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 == 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 
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 
164 static int check_req_msi(struct pci_dev *pdev, int nvec)
165 {
166 	return check_req(pdev, nvec, "ibm,req#msi");
167 }
168 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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