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