1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2006 Jake Moilanen <moilanen@austin.ibm.com>, IBM Corp.
4 * Copyright 2006-2007 Michael Ellerman, IBM Corp.
5 */
6
7 #include <linux/crash_dump.h>
8 #include <linux/device.h>
9 #include <linux/irq.h>
10 #include <linux/msi.h>
11
12 #include <asm/rtas.h>
13 #include <asm/hw_irq.h>
14 #include <asm/ppc-pci.h>
15 #include <asm/machdep.h>
16
17 #include "pseries.h"
18
19 static int query_token, change_token;
20
21 #define RTAS_QUERY_FN 0
22 #define RTAS_CHANGE_FN 1
23 #define RTAS_RESET_FN 2
24 #define RTAS_CHANGE_MSI_FN 3
25 #define RTAS_CHANGE_MSIX_FN 4
26 #define RTAS_CHANGE_32MSI_FN 5
27
28 /* RTAS Helpers */
29
rtas_change_msi(struct pci_dn * pdn,u32 func,u32 num_irqs)30 static int rtas_change_msi(struct pci_dn *pdn, u32 func, u32 num_irqs)
31 {
32 u32 addr, seq_num, rtas_ret[3];
33 unsigned long buid;
34 int rc;
35
36 addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
37 buid = pdn->phb->buid;
38
39 seq_num = 1;
40 do {
41 if (func == RTAS_CHANGE_MSI_FN || func == RTAS_CHANGE_MSIX_FN ||
42 func == RTAS_CHANGE_32MSI_FN)
43 rc = rtas_call(change_token, 6, 4, rtas_ret, addr,
44 BUID_HI(buid), BUID_LO(buid),
45 func, num_irqs, seq_num);
46 else
47 rc = rtas_call(change_token, 6, 3, rtas_ret, addr,
48 BUID_HI(buid), BUID_LO(buid),
49 func, num_irqs, seq_num);
50
51 seq_num = rtas_ret[1];
52 } while (rtas_busy_delay(rc));
53
54 /*
55 * If the RTAS call succeeded, return the number of irqs allocated.
56 * If not, make sure we return a negative error code.
57 */
58 if (rc == 0)
59 rc = rtas_ret[0];
60 else if (rc > 0)
61 rc = -rc;
62
63 pr_debug("rtas_msi: ibm,change_msi(func=%d,num=%d), got %d rc = %d\n",
64 func, num_irqs, rtas_ret[0], rc);
65
66 return rc;
67 }
68
rtas_disable_msi(struct pci_dev * pdev)69 static void rtas_disable_msi(struct pci_dev *pdev)
70 {
71 struct pci_dn *pdn;
72
73 pdn = pci_get_pdn(pdev);
74 if (!pdn)
75 return;
76
77 /*
78 * disabling MSI with the explicit interface also disables MSI-X
79 */
80 if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0) != 0) {
81 /*
82 * may have failed because explicit interface is not
83 * present
84 */
85 if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) {
86 pr_debug("rtas_msi: Setting MSIs to 0 failed!\n");
87 }
88 }
89 }
90
rtas_query_irq_number(struct pci_dn * pdn,int offset)91 static int rtas_query_irq_number(struct pci_dn *pdn, int offset)
92 {
93 u32 addr, rtas_ret[2];
94 unsigned long buid;
95 int rc;
96
97 addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
98 buid = pdn->phb->buid;
99
100 do {
101 rc = rtas_call(query_token, 4, 3, rtas_ret, addr,
102 BUID_HI(buid), BUID_LO(buid), offset);
103 } while (rtas_busy_delay(rc));
104
105 if (rc) {
106 pr_debug("rtas_msi: error (%d) querying source number\n", rc);
107 return rc;
108 }
109
110 return rtas_ret[0];
111 }
112
rtas_teardown_msi_irqs(struct pci_dev * pdev)113 static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
114 {
115 struct msi_desc *entry;
116
117 for_each_pci_msi_entry(entry, pdev) {
118 if (!entry->irq)
119 continue;
120
121 irq_set_msi_desc(entry->irq, NULL);
122 irq_dispose_mapping(entry->irq);
123 }
124
125 rtas_disable_msi(pdev);
126 }
127
check_req(struct pci_dev * pdev,int nvec,char * prop_name)128 static int check_req(struct pci_dev *pdev, int nvec, char *prop_name)
129 {
130 struct device_node *dn;
131 const __be32 *p;
132 u32 req_msi;
133
134 dn = pci_device_to_OF_node(pdev);
135
136 p = of_get_property(dn, prop_name, NULL);
137 if (!p) {
138 pr_debug("rtas_msi: No %s on %pOF\n", prop_name, dn);
139 return -ENOENT;
140 }
141
142 req_msi = be32_to_cpup(p);
143 if (req_msi < nvec) {
144 pr_debug("rtas_msi: %s requests < %d MSIs\n", prop_name, nvec);
145
146 if (req_msi == 0) /* Be paranoid */
147 return -ENOSPC;
148
149 return req_msi;
150 }
151
152 return 0;
153 }
154
check_req_msi(struct pci_dev * pdev,int nvec)155 static int check_req_msi(struct pci_dev *pdev, int nvec)
156 {
157 return check_req(pdev, nvec, "ibm,req#msi");
158 }
159
check_req_msix(struct pci_dev * pdev,int nvec)160 static int check_req_msix(struct pci_dev *pdev, int nvec)
161 {
162 return check_req(pdev, nvec, "ibm,req#msi-x");
163 }
164
165 /* Quota calculation */
166
find_pe_total_msi(struct pci_dev * dev,int * total)167 static struct device_node *find_pe_total_msi(struct pci_dev *dev, int *total)
168 {
169 struct device_node *dn;
170 const __be32 *p;
171
172 dn = of_node_get(pci_device_to_OF_node(dev));
173 while (dn) {
174 p = of_get_property(dn, "ibm,pe-total-#msi", NULL);
175 if (p) {
176 pr_debug("rtas_msi: found prop on dn %pOF\n",
177 dn);
178 *total = be32_to_cpup(p);
179 return dn;
180 }
181
182 dn = of_get_next_parent(dn);
183 }
184
185 return NULL;
186 }
187
find_pe_dn(struct pci_dev * dev,int * total)188 static struct device_node *find_pe_dn(struct pci_dev *dev, int *total)
189 {
190 struct device_node *dn;
191 struct eeh_dev *edev;
192
193 /* Found our PE and assume 8 at that point. */
194
195 dn = pci_device_to_OF_node(dev);
196 if (!dn)
197 return NULL;
198
199 /* Get the top level device in the PE */
200 edev = pdn_to_eeh_dev(PCI_DN(dn));
201 if (edev->pe)
202 edev = list_first_entry(&edev->pe->edevs, struct eeh_dev,
203 entry);
204 dn = pci_device_to_OF_node(edev->pdev);
205 if (!dn)
206 return NULL;
207
208 /* We actually want the parent */
209 dn = of_get_parent(dn);
210 if (!dn)
211 return NULL;
212
213 /* Hardcode of 8 for old firmwares */
214 *total = 8;
215 pr_debug("rtas_msi: using PE dn %pOF\n", dn);
216
217 return dn;
218 }
219
220 struct msi_counts {
221 struct device_node *requestor;
222 int num_devices;
223 int request;
224 int quota;
225 int spare;
226 int over_quota;
227 };
228
count_non_bridge_devices(struct device_node * dn,void * data)229 static void *count_non_bridge_devices(struct device_node *dn, void *data)
230 {
231 struct msi_counts *counts = data;
232 const __be32 *p;
233 u32 class;
234
235 pr_debug("rtas_msi: counting %pOF\n", dn);
236
237 p = of_get_property(dn, "class-code", NULL);
238 class = p ? be32_to_cpup(p) : 0;
239
240 if ((class >> 8) != PCI_CLASS_BRIDGE_PCI)
241 counts->num_devices++;
242
243 return NULL;
244 }
245
count_spare_msis(struct device_node * dn,void * data)246 static void *count_spare_msis(struct device_node *dn, void *data)
247 {
248 struct msi_counts *counts = data;
249 const __be32 *p;
250 int req;
251
252 if (dn == counts->requestor)
253 req = counts->request;
254 else {
255 /* We don't know if a driver will try to use MSI or MSI-X,
256 * so we just have to punt and use the larger of the two. */
257 req = 0;
258 p = of_get_property(dn, "ibm,req#msi", NULL);
259 if (p)
260 req = be32_to_cpup(p);
261
262 p = of_get_property(dn, "ibm,req#msi-x", NULL);
263 if (p)
264 req = max(req, (int)be32_to_cpup(p));
265 }
266
267 if (req < counts->quota)
268 counts->spare += counts->quota - req;
269 else if (req > counts->quota)
270 counts->over_quota++;
271
272 return NULL;
273 }
274
msi_quota_for_device(struct pci_dev * dev,int request)275 static int msi_quota_for_device(struct pci_dev *dev, int request)
276 {
277 struct device_node *pe_dn;
278 struct msi_counts counts;
279 int total;
280
281 pr_debug("rtas_msi: calc quota for %s, request %d\n", pci_name(dev),
282 request);
283
284 pe_dn = find_pe_total_msi(dev, &total);
285 if (!pe_dn)
286 pe_dn = find_pe_dn(dev, &total);
287
288 if (!pe_dn) {
289 pr_err("rtas_msi: couldn't find PE for %s\n", pci_name(dev));
290 goto out;
291 }
292
293 pr_debug("rtas_msi: found PE %pOF\n", pe_dn);
294
295 memset(&counts, 0, sizeof(struct msi_counts));
296
297 /* Work out how many devices we have below this PE */
298 pci_traverse_device_nodes(pe_dn, count_non_bridge_devices, &counts);
299
300 if (counts.num_devices == 0) {
301 pr_err("rtas_msi: found 0 devices under PE for %s\n",
302 pci_name(dev));
303 goto out;
304 }
305
306 counts.quota = total / counts.num_devices;
307 if (request <= counts.quota)
308 goto out;
309
310 /* else, we have some more calculating to do */
311 counts.requestor = pci_device_to_OF_node(dev);
312 counts.request = request;
313 pci_traverse_device_nodes(pe_dn, count_spare_msis, &counts);
314
315 /* If the quota isn't an integer multiple of the total, we can
316 * use the remainder as spare MSIs for anyone that wants them. */
317 counts.spare += total % counts.num_devices;
318
319 /* Divide any spare by the number of over-quota requestors */
320 if (counts.over_quota)
321 counts.quota += counts.spare / counts.over_quota;
322
323 /* And finally clamp the request to the possibly adjusted quota */
324 request = min(counts.quota, request);
325
326 pr_debug("rtas_msi: request clamped to quota %d\n", request);
327 out:
328 of_node_put(pe_dn);
329
330 return request;
331 }
332
check_msix_entries(struct pci_dev * pdev)333 static int check_msix_entries(struct pci_dev *pdev)
334 {
335 struct msi_desc *entry;
336 int expected;
337
338 /* There's no way for us to express to firmware that we want
339 * a discontiguous, or non-zero based, range of MSI-X entries.
340 * So we must reject such requests. */
341
342 expected = 0;
343 for_each_pci_msi_entry(entry, pdev) {
344 if (entry->msi_attrib.entry_nr != expected) {
345 pr_debug("rtas_msi: bad MSI-X entries.\n");
346 return -EINVAL;
347 }
348 expected++;
349 }
350
351 return 0;
352 }
353
rtas_hack_32bit_msi_gen2(struct pci_dev * pdev)354 static void rtas_hack_32bit_msi_gen2(struct pci_dev *pdev)
355 {
356 u32 addr_hi, addr_lo;
357
358 /*
359 * We should only get in here for IODA1 configs. This is based on the
360 * fact that we using RTAS for MSIs, we don't have the 32 bit MSI RTAS
361 * support, and we are in a PCIe Gen2 slot.
362 */
363 dev_info(&pdev->dev,
364 "rtas_msi: No 32 bit MSI firmware support, forcing 32 bit MSI\n");
365 pci_read_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, &addr_hi);
366 addr_lo = 0xffff0000 | ((addr_hi >> (48 - 32)) << 4);
367 pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_LO, addr_lo);
368 pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, 0);
369 }
370
rtas_setup_msi_irqs(struct pci_dev * pdev,int nvec_in,int type)371 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
372 {
373 struct pci_dn *pdn;
374 int hwirq, virq, i, quota, rc;
375 struct msi_desc *entry;
376 struct msi_msg msg;
377 int nvec = nvec_in;
378 int use_32bit_msi_hack = 0;
379
380 if (type == PCI_CAP_ID_MSIX)
381 rc = check_req_msix(pdev, nvec);
382 else
383 rc = check_req_msi(pdev, nvec);
384
385 if (rc)
386 return rc;
387
388 quota = msi_quota_for_device(pdev, nvec);
389
390 if (quota && quota < nvec)
391 return quota;
392
393 if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev))
394 return -EINVAL;
395
396 /*
397 * Firmware currently refuse any non power of two allocation
398 * so we round up if the quota will allow it.
399 */
400 if (type == PCI_CAP_ID_MSIX) {
401 int m = roundup_pow_of_two(nvec);
402 quota = msi_quota_for_device(pdev, m);
403
404 if (quota >= m)
405 nvec = m;
406 }
407
408 pdn = pci_get_pdn(pdev);
409
410 /*
411 * Try the new more explicit firmware interface, if that fails fall
412 * back to the old interface. The old interface is known to never
413 * return MSI-Xs.
414 */
415 again:
416 if (type == PCI_CAP_ID_MSI) {
417 if (pdev->no_64bit_msi) {
418 rc = rtas_change_msi(pdn, RTAS_CHANGE_32MSI_FN, nvec);
419 if (rc < 0) {
420 /*
421 * We only want to run the 32 bit MSI hack below if
422 * the max bus speed is Gen2 speed
423 */
424 if (pdev->bus->max_bus_speed != PCIE_SPEED_5_0GT)
425 return rc;
426
427 use_32bit_msi_hack = 1;
428 }
429 } else
430 rc = -1;
431
432 if (rc < 0)
433 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);
434
435 if (rc < 0) {
436 pr_debug("rtas_msi: trying the old firmware call.\n");
437 rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
438 }
439
440 if (use_32bit_msi_hack && rc > 0)
441 rtas_hack_32bit_msi_gen2(pdev);
442 } else
443 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
444
445 if (rc != nvec) {
446 if (nvec != nvec_in) {
447 nvec = nvec_in;
448 goto again;
449 }
450 pr_debug("rtas_msi: rtas_change_msi() failed\n");
451 return rc;
452 }
453
454 i = 0;
455 for_each_pci_msi_entry(entry, pdev) {
456 hwirq = rtas_query_irq_number(pdn, i++);
457 if (hwirq < 0) {
458 pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
459 return hwirq;
460 }
461
462 /*
463 * Depending on the number of online CPUs in the original
464 * kernel, it is likely for CPU #0 to be offline in a kdump
465 * kernel. The associated IRQs in the affinity mappings
466 * provided by irq_create_affinity_masks() are thus not
467 * started by irq_startup(), as per-design for managed IRQs.
468 * This can be a problem with multi-queue block devices driven
469 * by blk-mq : such a non-started IRQ is very likely paired
470 * with the single queue enforced by blk-mq during kdump (see
471 * blk_mq_alloc_tag_set()). This causes the device to remain
472 * silent and likely hangs the guest at some point.
473 *
474 * We don't really care for fine-grained affinity when doing
475 * kdump actually : simply ignore the pre-computed affinity
476 * masks in this case and let the default mask with all CPUs
477 * be used when creating the IRQ mappings.
478 */
479 if (is_kdump_kernel())
480 virq = irq_create_mapping(NULL, hwirq);
481 else
482 virq = irq_create_mapping_affinity(NULL, hwirq,
483 entry->affinity);
484
485 if (!virq) {
486 pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
487 return -ENOSPC;
488 }
489
490 dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
491 irq_set_msi_desc(virq, entry);
492
493 /* Read config space back so we can restore after reset */
494 __pci_read_msi_msg(entry, &msg);
495 entry->msg = msg;
496 }
497
498 return 0;
499 }
500
rtas_msi_pci_irq_fixup(struct pci_dev * pdev)501 static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
502 {
503 /* No LSI -> leave MSIs (if any) configured */
504 if (!pdev->irq) {
505 dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
506 return;
507 }
508
509 /* No MSI -> MSIs can't have been assigned by fw, leave LSI */
510 if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
511 dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
512 return;
513 }
514
515 dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
516 rtas_disable_msi(pdev);
517 }
518
rtas_msi_init(void)519 static int rtas_msi_init(void)
520 {
521 struct pci_controller *phb;
522
523 query_token = rtas_token("ibm,query-interrupt-source-number");
524 change_token = rtas_token("ibm,change-msi");
525
526 if ((query_token == RTAS_UNKNOWN_SERVICE) ||
527 (change_token == RTAS_UNKNOWN_SERVICE)) {
528 pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
529 return -1;
530 }
531
532 pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");
533
534 WARN_ON(pseries_pci_controller_ops.setup_msi_irqs);
535 pseries_pci_controller_ops.setup_msi_irqs = rtas_setup_msi_irqs;
536 pseries_pci_controller_ops.teardown_msi_irqs = rtas_teardown_msi_irqs;
537
538 list_for_each_entry(phb, &hose_list, list_node) {
539 WARN_ON(phb->controller_ops.setup_msi_irqs);
540 phb->controller_ops.setup_msi_irqs = rtas_setup_msi_irqs;
541 phb->controller_ops.teardown_msi_irqs = rtas_teardown_msi_irqs;
542 }
543
544 WARN_ON(ppc_md.pci_irq_fixup);
545 ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;
546
547 return 0;
548 }
549 machine_arch_initcall(pseries, rtas_msi_init);
550