci_msi_entry(entry, pdev) {
122 if (entry->irq == NO_IRQ)
123 continue;
124
125 irq_set_msi_desc(entry->irq, NULL);
126 irq_dispose_mapping(entry->irq);
127 }
128
129 rtas_disable_msi(pdev);
130 }
131
check_req(struct pci_dev * pdev,int nvec,char * prop_name)132 static int check_req(struct pci_dev *pdev, int nvec, char *prop_name)
133 {
134 struct device_node *dn;
135 struct pci_dn *pdn;
136 const __be32 *p;
137 u32 req_msi;
138
139 pdn = pci_get_pdn(pdev);
140 if (!pdn)
141 return -ENODEV;
142
143 dn = pdn->node;
144
145 p = of_get_property(dn, prop_name, NULL);
146 if (!p) {
147 pr_debug("rtas_msi: No %s on %s\n", prop_name, dn->full_name);
148 return -ENOENT;
149 }
150
151 req_msi = be32_to_cpup(p);
152 if (req_msi < nvec) {
153 pr_debug("rtas_msi: %s requests < %d MSIs\n", prop_name, nvec);
154
155 if (req_msi == 0) /* Be paranoid */
156 return -ENOSPC;
157
158 return req_msi;
159 }
160
161 return 0;
162 }
163
check_req_msi(struct pci_dev * pdev,int nvec)164 static int check_req_msi(struct pci_dev *pdev, int nvec)
165 {
166 return check_req(pdev, nvec, "ibm,req#msi");
167 }
168
check_req_msix(struct pci_dev * pdev,int nvec)169 static int check_req_msix(struct pci_dev *pdev, int nvec)
170 {
171 return check_req(pdev, nvec, "ibm,req#msi-x");
172 }
173
174 /* Quota calculation */
175
find_pe_total_msi(struct pci_dev * dev,int * total)176 static struct device_node *find_pe_total_msi(struct pci_dev *dev, int *total)
177 {
178 struct device_node *dn;
179 const __be32 *p;
180
181 dn = of_node_get(pci_device_to_OF_node(dev));
182 while (dn) {
183 p = of_get_property(dn, "ibm,pe-total-#msi", NULL);
184 if (p) {
185 pr_debug("rtas_msi: found prop on dn %s\n",
186 dn->full_name);
187 *total = be32_to_cpup(p);
188 return dn;
189 }
190
191 dn = of_get_next_parent(dn);
192 }
193
194 return NULL;
195 }
196
find_pe_dn(struct pci_dev * dev,int * total)197 static struct device_node *find_pe_dn(struct pci_dev *dev, int *total)
198 {
199 struct device_node *dn;
200 struct pci_dn *pdn;
201 struct eeh_dev *edev;
202
203 /* Found our PE and assume 8 at that point. */
204
205 dn = pci_device_to_OF_node(dev);
206 if (!dn)
207 return NULL;
208
209 /* Get the top level device in the PE */
210 edev = pdn_to_eeh_dev(PCI_DN(dn));
211 if (edev->pe)
212 edev = list_first_entry(&edev->pe->edevs, struct eeh_dev, list);
213 pdn = eeh_dev_to_pdn(edev);
214 dn = pdn ? pdn->node : NULL;
215 if (!dn)
216 return NULL;
217
218 /* We actually want the parent */
219 dn = of_get_parent(dn);
220 if (!dn)
221 return NULL;
222
223 /* Hardcode of 8 for old firmwares */
224 *total = 8;
225 pr_debug("rtas_msi: using PE dn %s\n", dn->full_name);
226
227 return dn;
228 }
229
230 struct msi_counts {
231 struct device_node *requestor;
232 int num_devices;
233 int request;
234 int quota;
235 int spare;
236 int over_quota;
237 };
238
count_non_bridge_devices(struct device_node * dn,void * data)239 static void *count_non_bridge_devices(struct device_node *dn, void *data)
240 {
241 struct msi_counts *counts = data;
242 const __be32 *p;
243 u32 class;
244
245 pr_debug("rtas_msi: counting %s\n", dn->full_name);
246
247 p = of_get_property(dn, "class-code", NULL);
248 class = p ? be32_to_cpup(p) : 0;
249
250 if ((class >> 8) != PCI_CLASS_BRIDGE_PCI)
251 counts->num_devices++;
252
253 return NULL;
254 }
255
count_spare_msis(struct device_node * dn,void * data)256 static void *count_spare_msis(struct device_node *dn, void *data)
257 {
258 struct msi_counts *counts = data;
259 const __be32 *p;
260 int req;
261
262 if (dn == counts->requestor)
263 req = counts->request;
264 else {
265 /* We don't know if a driver will try to use MSI or MSI-X,
266 * so we just have to punt and use the larger of the two. */
267 req = 0;
268 p = of_get_property(dn, "ibm,req#msi", NULL);
269 if (p)
270 req = be32_to_cpup(p);
271
272 p = of_get_property(dn, "ibm,req#msi-x", NULL);
273 if (p)
274 req = max(req, (int)be32_to_cpup(p));
275 }
276
277 if (req < counts->quota)
278 counts->spare += counts->quota - req;
279 else if (req > counts->quota)
280 counts->over_quota++;
281
282 return NULL;
283 }
284
msi_quota_for_device(struct pci_dev * dev,int request)285 static int msi_quota_for_device(struct pci_dev *dev, int request)
286 {
287 struct device_node *pe_dn;
288 struct msi_counts counts;
289 int total;
290
291 pr_debug("rtas_msi: calc quota for %s, request %d\n", pci_name(dev),
292 request);
293
294 pe_dn = find_pe_total_msi(dev, &total);
295 if (!pe_dn)
296 pe_dn = find_pe_dn(dev, &total);
297
298 if (!pe_dn) {
299 pr_err("rtas_msi: couldn't find PE for %s\n", pci_name(dev));
300 goto out;
301 }
302
303 pr_debug("rtas_msi: found PE %s\n", pe_dn->full_name);
304
305 memset(&counts, 0, sizeof(struct msi_counts));
306
307 /* Work out how many devices we have below this PE */
308 traverse_pci_devices(pe_dn, count_non_bridge_devices, &counts);
309
310 if (counts.num_devices == 0) {
311 pr_err("rtas_msi: found 0 devices under PE for %s\n",
312 pci_name(dev));
313 goto out;
314 }
315
316 counts.quota = total / counts.num_devices;
317 if (request <= counts.quota)
318 goto out;
319
320 /* else, we have some more calculating to do */
321 counts.requestor = pci_device_to_OF_node(dev);
322 counts.request = request;
323 traverse_pci_devices(pe_dn, count_spare_msis, &counts);
324
325 /* If the quota isn't an integer multiple of the total, we can
326 * use the remainder as spare MSIs for anyone that wants them. */
327 counts.spare += total % counts.num_devices;
328
329 /* Divide any spare by the number of over-quota requestors */
330 if (counts.over_quota)
331 counts.quota += counts.spare / counts.over_quota;
332
333 /* And finally clamp the request to the possibly adjusted quota */
334 request = min(counts.quota, request);
335
336 pr_debug("rtas_msi: request clamped to quota %d\n", request);
337 out:
338 of_node_put(pe_dn);
339
340 return request;
341 }
342
check_msix_entries(struct pci_dev * pdev)343 static int check_msix_entries(struct pci_dev *pdev)
344 {
345 struct msi_desc *entry;
346 int expected;
347
348 /* There's no way for us to express to firmware that we want
349 * a discontiguous, or non-zero based, range of MSI-X entries.
350 * So we must reject such requests. */
351
352 expected = 0;
353 for_each_pci_msi_entry(entry, pdev) {
354 if (entry->msi_attrib.entry_nr != expected) {
355 pr_debug("rtas_msi: bad MSI-X entries.\n");
356 return -EINVAL;
357 }
358 expected++;
359 }
360
361 return 0;
362 }
363
rtas_hack_32bit_msi_gen2(struct pci_dev * pdev)364 static void rtas_hack_32bit_msi_gen2(struct pci_dev *pdev)
365 {
366 u32 addr_hi, addr_lo;
367
368 /*
369 * We should only get in here for IODA1 configs. This is based on the
370 * fact that we using RTAS for MSIs, we don't have the 32 bit MSI RTAS
371 * support, and we are in a PCIe Gen2 slot.
372 */
373 dev_info(&pdev->dev,
374 "rtas_msi: No 32 bit MSI firmware support, forcing 32 bit MSI\n");
375 pci_read_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, &addr_hi);
376 addr_lo = 0xffff0000 | ((addr_hi >> (48 - 32)) << 4);
377 pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_LO, addr_lo);
378 pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, 0);
379 }
380
rtas_setup_msi_irqs(struct pci_dev * pdev,int nvec_in,int type)381 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
382 {
383 struct pci_dn *pdn;
384 int hwirq, virq, i, quota, rc;
385 struct msi_desc *entry;
386 struct msi_msg msg;
387 int nvec = nvec_in;
388 int use_32bit_msi_hack = 0;
389
390 if (type == PCI_CAP_ID_MSIX)
391 rc = check_req_msix(pdev, nvec);
392 else
393 rc = check_req_msi(pdev, nvec);
394
395 if (rc)
396 return rc;
397
398 quota = msi_quota_for_device(pdev, nvec);
399
400 if (quota && quota < nvec)
401 return quota;
402
403 if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev))
404 return -EINVAL;
405
406 /*
407 * Firmware currently refuse any non power of two allocation
408 * so we round up if the quota will allow it.
409 */
410 if (type == PCI_CAP_ID_MSIX) {
411 int m = roundup_pow_of_two(nvec);
412 quota = msi_quota_for_device(pdev, m);
413
414 if (quota >= m)
415 nvec = m;
416 }
417
418 pdn = pci_get_pdn(pdev);
419
420 /*
421 * Try the new more explicit firmware interface, if that fails fall
422 * back to the old interface. The old interface is known to never
423 * return MSI-Xs.
424 */
425 again:
426 if (type == PCI_CAP_ID_MSI) {
427 if (pdev->no_64bit_msi) {
428 rc = rtas_change_msi(pdn, RTAS_CHANGE_32MSI_FN, nvec);
429 if (rc < 0) {
430 /*
431 * We only want to run the 32 bit MSI hack below if
432 * the max bus speed is Gen2 speed
433 */
434 if (pdev->bus->max_bus_speed != PCIE_SPEED_5_0GT)
435 return rc;
436
437 use_32bit_msi_hack = 1;
438 }
439 } else
440 rc = -1;
441
442 if (rc < 0)
443 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);
444
445 if (rc < 0) {
446 pr_debug("rtas_msi: trying the old firmware call.\n");
447 rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
448 }
449
450 if (use_32bit_msi_hack && rc > 0)
451 rtas_hack_32bit_msi_gen2(pdev);
452 } else
453 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
454
455 if (rc != nvec) {
456 if (nvec != nvec_in) {
457 nvec = nvec_in;
458 goto again;
459 }
460 pr_debug("rtas_msi: rtas_change_msi() failed\n");
461 return rc;
462 }
463
464 i = 0;
465 for_each_pci_msi_entry(entry, pdev) {
466 hwirq = rtas_query_irq_number(pdn, i++);
467 if (hwirq < 0) {
468 pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
469 return hwirq;
470 }
471
472 virq = irq_create_mapping(NULL, hwirq);
473
474 if (virq == NO_IRQ) {
475 pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
476 return -ENOSPC;
477 }
478
479 dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
480 irq_set_msi_desc(virq, entry);
481
482 /* Read config space back so we can restore after reset */
483 __pci_read_msi_msg(entry, &msg);
484 entry->msg = msg;
485 }
486
487 return 0;
488 }
489
rtas_msi_pci_irq_fixup(struct pci_dev * pdev)490 static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
491 {
492 /* No LSI -> leave MSIs (if any) configured */
493 if (pdev->irq == NO_IRQ) {
494 dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
495 return;
496 }
497
498 /* No MSI -> MSIs can't have been assigned by fw, leave LSI */
499 if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
500 dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
501 return;
502 }
503
504 dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
505 rtas_disable_msi(pdev);
506 }
507
rtas_msi_init(void)508 static int rtas_msi_init(void)
509 {
510 struct pci_controller *phb;
511
512 query_token = rtas_token("ibm,query-interrupt-source-number");
513 change_token = rtas_token("ibm,change-msi");
514
515 if ((query_token == RTAS_UNKNOWN_SERVICE) ||
516 (change_token == RTAS_UNKNOWN_SERVICE)) {
517 pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
518 return -1;
519 }
520
521 pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");
522
523 WARN_ON(pseries_pci_controller_ops.setup_msi_irqs);
524 pseries_pci_controller_ops.setup_msi_irqs = rtas_setup_msi_irqs;
525 pseries_pci_controller_ops.teardown_msi_irqs = rtas_teardown_msi_irqs;
526
527 list_for_each_entry(phb, &hose_list, list_node) {
528 WARN_ON(phb->controller_ops.setup_msi_irqs);
529 phb->controller_ops.setup_msi_irqs = rtas_setup_msi_irqs;
530 phb->controller_ops.teardown_msi_irqs = rtas_teardown_msi_irqs;
531 }
532
533 WARN_ON(ppc_md.pci_irq_fixup);
534 ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;
535
536 return 0;
537 }
538 machine_arch_initcall(pseries, rtas_msi_init);
539