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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * MSI framework for platform devices
4 *
5 * Copyright (C) 2015 ARM Limited, All Rights Reserved.
6 * Author: Marc Zyngier <marc.zyngier@arm.com>
7 */
8
9#include <linux/device.h>
10#include <linux/idr.h>
11#include <linux/irq.h>
12#include <linux/irqdomain.h>
13#include <linux/msi.h>
14#include <linux/slab.h>
15
16#define DEV_ID_SHIFT 21
17#define MAX_DEV_MSIS (1 << (32 - DEV_ID_SHIFT))
18
19/*
20 * Internal data structure containing a (made up, but unique) devid
21 * and the callback to write the MSI message.
22 */
23struct platform_msi_priv_data {
24 struct device *dev;
25 void *host_data;
26 msi_alloc_info_t arg;
27 irq_write_msi_msg_t write_msg;
28 int devid;
29};
30
31/* The devid allocator */
32static DEFINE_IDA(platform_msi_devid_ida);
33
34#ifdef GENERIC_MSI_DOMAIN_OPS
35/*
36 * Convert an msi_desc to a globaly unique identifier (per-device
37 * devid + msi_desc position in the msi_list).
38 */
39static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
40{
41 u32 devid;
42
43 devid = desc->platform.msi_priv_data->devid;
44
45 return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
46}
47
48static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
49{
50 arg->desc = desc;
51 arg->hwirq = platform_msi_calc_hwirq(desc);
52}
53
54static int platform_msi_init(struct irq_domain *domain,
55 struct msi_domain_info *info,
56 unsigned int virq, irq_hw_number_t hwirq,
57 msi_alloc_info_t *arg)
58{
59 return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
60 info->chip, info->chip_data);
61}
62#else
63#define platform_msi_set_desc NULL
64#define platform_msi_init NULL
65#endif
66
67static void platform_msi_update_dom_ops(struct msi_domain_info *info)
68{
69 struct msi_domain_ops *ops = info->ops;
70
71 BUG_ON(!ops);
72
73 if (ops->msi_init == NULL)
74 ops->msi_init = platform_msi_init;
75 if (ops->set_desc == NULL)
76 ops->set_desc = platform_msi_set_desc;
77}
78
79static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
80{
81 struct msi_desc *desc = irq_data_get_msi_desc(data);
82 struct platform_msi_priv_data *priv_data;
83
84 priv_data = desc->platform.msi_priv_data;
85
86 priv_data->write_msg(desc, msg);
87}
88
89static void platform_msi_update_chip_ops(struct msi_domain_info *info)
90{
91 struct irq_chip *chip = info->chip;
92
93 BUG_ON(!chip);
94 if (!chip->irq_mask)
95 chip->irq_mask = irq_chip_mask_parent;
96 if (!chip->irq_unmask)
97 chip->irq_unmask = irq_chip_unmask_parent;
98 if (!chip->irq_eoi)
99 chip->irq_eoi = irq_chip_eoi_parent;
100 if (!chip->irq_set_affinity)
101 chip->irq_set_affinity = msi_domain_set_affinity;
102 if (!chip->irq_write_msi_msg)
103 chip->irq_write_msi_msg = platform_msi_write_msg;
104}
105
106static void platform_msi_free_descs(struct device *dev, int base, int nvec)
107{
108 struct msi_desc *desc, *tmp;
109
110 list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
111 if (desc->platform.msi_index >= base &&
112 desc->platform.msi_index < (base + nvec)) {
113 list_del(&desc->list);
114 free_msi_entry(desc);
115 }
116 }
117}
118
119static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq,
120 int nvec,
121 struct platform_msi_priv_data *data)
122
123{
124 struct msi_desc *desc;
125 int i, base = 0;
126
127 if (!list_empty(dev_to_msi_list(dev))) {
128 desc = list_last_entry(dev_to_msi_list(dev),
129 struct msi_desc, list);
130 base = desc->platform.msi_index + 1;
131 }
132
133 for (i = 0; i < nvec; i++) {
134 desc = alloc_msi_entry(dev, 1, NULL);
135 if (!desc)
136 break;
137
138 desc->platform.msi_priv_data = data;
139 desc->platform.msi_index = base + i;
140 desc->irq = virq ? virq + i : 0;
141
142 list_add_tail(&desc->list, dev_to_msi_list(dev));
143 }
144
145 if (i != nvec) {
146 /* Clean up the mess */
147 platform_msi_free_descs(dev, base, nvec);
148
149 return -ENOMEM;
150 }
151
152 return 0;
153}
154
155static int platform_msi_alloc_descs(struct device *dev, int nvec,
156 struct platform_msi_priv_data *data)
157
158{
159 return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data);
160}
161
162/**
163 * platform_msi_create_irq_domain - Create a platform MSI interrupt domain
164 * @fwnode: Optional fwnode of the interrupt controller
165 * @info: MSI domain info
166 * @parent: Parent irq domain
167 *
168 * Updates the domain and chip ops and creates a platform MSI
169 * interrupt domain.
170 *
171 * Returns:
172 * A domain pointer or NULL in case of failure.
173 */
174struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
175 struct msi_domain_info *info,
176 struct irq_domain *parent)
177{
178 struct irq_domain *domain;
179
180 if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
181 platform_msi_update_dom_ops(info);
182 if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
183 platform_msi_update_chip_ops(info);
184
185 domain = msi_create_irq_domain(fwnode, info, parent);
186 if (domain)
187 irq_domain_update_bus_token(domain, DOMAIN_BUS_PLATFORM_MSI);
188
189 return domain;
190}
191
192static struct platform_msi_priv_data *
193platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
194 irq_write_msi_msg_t write_msi_msg)
195{
196 struct platform_msi_priv_data *datap;
197 /*
198 * Limit the number of interrupts to 2048 per device. Should we
199 * need to bump this up, DEV_ID_SHIFT should be adjusted
200 * accordingly (which would impact the max number of MSI
201 * capable devices).
202 */
203 if (!dev->msi_domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS)
204 return ERR_PTR(-EINVAL);
205
206 if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
207 dev_err(dev, "Incompatible msi_domain, giving up\n");
208 return ERR_PTR(-EINVAL);
209 }
210
211 /* Already had a helping of MSI? Greed... */
212 if (!list_empty(dev_to_msi_list(dev)))
213 return ERR_PTR(-EBUSY);
214
215 datap = kzalloc(sizeof(*datap), GFP_KERNEL);
216 if (!datap)
217 return ERR_PTR(-ENOMEM);
218
219 datap->devid = ida_simple_get(&platform_msi_devid_ida,
220 0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
221 if (datap->devid < 0) {
222 int err = datap->devid;
223 kfree(datap);
224 return ERR_PTR(err);
225 }
226
227 datap->write_msg = write_msi_msg;
228 datap->dev = dev;
229
230 return datap;
231}
232
233static void platform_msi_free_priv_data(struct platform_msi_priv_data *data)
234{
235 ida_simple_remove(&platform_msi_devid_ida, data->devid);
236 kfree(data);
237}
238
239/**
240 * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
241 * @dev: The device for which to allocate interrupts
242 * @nvec: The number of interrupts to allocate
243 * @write_msi_msg: Callback to write an interrupt message for @dev
244 *
245 * Returns:
246 * Zero for success, or an error code in case of failure
247 */
248int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
249 irq_write_msi_msg_t write_msi_msg)
250{
251 struct platform_msi_priv_data *priv_data;
252 int err;
253
254 priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
255 if (IS_ERR(priv_data))
256 return PTR_ERR(priv_data);
257
258 err = platform_msi_alloc_descs(dev, nvec, priv_data);
259 if (err)
260 goto out_free_priv_data;
261
262 err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec);
263 if (err)
264 goto out_free_desc;
265
266 return 0;
267
268out_free_desc:
269 platform_msi_free_descs(dev, 0, nvec);
270out_free_priv_data:
271 platform_msi_free_priv_data(priv_data);
272
273 return err;
274}
275EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs);
276
277/**
278 * platform_msi_domain_free_irqs - Free MSI interrupts for @dev
279 * @dev: The device for which to free interrupts
280 */
281void platform_msi_domain_free_irqs(struct device *dev)
282{
283 if (!list_empty(dev_to_msi_list(dev))) {
284 struct msi_desc *desc;
285
286 desc = first_msi_entry(dev);
287 platform_msi_free_priv_data(desc->platform.msi_priv_data);
288 }
289
290 msi_domain_free_irqs(dev->msi_domain, dev);
291 platform_msi_free_descs(dev, 0, MAX_DEV_MSIS);
292}
293EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs);
294
295/**
296 * platform_msi_get_host_data - Query the private data associated with
297 * a platform-msi domain
298 * @domain: The platform-msi domain
299 *
300 * Returns the private data provided when calling
301 * platform_msi_create_device_domain.
302 */
303void *platform_msi_get_host_data(struct irq_domain *domain)
304{
305 struct platform_msi_priv_data *data = domain->host_data;
306 return data->host_data;
307}
308
309/**
310 * platform_msi_create_device_domain - Create a platform-msi domain
311 *
312 * @dev: The device generating the MSIs
313 * @nvec: The number of MSIs that need to be allocated
314 * @write_msi_msg: Callback to write an interrupt message for @dev
315 * @ops: The hierarchy domain operations to use
316 * @host_data: Private data associated to this domain
317 *
318 * Returns an irqdomain for @nvec interrupts
319 */
320struct irq_domain *
321platform_msi_create_device_domain(struct device *dev,
322 unsigned int nvec,
323 irq_write_msi_msg_t write_msi_msg,
324 const struct irq_domain_ops *ops,
325 void *host_data)
326{
327 struct platform_msi_priv_data *data;
328 struct irq_domain *domain;
329 int err;
330
331 data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
332 if (IS_ERR(data))
333 return NULL;
334
335 data->host_data = host_data;
336 domain = irq_domain_create_hierarchy(dev->msi_domain, 0, nvec,
337 dev->fwnode, ops, data);
338 if (!domain)
339 goto free_priv;
340
341 err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg);
342 if (err)
343 goto free_domain;
344
345 return domain;
346
347free_domain:
348 irq_domain_remove(domain);
349free_priv:
350 platform_msi_free_priv_data(data);
351 return NULL;
352}
353
354/**
355 * platform_msi_domain_free - Free interrupts associated with a platform-msi
356 * domain
357 *
358 * @domain: The platform-msi domain
359 * @virq: The base irq from which to perform the free operation
360 * @nvec: How many interrupts to free from @virq
361 */
362void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
363 unsigned int nvec)
364{
365 struct platform_msi_priv_data *data = domain->host_data;
366 struct msi_desc *desc;
367 for_each_msi_entry(desc, data->dev) {
368 if (WARN_ON(!desc->irq || desc->nvec_used != 1))
369 return;
370 if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
371 continue;
372
373 irq_domain_free_irqs_common(domain, desc->irq, 1);
374 }
375}
376
377/**
378 * platform_msi_domain_alloc - Allocate interrupts associated with
379 * a platform-msi domain
380 *
381 * @domain: The platform-msi domain
382 * @virq: The base irq from which to perform the allocate operation
383 * @nvec: How many interrupts to free from @virq
384 *
385 * Return 0 on success, or an error code on failure. Must be called
386 * with irq_domain_mutex held (which can only be done as part of a
387 * top-level interrupt allocation).
388 */
389int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
390 unsigned int nr_irqs)
391{
392 struct platform_msi_priv_data *data = domain->host_data;
393 int err;
394
395 err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data);
396 if (err)
397 return err;
398
399 err = msi_domain_populate_irqs(domain->parent, data->dev,
400 virq, nr_irqs, &data->arg);
401 if (err)
402 platform_msi_domain_free(domain, virq, nr_irqs);
403
404 return err;
405}