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3a29355a VK |
1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * GPIO driver for virtio-based virtual GPIO controllers | |
4 | * | |
5 | * Copyright (C) 2021 metux IT consult | |
6 | * Enrico Weigelt, metux IT consult <info@metux.net> | |
7 | * | |
8 | * Copyright (C) 2021 Linaro. | |
9 | * Viresh Kumar <viresh.kumar@linaro.org> | |
10 | */ | |
11 | ||
12 | #include <linux/completion.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/gpio/driver.h> | |
15 | #include <linux/io.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/mutex.h> | |
eff5cdd7 | 19 | #include <linux/spinlock.h> |
3a29355a VK |
20 | #include <linux/virtio_config.h> |
21 | #include <uapi/linux/virtio_gpio.h> | |
22 | #include <uapi/linux/virtio_ids.h> | |
23 | ||
24 | struct virtio_gpio_line { | |
25 | struct mutex lock; /* Protects line operation */ | |
26 | struct completion completion; | |
27 | struct virtio_gpio_request req ____cacheline_aligned; | |
28 | struct virtio_gpio_response res ____cacheline_aligned; | |
29 | unsigned int rxlen; | |
30 | }; | |
31 | ||
eff5cdd7 VK |
32 | struct vgpio_irq_line { |
33 | u8 type; | |
34 | bool disabled; | |
35 | bool masked; | |
36 | bool queued; | |
37 | bool update_pending; | |
38 | bool queue_pending; | |
39 | ||
40 | struct virtio_gpio_irq_request ireq ____cacheline_aligned; | |
41 | struct virtio_gpio_irq_response ires ____cacheline_aligned; | |
42 | }; | |
43 | ||
3a29355a VK |
44 | struct virtio_gpio { |
45 | struct virtio_device *vdev; | |
46 | struct mutex lock; /* Protects virtqueue operation */ | |
47 | struct gpio_chip gc; | |
3a29355a VK |
48 | struct virtio_gpio_line *lines; |
49 | struct virtqueue *request_vq; | |
eff5cdd7 VK |
50 | |
51 | /* irq support */ | |
52 | struct virtqueue *event_vq; | |
53 | struct mutex irq_lock; /* Protects irq operation */ | |
54 | raw_spinlock_t eventq_lock; /* Protects queuing of the buffer */ | |
55 | struct vgpio_irq_line *irq_lines; | |
3a29355a VK |
56 | }; |
57 | ||
58 | static int _virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio, | |
59 | u8 txvalue, u8 *rxvalue, void *response, u32 rxlen) | |
60 | { | |
61 | struct virtio_gpio_line *line = &vgpio->lines[gpio]; | |
62 | struct virtio_gpio_request *req = &line->req; | |
63 | struct virtio_gpio_response *res = response; | |
64 | struct scatterlist *sgs[2], req_sg, res_sg; | |
65 | struct device *dev = &vgpio->vdev->dev; | |
66 | int ret; | |
67 | ||
68 | /* | |
69 | * Prevent concurrent requests for the same line since we have | |
70 | * pre-allocated request/response buffers for each GPIO line. Moreover | |
71 | * Linux always accesses a GPIO line sequentially, so this locking shall | |
72 | * always go through without any delays. | |
73 | */ | |
74 | mutex_lock(&line->lock); | |
75 | ||
76 | req->type = cpu_to_le16(type); | |
77 | req->gpio = cpu_to_le16(gpio); | |
17395d77 | 78 | req->value = cpu_to_le32(txvalue); |
3a29355a VK |
79 | |
80 | sg_init_one(&req_sg, req, sizeof(*req)); | |
81 | sg_init_one(&res_sg, res, rxlen); | |
82 | sgs[0] = &req_sg; | |
83 | sgs[1] = &res_sg; | |
84 | ||
85 | line->rxlen = 0; | |
86 | reinit_completion(&line->completion); | |
87 | ||
88 | /* | |
89 | * Virtqueue callers need to ensure they don't call its APIs with other | |
90 | * virtqueue operations at the same time. | |
91 | */ | |
92 | mutex_lock(&vgpio->lock); | |
93 | ret = virtqueue_add_sgs(vgpio->request_vq, sgs, 1, 1, line, GFP_KERNEL); | |
94 | if (ret) { | |
95 | dev_err(dev, "failed to add request to vq\n"); | |
96 | mutex_unlock(&vgpio->lock); | |
97 | goto out; | |
98 | } | |
99 | ||
100 | virtqueue_kick(vgpio->request_vq); | |
101 | mutex_unlock(&vgpio->lock); | |
102 | ||
3e4d9a48 | 103 | wait_for_completion(&line->completion); |
3a29355a VK |
104 | |
105 | if (unlikely(res->status != VIRTIO_GPIO_STATUS_OK)) { | |
106 | dev_err(dev, "GPIO request failed: %d\n", gpio); | |
107 | ret = -EINVAL; | |
108 | goto out; | |
109 | } | |
110 | ||
111 | if (unlikely(line->rxlen != rxlen)) { | |
112 | dev_err(dev, "GPIO operation returned incorrect len (%u : %u)\n", | |
113 | rxlen, line->rxlen); | |
114 | ret = -EINVAL; | |
115 | goto out; | |
116 | } | |
117 | ||
118 | if (rxvalue) | |
119 | *rxvalue = res->value; | |
120 | ||
121 | out: | |
122 | mutex_unlock(&line->lock); | |
123 | return ret; | |
124 | } | |
125 | ||
126 | static int virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio, | |
127 | u8 txvalue, u8 *rxvalue) | |
128 | { | |
129 | struct virtio_gpio_line *line = &vgpio->lines[gpio]; | |
130 | struct virtio_gpio_response *res = &line->res; | |
131 | ||
132 | return _virtio_gpio_req(vgpio, type, gpio, txvalue, rxvalue, res, | |
133 | sizeof(*res)); | |
134 | } | |
135 | ||
136 | static void virtio_gpio_free(struct gpio_chip *gc, unsigned int gpio) | |
137 | { | |
138 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
139 | ||
140 | virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio, | |
141 | VIRTIO_GPIO_DIRECTION_NONE, NULL); | |
142 | } | |
143 | ||
144 | static int virtio_gpio_get_direction(struct gpio_chip *gc, unsigned int gpio) | |
145 | { | |
146 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
147 | u8 direction; | |
148 | int ret; | |
149 | ||
150 | ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_DIRECTION, gpio, 0, | |
151 | &direction); | |
152 | if (ret) | |
153 | return ret; | |
154 | ||
155 | switch (direction) { | |
156 | case VIRTIO_GPIO_DIRECTION_IN: | |
157 | return GPIO_LINE_DIRECTION_IN; | |
158 | case VIRTIO_GPIO_DIRECTION_OUT: | |
159 | return GPIO_LINE_DIRECTION_OUT; | |
160 | default: | |
161 | return -EINVAL; | |
162 | } | |
163 | } | |
164 | ||
165 | static int virtio_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio) | |
166 | { | |
167 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
168 | ||
169 | return virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio, | |
170 | VIRTIO_GPIO_DIRECTION_IN, NULL); | |
171 | } | |
172 | ||
173 | static int virtio_gpio_direction_output(struct gpio_chip *gc, unsigned int gpio, | |
174 | int value) | |
175 | { | |
176 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
177 | int ret; | |
178 | ||
179 | ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, value, NULL); | |
180 | if (ret) | |
181 | return ret; | |
182 | ||
183 | return virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio, | |
184 | VIRTIO_GPIO_DIRECTION_OUT, NULL); | |
185 | } | |
186 | ||
187 | static int virtio_gpio_get(struct gpio_chip *gc, unsigned int gpio) | |
188 | { | |
189 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
190 | u8 value; | |
191 | int ret; | |
192 | ||
193 | ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_VALUE, gpio, 0, &value); | |
194 | return ret ? ret : value; | |
195 | } | |
196 | ||
197 | static void virtio_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value) | |
198 | { | |
199 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
200 | ||
201 | virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, value, NULL); | |
202 | } | |
203 | ||
eff5cdd7 VK |
204 | /* Interrupt handling */ |
205 | static void virtio_gpio_irq_prepare(struct virtio_gpio *vgpio, u16 gpio) | |
206 | { | |
207 | struct vgpio_irq_line *irq_line = &vgpio->irq_lines[gpio]; | |
208 | struct virtio_gpio_irq_request *ireq = &irq_line->ireq; | |
209 | struct virtio_gpio_irq_response *ires = &irq_line->ires; | |
210 | struct scatterlist *sgs[2], req_sg, res_sg; | |
211 | int ret; | |
212 | ||
213 | if (WARN_ON(irq_line->queued || irq_line->masked || irq_line->disabled)) | |
214 | return; | |
215 | ||
216 | ireq->gpio = cpu_to_le16(gpio); | |
217 | sg_init_one(&req_sg, ireq, sizeof(*ireq)); | |
218 | sg_init_one(&res_sg, ires, sizeof(*ires)); | |
219 | sgs[0] = &req_sg; | |
220 | sgs[1] = &res_sg; | |
221 | ||
222 | ret = virtqueue_add_sgs(vgpio->event_vq, sgs, 1, 1, irq_line, GFP_ATOMIC); | |
223 | if (ret) { | |
224 | dev_err(&vgpio->vdev->dev, "failed to add request to eventq\n"); | |
225 | return; | |
226 | } | |
227 | ||
228 | irq_line->queued = true; | |
229 | virtqueue_kick(vgpio->event_vq); | |
230 | } | |
231 | ||
232 | static void virtio_gpio_irq_enable(struct irq_data *d) | |
233 | { | |
234 | struct gpio_chip *gc = irq_data_get_irq_chip_data(d); | |
235 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
236 | struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; | |
237 | ||
238 | raw_spin_lock(&vgpio->eventq_lock); | |
239 | irq_line->disabled = false; | |
240 | irq_line->masked = false; | |
241 | irq_line->queue_pending = true; | |
242 | raw_spin_unlock(&vgpio->eventq_lock); | |
243 | ||
244 | irq_line->update_pending = true; | |
245 | } | |
246 | ||
247 | static void virtio_gpio_irq_disable(struct irq_data *d) | |
248 | { | |
249 | struct gpio_chip *gc = irq_data_get_irq_chip_data(d); | |
250 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
251 | struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; | |
252 | ||
253 | raw_spin_lock(&vgpio->eventq_lock); | |
254 | irq_line->disabled = true; | |
255 | irq_line->masked = true; | |
256 | irq_line->queue_pending = false; | |
257 | raw_spin_unlock(&vgpio->eventq_lock); | |
258 | ||
259 | irq_line->update_pending = true; | |
260 | } | |
261 | ||
262 | static void virtio_gpio_irq_mask(struct irq_data *d) | |
263 | { | |
264 | struct gpio_chip *gc = irq_data_get_irq_chip_data(d); | |
265 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
266 | struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; | |
267 | ||
268 | raw_spin_lock(&vgpio->eventq_lock); | |
269 | irq_line->masked = true; | |
270 | raw_spin_unlock(&vgpio->eventq_lock); | |
271 | } | |
272 | ||
273 | static void virtio_gpio_irq_unmask(struct irq_data *d) | |
274 | { | |
275 | struct gpio_chip *gc = irq_data_get_irq_chip_data(d); | |
276 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
277 | struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; | |
278 | ||
279 | raw_spin_lock(&vgpio->eventq_lock); | |
280 | irq_line->masked = false; | |
281 | ||
282 | /* Queue the buffer unconditionally on unmask */ | |
283 | virtio_gpio_irq_prepare(vgpio, d->hwirq); | |
284 | raw_spin_unlock(&vgpio->eventq_lock); | |
285 | } | |
286 | ||
287 | static int virtio_gpio_irq_set_type(struct irq_data *d, unsigned int type) | |
288 | { | |
289 | struct gpio_chip *gc = irq_data_get_irq_chip_data(d); | |
290 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
291 | struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; | |
292 | ||
293 | switch (type) { | |
294 | case IRQ_TYPE_EDGE_RISING: | |
295 | type = VIRTIO_GPIO_IRQ_TYPE_EDGE_RISING; | |
296 | break; | |
297 | case IRQ_TYPE_EDGE_FALLING: | |
298 | type = VIRTIO_GPIO_IRQ_TYPE_EDGE_FALLING; | |
299 | break; | |
300 | case IRQ_TYPE_EDGE_BOTH: | |
301 | type = VIRTIO_GPIO_IRQ_TYPE_EDGE_BOTH; | |
302 | break; | |
303 | case IRQ_TYPE_LEVEL_LOW: | |
304 | type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_LOW; | |
305 | break; | |
306 | case IRQ_TYPE_LEVEL_HIGH: | |
307 | type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_HIGH; | |
308 | break; | |
309 | default: | |
310 | dev_err(&vgpio->vdev->dev, "unsupported irq type: %u\n", type); | |
311 | return -EINVAL; | |
312 | } | |
313 | ||
314 | irq_line->type = type; | |
315 | irq_line->update_pending = true; | |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
320 | static void virtio_gpio_irq_bus_lock(struct irq_data *d) | |
321 | { | |
322 | struct gpio_chip *gc = irq_data_get_irq_chip_data(d); | |
323 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
324 | ||
325 | mutex_lock(&vgpio->irq_lock); | |
326 | } | |
327 | ||
328 | static void virtio_gpio_irq_bus_sync_unlock(struct irq_data *d) | |
329 | { | |
330 | struct gpio_chip *gc = irq_data_get_irq_chip_data(d); | |
331 | struct virtio_gpio *vgpio = gpiochip_get_data(gc); | |
332 | struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; | |
333 | u8 type = irq_line->disabled ? VIRTIO_GPIO_IRQ_TYPE_NONE : irq_line->type; | |
334 | unsigned long flags; | |
335 | ||
336 | if (irq_line->update_pending) { | |
337 | irq_line->update_pending = false; | |
338 | virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_IRQ_TYPE, d->hwirq, type, | |
339 | NULL); | |
340 | ||
341 | /* Queue the buffer only after interrupt is enabled */ | |
342 | raw_spin_lock_irqsave(&vgpio->eventq_lock, flags); | |
343 | if (irq_line->queue_pending) { | |
344 | irq_line->queue_pending = false; | |
345 | virtio_gpio_irq_prepare(vgpio, d->hwirq); | |
346 | } | |
347 | raw_spin_unlock_irqrestore(&vgpio->eventq_lock, flags); | |
348 | } | |
349 | ||
350 | mutex_unlock(&vgpio->irq_lock); | |
351 | } | |
352 | ||
353 | static struct irq_chip vgpio_irq_chip = { | |
354 | .name = "virtio-gpio", | |
355 | .irq_enable = virtio_gpio_irq_enable, | |
356 | .irq_disable = virtio_gpio_irq_disable, | |
357 | .irq_mask = virtio_gpio_irq_mask, | |
358 | .irq_unmask = virtio_gpio_irq_unmask, | |
359 | .irq_set_type = virtio_gpio_irq_set_type, | |
360 | ||
361 | /* These are required to implement irqchip for slow busses */ | |
362 | .irq_bus_lock = virtio_gpio_irq_bus_lock, | |
363 | .irq_bus_sync_unlock = virtio_gpio_irq_bus_sync_unlock, | |
364 | }; | |
365 | ||
366 | static bool ignore_irq(struct virtio_gpio *vgpio, int gpio, | |
367 | struct vgpio_irq_line *irq_line) | |
368 | { | |
369 | bool ignore = false; | |
370 | ||
371 | raw_spin_lock(&vgpio->eventq_lock); | |
372 | irq_line->queued = false; | |
373 | ||
374 | /* Interrupt is disabled currently */ | |
375 | if (irq_line->masked || irq_line->disabled) { | |
376 | ignore = true; | |
377 | goto unlock; | |
378 | } | |
379 | ||
380 | /* | |
381 | * Buffer is returned as the interrupt was disabled earlier, but is | |
382 | * enabled again now. Requeue the buffers. | |
383 | */ | |
384 | if (irq_line->ires.status == VIRTIO_GPIO_IRQ_STATUS_INVALID) { | |
385 | virtio_gpio_irq_prepare(vgpio, gpio); | |
386 | ignore = true; | |
387 | goto unlock; | |
388 | } | |
389 | ||
390 | if (WARN_ON(irq_line->ires.status != VIRTIO_GPIO_IRQ_STATUS_VALID)) | |
391 | ignore = true; | |
392 | ||
393 | unlock: | |
394 | raw_spin_unlock(&vgpio->eventq_lock); | |
395 | ||
396 | return ignore; | |
397 | } | |
398 | ||
399 | static void virtio_gpio_event_vq(struct virtqueue *vq) | |
400 | { | |
401 | struct virtio_gpio *vgpio = vq->vdev->priv; | |
402 | struct device *dev = &vgpio->vdev->dev; | |
403 | struct vgpio_irq_line *irq_line; | |
404 | int gpio, ret; | |
405 | unsigned int len; | |
406 | ||
407 | while (true) { | |
408 | irq_line = virtqueue_get_buf(vgpio->event_vq, &len); | |
409 | if (!irq_line) | |
410 | break; | |
411 | ||
412 | if (len != sizeof(irq_line->ires)) { | |
413 | dev_err(dev, "irq with incorrect length (%u : %u)\n", | |
414 | len, (unsigned int)sizeof(irq_line->ires)); | |
415 | continue; | |
416 | } | |
417 | ||
418 | /* | |
419 | * Find GPIO line number from the offset of irq_line within the | |
420 | * irq_lines block. We can also get GPIO number from | |
421 | * irq-request, but better not to rely on a buffer returned by | |
422 | * remote. | |
423 | */ | |
424 | gpio = irq_line - vgpio->irq_lines; | |
425 | WARN_ON(gpio >= vgpio->gc.ngpio); | |
426 | ||
427 | if (unlikely(ignore_irq(vgpio, gpio, irq_line))) | |
428 | continue; | |
429 | ||
430 | ret = generic_handle_domain_irq(vgpio->gc.irq.domain, gpio); | |
431 | if (ret) | |
432 | dev_err(dev, "failed to handle interrupt: %d\n", ret); | |
f7715b3a | 433 | } |
eff5cdd7 VK |
434 | } |
435 | ||
3a29355a VK |
436 | static void virtio_gpio_request_vq(struct virtqueue *vq) |
437 | { | |
438 | struct virtio_gpio_line *line; | |
439 | unsigned int len; | |
440 | ||
441 | do { | |
442 | line = virtqueue_get_buf(vq, &len); | |
443 | if (!line) | |
444 | return; | |
445 | ||
446 | line->rxlen = len; | |
447 | complete(&line->completion); | |
448 | } while (1); | |
449 | } | |
450 | ||
451 | static void virtio_gpio_free_vqs(struct virtio_device *vdev) | |
452 | { | |
d9679d00 | 453 | virtio_reset_device(vdev); |
3a29355a VK |
454 | vdev->config->del_vqs(vdev); |
455 | } | |
456 | ||
457 | static int virtio_gpio_alloc_vqs(struct virtio_gpio *vgpio, | |
458 | struct virtio_device *vdev) | |
459 | { | |
eff5cdd7 | 460 | const char * const names[] = { "requestq", "eventq" }; |
3a29355a VK |
461 | vq_callback_t *cbs[] = { |
462 | virtio_gpio_request_vq, | |
eff5cdd7 | 463 | virtio_gpio_event_vq, |
3a29355a | 464 | }; |
eff5cdd7 | 465 | struct virtqueue *vqs[2] = { NULL, NULL }; |
3a29355a VK |
466 | int ret; |
467 | ||
eff5cdd7 | 468 | ret = virtio_find_vqs(vdev, vgpio->irq_lines ? 2 : 1, vqs, cbs, names, NULL); |
3a29355a VK |
469 | if (ret) { |
470 | dev_err(&vdev->dev, "failed to find vqs: %d\n", ret); | |
471 | return ret; | |
472 | } | |
473 | ||
474 | if (!vqs[0]) { | |
475 | dev_err(&vdev->dev, "failed to find requestq vq\n"); | |
eff5cdd7 | 476 | goto out; |
3a29355a VK |
477 | } |
478 | vgpio->request_vq = vqs[0]; | |
479 | ||
eff5cdd7 VK |
480 | if (vgpio->irq_lines && !vqs[1]) { |
481 | dev_err(&vdev->dev, "failed to find eventq vq\n"); | |
482 | goto out; | |
483 | } | |
484 | vgpio->event_vq = vqs[1]; | |
485 | ||
3a29355a | 486 | return 0; |
eff5cdd7 VK |
487 | |
488 | out: | |
489 | if (vqs[0] || vqs[1]) | |
490 | virtio_gpio_free_vqs(vdev); | |
491 | ||
492 | return -ENODEV; | |
3a29355a VK |
493 | } |
494 | ||
17395d77 VK |
495 | static const char **virtio_gpio_get_names(struct virtio_gpio *vgpio, |
496 | u32 gpio_names_size, u16 ngpio) | |
3a29355a | 497 | { |
3a29355a VK |
498 | struct virtio_gpio_response_get_names *res; |
499 | struct device *dev = &vgpio->vdev->dev; | |
500 | u8 *gpio_names, *str; | |
501 | const char **names; | |
502 | int i, ret, len; | |
503 | ||
17395d77 | 504 | if (!gpio_names_size) |
3a29355a VK |
505 | return NULL; |
506 | ||
17395d77 | 507 | len = sizeof(*res) + gpio_names_size; |
3a29355a VK |
508 | res = devm_kzalloc(dev, len, GFP_KERNEL); |
509 | if (!res) | |
510 | return NULL; | |
511 | gpio_names = res->value; | |
512 | ||
513 | ret = _virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_NAMES, 0, 0, NULL, | |
514 | res, len); | |
515 | if (ret) { | |
516 | dev_err(dev, "Failed to get GPIO names: %d\n", ret); | |
517 | return NULL; | |
518 | } | |
519 | ||
17395d77 | 520 | names = devm_kcalloc(dev, ngpio, sizeof(*names), GFP_KERNEL); |
3a29355a VK |
521 | if (!names) |
522 | return NULL; | |
523 | ||
524 | /* NULL terminate the string instead of checking it */ | |
17395d77 | 525 | gpio_names[gpio_names_size - 1] = '\0'; |
3a29355a | 526 | |
17395d77 | 527 | for (i = 0, str = gpio_names; i < ngpio; i++) { |
3a29355a VK |
528 | names[i] = str; |
529 | str += strlen(str) + 1; /* zero-length strings are allowed */ | |
530 | ||
17395d77 | 531 | if (str > gpio_names + gpio_names_size) { |
3a29355a VK |
532 | dev_err(dev, "gpio_names block is too short (%d)\n", i); |
533 | return NULL; | |
534 | } | |
535 | } | |
536 | ||
537 | return names; | |
538 | } | |
539 | ||
540 | static int virtio_gpio_probe(struct virtio_device *vdev) | |
541 | { | |
17395d77 | 542 | struct virtio_gpio_config config; |
3a29355a VK |
543 | struct device *dev = &vdev->dev; |
544 | struct virtio_gpio *vgpio; | |
17395d77 VK |
545 | u32 gpio_names_size; |
546 | u16 ngpio; | |
3a29355a VK |
547 | int ret, i; |
548 | ||
549 | vgpio = devm_kzalloc(dev, sizeof(*vgpio), GFP_KERNEL); | |
550 | if (!vgpio) | |
551 | return -ENOMEM; | |
552 | ||
3a29355a | 553 | /* Read configuration */ |
17395d77 VK |
554 | virtio_cread_bytes(vdev, 0, &config, sizeof(config)); |
555 | gpio_names_size = le32_to_cpu(config.gpio_names_size); | |
556 | ngpio = le16_to_cpu(config.ngpio); | |
557 | if (!ngpio) { | |
3a29355a VK |
558 | dev_err(dev, "Number of GPIOs can't be zero\n"); |
559 | return -EINVAL; | |
560 | } | |
561 | ||
17395d77 | 562 | vgpio->lines = devm_kcalloc(dev, ngpio, sizeof(*vgpio->lines), GFP_KERNEL); |
3a29355a VK |
563 | if (!vgpio->lines) |
564 | return -ENOMEM; | |
565 | ||
17395d77 | 566 | for (i = 0; i < ngpio; i++) { |
3a29355a VK |
567 | mutex_init(&vgpio->lines[i].lock); |
568 | init_completion(&vgpio->lines[i].completion); | |
569 | } | |
570 | ||
571 | mutex_init(&vgpio->lock); | |
572 | vdev->priv = vgpio; | |
573 | ||
574 | vgpio->vdev = vdev; | |
575 | vgpio->gc.free = virtio_gpio_free; | |
576 | vgpio->gc.get_direction = virtio_gpio_get_direction; | |
577 | vgpio->gc.direction_input = virtio_gpio_direction_input; | |
578 | vgpio->gc.direction_output = virtio_gpio_direction_output; | |
579 | vgpio->gc.get = virtio_gpio_get; | |
580 | vgpio->gc.set = virtio_gpio_set; | |
17395d77 | 581 | vgpio->gc.ngpio = ngpio; |
3a29355a VK |
582 | vgpio->gc.base = -1; /* Allocate base dynamically */ |
583 | vgpio->gc.label = dev_name(dev); | |
584 | vgpio->gc.parent = dev; | |
585 | vgpio->gc.owner = THIS_MODULE; | |
586 | vgpio->gc.can_sleep = true; | |
587 | ||
eff5cdd7 VK |
588 | /* Interrupt support */ |
589 | if (virtio_has_feature(vdev, VIRTIO_GPIO_F_IRQ)) { | |
590 | vgpio->irq_lines = devm_kcalloc(dev, ngpio, sizeof(*vgpio->irq_lines), GFP_KERNEL); | |
591 | if (!vgpio->irq_lines) | |
592 | return -ENOMEM; | |
593 | ||
594 | /* The event comes from the outside so no parent handler */ | |
595 | vgpio->gc.irq.parent_handler = NULL; | |
596 | vgpio->gc.irq.num_parents = 0; | |
597 | vgpio->gc.irq.parents = NULL; | |
598 | vgpio->gc.irq.default_type = IRQ_TYPE_NONE; | |
599 | vgpio->gc.irq.handler = handle_level_irq; | |
600 | vgpio->gc.irq.chip = &vgpio_irq_chip; | |
601 | ||
602 | for (i = 0; i < ngpio; i++) { | |
603 | vgpio->irq_lines[i].type = VIRTIO_GPIO_IRQ_TYPE_NONE; | |
604 | vgpio->irq_lines[i].disabled = true; | |
605 | vgpio->irq_lines[i].masked = true; | |
606 | } | |
607 | ||
608 | mutex_init(&vgpio->irq_lock); | |
609 | raw_spin_lock_init(&vgpio->eventq_lock); | |
610 | } | |
611 | ||
3a29355a VK |
612 | ret = virtio_gpio_alloc_vqs(vgpio, vdev); |
613 | if (ret) | |
614 | return ret; | |
615 | ||
616 | /* Mark the device ready to perform operations from within probe() */ | |
617 | virtio_device_ready(vdev); | |
618 | ||
17395d77 | 619 | vgpio->gc.names = virtio_gpio_get_names(vgpio, gpio_names_size, ngpio); |
3a29355a VK |
620 | |
621 | ret = gpiochip_add_data(&vgpio->gc, vgpio); | |
622 | if (ret) { | |
623 | virtio_gpio_free_vqs(vdev); | |
624 | dev_err(dev, "Failed to add virtio-gpio controller\n"); | |
625 | } | |
626 | ||
627 | return ret; | |
628 | } | |
629 | ||
630 | static void virtio_gpio_remove(struct virtio_device *vdev) | |
631 | { | |
632 | struct virtio_gpio *vgpio = vdev->priv; | |
633 | ||
634 | gpiochip_remove(&vgpio->gc); | |
635 | virtio_gpio_free_vqs(vdev); | |
636 | } | |
637 | ||
638 | static const struct virtio_device_id id_table[] = { | |
639 | { VIRTIO_ID_GPIO, VIRTIO_DEV_ANY_ID }, | |
640 | {}, | |
641 | }; | |
642 | MODULE_DEVICE_TABLE(virtio, id_table); | |
643 | ||
eff5cdd7 VK |
644 | static const unsigned int features[] = { |
645 | VIRTIO_GPIO_F_IRQ, | |
646 | }; | |
647 | ||
3a29355a | 648 | static struct virtio_driver virtio_gpio_driver = { |
eff5cdd7 VK |
649 | .feature_table = features, |
650 | .feature_table_size = ARRAY_SIZE(features), | |
3a29355a VK |
651 | .id_table = id_table, |
652 | .probe = virtio_gpio_probe, | |
653 | .remove = virtio_gpio_remove, | |
654 | .driver = { | |
655 | .name = KBUILD_MODNAME, | |
656 | .owner = THIS_MODULE, | |
657 | }, | |
658 | }; | |
659 | module_virtio_driver(virtio_gpio_driver); | |
660 | ||
661 | MODULE_AUTHOR("Enrico Weigelt, metux IT consult <info@metux.net>"); | |
662 | MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); | |
663 | MODULE_DESCRIPTION("VirtIO GPIO driver"); | |
664 | MODULE_LICENSE("GPL"); |