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)
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 const __be32 *p;
136 u32 req_msi;
137
138 dn = pci_device_to_OF_node(pdev);
139
140 p = of_get_property(dn, prop_name, NULL);
141 if (!p) {
142 pr_debug("rtas_msi: No %s on %pOF\n", prop_name, dn);
143 return -ENOENT;
144 }
145
146 req_msi = be32_to_cpup(p);
147 if (req_msi < nvec) {
148 pr_debug("rtas_msi: %s requests < %d MSIs\n", prop_name, nvec);
149
150 if (req_msi == 0) /* Be paranoid */
151 return -ENOSPC;
152
153 return req_msi;
154 }
155
156 return 0;
157 }
158
check_req_msi(struct pci_dev * pdev,int nvec)159 static int check_req_msi(struct pci_dev *pdev, int nvec)
160 {
161 return check_req(pdev, nvec, "ibm,req#msi");
162 }
163
check_req_msix(struct pci_dev * pdev,int nvec)164 static int check_req_msix(struct pci_dev *pdev, int nvec)
165 {
166 return check_req(pdev, nvec, "ibm,req#msi-x");
167 }
168
169 /* Quota calculation */
170
find_pe_total_msi(struct pci_dev * dev,int * total)171 static struct device_node *find_pe_total_msi(struct pci_dev *dev, int *total)
172 {
173 struct device_node *dn;
174 const __be32 *p;
175
176 dn = of_node_get(pci_device_to_OF_node(dev));
177 while (dn) {
178 p = of_get_property(dn, "ibm,pe-total-#msi", NULL);
179 if (p) {
180 pr_debug("rtas_msi: found prop on dn %pOF\n",
181 dn);
182 *total = be32_to_cpup(p);
183 return dn;
184 }
185
186 dn = of_get_next_parent(dn);
187 }
188
189 return NULL;
190 }
191
find_pe_dn(struct pci_dev * dev,int * total)192 static struct device_node *find_pe_dn(struct pci_dev *dev, int *total)
193 {
194 struct device_node *dn;
195 struct eeh_dev *edev;
196
197 /* Found our PE and assume 8 at that point. */
198
199 dn = pci_device_to_OF_node(dev);
200 if (!dn)
201 return NULL;
202
203 /* Get the top level device in the PE */
204 edev = pdn_to_eeh_dev(PCI_DN(dn));
205 if (edev->pe)
206 edev = list_first_entry(&edev->pe->edevs, struct eeh_dev, list);
207 dn = pci_device_to_OF_node(edev->pdev);
208 if (!dn)
209 return NULL;
210
211 /* We actually want the parent */
212 dn = of_get_parent(dn);
213 if (!dn)
214 return NULL;
215
216 /* Hardcode of 8 for old firmwares */
217 *total = 8;
218 pr_debug("rtas_msi: using PE dn %pOF\n", dn);
219
220 return dn;
221 }
222
223 struct msi_counts {
224 struct device_node *requestor;
225 int num_devices;
226 int request;
227 int quota;
228 int spare;
229 int over_quota;
230 };
231
count_non_bridge_devices(struct device_node * dn,void * data)232 static void *count_non_bridge_devices(struct device_node *dn, void *data)
233 {
234 struct msi_counts *counts = data;
235 const __be32 *p;
236 u32 class;
237
238 pr_debug("rtas_msi: counting %pOF\n", dn);
239
240 p = of_get_property(dn, "class-code", NULL);
241 class = p ? be32_to_cpup(p) : 0;
242
243 if ((class >> 8) != PCI_CLASS_BRIDGE_PCI)
244 counts->num_devices++;
245
246 return NULL;
247 }
248
count_spare_msis(struct device_node * dn,void * data)249 static void *count_spare_msis(struct device_node *dn, void *data)
250 {
251 struct msi_counts *counts = data;
252 const __be32 *p;
253 int req;
254
255 if (dn == counts->requestor)
256 req = counts->request;
257 else {
258 /* We don't know if a driver will try to use MSI or MSI-X,
259 * so we just have to punt and use the larger of the two. */
260 req = 0;
261 p = of_get_property(dn, "ibm,req#msi", NULL);
262 if (p)
263 req = be32_to_cpup(p);
264
265 p = of_get_property(dn, "ibm,req#msi-x", NULL);
266 if (p)
267 req = max(req, (int)be32_to_cpup(p));
268 }
269
270 if (req < counts->quota)
271 counts->spare += counts->quota - req;
272 else if (req > counts->quota)
273 counts->over_quota++;
274
275 return NULL;
276 }
277
msi_quota_for_device(struct pci_dev * dev,int request)278 static int msi_quota_for_device(struct pci_dev *dev, int request)
279 {
280 struct device_node *pe_dn;
281 struct msi_counts counts;
282 int total;
283
284 pr_debug("rtas_msi: calc quota for %s, request %d\n", pci_name(dev),
285 request);
286
287 pe_dn = find_pe_total_msi(dev, &total);
288 if (!pe_dn)
289 pe_dn = find_pe_dn(dev, &total);
290
291 if (!pe_dn) {
292 pr_err("rtas_msi: couldn't find PE for %s\n", pci_name(dev));
293 goto out;
294 }
295
296 pr_debug("rtas_msi: found PE %pOF\n", pe_dn);
297
298 memset(&counts, 0, sizeof(struct msi_counts));
299
300 /* Work out how many devices we have below this PE */
301 pci_traverse_device_nodes(pe_dn, count_non_bridge_devices, &counts);
302
303 if (counts.num_devices == 0) {
304 pr_err("rtas_msi: found 0 devices under PE for %s\n",
305 pci_name(dev));
306 goto out;
307 }
308
309 counts.quota = total / counts.num_devices;
310 if (request <= counts.quota)
311 goto out;
312
313 /* else, we have some more calculating to do */
314 counts.requestor = pci_device_to_OF_node(dev);
315 counts.request = request;
316 pci_traverse_device_nodes(pe_dn, count_spare_msis, &counts);
317
318 /* If the quota isn't an integer multiple of the total, we can
319 * use the remainder as spare MSIs for anyone that wants them. */
320 counts.spare += total % counts.num_devices;
321
322 /* Divide any spare by the number of over-quota requestors */
323 if (counts.over_quota)
324 counts.quota += counts.spare / counts.over_quota;
325
326 /* And finally clamp the request to the possibly adjusted quota */
327 request = min(counts.quota, request);
328
329 pr_debug("rtas_msi: request clamped to quota %d\n", request);
330 out:
331 of_node_put(pe_dn);
332
333 return request;
334 }
335
check_msix_entries(struct pci_dev * pdev)336 static int check_msix_entries(struct pci_dev *pdev)
337 {
338 struct msi_desc *entry;
339 int expected;
340
341 /* There's no way for us to express to firmware that we want
342 * a discontiguous, or non-zero based, range of MSI-X entries.
343 * So we must reject such requests. */
344
345 expected = 0;
346 for_each_pci_msi_entry(entry, pdev) {
347 if (entry->msi_attrib.entry_nr != expected) {
348 pr_debug("rtas_msi: bad MSI-X entries.\n");
349 return -EINVAL;
350 }
351 expected++;
352 }
353
354 return 0;
355 }
356
rtas_hack_32bit_msi_gen2(struct pci_dev * pdev)357 static void rtas_hack_32bit_msi_gen2(struct pci_dev *pdev)
358 {
359 u32 addr_hi, addr_lo;
360
361 /*
362 * We should only get in here for IODA1 configs. This is based on the
363 * fact that we using RTAS for MSIs, we don't have the 32 bit MSI RTAS
364 * support, and we are in a PCIe Gen2 slot.
365 */
366 dev_info(&pdev->dev,
367 "rtas_msi: No 32 bit MSI firmware support, forcing 32 bit MSI\n");
368 pci_read_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, &addr_hi);
369 addr_lo = 0xffff0000 | ((addr_hi >> (48 - 32)) << 4);
370 pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_LO, addr_lo);
371 pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, 0);
372 }
373
rtas_setup_msi_irqs(struct pci_dev * pdev,int nvec_in,int type)374 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
375 {
376 struct pci_dn *pdn;
377 int hwirq, virq, i, quota, rc;
378 struct msi_desc *entry;
379 struct msi_msg msg;
380 int nvec = nvec_in;
381 int use_32bit_msi_hack = 0;
382
383 if (type == PCI_CAP_ID_MSIX)
384 rc = check_req_msix(pdev, nvec);
385 else
386 rc = check_req_msi(pdev, nvec);
387
388 if (rc)
389 return rc;
390
391 quota = msi_quota_for_device(pdev, nvec);
392
393 if (quota && quota < nvec)
394 return quota;
395
396 if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev))
397 return -EINVAL;
398
399 /*
400 * Firmware currently refuse any non power of two allocation
401 * so we round up if the quota will allow it.
402 */
403 if (type == PCI_CAP_ID_MSIX) {
404 int m = roundup_pow_of_two(nvec);
405 quota = msi_quota_for_device(pdev, m);
406
407 if (quota >= m)
408 nvec = m;
409 }
410
411 pdn = pci_get_pdn(pdev);
412
413 /*
414 * Try the new more explicit firmware interface, if that fails fall
415 * back to the old interface. The old interface is known to never
416 * return MSI-Xs.
417 */
418 again:
419 if (type == PCI_CAP_ID_MSI) {
420 if (pdev->no_64bit_msi) {
421 rc = rtas_change_msi(pdn, RTAS_CHANGE_32MSI_FN, nvec);
422 if (rc < 0) {
423 /*
424 * We only want to run the 32 bit MSI hack below if
425 * the max bus speed is Gen2 speed
426 */
427 if (pdev->bus->max_bus_speed != PCIE_SPEED_5_0GT)
428 return rc;
429
430 use_32bit_msi_hack = 1;
431 }
432 } else
433 rc = -1;
434
435 if (rc < 0)
436 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);
437
438 if (rc < 0) {
439 pr_debug("rtas_msi: trying the old firmware call.\n");
440 rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
441 }
442
443 if (use_32bit_msi_hack && rc > 0)
444 rtas_hack_32bit_msi_gen2(pdev);
445 } else
446 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
447
448 if (rc != nvec) {
449 if (nvec != nvec_in) {
450 nvec = nvec_in;
451 goto again;
452 }
453 pr_debug("rtas_msi: rtas_change_msi() failed\n");
454 return rc;
455 }
456
457 i = 0;
458 for_each_pci_msi_entry(entry, pdev) {
459 hwirq = rtas_query_irq_number(pdn, i++);
460 if (hwirq < 0) {
461 pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
462 return hwirq;
463 }
464
465 virq = irq_create_mapping(NULL, hwirq);
466
467 if (!virq) {
468 pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
469 return -ENOSPC;
470 }
471
472 dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
473 irq_set_msi_desc(virq, entry);
474
475 /* Read config space back so we can restore after reset */
476 __pci_read_msi_msg(entry, &msg);
477 entry->msg = msg;
478 }
479
480 return 0;
481 }
482
rtas_msi_pci_irq_fixup(struct pci_dev * pdev)483 static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
484 {
485 /* No LSI -> leave MSIs (if any) configured */
486 if (!pdev->irq) {
487 dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
488 return;
489 }
490
491 /* No MSI -> MSIs can't have been assigned by fw, leave LSI */
492 if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
493 dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
494 return;
495 }
496
497 dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
498 rtas_disable_msi(pdev);
499 }
500
rtas_msi_init(void)501 static int rtas_msi_init(void)
502 {
503 struct pci_controller *phb;
504
505 query_token = rtas_token("ibm,query-interrupt-source-number");
506 change_token = rtas_token("ibm,change-msi");
507
508 if ((query_token == RTAS_UNKNOWN_SERVICE) ||
509 (change_token == RTAS_UNKNOWN_SERVICE)) {
510 pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
511 return -1;
512 }
513
514 pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");
515
516 WARN_ON(pseries_pci_controller_ops.setup_msi_irqs);
517 pseries_pci_controller_ops.setup_msi_irqs = rtas_setup_msi_irqs;
518 pseries_pci_controller_ops.teardown_msi_irqs = rtas_teardown_msi_irqs;
519
520 list_for_each_entry(phb, &hose_list, list_node) {
521 WARN_ON(phb->controller_ops.setup_msi_irqs);
522 phb->controller_ops.setup_msi_irqs = rtas_setup_msi_irqs;
523 phb->controller_ops.teardown_msi_irqs = rtas_teardown_msi_irqs;
524 }
525
526 WARN_ON(ppc_md.pci_irq_fixup);
527 ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;
528
529 return 0;
530 }
531 machine_arch_initcall(pseries, rtas_msi_init);
532