xref: /linux/drivers/slimbus/core.c (revision a1c3be890440a1769ed6f822376a3e3ab0d42994) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2011-2017, The Linux Foundation
4  */
5 
6 #include <linux/kernel.h>
7 #include <linux/errno.h>
8 #include <linux/slab.h>
9 #include <linux/init.h>
10 #include <linux/idr.h>
11 #include <linux/of.h>
12 #include <linux/of_device.h>
13 #include <linux/pm_runtime.h>
14 #include <linux/slimbus.h>
15 #include "slimbus.h"
16 
17 static DEFINE_IDA(ctrl_ida);
18 
19 static const struct slim_device_id *slim_match(const struct slim_device_id *id,
20 					       const struct slim_device *sbdev)
21 {
22 	while (id->manf_id != 0 || id->prod_code != 0) {
23 		if (id->manf_id == sbdev->e_addr.manf_id &&
24 		    id->prod_code == sbdev->e_addr.prod_code &&
25 		    id->dev_index == sbdev->e_addr.dev_index &&
26 		    id->instance == sbdev->e_addr.instance)
27 			return id;
28 		id++;
29 	}
30 	return NULL;
31 }
32 
33 static int slim_device_match(struct device *dev, struct device_driver *drv)
34 {
35 	struct slim_device *sbdev = to_slim_device(dev);
36 	struct slim_driver *sbdrv = to_slim_driver(drv);
37 
38 	/* Attempt an OF style match first */
39 	if (of_driver_match_device(dev, drv))
40 		return 1;
41 
42 	return !!slim_match(sbdrv->id_table, sbdev);
43 }
44 
45 static void slim_device_update_status(struct slim_device *sbdev,
46 				      enum slim_device_status status)
47 {
48 	struct slim_driver *sbdrv;
49 
50 	if (sbdev->status == status)
51 		return;
52 
53 	sbdev->status = status;
54 	if (!sbdev->dev.driver)
55 		return;
56 
57 	sbdrv = to_slim_driver(sbdev->dev.driver);
58 	if (sbdrv->device_status)
59 		sbdrv->device_status(sbdev, sbdev->status);
60 }
61 
62 static int slim_device_probe(struct device *dev)
63 {
64 	struct slim_device	*sbdev = to_slim_device(dev);
65 	struct slim_driver	*sbdrv = to_slim_driver(dev->driver);
66 	int ret;
67 
68 	ret = sbdrv->probe(sbdev);
69 	if (ret)
70 		return ret;
71 
72 	/* try getting the logical address after probe */
73 	ret = slim_get_logical_addr(sbdev);
74 	if (!ret) {
75 		slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_UP);
76 	} else {
77 		dev_err(&sbdev->dev, "Failed to get logical address\n");
78 		ret = -EPROBE_DEFER;
79 	}
80 
81 	return ret;
82 }
83 
84 static int slim_device_remove(struct device *dev)
85 {
86 	struct slim_device *sbdev = to_slim_device(dev);
87 	struct slim_driver *sbdrv;
88 
89 	if (dev->driver) {
90 		sbdrv = to_slim_driver(dev->driver);
91 		if (sbdrv->remove)
92 			sbdrv->remove(sbdev);
93 	}
94 
95 	return 0;
96 }
97 
98 static int slim_device_uevent(struct device *dev, struct kobj_uevent_env *env)
99 {
100 	struct slim_device *sbdev = to_slim_device(dev);
101 
102 	return add_uevent_var(env, "MODALIAS=slim:%s", dev_name(&sbdev->dev));
103 }
104 
105 struct bus_type slimbus_bus = {
106 	.name		= "slimbus",
107 	.match		= slim_device_match,
108 	.probe		= slim_device_probe,
109 	.remove		= slim_device_remove,
110 	.uevent		= slim_device_uevent,
111 };
112 EXPORT_SYMBOL_GPL(slimbus_bus);
113 
114 /*
115  * __slim_driver_register() - Client driver registration with SLIMbus
116  *
117  * @drv:Client driver to be associated with client-device.
118  * @owner: owning module/driver
119  *
120  * This API will register the client driver with the SLIMbus
121  * It is called from the driver's module-init function.
122  */
123 int __slim_driver_register(struct slim_driver *drv, struct module *owner)
124 {
125 	/* ID table and probe are mandatory */
126 	if (!(drv->driver.of_match_table || drv->id_table) || !drv->probe)
127 		return -EINVAL;
128 
129 	drv->driver.bus = &slimbus_bus;
130 	drv->driver.owner = owner;
131 
132 	return driver_register(&drv->driver);
133 }
134 EXPORT_SYMBOL_GPL(__slim_driver_register);
135 
136 /*
137  * slim_driver_unregister() - Undo effect of slim_driver_register
138  *
139  * @drv: Client driver to be unregistered
140  */
141 void slim_driver_unregister(struct slim_driver *drv)
142 {
143 	driver_unregister(&drv->driver);
144 }
145 EXPORT_SYMBOL_GPL(slim_driver_unregister);
146 
147 static void slim_dev_release(struct device *dev)
148 {
149 	struct slim_device *sbdev = to_slim_device(dev);
150 
151 	kfree(sbdev);
152 }
153 
154 static int slim_add_device(struct slim_controller *ctrl,
155 			   struct slim_device *sbdev,
156 			   struct device_node *node)
157 {
158 	sbdev->dev.bus = &slimbus_bus;
159 	sbdev->dev.parent = ctrl->dev;
160 	sbdev->dev.release = slim_dev_release;
161 	sbdev->dev.driver = NULL;
162 	sbdev->ctrl = ctrl;
163 	INIT_LIST_HEAD(&sbdev->stream_list);
164 	spin_lock_init(&sbdev->stream_list_lock);
165 	sbdev->dev.of_node = of_node_get(node);
166 	sbdev->dev.fwnode = of_fwnode_handle(node);
167 
168 	dev_set_name(&sbdev->dev, "%x:%x:%x:%x",
169 				  sbdev->e_addr.manf_id,
170 				  sbdev->e_addr.prod_code,
171 				  sbdev->e_addr.dev_index,
172 				  sbdev->e_addr.instance);
173 
174 	return device_register(&sbdev->dev);
175 }
176 
177 static struct slim_device *slim_alloc_device(struct slim_controller *ctrl,
178 					     struct slim_eaddr *eaddr,
179 					     struct device_node *node)
180 {
181 	struct slim_device *sbdev;
182 	int ret;
183 
184 	sbdev = kzalloc(sizeof(*sbdev), GFP_KERNEL);
185 	if (!sbdev)
186 		return NULL;
187 
188 	sbdev->e_addr = *eaddr;
189 	ret = slim_add_device(ctrl, sbdev, node);
190 	if (ret) {
191 		put_device(&sbdev->dev);
192 		return NULL;
193 	}
194 
195 	return sbdev;
196 }
197 
198 static void of_register_slim_devices(struct slim_controller *ctrl)
199 {
200 	struct device *dev = ctrl->dev;
201 	struct device_node *node;
202 
203 	if (!ctrl->dev->of_node)
204 		return;
205 
206 	for_each_child_of_node(ctrl->dev->of_node, node) {
207 		struct slim_device *sbdev;
208 		struct slim_eaddr e_addr;
209 		const char *compat = NULL;
210 		int reg[2], ret;
211 		int manf_id, prod_code;
212 
213 		compat = of_get_property(node, "compatible", NULL);
214 		if (!compat)
215 			continue;
216 
217 		ret = sscanf(compat, "slim%x,%x", &manf_id, &prod_code);
218 		if (ret != 2) {
219 			dev_err(dev, "Manf ID & Product code not found %s\n",
220 				compat);
221 			continue;
222 		}
223 
224 		ret = of_property_read_u32_array(node, "reg", reg, 2);
225 		if (ret) {
226 			dev_err(dev, "Device and Instance id not found:%d\n",
227 				ret);
228 			continue;
229 		}
230 
231 		e_addr.dev_index = reg[0];
232 		e_addr.instance = reg[1];
233 		e_addr.manf_id = manf_id;
234 		e_addr.prod_code = prod_code;
235 
236 		sbdev = slim_alloc_device(ctrl, &e_addr, node);
237 		if (!sbdev)
238 			continue;
239 	}
240 }
241 
242 /*
243  * slim_register_controller() - Controller bring-up and registration.
244  *
245  * @ctrl: Controller to be registered.
246  *
247  * A controller is registered with the framework using this API.
248  * If devices on a controller were registered before controller,
249  * this will make sure that they get probed when controller is up
250  */
251 int slim_register_controller(struct slim_controller *ctrl)
252 {
253 	int id;
254 
255 	id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
256 	if (id < 0)
257 		return id;
258 
259 	ctrl->id = id;
260 
261 	if (!ctrl->min_cg)
262 		ctrl->min_cg = SLIM_MIN_CLK_GEAR;
263 	if (!ctrl->max_cg)
264 		ctrl->max_cg = SLIM_MAX_CLK_GEAR;
265 
266 	ida_init(&ctrl->laddr_ida);
267 	idr_init(&ctrl->tid_idr);
268 	mutex_init(&ctrl->lock);
269 	mutex_init(&ctrl->sched.m_reconf);
270 	init_completion(&ctrl->sched.pause_comp);
271 	spin_lock_init(&ctrl->txn_lock);
272 
273 	dev_dbg(ctrl->dev, "Bus [%s] registered:dev:%p\n",
274 		ctrl->name, ctrl->dev);
275 
276 	of_register_slim_devices(ctrl);
277 
278 	return 0;
279 }
280 EXPORT_SYMBOL_GPL(slim_register_controller);
281 
282 /* slim_remove_device: Remove the effect of slim_add_device() */
283 static void slim_remove_device(struct slim_device *sbdev)
284 {
285 	of_node_put(sbdev->dev.of_node);
286 	device_unregister(&sbdev->dev);
287 }
288 
289 static int slim_ctrl_remove_device(struct device *dev, void *null)
290 {
291 	slim_remove_device(to_slim_device(dev));
292 	return 0;
293 }
294 
295 /**
296  * slim_unregister_controller() - Controller tear-down.
297  *
298  * @ctrl: Controller to tear-down.
299  */
300 int slim_unregister_controller(struct slim_controller *ctrl)
301 {
302 	/* Remove all clients */
303 	device_for_each_child(ctrl->dev, NULL, slim_ctrl_remove_device);
304 	ida_simple_remove(&ctrl_ida, ctrl->id);
305 
306 	return 0;
307 }
308 EXPORT_SYMBOL_GPL(slim_unregister_controller);
309 
310 /**
311  * slim_report_absent() - Controller calls this function when a device
312  *	reports absent, OR when the device cannot be communicated with
313  *
314  * @sbdev: Device that cannot be reached, or sent report absent
315  */
316 void slim_report_absent(struct slim_device *sbdev)
317 {
318 	struct slim_controller *ctrl = sbdev->ctrl;
319 
320 	if (!ctrl)
321 		return;
322 
323 	/* invalidate logical addresses */
324 	mutex_lock(&ctrl->lock);
325 	sbdev->is_laddr_valid = false;
326 	mutex_unlock(&ctrl->lock);
327 	if (!ctrl->get_laddr)
328 		ida_simple_remove(&ctrl->laddr_ida, sbdev->laddr);
329 	slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_DOWN);
330 }
331 EXPORT_SYMBOL_GPL(slim_report_absent);
332 
333 static bool slim_eaddr_equal(struct slim_eaddr *a, struct slim_eaddr *b)
334 {
335 	return (a->manf_id == b->manf_id &&
336 		a->prod_code == b->prod_code &&
337 		a->dev_index == b->dev_index &&
338 		a->instance == b->instance);
339 }
340 
341 static int slim_match_dev(struct device *dev, void *data)
342 {
343 	struct slim_eaddr *e_addr = data;
344 	struct slim_device *sbdev = to_slim_device(dev);
345 
346 	return slim_eaddr_equal(&sbdev->e_addr, e_addr);
347 }
348 
349 static struct slim_device *find_slim_device(struct slim_controller *ctrl,
350 					    struct slim_eaddr *eaddr)
351 {
352 	struct slim_device *sbdev;
353 	struct device *dev;
354 
355 	dev = device_find_child(ctrl->dev, eaddr, slim_match_dev);
356 	if (dev) {
357 		sbdev = to_slim_device(dev);
358 		return sbdev;
359 	}
360 
361 	return NULL;
362 }
363 
364 /**
365  * slim_get_device() - get handle to a device.
366  *
367  * @ctrl: Controller on which this device will be added/queried
368  * @e_addr: Enumeration address of the device to be queried
369  *
370  * Return: pointer to a device if it has already reported. Creates a new
371  * device and returns pointer to it if the device has not yet enumerated.
372  */
373 struct slim_device *slim_get_device(struct slim_controller *ctrl,
374 				    struct slim_eaddr *e_addr)
375 {
376 	struct slim_device *sbdev;
377 
378 	sbdev = find_slim_device(ctrl, e_addr);
379 	if (!sbdev) {
380 		sbdev = slim_alloc_device(ctrl, e_addr, NULL);
381 		if (!sbdev)
382 			return ERR_PTR(-ENOMEM);
383 	}
384 
385 	return sbdev;
386 }
387 EXPORT_SYMBOL_GPL(slim_get_device);
388 
389 static int of_slim_match_dev(struct device *dev, void *data)
390 {
391 	struct device_node *np = data;
392 	struct slim_device *sbdev = to_slim_device(dev);
393 
394 	return (sbdev->dev.of_node == np);
395 }
396 
397 static struct slim_device *of_find_slim_device(struct slim_controller *ctrl,
398 					       struct device_node *np)
399 {
400 	struct slim_device *sbdev;
401 	struct device *dev;
402 
403 	dev = device_find_child(ctrl->dev, np, of_slim_match_dev);
404 	if (dev) {
405 		sbdev = to_slim_device(dev);
406 		return sbdev;
407 	}
408 
409 	return NULL;
410 }
411 
412 /**
413  * of_slim_get_device() - get handle to a device using dt node.
414  *
415  * @ctrl: Controller on which this device will be added/queried
416  * @np: node pointer to device
417  *
418  * Return: pointer to a device if it has already reported. Creates a new
419  * device and returns pointer to it if the device has not yet enumerated.
420  */
421 struct slim_device *of_slim_get_device(struct slim_controller *ctrl,
422 				       struct device_node *np)
423 {
424 	return of_find_slim_device(ctrl, np);
425 }
426 EXPORT_SYMBOL_GPL(of_slim_get_device);
427 
428 static int slim_device_alloc_laddr(struct slim_device *sbdev,
429 				   bool report_present)
430 {
431 	struct slim_controller *ctrl = sbdev->ctrl;
432 	u8 laddr;
433 	int ret;
434 
435 	mutex_lock(&ctrl->lock);
436 	if (ctrl->get_laddr) {
437 		ret = ctrl->get_laddr(ctrl, &sbdev->e_addr, &laddr);
438 		if (ret < 0)
439 			goto err;
440 	} else if (report_present) {
441 		ret = ida_simple_get(&ctrl->laddr_ida,
442 				     0, SLIM_LA_MANAGER - 1, GFP_KERNEL);
443 		if (ret < 0)
444 			goto err;
445 
446 		laddr = ret;
447 	} else {
448 		ret = -EINVAL;
449 		goto err;
450 	}
451 
452 	if (ctrl->set_laddr) {
453 		ret = ctrl->set_laddr(ctrl, &sbdev->e_addr, laddr);
454 		if (ret) {
455 			ret = -EINVAL;
456 			goto err;
457 		}
458 	}
459 
460 	sbdev->laddr = laddr;
461 	sbdev->is_laddr_valid = true;
462 	mutex_unlock(&ctrl->lock);
463 
464 	slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_UP);
465 
466 	dev_dbg(ctrl->dev, "setting slimbus l-addr:%x, ea:%x,%x,%x,%x\n",
467 		laddr, sbdev->e_addr.manf_id, sbdev->e_addr.prod_code,
468 		sbdev->e_addr.dev_index, sbdev->e_addr.instance);
469 
470 	return 0;
471 
472 err:
473 	mutex_unlock(&ctrl->lock);
474 	return ret;
475 
476 }
477 
478 /**
479  * slim_device_report_present() - Report enumerated device.
480  *
481  * @ctrl: Controller with which device is enumerated.
482  * @e_addr: Enumeration address of the device.
483  * @laddr: Return logical address (if valid flag is false)
484  *
485  * Called by controller in response to REPORT_PRESENT. Framework will assign
486  * a logical address to this enumeration address.
487  * Function returns -EXFULL to indicate that all logical addresses are already
488  * taken.
489  */
490 int slim_device_report_present(struct slim_controller *ctrl,
491 			       struct slim_eaddr *e_addr, u8 *laddr)
492 {
493 	struct slim_device *sbdev;
494 	int ret;
495 
496 	ret = pm_runtime_get_sync(ctrl->dev);
497 
498 	if (ctrl->sched.clk_state != SLIM_CLK_ACTIVE) {
499 		dev_err(ctrl->dev, "slim ctrl not active,state:%d, ret:%d\n",
500 				    ctrl->sched.clk_state, ret);
501 		goto slimbus_not_active;
502 	}
503 
504 	sbdev = slim_get_device(ctrl, e_addr);
505 	if (IS_ERR(sbdev))
506 		return -ENODEV;
507 
508 	if (sbdev->is_laddr_valid) {
509 		*laddr = sbdev->laddr;
510 		return 0;
511 	}
512 
513 	ret = slim_device_alloc_laddr(sbdev, true);
514 
515 slimbus_not_active:
516 	pm_runtime_mark_last_busy(ctrl->dev);
517 	pm_runtime_put_autosuspend(ctrl->dev);
518 	return ret;
519 }
520 EXPORT_SYMBOL_GPL(slim_device_report_present);
521 
522 /**
523  * slim_get_logical_addr() - get/allocate logical address of a SLIMbus device.
524  *
525  * @sbdev: client handle requesting the address.
526  *
527  * Return: zero if a logical address is valid or a new logical address
528  * has been assigned. error code in case of error.
529  */
530 int slim_get_logical_addr(struct slim_device *sbdev)
531 {
532 	if (!sbdev->is_laddr_valid)
533 		return slim_device_alloc_laddr(sbdev, false);
534 
535 	return 0;
536 }
537 EXPORT_SYMBOL_GPL(slim_get_logical_addr);
538 
539 static void __exit slimbus_exit(void)
540 {
541 	bus_unregister(&slimbus_bus);
542 }
543 module_exit(slimbus_exit);
544 
545 static int __init slimbus_init(void)
546 {
547 	return bus_register(&slimbus_bus);
548 }
549 postcore_initcall(slimbus_init);
550 
551 MODULE_LICENSE("GPL v2");
552 MODULE_DESCRIPTION("SLIMbus core");
553