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 */
zpci_set_airq(struct zpci_dev * zdev)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 */
zpci_clear_airq(struct zpci_dev * zdev)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 */
zpci_set_directed_irq(struct zpci_dev * zdev)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 */
zpci_clear_directed_irq(struct zpci_dev * zdev)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 */
zpci_set_irq(struct zpci_dev * zdev)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 */
zpci_clear_irq(struct zpci_dev * zdev)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
zpci_set_irq_affinity(struct irq_data * data,const struct cpumask * dest,bool force)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_get_msi_desc(data->irq);
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
zpci_handle_cpu_local_irq(bool rescan)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, reenable 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
zpci_handle_remote_irq(void * data)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
zpci_handle_fallback_irq(void)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, reenable 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
zpci_directed_irq_handler(struct airq_struct * airq,struct tpi_info * tpi_info)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
zpci_floating_irq_handler(struct airq_struct * airq,struct tpi_info * tpi_info)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, reenable 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
arch_setup_msi_irqs(struct pci_dev * pdev,int nvec,int type)271 int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
272 {
273 struct zpci_dev *zdev = to_zpci(pdev);
274 unsigned int hwirq, msi_vecs, cpu;
275 unsigned long bit;
276 struct msi_desc *msi;
277 struct msi_msg msg;
278 int cpu_addr;
279 int rc, irq;
280
281 zdev->aisb = -1UL;
282 zdev->msi_first_bit = -1U;
283 if (type == PCI_CAP_ID_MSI && nvec > 1)
284 return 1;
285 msi_vecs = min_t(unsigned int, nvec, zdev->max_msi);
286
287 if (irq_delivery == DIRECTED) {
288 /* Allocate cpu vector bits */
289 bit = airq_iv_alloc(zpci_ibv[0], msi_vecs);
290 if (bit == -1UL)
291 return -EIO;
292 } else {
293 /* Allocate adapter summary indicator bit */
294 bit = airq_iv_alloc_bit(zpci_sbv);
295 if (bit == -1UL)
296 return -EIO;
297 zdev->aisb = bit;
298
299 /* Create adapter interrupt vector */
300 zdev->aibv = airq_iv_create(msi_vecs, AIRQ_IV_DATA | AIRQ_IV_BITLOCK, NULL);
301 if (!zdev->aibv)
302 return -ENOMEM;
303
304 /* Wire up shortcut pointer */
305 zpci_ibv[bit] = zdev->aibv;
306 /* Each function has its own interrupt vector */
307 bit = 0;
308 }
309
310 /* Request MSI interrupts */
311 hwirq = bit;
312 msi_for_each_desc(msi, &pdev->dev, MSI_DESC_NOTASSOCIATED) {
313 rc = -EIO;
314 if (hwirq - bit >= msi_vecs)
315 break;
316 irq = __irq_alloc_descs(-1, 0, 1, 0, THIS_MODULE,
317 (irq_delivery == DIRECTED) ?
318 msi->affinity : NULL);
319 if (irq < 0)
320 return -ENOMEM;
321 rc = irq_set_msi_desc(irq, msi);
322 if (rc)
323 return rc;
324 irq_set_chip_and_handler(irq, &zpci_irq_chip,
325 handle_percpu_irq);
326 msg.data = hwirq - bit;
327 if (irq_delivery == DIRECTED) {
328 if (msi->affinity)
329 cpu = cpumask_first(&msi->affinity->mask);
330 else
331 cpu = 0;
332 cpu_addr = smp_cpu_get_cpu_address(cpu);
333
334 msg.address_lo = zdev->msi_addr & 0xff0000ff;
335 msg.address_lo |= (cpu_addr << 8);
336
337 for_each_possible_cpu(cpu) {
338 airq_iv_set_data(zpci_ibv[cpu], hwirq, irq);
339 }
340 } else {
341 msg.address_lo = zdev->msi_addr & 0xffffffff;
342 airq_iv_set_data(zdev->aibv, hwirq, irq);
343 }
344 msg.address_hi = zdev->msi_addr >> 32;
345 pci_write_msi_msg(irq, &msg);
346 hwirq++;
347 }
348
349 zdev->msi_first_bit = bit;
350 zdev->msi_nr_irqs = msi_vecs;
351
352 rc = zpci_set_irq(zdev);
353 if (rc)
354 return rc;
355
356 return (msi_vecs == nvec) ? 0 : msi_vecs;
357 }
358
arch_teardown_msi_irqs(struct pci_dev * pdev)359 void arch_teardown_msi_irqs(struct pci_dev *pdev)
360 {
361 struct zpci_dev *zdev = to_zpci(pdev);
362 struct msi_desc *msi;
363 int rc;
364
365 /* Disable interrupts */
366 rc = zpci_clear_irq(zdev);
367 if (rc)
368 return;
369
370 /* Release MSI interrupts */
371 msi_for_each_desc(msi, &pdev->dev, MSI_DESC_ASSOCIATED) {
372 irq_set_msi_desc(msi->irq, NULL);
373 irq_free_desc(msi->irq);
374 msi->msg.address_lo = 0;
375 msi->msg.address_hi = 0;
376 msi->msg.data = 0;
377 msi->irq = 0;
378 }
379
380 if (zdev->aisb != -1UL) {
381 zpci_ibv[zdev->aisb] = NULL;
382 airq_iv_free_bit(zpci_sbv, zdev->aisb);
383 zdev->aisb = -1UL;
384 }
385 if (zdev->aibv) {
386 airq_iv_release(zdev->aibv);
387 zdev->aibv = NULL;
388 }
389
390 if ((irq_delivery == DIRECTED) && zdev->msi_first_bit != -1U)
391 airq_iv_free(zpci_ibv[0], zdev->msi_first_bit, zdev->msi_nr_irqs);
392 }
393
arch_restore_msi_irqs(struct pci_dev * pdev)394 bool arch_restore_msi_irqs(struct pci_dev *pdev)
395 {
396 struct zpci_dev *zdev = to_zpci(pdev);
397
398 if (!zdev->irqs_registered)
399 zpci_set_irq(zdev);
400 return true;
401 }
402
403 static struct airq_struct zpci_airq = {
404 .handler = zpci_floating_irq_handler,
405 .isc = PCI_ISC,
406 };
407
cpu_enable_directed_irq(void * unused)408 static void __init cpu_enable_directed_irq(void *unused)
409 {
410 union zpci_sic_iib iib = {{0}};
411 union zpci_sic_iib ziib = {{0}};
412
413 iib.cdiib.dibv_addr = (u64) zpci_ibv[smp_processor_id()]->vector;
414
415 zpci_set_irq_ctrl(SIC_IRQ_MODE_SET_CPU, 0, &iib);
416 zpci_set_irq_ctrl(SIC_IRQ_MODE_D_SINGLE, PCI_ISC, &ziib);
417 }
418
zpci_directed_irq_init(void)419 static int __init zpci_directed_irq_init(void)
420 {
421 union zpci_sic_iib iib = {{0}};
422 unsigned int cpu;
423
424 zpci_sbv = airq_iv_create(num_possible_cpus(), 0, NULL);
425 if (!zpci_sbv)
426 return -ENOMEM;
427
428 iib.diib.isc = PCI_ISC;
429 iib.diib.nr_cpus = num_possible_cpus();
430 iib.diib.disb_addr = virt_to_phys(zpci_sbv->vector);
431 zpci_set_irq_ctrl(SIC_IRQ_MODE_DIRECT, 0, &iib);
432
433 zpci_ibv = kcalloc(num_possible_cpus(), sizeof(*zpci_ibv),
434 GFP_KERNEL);
435 if (!zpci_ibv)
436 return -ENOMEM;
437
438 for_each_possible_cpu(cpu) {
439 /*
440 * Per CPU IRQ vectors look the same but bit-allocation
441 * is only done on the first vector.
442 */
443 zpci_ibv[cpu] = airq_iv_create(cache_line_size() * BITS_PER_BYTE,
444 AIRQ_IV_DATA |
445 AIRQ_IV_CACHELINE |
446 (!cpu ? AIRQ_IV_ALLOC : 0), NULL);
447 if (!zpci_ibv[cpu])
448 return -ENOMEM;
449 }
450 on_each_cpu(cpu_enable_directed_irq, NULL, 1);
451
452 zpci_irq_chip.irq_set_affinity = zpci_set_irq_affinity;
453
454 return 0;
455 }
456
zpci_floating_irq_init(void)457 static int __init zpci_floating_irq_init(void)
458 {
459 zpci_ibv = kcalloc(ZPCI_NR_DEVICES, sizeof(*zpci_ibv), GFP_KERNEL);
460 if (!zpci_ibv)
461 return -ENOMEM;
462
463 zpci_sbv = airq_iv_create(ZPCI_NR_DEVICES, AIRQ_IV_ALLOC, NULL);
464 if (!zpci_sbv)
465 goto out_free;
466
467 return 0;
468
469 out_free:
470 kfree(zpci_ibv);
471 return -ENOMEM;
472 }
473
zpci_irq_init(void)474 int __init zpci_irq_init(void)
475 {
476 union zpci_sic_iib iib = {{0}};
477 int rc;
478
479 irq_delivery = sclp.has_dirq ? DIRECTED : FLOATING;
480 if (s390_pci_force_floating)
481 irq_delivery = FLOATING;
482
483 if (irq_delivery == DIRECTED)
484 zpci_airq.handler = zpci_directed_irq_handler;
485
486 rc = register_adapter_interrupt(&zpci_airq);
487 if (rc)
488 goto out;
489 /* Set summary to 1 to be called every time for the ISC. */
490 *zpci_airq.lsi_ptr = 1;
491
492 switch (irq_delivery) {
493 case FLOATING:
494 rc = zpci_floating_irq_init();
495 break;
496 case DIRECTED:
497 rc = zpci_directed_irq_init();
498 break;
499 }
500
501 if (rc)
502 goto out_airq;
503
504 /*
505 * Enable floating IRQs (with suppression after one IRQ). When using
506 * directed IRQs this enables the fallback path.
507 */
508 zpci_set_irq_ctrl(SIC_IRQ_MODE_SINGLE, PCI_ISC, &iib);
509
510 return 0;
511 out_airq:
512 unregister_adapter_interrupt(&zpci_airq);
513 out:
514 return rc;
515 }
516
zpci_irq_exit(void)517 void __init zpci_irq_exit(void)
518 {
519 unsigned int cpu;
520
521 if (irq_delivery == DIRECTED) {
522 for_each_possible_cpu(cpu) {
523 airq_iv_release(zpci_ibv[cpu]);
524 }
525 }
526 kfree(zpci_ibv);
527 if (zpci_sbv)
528 airq_iv_release(zpci_sbv);
529 unregister_adapter_interrupt(&zpci_airq);
530 }
531