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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
15static 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 */
29static 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 */
36static struct airq_iv **zpci_ibv;
37
38/* Modify PCI: Register adapter interruptions */
39static 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 = (unsigned long) zdev->aibv->vector;
49 fib.fmt0.aibvo = 0; /* each zdev has its own interrupt vector */
50 fib.fmt0.aisb = (unsigned long) 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 adapter interruptions */
57static 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 */
72static 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 */
86static 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
101static int zpci_set_irq_affinity(struct irq_data *data, const struct cpumask *dest,
102 bool force)
103{
104 struct msi_desc *entry = irq_get_msi_desc(data->irq);
105 struct msi_msg msg = entry->msg;
106
107 msg.address_lo &= 0xff0000ff;
108 msg.address_lo |= (cpumask_first(dest) << 8);
109 pci_write_msi_msg(data->irq, &msg);
110
111 return IRQ_SET_MASK_OK;
112}
113
114static struct irq_chip zpci_irq_chip = {
115 .name = "PCI-MSI",
116 .irq_unmask = pci_msi_unmask_irq,
117 .irq_mask = pci_msi_mask_irq,
118};
119
120static void zpci_handle_cpu_local_irq(bool rescan)
121{
122 struct airq_iv *dibv = zpci_ibv[smp_processor_id()];
123 unsigned long bit;
124 int irqs_on = 0;
125
126 for (bit = 0;;) {
127 /* Scan the directed IRQ bit vector */
128 bit = airq_iv_scan(dibv, bit, airq_iv_end(dibv));
129 if (bit == -1UL) {
130 if (!rescan || irqs_on++)
131 /* End of second scan with interrupts on. */
132 break;
133 /* First scan complete, reenable interrupts. */
134 if (zpci_set_irq_ctrl(SIC_IRQ_MODE_D_SINGLE, PCI_ISC))
135 break;
136 bit = 0;
137 continue;
138 }
139 inc_irq_stat(IRQIO_MSI);
140 generic_handle_irq(airq_iv_get_data(dibv, bit));
141 }
142}
143
144struct cpu_irq_data {
145 call_single_data_t csd;
146 atomic_t scheduled;
147};
148static DEFINE_PER_CPU_SHARED_ALIGNED(struct cpu_irq_data, irq_data);
149
150static void zpci_handle_remote_irq(void *data)
151{
152 atomic_t *scheduled = data;
153
154 do {
155 zpci_handle_cpu_local_irq(false);
156 } while (atomic_dec_return(scheduled));
157}
158
159static void zpci_handle_fallback_irq(void)
160{
161 struct cpu_irq_data *cpu_data;
162 unsigned long cpu;
163 int irqs_on = 0;
164
165 for (cpu = 0;;) {
166 cpu = airq_iv_scan(zpci_sbv, cpu, airq_iv_end(zpci_sbv));
167 if (cpu == -1UL) {
168 if (irqs_on++)
169 /* End of second scan with interrupts on. */
170 break;
171 /* First scan complete, reenable interrupts. */
172 if (zpci_set_irq_ctrl(SIC_IRQ_MODE_SINGLE, PCI_ISC))
173 break;
174 cpu = 0;
175 continue;
176 }
177 cpu_data = &per_cpu(irq_data, cpu);
178 if (atomic_inc_return(&cpu_data->scheduled) > 1)
179 continue;
180
181 cpu_data->csd.func = zpci_handle_remote_irq;
182 cpu_data->csd.info = &cpu_data->scheduled;
183 cpu_data->csd.flags = 0;
184 smp_call_function_single_async(cpu, &cpu_data->csd);
185 }
186}
187
188static void zpci_directed_irq_handler(struct airq_struct *airq, bool floating)
189{
190 if (floating) {
191 inc_irq_stat(IRQIO_PCF);
192 zpci_handle_fallback_irq();
193 } else {
194 inc_irq_stat(IRQIO_PCD);
195 zpci_handle_cpu_local_irq(true);
196 }
197}
198
199static void zpci_floating_irq_handler(struct airq_struct *airq, bool floating)
200{
201 unsigned long si, ai;
202 struct airq_iv *aibv;
203 int irqs_on = 0;
204
205 inc_irq_stat(IRQIO_PCF);
206 for (si = 0;;) {
207 /* Scan adapter summary indicator bit vector */
208 si = airq_iv_scan(zpci_sbv, si, airq_iv_end(zpci_sbv));
209 if (si == -1UL) {
210 if (irqs_on++)
211 /* End of second scan with interrupts on. */
212 break;
213 /* First scan complete, reenable interrupts. */
214 if (zpci_set_irq_ctrl(SIC_IRQ_MODE_SINGLE, PCI_ISC))
215 break;
216 si = 0;
217 continue;
218 }
219
220 /* Scan the adapter interrupt vector for this device. */
221 aibv = zpci_ibv[si];
222 for (ai = 0;;) {
223 ai = airq_iv_scan(aibv, ai, airq_iv_end(aibv));
224 if (ai == -1UL)
225 break;
226 inc_irq_stat(IRQIO_MSI);
227 airq_iv_lock(aibv, ai);
228 generic_handle_irq(airq_iv_get_data(aibv, ai));
229 airq_iv_unlock(aibv, ai);
230 }
231 }
232}
233
234int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
235{
236 struct zpci_dev *zdev = to_zpci(pdev);
237 unsigned int hwirq, msi_vecs, cpu;
238 unsigned long bit;
239 struct msi_desc *msi;
240 struct msi_msg msg;
241 int rc, irq;
242
243 zdev->aisb = -1UL;
244 zdev->msi_first_bit = -1U;
245 if (type == PCI_CAP_ID_MSI && nvec > 1)
246 return 1;
247 msi_vecs = min_t(unsigned int, nvec, zdev->max_msi);
248
249 if (irq_delivery == DIRECTED) {
250 /* Allocate cpu vector bits */
251 bit = airq_iv_alloc(zpci_ibv[0], msi_vecs);
252 if (bit == -1UL)
253 return -EIO;
254 } else {
255 /* Allocate adapter summary indicator bit */
256 bit = airq_iv_alloc_bit(zpci_sbv);
257 if (bit == -1UL)
258 return -EIO;
259 zdev->aisb = bit;
260
261 /* Create adapter interrupt vector */
262 zdev->aibv = airq_iv_create(msi_vecs, AIRQ_IV_DATA | AIRQ_IV_BITLOCK);
263 if (!zdev->aibv)
264 return -ENOMEM;
265
266 /* Wire up shortcut pointer */
267 zpci_ibv[bit] = zdev->aibv;
268 /* Each function has its own interrupt vector */
269 bit = 0;
270 }
271
272 /* Request MSI interrupts */
273 hwirq = bit;
274 for_each_pci_msi_entry(msi, pdev) {
275 rc = -EIO;
276 if (hwirq - bit >= msi_vecs)
277 break;
278 irq = __irq_alloc_descs(-1, 0, 1, 0, THIS_MODULE,
279 (irq_delivery == DIRECTED) ?
280 msi->affinity : NULL);
281 if (irq < 0)
282 return -ENOMEM;
283 rc = irq_set_msi_desc(irq, msi);
284 if (rc)
285 return rc;
286 irq_set_chip_and_handler(irq, &zpci_irq_chip,
287 handle_percpu_irq);
288 msg.data = hwirq - bit;
289 if (irq_delivery == DIRECTED) {
290 msg.address_lo = zdev->msi_addr & 0xff0000ff;
291 msg.address_lo |= msi->affinity ?
292 (cpumask_first(&msi->affinity->mask) << 8) : 0;
293 for_each_possible_cpu(cpu) {
294 airq_iv_set_data(zpci_ibv[cpu], hwirq, irq);
295 }
296 } else {
297 msg.address_lo = zdev->msi_addr & 0xffffffff;
298 airq_iv_set_data(zdev->aibv, hwirq, irq);
299 }
300 msg.address_hi = zdev->msi_addr >> 32;
301 pci_write_msi_msg(irq, &msg);
302 hwirq++;
303 }
304
305 zdev->msi_first_bit = bit;
306 zdev->msi_nr_irqs = msi_vecs;
307
308 if (irq_delivery == DIRECTED)
309 rc = zpci_set_directed_irq(zdev);
310 else
311 rc = zpci_set_airq(zdev);
312 if (rc)
313 return rc;
314
315 return (msi_vecs == nvec) ? 0 : msi_vecs;
316}
317
318void arch_teardown_msi_irqs(struct pci_dev *pdev)
319{
320 struct zpci_dev *zdev = to_zpci(pdev);
321 struct msi_desc *msi;
322 int rc;
323
324 /* Disable interrupts */
325 if (irq_delivery == DIRECTED)
326 rc = zpci_clear_directed_irq(zdev);
327 else
328 rc = zpci_clear_airq(zdev);
329 if (rc)
330 return;
331
332 /* Release MSI interrupts */
333 for_each_pci_msi_entry(msi, pdev) {
334 if (!msi->irq)
335 continue;
336 if (msi->msi_attrib.is_msix)
337 __pci_msix_desc_mask_irq(msi, 1);
338 else
339 __pci_msi_desc_mask_irq(msi, 1, 1);
340 irq_set_msi_desc(msi->irq, NULL);
341 irq_free_desc(msi->irq);
342 msi->msg.address_lo = 0;
343 msi->msg.address_hi = 0;
344 msi->msg.data = 0;
345 msi->irq = 0;
346 }
347
348 if (zdev->aisb != -1UL) {
349 zpci_ibv[zdev->aisb] = NULL;
350 airq_iv_free_bit(zpci_sbv, zdev->aisb);
351 zdev->aisb = -1UL;
352 }
353 if (zdev->aibv) {
354 airq_iv_release(zdev->aibv);
355 zdev->aibv = NULL;
356 }
357
358 if ((irq_delivery == DIRECTED) && zdev->msi_first_bit != -1U)
359 airq_iv_free(zpci_ibv[0], zdev->msi_first_bit, zdev->msi_nr_irqs);
360}
361
362static struct airq_struct zpci_airq = {
363 .handler = zpci_floating_irq_handler,
364 .isc = PCI_ISC,
365};
366
367static void __init cpu_enable_directed_irq(void *unused)
368{
369 union zpci_sic_iib iib = {{0}};
370
371 iib.cdiib.dibv_addr = (u64) zpci_ibv[smp_processor_id()]->vector;
372
373 __zpci_set_irq_ctrl(SIC_IRQ_MODE_SET_CPU, 0, &iib);
374 zpci_set_irq_ctrl(SIC_IRQ_MODE_D_SINGLE, PCI_ISC);
375}
376
377static int __init zpci_directed_irq_init(void)
378{
379 union zpci_sic_iib iib = {{0}};
380 unsigned int cpu;
381
382 zpci_sbv = airq_iv_create(num_possible_cpus(), 0);
383 if (!zpci_sbv)
384 return -ENOMEM;
385
386 iib.diib.isc = PCI_ISC;
387 iib.diib.nr_cpus = num_possible_cpus();
388 iib.diib.disb_addr = (u64) zpci_sbv->vector;
389 __zpci_set_irq_ctrl(SIC_IRQ_MODE_DIRECT, 0, &iib);
390
391 zpci_ibv = kcalloc(num_possible_cpus(), sizeof(*zpci_ibv),
392 GFP_KERNEL);
393 if (!zpci_ibv)
394 return -ENOMEM;
395
396 for_each_possible_cpu(cpu) {
397 /*
398 * Per CPU IRQ vectors look the same but bit-allocation
399 * is only done on the first vector.
400 */
401 zpci_ibv[cpu] = airq_iv_create(cache_line_size() * BITS_PER_BYTE,
402 AIRQ_IV_DATA |
403 AIRQ_IV_CACHELINE |
404 (!cpu ? AIRQ_IV_ALLOC : 0));
405 if (!zpci_ibv[cpu])
406 return -ENOMEM;
407 }
408 on_each_cpu(cpu_enable_directed_irq, NULL, 1);
409
410 zpci_irq_chip.irq_set_affinity = zpci_set_irq_affinity;
411
412 return 0;
413}
414
415static int __init zpci_floating_irq_init(void)
416{
417 zpci_ibv = kcalloc(ZPCI_NR_DEVICES, sizeof(*zpci_ibv), GFP_KERNEL);
418 if (!zpci_ibv)
419 return -ENOMEM;
420
421 zpci_sbv = airq_iv_create(ZPCI_NR_DEVICES, AIRQ_IV_ALLOC);
422 if (!zpci_sbv)
423 goto out_free;
424
425 return 0;
426
427out_free:
428 kfree(zpci_ibv);
429 return -ENOMEM;
430}
431
432int __init zpci_irq_init(void)
433{
434 int rc;
435
436 irq_delivery = sclp.has_dirq ? DIRECTED : FLOATING;
437 if (s390_pci_force_floating)
438 irq_delivery = FLOATING;
439
440 if (irq_delivery == DIRECTED)
441 zpci_airq.handler = zpci_directed_irq_handler;
442
443 rc = register_adapter_interrupt(&zpci_airq);
444 if (rc)
445 goto out;
446 /* Set summary to 1 to be called every time for the ISC. */
447 *zpci_airq.lsi_ptr = 1;
448
449 switch (irq_delivery) {
450 case FLOATING:
451 rc = zpci_floating_irq_init();
452 break;
453 case DIRECTED:
454 rc = zpci_directed_irq_init();
455 break;
456 }
457
458 if (rc)
459 goto out_airq;
460
461 /*
462 * Enable floating IRQs (with suppression after one IRQ). When using
463 * directed IRQs this enables the fallback path.
464 */
465 zpci_set_irq_ctrl(SIC_IRQ_MODE_SINGLE, PCI_ISC);
466
467 return 0;
468out_airq:
469 unregister_adapter_interrupt(&zpci_airq);
470out:
471 return rc;
472}
473
474void __init zpci_irq_exit(void)
475{
476 unsigned int cpu;
477
478 if (irq_delivery == DIRECTED) {
479 for_each_possible_cpu(cpu) {
480 airq_iv_release(zpci_ibv[cpu]);
481 }
482 }
483 kfree(zpci_ibv);
484 if (zpci_sbv)
485 airq_iv_release(zpci_sbv);
486 unregister_adapter_interrupt(&zpci_airq);
487}