1 // SPDX-License-Identifier: GPL-2.0
2 #define KMSG_COMPONENT "zpci"
3 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
4
5 #include <linux/kernel.h>
6 #include <linux/irq.h>
7 #include <linux/kernel_stat.h>
8 #include <linux/pci.h>
9 #include <linux/msi.h>
10 #include <linux/smp.h>
11
12 #include <asm/isc.h>
13 #include <asm/airq.h>
14 #include <asm/tpi.h>
15
16 static enum {FLOATING, DIRECTED} irq_delivery;
17
18 /*
19 * summary bit vector
20 * FLOATING - summary bit per function
21 * DIRECTED - summary bit per cpu (only used in fallback path)
22 */
23 static struct airq_iv *zpci_sbv;
24
25 /*
26 * interrupt bit vectors
27 * FLOATING - interrupt bit vector per function
28 * DIRECTED - interrupt bit vector per cpu
29 */
30 static struct airq_iv **zpci_ibv;
31
32 /* Modify PCI: Register floating adapter interruptions */
33 static int zpci_set_airq(struct zpci_dev *zdev)
34 {
35 u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_REG_INT);
36 struct zpci_fib fib = {0};
37 u8 status;
38
39 fib.fmt0.isc = PCI_ISC;
40 fib.fmt0.sum = 1; /* enable summary notifications */
41 fib.fmt0.noi = airq_iv_end(zdev->aibv);
42 fib.fmt0.aibv = virt_to_phys(zdev->aibv->vector);
43 fib.fmt0.aibvo = 0; /* each zdev has its own interrupt vector */
44 fib.fmt0.aisb = virt_to_phys(zpci_sbv->vector) + (zdev->aisb / 64) * 8;
45 fib.fmt0.aisbo = zdev->aisb & 63;
46 fib.gd = zdev->gisa;
47
48 return zpci_mod_fc(req, &fib, &status) ? -EIO : 0;
49 }
50
51 /* Modify PCI: Unregister floating adapter interruptions */
52 static int zpci_clear_airq(struct zpci_dev *zdev)
53 {
54 u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_DEREG_INT);
55 struct zpci_fib fib = {0};
56 u8 cc, status;
57
58 fib.gd = zdev->gisa;
59
60 cc = zpci_mod_fc(req, &fib, &status);
61 if (cc == 3 || (cc == 1 && status == 24))
62 /* Function already gone or IRQs already deregistered. */
63 cc = 0;
64
65 return cc ? -EIO : 0;
66 }
67
68 /* Modify PCI: Register CPU directed interruptions */
69 static int zpci_set_directed_irq(struct zpci_dev *zdev)
70 {
71 u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_REG_INT_D);
72 struct zpci_fib fib = {0};
73 u8 status;
74
75 fib.fmt = 1;
76 fib.fmt1.noi = zdev->msi_nr_irqs;
77 fib.fmt1.dibvo = zdev->msi_first_bit;
78 fib.gd = zdev->gisa;
79
80 return zpci_mod_fc(req, &fib, &status) ? -EIO : 0;
81 }
82
83 /* Modify PCI: Unregister CPU directed interruptions */
84 static int zpci_clear_directed_irq(struct zpci_dev *zdev)
85 {
86 u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_DEREG_INT_D);
87 struct zpci_fib fib = {0};
88 u8 cc, status;
89
90 fib.fmt = 1;
91 fib.gd = zdev->gisa;
92 cc = zpci_mod_fc(req, &fib, &status);
93 if (cc == 3 || (cc == 1 && status == 24))
94 /* Function already gone or IRQs already deregistered. */
95 cc = 0;
96
97 return cc ? -EIO : 0;
98 }
99
100 /* Register adapter interruptions */
101 static int zpci_set_irq(struct zpci_dev *zdev)
102 {
103 int rc;
104
105 if (irq_delivery == DIRECTED)
106 rc = zpci_set_directed_irq(zdev);
107 else
108 rc = zpci_set_airq(zdev);
109
110 if (!rc)
111 zdev->irqs_registered = 1;
112
113 return rc;
114 }
115
116 /* Clear adapter interruptions */
117 static int zpci_clear_irq(struct zpci_dev *zdev)
118 {
119 int rc;
120
121 if (irq_delivery == DIRECTED)
122 rc = zpci_clear_directed_irq(zdev);
123 else
124 rc = zpci_clear_airq(zdev);
125
126 if (!rc)
127 zdev->irqs_registered = 0;
128
129 return rc;
130 }
131
132 static int zpci_set_irq_affinity(struct irq_data *data, const struct cpumask *dest,
133 bool force)
134 {
135 struct msi_desc *entry = irq_data_get_msi_desc(data);
136 struct msi_msg msg = entry->msg;
137 int cpu_addr = smp_cpu_get_cpu_address(cpumask_first(dest));
138
139 msg.address_lo &= 0xff0000ff;
140 msg.address_lo |= (cpu_addr << 8);
141 pci_write_msi_msg(data->irq, &msg);
142
143 return IRQ_SET_MASK_OK;
144 }
145
146 static struct irq_chip zpci_irq_chip = {
147 .name = "PCI-MSI",
148 .irq_unmask = pci_msi_unmask_irq,
149 .irq_mask = pci_msi_mask_irq,
150 };
151
152 static void zpci_handle_cpu_local_irq(bool rescan)
153 {
154 struct airq_iv *dibv = zpci_ibv[smp_processor_id()];
155 union zpci_sic_iib iib = {{0}};
156 unsigned long bit;
157 int irqs_on = 0;
158
159 for (bit = 0;;) {
160 /* Scan the directed IRQ bit vector */
161 bit = airq_iv_scan(dibv, bit, airq_iv_end(dibv));
162 if (bit == -1UL) {
163 if (!rescan || irqs_on++)
164 /* End of second scan with interrupts on. */
165 break;
166 /* First scan complete, re-enable interrupts. */
167 if (zpci_set_irq_ctrl(SIC_IRQ_MODE_D_SINGLE, PCI_ISC, &iib))
168 break;
169 bit = 0;
170 continue;
171 }
172 inc_irq_stat(IRQIO_MSI);
173 generic_handle_irq(airq_iv_get_data(dibv, bit));
174 }
175 }
176
177 struct cpu_irq_data {
178 call_single_data_t csd;
179 atomic_t scheduled;
180 };
181 static DEFINE_PER_CPU_SHARED_ALIGNED(struct cpu_irq_data, irq_data);
182
183 static void zpci_handle_remote_irq(void *data)
184 {
185 atomic_t *scheduled = data;
186
187 do {
188 zpci_handle_cpu_local_irq(false);
189 } while (atomic_dec_return(scheduled));
190 }
191
192 static void zpci_handle_fallback_irq(void)
193 {
194 struct cpu_irq_data *cpu_data;
195 union zpci_sic_iib iib = {{0}};
196 unsigned long cpu;
197 int irqs_on = 0;
198
199 for (cpu = 0;;) {
200 cpu = airq_iv_scan(zpci_sbv, cpu, airq_iv_end(zpci_sbv));
201 if (cpu == -1UL) {
202 if (irqs_on++)
203 /* End of second scan with interrupts on. */
204 break;
205 /* First scan complete, re-enable interrupts. */
206 if (zpci_set_irq_ctrl(SIC_IRQ_MODE_SINGLE, PCI_ISC, &iib))
207 break;
208 cpu = 0;
209 continue;
210 }
211 cpu_data = &per_cpu(irq_data, cpu);
212 if (atomic_inc_return(&cpu_data->scheduled) > 1)
213 continue;
214
215 INIT_CSD(&cpu_data->csd, zpci_handle_remote_irq, &cpu_data->scheduled);
216 smp_call_function_single_async(cpu, &cpu_data->csd);
217 }
218 }
219
220 static void zpci_directed_irq_handler(struct airq_struct *airq,
221 struct tpi_info *tpi_info)
222 {
223 bool floating = !tpi_info->directed_irq;
224
225 if (floating) {
226 inc_irq_stat(IRQIO_PCF);
227 zpci_handle_fallback_irq();
228 } else {
229 inc_irq_stat(IRQIO_PCD);
230 zpci_handle_cpu_local_irq(true);
231 }
232 }
233
234 static void zpci_floating_irq_handler(struct airq_struct *airq,
235 struct tpi_info *tpi_info)
236 {
237 union zpci_sic_iib iib = {{0}};
238 unsigned long si, ai;
239 struct airq_iv *aibv;
240 int irqs_on = 0;
241
242 inc_irq_stat(IRQIO_PCF);
243 for (si = 0;;) {
244 /* Scan adapter summary indicator bit vector */
245 si = airq_iv_scan(zpci_sbv, si, airq_iv_end(zpci_sbv));
246 if (si == -1UL) {
247 if (irqs_on++)
248 /* End of second scan with interrupts on. */
249 break;
250 /* First scan complete, re-enable interrupts. */
251 if (zpci_set_irq_ctrl(SIC_IRQ_MODE_SINGLE, PCI_ISC, &iib))
252 break;
253 si = 0;
254 continue;
255 }
256
257 /* Scan the adapter interrupt vector for this device. */
258 aibv = zpci_ibv[si];
259 for (ai = 0;;) {
260 ai = airq_iv_scan(aibv, ai, airq_iv_end(aibv));
261 if (ai == -1UL)
262 break;
263 inc_irq_stat(IRQIO_MSI);
264 airq_iv_lock(aibv, ai);
265 generic_handle_irq(airq_iv_get_data(aibv, ai));
266 airq_iv_unlock(aibv, ai);
267 }
268 }
269 }
270
271 static int __alloc_airq(struct zpci_dev *zdev, int msi_vecs,
272 unsigned long *bit)
273 {
274 if (irq_delivery == DIRECTED) {
275 /* Allocate cpu vector bits */
276 *bit = airq_iv_alloc(zpci_ibv[0], msi_vecs);
277 if (*bit == -1UL)
278 return -EIO;
279 } else {
280 /* Allocate adapter summary indicator bit */
281 *bit = airq_iv_alloc_bit(zpci_sbv);
282 if (*bit == -1UL)
283 return -EIO;
284 zdev->aisb = *bit;
285
286 /* Create adapter interrupt vector */
287 zdev->aibv = airq_iv_create(msi_vecs, AIRQ_IV_DATA | AIRQ_IV_BITLOCK, NULL);
288 if (!zdev->aibv)
289 return -ENOMEM;
290
291 /* Wire up shortcut pointer */
292 zpci_ibv[*bit] = zdev->aibv;
293 /* Each function has its own interrupt vector */
294 *bit = 0;
295 }
296 return 0;
297 }
298
299 int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
300 {
301 unsigned int hwirq, msi_vecs, irqs_per_msi, i, cpu;
302 struct zpci_dev *zdev = to_zpci(pdev);
303 struct msi_desc *msi;
304 struct msi_msg msg;
305 unsigned long bit;
306 int cpu_addr;
307 int rc, irq;
308
309 zdev->aisb = -1UL;
310 zdev->msi_first_bit = -1U;
311
312 msi_vecs = min_t(unsigned int, nvec, zdev->max_msi);
313 if (msi_vecs < nvec) {
314 pr_info("%s requested %d irqs, allocate system limit of %d",
315 pci_name(pdev), nvec, zdev->max_msi);
316 }
317
318 rc = __alloc_airq(zdev, msi_vecs, &bit);
319 if (rc < 0)
320 return rc;
321
322 /*
323 * Request MSI interrupts:
324 * When using MSI, nvec_used interrupt sources and their irq
325 * descriptors are controlled through one msi descriptor.
326 * Thus the outer loop over msi descriptors shall run only once,
327 * while two inner loops iterate over the interrupt vectors.
328 * When using MSI-X, each interrupt vector/irq descriptor
329 * is bound to exactly one msi descriptor (nvec_used is one).
330 * So the inner loops are executed once, while the outer iterates
331 * over the MSI-X descriptors.
332 */
333 hwirq = bit;
334 msi_for_each_desc(msi, &pdev->dev, MSI_DESC_NOTASSOCIATED) {
335 if (hwirq - bit >= msi_vecs)
336 break;
337 irqs_per_msi = min_t(unsigned int, msi_vecs, msi->nvec_used);
338 irq = __irq_alloc_descs(-1, 0, irqs_per_msi, 0, THIS_MODULE,
339 (irq_delivery == DIRECTED) ?
340 msi->affinity : NULL);
341 if (irq < 0)
342 return -ENOMEM;
343
344 for (i = 0; i < irqs_per_msi; i++) {
345 rc = irq_set_msi_desc_off(irq, i, msi);
346 if (rc)
347 return rc;
348 irq_set_chip_and_handler(irq + i, &zpci_irq_chip,
349 handle_percpu_irq);
350 }
351
352 msg.data = hwirq - bit;
353 if (irq_delivery == DIRECTED) {
354 if (msi->affinity)
355 cpu = cpumask_first(&msi->affinity->mask);
356 else
357 cpu = 0;
358 cpu_addr = smp_cpu_get_cpu_address(cpu);
359
360 msg.address_lo = zdev->msi_addr & 0xff0000ff;
361 msg.address_lo |= (cpu_addr << 8);
362
363 for_each_possible_cpu(cpu) {
364 for (i = 0; i < irqs_per_msi; i++)
365 airq_iv_set_data(zpci_ibv[cpu],
366 hwirq + i, irq + i);
367 }
368 } else {
369 msg.address_lo = zdev->msi_addr & 0xffffffff;
370 for (i = 0; i < irqs_per_msi; i++)
371 airq_iv_set_data(zdev->aibv, hwirq + i, irq + i);
372 }
373 msg.address_hi = zdev->msi_addr >> 32;
374 pci_write_msi_msg(irq, &msg);
375 hwirq += irqs_per_msi;
376 }
377
378 zdev->msi_first_bit = bit;
379 zdev->msi_nr_irqs = hwirq - bit;
380
381 rc = zpci_set_irq(zdev);
382 if (rc)
383 return rc;
384
385 return (zdev->msi_nr_irqs == nvec) ? 0 : zdev->msi_nr_irqs;
386 }
387
388 void arch_teardown_msi_irqs(struct pci_dev *pdev)
389 {
390 struct zpci_dev *zdev = to_zpci(pdev);
391 struct msi_desc *msi;
392 unsigned int i;
393 int rc;
394
395 /* Disable interrupts */
396 rc = zpci_clear_irq(zdev);
397 if (rc)
398 return;
399
400 /* Release MSI interrupts */
401 msi_for_each_desc(msi, &pdev->dev, MSI_DESC_ASSOCIATED) {
402 for (i = 0; i < msi->nvec_used; i++) {
403 irq_set_msi_desc(msi->irq + i, NULL);
404 irq_free_desc(msi->irq + i);
405 }
406 msi->msg.address_lo = 0;
407 msi->msg.address_hi = 0;
408 msi->msg.data = 0;
409 msi->irq = 0;
410 }
411
412 if (zdev->aisb != -1UL) {
413 zpci_ibv[zdev->aisb] = NULL;
414 airq_iv_free_bit(zpci_sbv, zdev->aisb);
415 zdev->aisb = -1UL;
416 }
417 if (zdev->aibv) {
418 airq_iv_release(zdev->aibv);
419 zdev->aibv = NULL;
420 }
421
422 if ((irq_delivery == DIRECTED) && zdev->msi_first_bit != -1U)
423 airq_iv_free(zpci_ibv[0], zdev->msi_first_bit, zdev->msi_nr_irqs);
424 }
425
426 bool arch_restore_msi_irqs(struct pci_dev *pdev)
427 {
428 struct zpci_dev *zdev = to_zpci(pdev);
429
430 if (!zdev->irqs_registered)
431 zpci_set_irq(zdev);
432 return true;
433 }
434
435 static struct airq_struct zpci_airq = {
436 .handler = zpci_floating_irq_handler,
437 .isc = PCI_ISC,
438 };
439
440 static void __init cpu_enable_directed_irq(void *unused)
441 {
442 union zpci_sic_iib iib = {{0}};
443 union zpci_sic_iib ziib = {{0}};
444
445 iib.cdiib.dibv_addr = virt_to_phys(zpci_ibv[smp_processor_id()]->vector);
446
447 zpci_set_irq_ctrl(SIC_IRQ_MODE_SET_CPU, 0, &iib);
448 zpci_set_irq_ctrl(SIC_IRQ_MODE_D_SINGLE, PCI_ISC, &ziib);
449 }
450
451 static int __init zpci_directed_irq_init(void)
452 {
453 union zpci_sic_iib iib = {{0}};
454 unsigned int cpu;
455
456 zpci_sbv = airq_iv_create(num_possible_cpus(), 0, NULL);
457 if (!zpci_sbv)
458 return -ENOMEM;
459
460 iib.diib.isc = PCI_ISC;
461 iib.diib.nr_cpus = num_possible_cpus();
462 iib.diib.disb_addr = virt_to_phys(zpci_sbv->vector);
463 zpci_set_irq_ctrl(SIC_IRQ_MODE_DIRECT, 0, &iib);
464
465 zpci_ibv = kcalloc(num_possible_cpus(), sizeof(*zpci_ibv),
466 GFP_KERNEL);
467 if (!zpci_ibv)
468 return -ENOMEM;
469
470 for_each_possible_cpu(cpu) {
471 /*
472 * Per CPU IRQ vectors look the same but bit-allocation
473 * is only done on the first vector.
474 */
475 zpci_ibv[cpu] = airq_iv_create(cache_line_size() * BITS_PER_BYTE,
476 AIRQ_IV_DATA |
477 AIRQ_IV_CACHELINE |
478 (!cpu ? AIRQ_IV_ALLOC : 0), NULL);
479 if (!zpci_ibv[cpu])
480 return -ENOMEM;
481 }
482 on_each_cpu(cpu_enable_directed_irq, NULL, 1);
483
484 zpci_irq_chip.irq_set_affinity = zpci_set_irq_affinity;
485
486 return 0;
487 }
488
489 static int __init zpci_floating_irq_init(void)
490 {
491 zpci_ibv = kcalloc(ZPCI_NR_DEVICES, sizeof(*zpci_ibv), GFP_KERNEL);
492 if (!zpci_ibv)
493 return -ENOMEM;
494
495 zpci_sbv = airq_iv_create(ZPCI_NR_DEVICES, AIRQ_IV_ALLOC, NULL);
496 if (!zpci_sbv)
497 goto out_free;
498
499 return 0;
500
501 out_free:
502 kfree(zpci_ibv);
503 return -ENOMEM;
504 }
505
506 int __init zpci_irq_init(void)
507 {
508 union zpci_sic_iib iib = {{0}};
509 int rc;
510
511 irq_delivery = sclp.has_dirq ? DIRECTED : FLOATING;
512 if (s390_pci_force_floating)
513 irq_delivery = FLOATING;
514
515 if (irq_delivery == DIRECTED)
516 zpci_airq.handler = zpci_directed_irq_handler;
517
518 rc = register_adapter_interrupt(&zpci_airq);
519 if (rc)
520 goto out;
521 /* Set summary to 1 to be called every time for the ISC. */
522 *zpci_airq.lsi_ptr = 1;
523
524 switch (irq_delivery) {
525 case FLOATING:
526 rc = zpci_floating_irq_init();
527 break;
528 case DIRECTED:
529 rc = zpci_directed_irq_init();
530 break;
531 }
532
533 if (rc)
534 goto out_airq;
535
536 /*
537 * Enable floating IRQs (with suppression after one IRQ). When using
538 * directed IRQs this enables the fallback path.
539 */
540 zpci_set_irq_ctrl(SIC_IRQ_MODE_SINGLE, PCI_ISC, &iib);
541
542 return 0;
543 out_airq:
544 unregister_adapter_interrupt(&zpci_airq);
545 out:
546 return rc;
547 }
548
549 void __init zpci_irq_exit(void)
550 {
551 unsigned int cpu;
552
553 if (irq_delivery == DIRECTED) {
554 for_each_possible_cpu(cpu) {
555 airq_iv_release(zpci_ibv[cpu]);
556 }
557 }
558 kfree(zpci_ibv);
559 if (zpci_sbv)
560 airq_iv_release(zpci_sbv);
561 unregister_adapter_interrupt(&zpci_airq);
562 }
563
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