1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2007, Michael Ellerman, IBM Corporation.
4 */
5
6
7 #include <linux/interrupt.h>
8 #include <linux/irq.h>
9 #include <linux/kernel.h>
10 #include <linux/pci.h>
11 #include <linux/msi.h>
12 #include <linux/export.h>
13 #include <linux/slab.h>
14 #include <linux/debugfs.h>
15 #include <linux/of.h>
16 #include <linux/of_irq.h>
17 #include <linux/platform_device.h>
18
19 #include <asm/dcr.h>
20 #include <asm/machdep.h>
21
22 #include "cell.h"
23
24 /*
25 * MSIC registers, specified as offsets from dcr_base
26 */
27 #define MSIC_CTRL_REG 0x0
28
29 /* Base Address registers specify FIFO location in BE memory */
30 #define MSIC_BASE_ADDR_HI_REG 0x3
31 #define MSIC_BASE_ADDR_LO_REG 0x4
32
33 /* Hold the read/write offsets into the FIFO */
34 #define MSIC_READ_OFFSET_REG 0x5
35 #define MSIC_WRITE_OFFSET_REG 0x6
36
37
38 /* MSIC control register flags */
39 #define MSIC_CTRL_ENABLE 0x0001
40 #define MSIC_CTRL_FIFO_FULL_ENABLE 0x0002
41 #define MSIC_CTRL_IRQ_ENABLE 0x0008
42 #define MSIC_CTRL_FULL_STOP_ENABLE 0x0010
43
44 /*
45 * The MSIC can be configured to use a FIFO of 32KB, 64KB, 128KB or 256KB.
46 * Currently we're using a 64KB FIFO size.
47 */
48 #define MSIC_FIFO_SIZE_SHIFT 16
49 #define MSIC_FIFO_SIZE_BYTES (1 << MSIC_FIFO_SIZE_SHIFT)
50
51 /*
52 * To configure the FIFO size as (1 << n) bytes, we write (n - 15) into bits
53 * 8-9 of the MSIC control reg.
54 */
55 #define MSIC_CTRL_FIFO_SIZE (((MSIC_FIFO_SIZE_SHIFT - 15) << 8) & 0x300)
56
57 /*
58 * We need to mask the read/write offsets to make sure they stay within
59 * the bounds of the FIFO. Also they should always be 16-byte aligned.
60 */
61 #define MSIC_FIFO_SIZE_MASK ((MSIC_FIFO_SIZE_BYTES - 1) & ~0xFu)
62
63 /* Each entry in the FIFO is 16 bytes, the first 4 bytes hold the irq # */
64 #define MSIC_FIFO_ENTRY_SIZE 0x10
65
66
67 struct axon_msic {
68 struct irq_domain *irq_domain;
69 __le32 *fifo_virt;
70 dma_addr_t fifo_phys;
71 dcr_host_t dcr_host;
72 u32 read_offset;
73 #ifdef DEBUG
74 u32 __iomem *trigger;
75 #endif
76 };
77
78 #ifdef DEBUG
79 void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic);
80 #else
81 static inline void axon_msi_debug_setup(struct device_node *dn,
82 struct axon_msic *msic) { }
83 #endif
84
85
86 static void msic_dcr_write(struct axon_msic *msic, unsigned int dcr_n, u32 val)
87 {
88 pr_devel("axon_msi: dcr_write(0x%x, 0x%x)\n", val, dcr_n);
89
90 dcr_write(msic->dcr_host, dcr_n, val);
91 }
92
93 static void axon_msi_cascade(struct irq_desc *desc)
94 {
95 struct irq_chip *chip = irq_desc_get_chip(desc);
96 struct axon_msic *msic = irq_desc_get_handler_data(desc);
97 u32 write_offset, msi;
98 int idx;
99 int retry = 0;
100
101 write_offset = dcr_read(msic->dcr_host, MSIC_WRITE_OFFSET_REG);
102 pr_devel("axon_msi: original write_offset 0x%x\n", write_offset);
103
104 /* write_offset doesn't wrap properly, so we have to mask it */
105 write_offset &= MSIC_FIFO_SIZE_MASK;
106
107 while (msic->read_offset != write_offset && retry < 100) {
108 idx = msic->read_offset / sizeof(__le32);
109 msi = le32_to_cpu(msic->fifo_virt[idx]);
110 msi &= 0xFFFF;
111
112 pr_devel("axon_msi: woff %x roff %x msi %x\n",
113 write_offset, msic->read_offset, msi);
114
115 if (msi < nr_irqs && irq_get_chip_data(msi) == msic) {
116 generic_handle_irq(msi);
117 msic->fifo_virt[idx] = cpu_to_le32(0xffffffff);
118 } else {
119 /*
120 * Reading the MSIC_WRITE_OFFSET_REG does not
121 * reliably flush the outstanding DMA to the
122 * FIFO buffer. Here we were reading stale
123 * data, so we need to retry.
124 */
125 udelay(1);
126 retry++;
127 pr_devel("axon_msi: invalid irq 0x%x!\n", msi);
128 continue;
129 }
130
131 if (retry) {
132 pr_devel("axon_msi: late irq 0x%x, retry %d\n",
133 msi, retry);
134 retry = 0;
135 }
136
137 msic->read_offset += MSIC_FIFO_ENTRY_SIZE;
138 msic->read_offset &= MSIC_FIFO_SIZE_MASK;
139 }
140
141 if (retry) {
142 printk(KERN_WARNING "axon_msi: irq timed out\n");
143
144 msic->read_offset += MSIC_FIFO_ENTRY_SIZE;
145 msic->read_offset &= MSIC_FIFO_SIZE_MASK;
146 }
147
148 chip->irq_eoi(&desc->irq_data);
149 }
150
151 static struct axon_msic *find_msi_translator(struct pci_dev *dev)
152 {
153 struct irq_domain *irq_domain;
154 struct device_node *dn, *tmp;
155 const phandle *ph;
156 struct axon_msic *msic = NULL;
157
158 dn = of_node_get(pci_device_to_OF_node(dev));
159 if (!dn) {
160 dev_dbg(&dev->dev, "axon_msi: no pci_dn found\n");
161 return NULL;
162 }
163
164 for (; dn; dn = of_get_next_parent(dn)) {
165 ph = of_get_property(dn, "msi-translator", NULL);
166 if (ph)
167 break;
168 }
169
170 if (!ph) {
171 dev_dbg(&dev->dev,
172 "axon_msi: no msi-translator property found\n");
173 goto out_error;
174 }
175
176 tmp = dn;
177 dn = of_find_node_by_phandle(*ph);
178 of_node_put(tmp);
179 if (!dn) {
180 dev_dbg(&dev->dev,
181 "axon_msi: msi-translator doesn't point to a node\n");
182 goto out_error;
183 }
184
185 irq_domain = irq_find_host(dn);
186 if (!irq_domain) {
187 dev_dbg(&dev->dev, "axon_msi: no irq_domain found for node %pOF\n",
188 dn);
189 goto out_error;
190 }
191
192 msic = irq_domain->host_data;
193
194 out_error:
195 of_node_put(dn);
196
197 return msic;
198 }
199
200 static int setup_msi_msg_address(struct pci_dev *dev, struct msi_msg *msg)
201 {
202 struct device_node *dn;
203 int len;
204 const u32 *prop;
205
206 dn = of_node_get(pci_device_to_OF_node(dev));
207 if (!dn) {
208 dev_dbg(&dev->dev, "axon_msi: no pci_dn found\n");
209 return -ENODEV;
210 }
211
212 for (; dn; dn = of_get_next_parent(dn)) {
213 if (!dev->no_64bit_msi) {
214 prop = of_get_property(dn, "msi-address-64", &len);
215 if (prop)
216 break;
217 }
218
219 prop = of_get_property(dn, "msi-address-32", &len);
220 if (prop)
221 break;
222 }
223
224 if (!prop) {
225 dev_dbg(&dev->dev,
226 "axon_msi: no msi-address-(32|64) properties found\n");
227 of_node_put(dn);
228 return -ENOENT;
229 }
230
231 switch (len) {
232 case 8:
233 msg->address_hi = prop[0];
234 msg->address_lo = prop[1];
235 break;
236 case 4:
237 msg->address_hi = 0;
238 msg->address_lo = prop[0];
239 break;
240 default:
241 dev_dbg(&dev->dev,
242 "axon_msi: malformed msi-address-(32|64) property\n");
243 of_node_put(dn);
244 return -EINVAL;
245 }
246
247 of_node_put(dn);
248
249 return 0;
250 }
251
252 static int axon_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
253 {
254 unsigned int virq, rc;
255 struct msi_desc *entry;
256 struct msi_msg msg;
257 struct axon_msic *msic;
258
259 msic = find_msi_translator(dev);
260 if (!msic)
261 return -ENODEV;
262
263 rc = setup_msi_msg_address(dev, &msg);
264 if (rc)
265 return rc;
266
267 msi_for_each_desc(entry, &dev->dev, MSI_DESC_NOTASSOCIATED) {
268 virq = irq_create_direct_mapping(msic->irq_domain);
269 if (!virq) {
270 dev_warn(&dev->dev,
271 "axon_msi: virq allocation failed!\n");
272 return -1;
273 }
274 dev_dbg(&dev->dev, "axon_msi: allocated virq 0x%x\n", virq);
275
276 irq_set_msi_desc(virq, entry);
277 msg.data = virq;
278 pci_write_msi_msg(virq, &msg);
279 }
280
281 return 0;
282 }
283
284 static void axon_msi_teardown_msi_irqs(struct pci_dev *dev)
285 {
286 struct msi_desc *entry;
287
288 dev_dbg(&dev->dev, "axon_msi: tearing down msi irqs\n");
289
290 msi_for_each_desc(entry, &dev->dev, MSI_DESC_ASSOCIATED) {
291 irq_set_msi_desc(entry->irq, NULL);
292 irq_dispose_mapping(entry->irq);
293 entry->irq = 0;
294 }
295 }
296
297 static struct irq_chip msic_irq_chip = {
298 .irq_mask = pci_msi_mask_irq,
299 .irq_unmask = pci_msi_unmask_irq,
300 .irq_shutdown = pci_msi_mask_irq,
301 .name = "AXON-MSI",
302 };
303
304 static int msic_host_map(struct irq_domain *h, unsigned int virq,
305 irq_hw_number_t hw)
306 {
307 irq_set_chip_data(virq, h->host_data);
308 irq_set_chip_and_handler(virq, &msic_irq_chip, handle_simple_irq);
309
310 return 0;
311 }
312
313 static const struct irq_domain_ops msic_host_ops = {
314 .map = msic_host_map,
315 };
316
317 static void axon_msi_shutdown(struct platform_device *device)
318 {
319 struct axon_msic *msic = dev_get_drvdata(&device->dev);
320 u32 tmp;
321
322 pr_devel("axon_msi: disabling %pOF\n",
323 irq_domain_get_of_node(msic->irq_domain));
324 tmp = dcr_read(msic->dcr_host, MSIC_CTRL_REG);
325 tmp &= ~MSIC_CTRL_ENABLE & ~MSIC_CTRL_IRQ_ENABLE;
326 msic_dcr_write(msic, MSIC_CTRL_REG, tmp);
327 }
328
329 static int axon_msi_probe(struct platform_device *device)
330 {
331 struct device_node *dn = device->dev.of_node;
332 struct axon_msic *msic;
333 unsigned int virq;
334 int dcr_base, dcr_len;
335
336 pr_devel("axon_msi: setting up dn %pOF\n", dn);
337
338 msic = kzalloc(sizeof(*msic), GFP_KERNEL);
339 if (!msic) {
340 printk(KERN_ERR "axon_msi: couldn't allocate msic for %pOF\n",
341 dn);
342 goto out;
343 }
344
345 dcr_base = dcr_resource_start(dn, 0);
346 dcr_len = dcr_resource_len(dn, 0);
347
348 if (dcr_base == 0 || dcr_len == 0) {
349 printk(KERN_ERR
350 "axon_msi: couldn't parse dcr properties on %pOF\n",
351 dn);
352 goto out_free_msic;
353 }
354
355 msic->dcr_host = dcr_map(dn, dcr_base, dcr_len);
356 if (!DCR_MAP_OK(msic->dcr_host)) {
357 printk(KERN_ERR "axon_msi: dcr_map failed for %pOF\n",
358 dn);
359 goto out_free_msic;
360 }
361
362 msic->fifo_virt = dma_alloc_coherent(&device->dev, MSIC_FIFO_SIZE_BYTES,
363 &msic->fifo_phys, GFP_KERNEL);
364 if (!msic->fifo_virt) {
365 printk(KERN_ERR "axon_msi: couldn't allocate fifo for %pOF\n",
366 dn);
367 goto out_free_msic;
368 }
369
370 virq = irq_of_parse_and_map(dn, 0);
371 if (!virq) {
372 printk(KERN_ERR "axon_msi: irq parse and map failed for %pOF\n",
373 dn);
374 goto out_free_fifo;
375 }
376 memset(msic->fifo_virt, 0xff, MSIC_FIFO_SIZE_BYTES);
377
378 /* We rely on being able to stash a virq in a u16, so limit irqs to < 65536 */
379 msic->irq_domain = irq_domain_add_nomap(dn, 65536, &msic_host_ops, msic);
380 if (!msic->irq_domain) {
381 printk(KERN_ERR "axon_msi: couldn't allocate irq_domain for %pOF\n",
382 dn);
383 goto out_free_fifo;
384 }
385
386 irq_set_handler_data(virq, msic);
387 irq_set_chained_handler(virq, axon_msi_cascade);
388 pr_devel("axon_msi: irq 0x%x setup for axon_msi\n", virq);
389
390 /* Enable the MSIC hardware */
391 msic_dcr_write(msic, MSIC_BASE_ADDR_HI_REG, msic->fifo_phys >> 32);
392 msic_dcr_write(msic, MSIC_BASE_ADDR_LO_REG,
393 msic->fifo_phys & 0xFFFFFFFF);
394 msic_dcr_write(msic, MSIC_CTRL_REG,
395 MSIC_CTRL_IRQ_ENABLE | MSIC_CTRL_ENABLE |
396 MSIC_CTRL_FIFO_SIZE);
397
398 msic->read_offset = dcr_read(msic->dcr_host, MSIC_WRITE_OFFSET_REG)
399 & MSIC_FIFO_SIZE_MASK;
400
401 dev_set_drvdata(&device->dev, msic);
402
403 cell_pci_controller_ops.setup_msi_irqs = axon_msi_setup_msi_irqs;
404 cell_pci_controller_ops.teardown_msi_irqs = axon_msi_teardown_msi_irqs;
405
406 axon_msi_debug_setup(dn, msic);
407
408 printk(KERN_DEBUG "axon_msi: setup MSIC on %pOF\n", dn);
409
410 return 0;
411
412 out_free_fifo:
413 dma_free_coherent(&device->dev, MSIC_FIFO_SIZE_BYTES, msic->fifo_virt,
414 msic->fifo_phys);
415 out_free_msic:
416 kfree(msic);
417 out:
418
419 return -1;
420 }
421
422 static const struct of_device_id axon_msi_device_id[] = {
423 {
424 .compatible = "ibm,axon-msic"
425 },
426 {}
427 };
428
429 static struct platform_driver axon_msi_driver = {
430 .probe = axon_msi_probe,
431 .shutdown = axon_msi_shutdown,
432 .driver = {
433 .name = "axon-msi",
434 .of_match_table = axon_msi_device_id,
435 },
436 };
437
438 static int __init axon_msi_init(void)
439 {
440 return platform_driver_register(&axon_msi_driver);
441 }
442 subsys_initcall(axon_msi_init);
443
444
445 #ifdef DEBUG
446 static int msic_set(void *data, u64 val)
447 {
448 struct axon_msic *msic = data;
449 out_le32(msic->trigger, val);
450 return 0;
451 }
452
453 static int msic_get(void *data, u64 *val)
454 {
455 *val = 0;
456 return 0;
457 }
458
459 DEFINE_SIMPLE_ATTRIBUTE(fops_msic, msic_get, msic_set, "%llu\n");
460
461 void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic)
462 {
463 char name[8];
464 struct resource res;
465
466 if (of_address_to_resource(dn, 0, &res)) {
467 pr_devel("axon_msi: couldn't get reg property\n");
468 return;
469 }
470
471 msic->trigger = ioremap(res.start, 0x4);
472 if (!msic->trigger) {
473 pr_devel("axon_msi: ioremap failed\n");
474 return;
475 }
476
477 snprintf(name, sizeof(name), "msic_%d", of_node_to_nid(dn));
478
479 debugfs_create_file(name, 0600, arch_debugfs_dir, msic, &fops_msic);
480 }
481 #endif /* DEBUG */
482
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