xref: /linux/drivers/slimbus/core.c (revision 2ab002c755bfa88777e3f2db884d531f3010736c)
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, const struct device_driver *drv)
34 {
35 	struct slim_device *sbdev = to_slim_device(dev);
36 	const 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 void 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 
96 static int slim_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
97 {
98 	const struct slim_device *sbdev = to_slim_device(dev);
99 
100 	return add_uevent_var(env, "MODALIAS=slim:%s", dev_name(&sbdev->dev));
101 }
102 
103 const struct bus_type slimbus_bus = {
104 	.name		= "slimbus",
105 	.match		= slim_device_match,
106 	.probe		= slim_device_probe,
107 	.remove		= slim_device_remove,
108 	.uevent		= slim_device_uevent,
109 };
110 EXPORT_SYMBOL_GPL(slimbus_bus);
111 
112 /*
113  * __slim_driver_register() - Client driver registration with SLIMbus
114  *
115  * @drv:Client driver to be associated with client-device.
116  * @owner: owning module/driver
117  *
118  * This API will register the client driver with the SLIMbus
119  * It is called from the driver's module-init function.
120  */
121 int __slim_driver_register(struct slim_driver *drv, struct module *owner)
122 {
123 	/* ID table and probe are mandatory */
124 	if (!(drv->driver.of_match_table || drv->id_table) || !drv->probe)
125 		return -EINVAL;
126 
127 	drv->driver.bus = &slimbus_bus;
128 	drv->driver.owner = owner;
129 
130 	return driver_register(&drv->driver);
131 }
132 EXPORT_SYMBOL_GPL(__slim_driver_register);
133 
134 /*
135  * slim_driver_unregister() - Undo effect of slim_driver_register
136  *
137  * @drv: Client driver to be unregistered
138  */
139 void slim_driver_unregister(struct slim_driver *drv)
140 {
141 	driver_unregister(&drv->driver);
142 }
143 EXPORT_SYMBOL_GPL(slim_driver_unregister);
144 
145 static void slim_dev_release(struct device *dev)
146 {
147 	struct slim_device *sbdev = to_slim_device(dev);
148 
149 	kfree(sbdev);
150 }
151 
152 static int slim_add_device(struct slim_controller *ctrl,
153 			   struct slim_device *sbdev,
154 			   struct device_node *node)
155 {
156 	sbdev->dev.bus = &slimbus_bus;
157 	sbdev->dev.parent = ctrl->dev;
158 	sbdev->dev.release = slim_dev_release;
159 	sbdev->dev.driver = NULL;
160 	sbdev->ctrl = ctrl;
161 	INIT_LIST_HEAD(&sbdev->stream_list);
162 	spin_lock_init(&sbdev->stream_list_lock);
163 	sbdev->dev.of_node = of_node_get(node);
164 	sbdev->dev.fwnode = of_fwnode_handle(node);
165 
166 	dev_set_name(&sbdev->dev, "%x:%x:%x:%x",
167 				  sbdev->e_addr.manf_id,
168 				  sbdev->e_addr.prod_code,
169 				  sbdev->e_addr.dev_index,
170 				  sbdev->e_addr.instance);
171 
172 	return device_register(&sbdev->dev);
173 }
174 
175 static struct slim_device *slim_alloc_device(struct slim_controller *ctrl,
176 					     struct slim_eaddr *eaddr,
177 					     struct device_node *node)
178 {
179 	struct slim_device *sbdev;
180 	int ret;
181 
182 	sbdev = kzalloc(sizeof(*sbdev), GFP_KERNEL);
183 	if (!sbdev)
184 		return NULL;
185 
186 	sbdev->e_addr = *eaddr;
187 	ret = slim_add_device(ctrl, sbdev, node);
188 	if (ret) {
189 		put_device(&sbdev->dev);
190 		return NULL;
191 	}
192 
193 	return sbdev;
194 }
195 
196 static void of_register_slim_devices(struct slim_controller *ctrl)
197 {
198 	struct device *dev = ctrl->dev;
199 	struct device_node *node;
200 
201 	if (!ctrl->dev->of_node)
202 		return;
203 
204 	for_each_child_of_node(ctrl->dev->of_node, node) {
205 		struct slim_device *sbdev;
206 		struct slim_eaddr e_addr;
207 		const char *compat = NULL;
208 		int reg[2], ret;
209 		int manf_id, prod_code;
210 
211 		compat = of_get_property(node, "compatible", NULL);
212 		if (!compat)
213 			continue;
214 
215 		ret = sscanf(compat, "slim%x,%x", &manf_id, &prod_code);
216 		if (ret != 2) {
217 			dev_err(dev, "Manf ID & Product code not found %s\n",
218 				compat);
219 			continue;
220 		}
221 
222 		ret = of_property_read_u32_array(node, "reg", reg, 2);
223 		if (ret) {
224 			dev_err(dev, "Device and Instance id not found:%d\n",
225 				ret);
226 			continue;
227 		}
228 
229 		e_addr.dev_index = reg[0];
230 		e_addr.instance = reg[1];
231 		e_addr.manf_id = manf_id;
232 		e_addr.prod_code = prod_code;
233 
234 		sbdev = slim_alloc_device(ctrl, &e_addr, node);
235 		if (!sbdev)
236 			continue;
237 	}
238 }
239 
240 /*
241  * slim_register_controller() - Controller bring-up and registration.
242  *
243  * @ctrl: Controller to be registered.
244  *
245  * A controller is registered with the framework using this API.
246  * If devices on a controller were registered before controller,
247  * this will make sure that they get probed when controller is up
248  */
249 int slim_register_controller(struct slim_controller *ctrl)
250 {
251 	int id;
252 
253 	id = ida_alloc(&ctrl_ida, GFP_KERNEL);
254 	if (id < 0)
255 		return id;
256 
257 	ctrl->id = id;
258 
259 	if (!ctrl->min_cg)
260 		ctrl->min_cg = SLIM_MIN_CLK_GEAR;
261 	if (!ctrl->max_cg)
262 		ctrl->max_cg = SLIM_MAX_CLK_GEAR;
263 
264 	ida_init(&ctrl->laddr_ida);
265 	idr_init(&ctrl->tid_idr);
266 	mutex_init(&ctrl->lock);
267 	mutex_init(&ctrl->sched.m_reconf);
268 	init_completion(&ctrl->sched.pause_comp);
269 	spin_lock_init(&ctrl->txn_lock);
270 
271 	dev_dbg(ctrl->dev, "Bus [%s] registered:dev:%p\n",
272 		ctrl->name, ctrl->dev);
273 
274 	of_register_slim_devices(ctrl);
275 
276 	return 0;
277 }
278 EXPORT_SYMBOL_GPL(slim_register_controller);
279 
280 /* slim_remove_device: Remove the effect of slim_add_device() */
281 static void slim_remove_device(struct slim_device *sbdev)
282 {
283 	of_node_put(sbdev->dev.of_node);
284 	device_unregister(&sbdev->dev);
285 }
286 
287 static int slim_ctrl_remove_device(struct device *dev, void *null)
288 {
289 	slim_remove_device(to_slim_device(dev));
290 	return 0;
291 }
292 
293 /**
294  * slim_unregister_controller() - Controller tear-down.
295  *
296  * @ctrl: Controller to tear-down.
297  */
298 int slim_unregister_controller(struct slim_controller *ctrl)
299 {
300 	/* Remove all clients */
301 	device_for_each_child(ctrl->dev, NULL, slim_ctrl_remove_device);
302 	ida_free(&ctrl_ida, ctrl->id);
303 
304 	return 0;
305 }
306 EXPORT_SYMBOL_GPL(slim_unregister_controller);
307 
308 /**
309  * slim_report_absent() - Controller calls this function when a device
310  *	reports absent, OR when the device cannot be communicated with
311  *
312  * @sbdev: Device that cannot be reached, or sent report absent
313  */
314 void slim_report_absent(struct slim_device *sbdev)
315 {
316 	struct slim_controller *ctrl = sbdev->ctrl;
317 
318 	if (!ctrl)
319 		return;
320 
321 	/* invalidate logical addresses */
322 	mutex_lock(&ctrl->lock);
323 	sbdev->is_laddr_valid = false;
324 	mutex_unlock(&ctrl->lock);
325 	if (!ctrl->get_laddr)
326 		ida_free(&ctrl->laddr_ida, sbdev->laddr);
327 	slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_DOWN);
328 }
329 EXPORT_SYMBOL_GPL(slim_report_absent);
330 
331 static bool slim_eaddr_equal(const struct slim_eaddr *a,
332 			     const struct slim_eaddr *b)
333 {
334 	return (a->manf_id == b->manf_id &&
335 		a->prod_code == b->prod_code &&
336 		a->dev_index == b->dev_index &&
337 		a->instance == b->instance);
338 }
339 
340 static int slim_match_dev(struct device *dev, const void *data)
341 {
342 	const struct slim_eaddr *e_addr = data;
343 	struct slim_device *sbdev = to_slim_device(dev);
344 
345 	return slim_eaddr_equal(&sbdev->e_addr, e_addr);
346 }
347 
348 static struct slim_device *find_slim_device(struct slim_controller *ctrl,
349 					    struct slim_eaddr *eaddr)
350 {
351 	struct slim_device *sbdev;
352 	struct device *dev;
353 
354 	dev = device_find_child(ctrl->dev, eaddr, slim_match_dev);
355 	if (dev) {
356 		sbdev = to_slim_device(dev);
357 		return sbdev;
358 	}
359 
360 	return NULL;
361 }
362 
363 /**
364  * slim_get_device() - get handle to a device.
365  *
366  * @ctrl: Controller on which this device will be added/queried
367  * @e_addr: Enumeration address of the device to be queried
368  *
369  * Return: pointer to a device if it has already reported. Creates a new
370  * device and returns pointer to it if the device has not yet enumerated.
371  */
372 struct slim_device *slim_get_device(struct slim_controller *ctrl,
373 				    struct slim_eaddr *e_addr)
374 {
375 	struct slim_device *sbdev;
376 
377 	sbdev = find_slim_device(ctrl, e_addr);
378 	if (!sbdev) {
379 		sbdev = slim_alloc_device(ctrl, e_addr, NULL);
380 		if (!sbdev)
381 			return ERR_PTR(-ENOMEM);
382 	}
383 
384 	return sbdev;
385 }
386 EXPORT_SYMBOL_GPL(slim_get_device);
387 
388 static struct slim_device *of_find_slim_device(struct slim_controller *ctrl,
389 					       struct device_node *np)
390 {
391 	struct slim_device *sbdev;
392 	struct device *dev;
393 
394 	dev = device_find_child(ctrl->dev, np, device_match_of_node);
395 	if (dev) {
396 		sbdev = to_slim_device(dev);
397 		return sbdev;
398 	}
399 
400 	return NULL;
401 }
402 
403 /**
404  * of_slim_get_device() - get handle to a device using dt node.
405  *
406  * @ctrl: Controller on which this device will be added/queried
407  * @np: node pointer to device
408  *
409  * Return: pointer to a device if it has already reported. Creates a new
410  * device and returns pointer to it if the device has not yet enumerated.
411  */
412 struct slim_device *of_slim_get_device(struct slim_controller *ctrl,
413 				       struct device_node *np)
414 {
415 	return of_find_slim_device(ctrl, np);
416 }
417 EXPORT_SYMBOL_GPL(of_slim_get_device);
418 
419 static int slim_device_alloc_laddr(struct slim_device *sbdev,
420 				   bool report_present)
421 {
422 	struct slim_controller *ctrl = sbdev->ctrl;
423 	u8 laddr;
424 	int ret;
425 
426 	mutex_lock(&ctrl->lock);
427 	if (ctrl->get_laddr) {
428 		ret = ctrl->get_laddr(ctrl, &sbdev->e_addr, &laddr);
429 		if (ret < 0)
430 			goto err;
431 	} else if (report_present) {
432 		ret = ida_alloc_max(&ctrl->laddr_ida,
433 				    SLIM_LA_MANAGER - 1, GFP_KERNEL);
434 		if (ret < 0)
435 			goto err;
436 
437 		laddr = ret;
438 	} else {
439 		ret = -EINVAL;
440 		goto err;
441 	}
442 
443 	if (ctrl->set_laddr) {
444 		ret = ctrl->set_laddr(ctrl, &sbdev->e_addr, laddr);
445 		if (ret) {
446 			ret = -EINVAL;
447 			goto err;
448 		}
449 	}
450 
451 	sbdev->laddr = laddr;
452 	sbdev->is_laddr_valid = true;
453 	mutex_unlock(&ctrl->lock);
454 
455 	slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_UP);
456 
457 	dev_dbg(ctrl->dev, "setting slimbus l-addr:%x, ea:%x,%x,%x,%x\n",
458 		laddr, sbdev->e_addr.manf_id, sbdev->e_addr.prod_code,
459 		sbdev->e_addr.dev_index, sbdev->e_addr.instance);
460 
461 	return 0;
462 
463 err:
464 	mutex_unlock(&ctrl->lock);
465 	return ret;
466 
467 }
468 
469 /**
470  * slim_device_report_present() - Report enumerated device.
471  *
472  * @ctrl: Controller with which device is enumerated.
473  * @e_addr: Enumeration address of the device.
474  * @laddr: Return logical address (if valid flag is false)
475  *
476  * Called by controller in response to REPORT_PRESENT. Framework will assign
477  * a logical address to this enumeration address.
478  * Function returns -EXFULL to indicate that all logical addresses are already
479  * taken.
480  */
481 int slim_device_report_present(struct slim_controller *ctrl,
482 			       struct slim_eaddr *e_addr, u8 *laddr)
483 {
484 	struct slim_device *sbdev;
485 	int ret;
486 
487 	ret = pm_runtime_get_sync(ctrl->dev);
488 
489 	if (ctrl->sched.clk_state != SLIM_CLK_ACTIVE) {
490 		dev_err(ctrl->dev, "slim ctrl not active,state:%d, ret:%d\n",
491 				    ctrl->sched.clk_state, ret);
492 		goto slimbus_not_active;
493 	}
494 
495 	sbdev = slim_get_device(ctrl, e_addr);
496 	if (IS_ERR(sbdev))
497 		return -ENODEV;
498 
499 	if (sbdev->is_laddr_valid) {
500 		*laddr = sbdev->laddr;
501 		return 0;
502 	}
503 
504 	ret = slim_device_alloc_laddr(sbdev, true);
505 
506 slimbus_not_active:
507 	pm_runtime_mark_last_busy(ctrl->dev);
508 	pm_runtime_put_autosuspend(ctrl->dev);
509 	return ret;
510 }
511 EXPORT_SYMBOL_GPL(slim_device_report_present);
512 
513 /**
514  * slim_get_logical_addr() - get/allocate logical address of a SLIMbus device.
515  *
516  * @sbdev: client handle requesting the address.
517  *
518  * Return: zero if a logical address is valid or a new logical address
519  * has been assigned. error code in case of error.
520  */
521 int slim_get_logical_addr(struct slim_device *sbdev)
522 {
523 	if (!sbdev->is_laddr_valid)
524 		return slim_device_alloc_laddr(sbdev, false);
525 
526 	return 0;
527 }
528 EXPORT_SYMBOL_GPL(slim_get_logical_addr);
529 
530 static void __exit slimbus_exit(void)
531 {
532 	bus_unregister(&slimbus_bus);
533 }
534 module_exit(slimbus_exit);
535 
536 static int __init slimbus_init(void)
537 {
538 	return bus_register(&slimbus_bus);
539 }
540 postcore_initcall(slimbus_init);
541 
542 MODULE_LICENSE("GPL v2");
543 MODULE_DESCRIPTION("SLIMbus core");
544