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