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TOMOYO Linux Cross Reference
Linux/arch/powerpc/platforms/pseries/msi.c

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  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 
 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 
 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 
 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 
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 
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 
159 static int check_req_msi(struct pci_dev *pdev, int nvec)
160 {
161         return check_req(pdev, nvec, "ibm,req#msi");
162 }
163 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 

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