xref: /openbmc/linux/drivers/base/platform-msi.c (revision 0edbfea5)
1 /*
2  * MSI framework for platform devices
3  *
4  * Copyright (C) 2015 ARM Limited, All Rights Reserved.
5  * Author: Marc Zyngier <marc.zyngier@arm.com>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include <linux/device.h>
21 #include <linux/idr.h>
22 #include <linux/irq.h>
23 #include <linux/irqdomain.h>
24 #include <linux/msi.h>
25 #include <linux/slab.h>
26 
27 #define DEV_ID_SHIFT	21
28 #define MAX_DEV_MSIS	(1 << (32 - DEV_ID_SHIFT))
29 
30 /*
31  * Internal data structure containing a (made up, but unique) devid
32  * and the callback to write the MSI message.
33  */
34 struct platform_msi_priv_data {
35 	struct device		*dev;
36 	void 			*host_data;
37 	msi_alloc_info_t	arg;
38 	irq_write_msi_msg_t	write_msg;
39 	int			devid;
40 };
41 
42 /* The devid allocator */
43 static DEFINE_IDA(platform_msi_devid_ida);
44 
45 #ifdef GENERIC_MSI_DOMAIN_OPS
46 /*
47  * Convert an msi_desc to a globaly unique identifier (per-device
48  * devid + msi_desc position in the msi_list).
49  */
50 static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
51 {
52 	u32 devid;
53 
54 	devid = desc->platform.msi_priv_data->devid;
55 
56 	return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
57 }
58 
59 static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
60 {
61 	arg->desc = desc;
62 	arg->hwirq = platform_msi_calc_hwirq(desc);
63 }
64 
65 static int platform_msi_init(struct irq_domain *domain,
66 			     struct msi_domain_info *info,
67 			     unsigned int virq, irq_hw_number_t hwirq,
68 			     msi_alloc_info_t *arg)
69 {
70 	return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
71 					     info->chip, info->chip_data);
72 }
73 #else
74 #define platform_msi_set_desc		NULL
75 #define platform_msi_init		NULL
76 #endif
77 
78 static void platform_msi_update_dom_ops(struct msi_domain_info *info)
79 {
80 	struct msi_domain_ops *ops = info->ops;
81 
82 	BUG_ON(!ops);
83 
84 	if (ops->msi_init == NULL)
85 		ops->msi_init = platform_msi_init;
86 	if (ops->set_desc == NULL)
87 		ops->set_desc = platform_msi_set_desc;
88 }
89 
90 static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
91 {
92 	struct msi_desc *desc = irq_data_get_msi_desc(data);
93 	struct platform_msi_priv_data *priv_data;
94 
95 	priv_data = desc->platform.msi_priv_data;
96 
97 	priv_data->write_msg(desc, msg);
98 }
99 
100 static void platform_msi_update_chip_ops(struct msi_domain_info *info)
101 {
102 	struct irq_chip *chip = info->chip;
103 
104 	BUG_ON(!chip);
105 	if (!chip->irq_mask)
106 		chip->irq_mask = irq_chip_mask_parent;
107 	if (!chip->irq_unmask)
108 		chip->irq_unmask = irq_chip_unmask_parent;
109 	if (!chip->irq_eoi)
110 		chip->irq_eoi = irq_chip_eoi_parent;
111 	if (!chip->irq_set_affinity)
112 		chip->irq_set_affinity = msi_domain_set_affinity;
113 	if (!chip->irq_write_msi_msg)
114 		chip->irq_write_msi_msg = platform_msi_write_msg;
115 }
116 
117 static void platform_msi_free_descs(struct device *dev, int base, int nvec)
118 {
119 	struct msi_desc *desc, *tmp;
120 
121 	list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
122 		if (desc->platform.msi_index >= base &&
123 		    desc->platform.msi_index < (base + nvec)) {
124 			list_del(&desc->list);
125 			free_msi_entry(desc);
126 		}
127 	}
128 }
129 
130 static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq,
131 					     int nvec,
132 					     struct platform_msi_priv_data *data)
133 
134 {
135 	struct msi_desc *desc;
136 	int i, base = 0;
137 
138 	if (!list_empty(dev_to_msi_list(dev))) {
139 		desc = list_last_entry(dev_to_msi_list(dev),
140 				       struct msi_desc, list);
141 		base = desc->platform.msi_index + 1;
142 	}
143 
144 	for (i = 0; i < nvec; i++) {
145 		desc = alloc_msi_entry(dev);
146 		if (!desc)
147 			break;
148 
149 		desc->platform.msi_priv_data = data;
150 		desc->platform.msi_index = base + i;
151 		desc->nvec_used = 1;
152 		desc->irq = virq ? virq + i : 0;
153 
154 		list_add_tail(&desc->list, dev_to_msi_list(dev));
155 	}
156 
157 	if (i != nvec) {
158 		/* Clean up the mess */
159 		platform_msi_free_descs(dev, base, nvec);
160 
161 		return -ENOMEM;
162 	}
163 
164 	return 0;
165 }
166 
167 static int platform_msi_alloc_descs(struct device *dev, int nvec,
168 				    struct platform_msi_priv_data *data)
169 
170 {
171 	return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data);
172 }
173 
174 /**
175  * platform_msi_create_irq_domain - Create a platform MSI interrupt domain
176  * @fwnode:		Optional fwnode of the interrupt controller
177  * @info:	MSI domain info
178  * @parent:	Parent irq domain
179  *
180  * Updates the domain and chip ops and creates a platform MSI
181  * interrupt domain.
182  *
183  * Returns:
184  * A domain pointer or NULL in case of failure.
185  */
186 struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
187 						  struct msi_domain_info *info,
188 						  struct irq_domain *parent)
189 {
190 	struct irq_domain *domain;
191 
192 	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
193 		platform_msi_update_dom_ops(info);
194 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
195 		platform_msi_update_chip_ops(info);
196 
197 	domain = msi_create_irq_domain(fwnode, info, parent);
198 	if (domain)
199 		domain->bus_token = DOMAIN_BUS_PLATFORM_MSI;
200 
201 	return domain;
202 }
203 
204 static struct platform_msi_priv_data *
205 platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
206 			     irq_write_msi_msg_t write_msi_msg)
207 {
208 	struct platform_msi_priv_data *datap;
209 	/*
210 	 * Limit the number of interrupts to 256 per device. Should we
211 	 * need to bump this up, DEV_ID_SHIFT should be adjusted
212 	 * accordingly (which would impact the max number of MSI
213 	 * capable devices).
214 	 */
215 	if (!dev->msi_domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS)
216 		return ERR_PTR(-EINVAL);
217 
218 	if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
219 		dev_err(dev, "Incompatible msi_domain, giving up\n");
220 		return ERR_PTR(-EINVAL);
221 	}
222 
223 	/* Already had a helping of MSI? Greed... */
224 	if (!list_empty(dev_to_msi_list(dev)))
225 		return ERR_PTR(-EBUSY);
226 
227 	datap = kzalloc(sizeof(*datap), GFP_KERNEL);
228 	if (!datap)
229 		return ERR_PTR(-ENOMEM);
230 
231 	datap->devid = ida_simple_get(&platform_msi_devid_ida,
232 				      0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
233 	if (datap->devid < 0) {
234 		int err = datap->devid;
235 		kfree(datap);
236 		return ERR_PTR(err);
237 	}
238 
239 	datap->write_msg = write_msi_msg;
240 	datap->dev = dev;
241 
242 	return datap;
243 }
244 
245 static void platform_msi_free_priv_data(struct platform_msi_priv_data *data)
246 {
247 	ida_simple_remove(&platform_msi_devid_ida, data->devid);
248 	kfree(data);
249 }
250 
251 /**
252  * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
253  * @dev:		The device for which to allocate interrupts
254  * @nvec:		The number of interrupts to allocate
255  * @write_msi_msg:	Callback to write an interrupt message for @dev
256  *
257  * Returns:
258  * Zero for success, or an error code in case of failure
259  */
260 int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
261 				   irq_write_msi_msg_t write_msi_msg)
262 {
263 	struct platform_msi_priv_data *priv_data;
264 	int err;
265 
266 	priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
267 	if (IS_ERR(priv_data))
268 		return PTR_ERR(priv_data);
269 
270 	err = platform_msi_alloc_descs(dev, nvec, priv_data);
271 	if (err)
272 		goto out_free_priv_data;
273 
274 	err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec);
275 	if (err)
276 		goto out_free_desc;
277 
278 	return 0;
279 
280 out_free_desc:
281 	platform_msi_free_descs(dev, 0, nvec);
282 out_free_priv_data:
283 	platform_msi_free_priv_data(priv_data);
284 
285 	return err;
286 }
287 EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs);
288 
289 /**
290  * platform_msi_domain_free_irqs - Free MSI interrupts for @dev
291  * @dev:	The device for which to free interrupts
292  */
293 void platform_msi_domain_free_irqs(struct device *dev)
294 {
295 	if (!list_empty(dev_to_msi_list(dev))) {
296 		struct msi_desc *desc;
297 
298 		desc = first_msi_entry(dev);
299 		platform_msi_free_priv_data(desc->platform.msi_priv_data);
300 	}
301 
302 	msi_domain_free_irqs(dev->msi_domain, dev);
303 	platform_msi_free_descs(dev, 0, MAX_DEV_MSIS);
304 }
305 EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs);
306 
307 /**
308  * platform_msi_get_host_data - Query the private data associated with
309  *                              a platform-msi domain
310  * @domain:	The platform-msi domain
311  *
312  * Returns the private data provided when calling
313  * platform_msi_create_device_domain.
314  */
315 void *platform_msi_get_host_data(struct irq_domain *domain)
316 {
317 	struct platform_msi_priv_data *data = domain->host_data;
318 	return data->host_data;
319 }
320 
321 /**
322  * platform_msi_create_device_domain - Create a platform-msi domain
323  *
324  * @dev:		The device generating the MSIs
325  * @nvec:		The number of MSIs that need to be allocated
326  * @write_msi_msg:	Callback to write an interrupt message for @dev
327  * @ops:		The hierarchy domain operations to use
328  * @host_data:		Private data associated to this domain
329  *
330  * Returns an irqdomain for @nvec interrupts
331  */
332 struct irq_domain *
333 platform_msi_create_device_domain(struct device *dev,
334 				  unsigned int nvec,
335 				  irq_write_msi_msg_t write_msi_msg,
336 				  const struct irq_domain_ops *ops,
337 				  void *host_data)
338 {
339 	struct platform_msi_priv_data *data;
340 	struct irq_domain *domain;
341 	int err;
342 
343 	data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
344 	if (IS_ERR(data))
345 		return NULL;
346 
347 	data->host_data = host_data;
348 	domain = irq_domain_create_hierarchy(dev->msi_domain, 0, nvec,
349 					     of_node_to_fwnode(dev->of_node),
350 					     ops, data);
351 	if (!domain)
352 		goto free_priv;
353 
354 	err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg);
355 	if (err)
356 		goto free_domain;
357 
358 	return domain;
359 
360 free_domain:
361 	irq_domain_remove(domain);
362 free_priv:
363 	platform_msi_free_priv_data(data);
364 	return NULL;
365 }
366 
367 /**
368  * platform_msi_domain_free - Free interrupts associated with a platform-msi
369  *                            domain
370  *
371  * @domain:	The platform-msi domain
372  * @virq:	The base irq from which to perform the free operation
373  * @nvec:	How many interrupts to free from @virq
374  */
375 void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
376 			      unsigned int nvec)
377 {
378 	struct platform_msi_priv_data *data = domain->host_data;
379 	struct msi_desc *desc;
380 	for_each_msi_entry(desc, data->dev) {
381 		if (WARN_ON(!desc->irq || desc->nvec_used != 1))
382 			return;
383 		if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
384 			continue;
385 
386 		irq_domain_free_irqs_common(domain, desc->irq, 1);
387 	}
388 }
389 
390 /**
391  * platform_msi_domain_alloc - Allocate interrupts associated with
392  *			       a platform-msi domain
393  *
394  * @domain:	The platform-msi domain
395  * @virq:	The base irq from which to perform the allocate operation
396  * @nvec:	How many interrupts to free from @virq
397  *
398  * Return 0 on success, or an error code on failure. Must be called
399  * with irq_domain_mutex held (which can only be done as part of a
400  * top-level interrupt allocation).
401  */
402 int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
403 			      unsigned int nr_irqs)
404 {
405 	struct platform_msi_priv_data *data = domain->host_data;
406 	int err;
407 
408 	err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data);
409 	if (err)
410 		return err;
411 
412 	err = msi_domain_populate_irqs(domain->parent, data->dev,
413 				       virq, nr_irqs, &data->arg);
414 	if (err)
415 		platform_msi_domain_free(domain, virq, nr_irqs);
416 
417 	return err;
418 }
419