1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * STi Mailbox |
4 | * |
5 | * Copyright (C) 2015 ST Microelectronics |
6 | * |
7 | * Author: Lee Jones <lee.jones@linaro.org> for ST Microelectronics |
8 | * |
9 | * Based on the original driver written by; |
10 | * Alexandre Torgue, Olivier Lebreton and Loic Pallardy |
11 | */ |
12 | |
13 | #include <linux/err.h> |
14 | #include <linux/interrupt.h> |
15 | #include <linux/io.h> |
16 | #include <linux/kernel.h> |
17 | #include <linux/mailbox_controller.h> |
18 | #include <linux/module.h> |
19 | #include <linux/of.h> |
20 | #include <linux/platform_device.h> |
21 | #include <linux/property.h> |
22 | #include <linux/slab.h> |
23 | |
24 | #include "mailbox.h" |
25 | |
26 | #define STI_MBOX_INST_MAX 4 /* RAM saving: Max supported instances */ |
27 | #define STI_MBOX_CHAN_MAX 20 /* RAM saving: Max supported channels */ |
28 | |
29 | #define STI_IRQ_VAL_OFFSET 0x04 /* Read interrupt status */ |
30 | #define STI_IRQ_SET_OFFSET 0x24 /* Generate a Tx channel interrupt */ |
31 | #define STI_IRQ_CLR_OFFSET 0x44 /* Clear pending Rx interrupts */ |
32 | #define STI_ENA_VAL_OFFSET 0x64 /* Read enable status */ |
33 | #define STI_ENA_SET_OFFSET 0x84 /* Enable a channel */ |
34 | #define STI_ENA_CLR_OFFSET 0xa4 /* Disable a channel */ |
35 | |
36 | #define MBOX_BASE(mdev, inst) ((mdev)->base + ((inst) * 4)) |
37 | |
38 | /** |
39 | * struct sti_mbox_device - STi Mailbox device data |
40 | * |
41 | * @dev: Device to which it is attached |
42 | * @mbox: Representation of a communication channel controller |
43 | * @base: Base address of the register mapping region |
44 | * @name: Name of the mailbox |
45 | * @enabled: Local copy of enabled channels |
46 | * @lock: Mutex protecting enabled status |
47 | * |
48 | * An IP Mailbox is currently composed of 4 instances |
49 | * Each instance is currently composed of 32 channels |
50 | * This means that we have 128 channels per Mailbox |
51 | * A channel an be used for TX or RX |
52 | */ |
53 | struct sti_mbox_device { |
54 | struct device *dev; |
55 | struct mbox_controller *mbox; |
56 | void __iomem *base; |
57 | const char *name; |
58 | u32 enabled[STI_MBOX_INST_MAX]; |
59 | spinlock_t lock; |
60 | }; |
61 | |
62 | /** |
63 | * struct sti_mbox_pdata - STi Mailbox platform specific configuration |
64 | * |
65 | * @num_inst: Maximum number of instances in one HW Mailbox |
66 | * @num_chan: Maximum number of channel per instance |
67 | */ |
68 | struct sti_mbox_pdata { |
69 | unsigned int num_inst; |
70 | unsigned int num_chan; |
71 | }; |
72 | |
73 | /** |
74 | * struct sti_channel - STi Mailbox allocated channel information |
75 | * |
76 | * @mdev: Pointer to parent Mailbox device |
77 | * @instance: Instance number channel resides in |
78 | * @channel: Channel number pertaining to this container |
79 | */ |
80 | struct sti_channel { |
81 | struct sti_mbox_device *mdev; |
82 | unsigned int instance; |
83 | unsigned int channel; |
84 | }; |
85 | |
86 | static inline bool sti_mbox_channel_is_enabled(struct mbox_chan *chan) |
87 | { |
88 | struct sti_channel *chan_info = chan->con_priv; |
89 | struct sti_mbox_device *mdev = chan_info->mdev; |
90 | unsigned int instance = chan_info->instance; |
91 | unsigned int channel = chan_info->channel; |
92 | |
93 | return mdev->enabled[instance] & BIT(channel); |
94 | } |
95 | |
96 | static inline |
97 | struct mbox_chan *sti_mbox_to_channel(struct mbox_controller *mbox, |
98 | unsigned int instance, |
99 | unsigned int channel) |
100 | { |
101 | struct sti_channel *chan_info; |
102 | int i; |
103 | |
104 | for (i = 0; i < mbox->num_chans; i++) { |
105 | chan_info = mbox->chans[i].con_priv; |
106 | if (chan_info && |
107 | chan_info->instance == instance && |
108 | chan_info->channel == channel) |
109 | return &mbox->chans[i]; |
110 | } |
111 | |
112 | dev_err(mbox->dev, |
113 | "Channel not registered: instance: %d channel: %d\n" , |
114 | instance, channel); |
115 | |
116 | return NULL; |
117 | } |
118 | |
119 | static void sti_mbox_enable_channel(struct mbox_chan *chan) |
120 | { |
121 | struct sti_channel *chan_info = chan->con_priv; |
122 | struct sti_mbox_device *mdev = chan_info->mdev; |
123 | unsigned int instance = chan_info->instance; |
124 | unsigned int channel = chan_info->channel; |
125 | unsigned long flags; |
126 | void __iomem *base = MBOX_BASE(mdev, instance); |
127 | |
128 | spin_lock_irqsave(&mdev->lock, flags); |
129 | mdev->enabled[instance] |= BIT(channel); |
130 | writel_relaxed(BIT(channel), base + STI_ENA_SET_OFFSET); |
131 | spin_unlock_irqrestore(lock: &mdev->lock, flags); |
132 | } |
133 | |
134 | static void sti_mbox_disable_channel(struct mbox_chan *chan) |
135 | { |
136 | struct sti_channel *chan_info = chan->con_priv; |
137 | struct sti_mbox_device *mdev = chan_info->mdev; |
138 | unsigned int instance = chan_info->instance; |
139 | unsigned int channel = chan_info->channel; |
140 | unsigned long flags; |
141 | void __iomem *base = MBOX_BASE(mdev, instance); |
142 | |
143 | spin_lock_irqsave(&mdev->lock, flags); |
144 | mdev->enabled[instance] &= ~BIT(channel); |
145 | writel_relaxed(BIT(channel), base + STI_ENA_CLR_OFFSET); |
146 | spin_unlock_irqrestore(lock: &mdev->lock, flags); |
147 | } |
148 | |
149 | static void sti_mbox_clear_irq(struct mbox_chan *chan) |
150 | { |
151 | struct sti_channel *chan_info = chan->con_priv; |
152 | struct sti_mbox_device *mdev = chan_info->mdev; |
153 | unsigned int instance = chan_info->instance; |
154 | unsigned int channel = chan_info->channel; |
155 | void __iomem *base = MBOX_BASE(mdev, instance); |
156 | |
157 | writel_relaxed(BIT(channel), base + STI_IRQ_CLR_OFFSET); |
158 | } |
159 | |
160 | static struct mbox_chan *sti_mbox_irq_to_channel(struct sti_mbox_device *mdev, |
161 | unsigned int instance) |
162 | { |
163 | struct mbox_controller *mbox = mdev->mbox; |
164 | struct mbox_chan *chan = NULL; |
165 | unsigned int channel; |
166 | unsigned long bits; |
167 | void __iomem *base = MBOX_BASE(mdev, instance); |
168 | |
169 | bits = readl_relaxed(base + STI_IRQ_VAL_OFFSET); |
170 | if (!bits) |
171 | /* No IRQs fired in specified instance */ |
172 | return NULL; |
173 | |
174 | /* An IRQ has fired, find the associated channel */ |
175 | for (channel = 0; bits; channel++) { |
176 | if (!test_and_clear_bit(nr: channel, addr: &bits)) |
177 | continue; |
178 | |
179 | chan = sti_mbox_to_channel(mbox, instance, channel); |
180 | if (chan) { |
181 | dev_dbg(mbox->dev, |
182 | "IRQ fired on instance: %d channel: %d\n" , |
183 | instance, channel); |
184 | break; |
185 | } |
186 | } |
187 | |
188 | return chan; |
189 | } |
190 | |
191 | static irqreturn_t sti_mbox_thread_handler(int irq, void *data) |
192 | { |
193 | struct sti_mbox_device *mdev = data; |
194 | struct sti_mbox_pdata *pdata = dev_get_platdata(dev: mdev->dev); |
195 | struct mbox_chan *chan; |
196 | unsigned int instance; |
197 | |
198 | for (instance = 0; instance < pdata->num_inst; instance++) { |
199 | keep_looking: |
200 | chan = sti_mbox_irq_to_channel(mdev, instance); |
201 | if (!chan) |
202 | continue; |
203 | |
204 | mbox_chan_received_data(chan, NULL); |
205 | sti_mbox_clear_irq(chan); |
206 | sti_mbox_enable_channel(chan); |
207 | goto keep_looking; |
208 | } |
209 | |
210 | return IRQ_HANDLED; |
211 | } |
212 | |
213 | static irqreturn_t sti_mbox_irq_handler(int irq, void *data) |
214 | { |
215 | struct sti_mbox_device *mdev = data; |
216 | struct sti_mbox_pdata *pdata = dev_get_platdata(dev: mdev->dev); |
217 | struct sti_channel *chan_info; |
218 | struct mbox_chan *chan; |
219 | unsigned int instance; |
220 | int ret = IRQ_NONE; |
221 | |
222 | for (instance = 0; instance < pdata->num_inst; instance++) { |
223 | chan = sti_mbox_irq_to_channel(mdev, instance); |
224 | if (!chan) |
225 | continue; |
226 | chan_info = chan->con_priv; |
227 | |
228 | if (!sti_mbox_channel_is_enabled(chan)) { |
229 | dev_warn(mdev->dev, |
230 | "Unexpected IRQ: %s\n" |
231 | " instance: %d: channel: %d [enabled: %x]\n" , |
232 | mdev->name, chan_info->instance, |
233 | chan_info->channel, mdev->enabled[instance]); |
234 | |
235 | /* Only handle IRQ if no other valid IRQs were found */ |
236 | if (ret == IRQ_NONE) |
237 | ret = IRQ_HANDLED; |
238 | continue; |
239 | } |
240 | |
241 | sti_mbox_disable_channel(chan); |
242 | ret = IRQ_WAKE_THREAD; |
243 | } |
244 | |
245 | if (ret == IRQ_NONE) |
246 | dev_err(mdev->dev, "Spurious IRQ - was a channel requested?\n" ); |
247 | |
248 | return ret; |
249 | } |
250 | |
251 | static bool sti_mbox_tx_is_ready(struct mbox_chan *chan) |
252 | { |
253 | struct sti_channel *chan_info = chan->con_priv; |
254 | struct sti_mbox_device *mdev = chan_info->mdev; |
255 | unsigned int instance = chan_info->instance; |
256 | unsigned int channel = chan_info->channel; |
257 | void __iomem *base = MBOX_BASE(mdev, instance); |
258 | |
259 | if (!(readl_relaxed(base + STI_ENA_VAL_OFFSET) & BIT(channel))) { |
260 | dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d disabled\n" , |
261 | mdev->name, instance, channel); |
262 | return false; |
263 | } |
264 | |
265 | if (readl_relaxed(base + STI_IRQ_VAL_OFFSET) & BIT(channel)) { |
266 | dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d not ready\n" , |
267 | mdev->name, instance, channel); |
268 | return false; |
269 | } |
270 | |
271 | return true; |
272 | } |
273 | |
274 | static int sti_mbox_send_data(struct mbox_chan *chan, void *data) |
275 | { |
276 | struct sti_channel *chan_info = chan->con_priv; |
277 | struct sti_mbox_device *mdev = chan_info->mdev; |
278 | unsigned int instance = chan_info->instance; |
279 | unsigned int channel = chan_info->channel; |
280 | void __iomem *base = MBOX_BASE(mdev, instance); |
281 | |
282 | /* Send event to co-processor */ |
283 | writel_relaxed(BIT(channel), base + STI_IRQ_SET_OFFSET); |
284 | |
285 | dev_dbg(mdev->dev, |
286 | "Sent via Mailbox %s: instance: %d channel: %d\n" , |
287 | mdev->name, instance, channel); |
288 | |
289 | return 0; |
290 | } |
291 | |
292 | static int sti_mbox_startup_chan(struct mbox_chan *chan) |
293 | { |
294 | sti_mbox_clear_irq(chan); |
295 | sti_mbox_enable_channel(chan); |
296 | |
297 | return 0; |
298 | } |
299 | |
300 | static void sti_mbox_shutdown_chan(struct mbox_chan *chan) |
301 | { |
302 | struct sti_channel *chan_info = chan->con_priv; |
303 | struct mbox_controller *mbox = chan_info->mdev->mbox; |
304 | int i; |
305 | |
306 | for (i = 0; i < mbox->num_chans; i++) |
307 | if (chan == &mbox->chans[i]) |
308 | break; |
309 | |
310 | if (mbox->num_chans == i) { |
311 | dev_warn(mbox->dev, "Request to free non-existent channel\n" ); |
312 | return; |
313 | } |
314 | |
315 | /* Reset channel */ |
316 | sti_mbox_disable_channel(chan); |
317 | sti_mbox_clear_irq(chan); |
318 | chan->con_priv = NULL; |
319 | } |
320 | |
321 | static struct mbox_chan *sti_mbox_xlate(struct mbox_controller *mbox, |
322 | const struct of_phandle_args *spec) |
323 | { |
324 | struct sti_mbox_device *mdev = dev_get_drvdata(dev: mbox->dev); |
325 | struct sti_mbox_pdata *pdata = dev_get_platdata(dev: mdev->dev); |
326 | struct sti_channel *chan_info; |
327 | struct mbox_chan *chan = NULL; |
328 | unsigned int instance = spec->args[0]; |
329 | unsigned int channel = spec->args[1]; |
330 | int i; |
331 | |
332 | /* Bounds checking */ |
333 | if (instance >= pdata->num_inst || channel >= pdata->num_chan) { |
334 | dev_err(mbox->dev, |
335 | "Invalid channel requested instance: %d channel: %d\n" , |
336 | instance, channel); |
337 | return ERR_PTR(error: -EINVAL); |
338 | } |
339 | |
340 | for (i = 0; i < mbox->num_chans; i++) { |
341 | chan_info = mbox->chans[i].con_priv; |
342 | |
343 | /* Is requested channel free? */ |
344 | if (chan_info && |
345 | mbox->dev == chan_info->mdev->dev && |
346 | instance == chan_info->instance && |
347 | channel == chan_info->channel) { |
348 | |
349 | dev_err(mbox->dev, "Channel in use\n" ); |
350 | return ERR_PTR(error: -EBUSY); |
351 | } |
352 | |
353 | /* |
354 | * Find the first free slot, then continue checking |
355 | * to see if requested channel is in use |
356 | */ |
357 | if (!chan && !chan_info) |
358 | chan = &mbox->chans[i]; |
359 | } |
360 | |
361 | if (!chan) { |
362 | dev_err(mbox->dev, "No free channels left\n" ); |
363 | return ERR_PTR(error: -EBUSY); |
364 | } |
365 | |
366 | chan_info = devm_kzalloc(dev: mbox->dev, size: sizeof(*chan_info), GFP_KERNEL); |
367 | if (!chan_info) |
368 | return ERR_PTR(error: -ENOMEM); |
369 | |
370 | chan_info->mdev = mdev; |
371 | chan_info->instance = instance; |
372 | chan_info->channel = channel; |
373 | |
374 | chan->con_priv = chan_info; |
375 | |
376 | dev_info(mbox->dev, |
377 | "Mbox: %s: Created channel: instance: %d channel: %d\n" , |
378 | mdev->name, instance, channel); |
379 | |
380 | return chan; |
381 | } |
382 | |
383 | static const struct mbox_chan_ops sti_mbox_ops = { |
384 | .startup = sti_mbox_startup_chan, |
385 | .shutdown = sti_mbox_shutdown_chan, |
386 | .send_data = sti_mbox_send_data, |
387 | .last_tx_done = sti_mbox_tx_is_ready, |
388 | }; |
389 | |
390 | static const struct sti_mbox_pdata mbox_stih407_pdata = { |
391 | .num_inst = 4, |
392 | .num_chan = 32, |
393 | }; |
394 | |
395 | static const struct of_device_id sti_mailbox_match[] = { |
396 | { |
397 | .compatible = "st,stih407-mailbox" , |
398 | .data = (void *)&mbox_stih407_pdata |
399 | }, |
400 | { } |
401 | }; |
402 | MODULE_DEVICE_TABLE(of, sti_mailbox_match); |
403 | |
404 | static int sti_mbox_probe(struct platform_device *pdev) |
405 | { |
406 | struct mbox_controller *mbox; |
407 | struct sti_mbox_device *mdev; |
408 | struct device_node *np = pdev->dev.of_node; |
409 | struct mbox_chan *chans; |
410 | int irq; |
411 | int ret; |
412 | |
413 | pdev->dev.platform_data = (struct sti_mbox_pdata *)device_get_match_data(dev: &pdev->dev); |
414 | if (!pdev->dev.platform_data) { |
415 | dev_err(&pdev->dev, "No configuration found\n" ); |
416 | return -ENODEV; |
417 | } |
418 | |
419 | mdev = devm_kzalloc(dev: &pdev->dev, size: sizeof(*mdev), GFP_KERNEL); |
420 | if (!mdev) |
421 | return -ENOMEM; |
422 | |
423 | platform_set_drvdata(pdev, data: mdev); |
424 | |
425 | mdev->base = devm_platform_ioremap_resource(pdev, index: 0); |
426 | if (IS_ERR(ptr: mdev->base)) |
427 | return PTR_ERR(ptr: mdev->base); |
428 | |
429 | ret = of_property_read_string(np, propname: "mbox-name" , out_string: &mdev->name); |
430 | if (ret) |
431 | mdev->name = np->full_name; |
432 | |
433 | mbox = devm_kzalloc(dev: &pdev->dev, size: sizeof(*mbox), GFP_KERNEL); |
434 | if (!mbox) |
435 | return -ENOMEM; |
436 | |
437 | chans = devm_kcalloc(dev: &pdev->dev, |
438 | STI_MBOX_CHAN_MAX, size: sizeof(*chans), GFP_KERNEL); |
439 | if (!chans) |
440 | return -ENOMEM; |
441 | |
442 | mdev->dev = &pdev->dev; |
443 | mdev->mbox = mbox; |
444 | |
445 | spin_lock_init(&mdev->lock); |
446 | |
447 | /* STi Mailbox does not have a Tx-Done or Tx-Ready IRQ */ |
448 | mbox->txdone_irq = false; |
449 | mbox->txdone_poll = true; |
450 | mbox->txpoll_period = 100; |
451 | mbox->ops = &sti_mbox_ops; |
452 | mbox->dev = mdev->dev; |
453 | mbox->of_xlate = sti_mbox_xlate; |
454 | mbox->chans = chans; |
455 | mbox->num_chans = STI_MBOX_CHAN_MAX; |
456 | |
457 | ret = devm_mbox_controller_register(dev: &pdev->dev, mbox); |
458 | if (ret) |
459 | return ret; |
460 | |
461 | /* It's okay for Tx Mailboxes to not supply IRQs */ |
462 | irq = platform_get_irq(pdev, 0); |
463 | if (irq < 0) { |
464 | dev_info(&pdev->dev, |
465 | "%s: Registered Tx only Mailbox\n" , mdev->name); |
466 | return 0; |
467 | } |
468 | |
469 | ret = devm_request_threaded_irq(dev: &pdev->dev, irq, |
470 | handler: sti_mbox_irq_handler, |
471 | thread_fn: sti_mbox_thread_handler, |
472 | IRQF_ONESHOT, devname: mdev->name, dev_id: mdev); |
473 | if (ret) { |
474 | dev_err(&pdev->dev, "Can't claim IRQ %d\n" , irq); |
475 | return -EINVAL; |
476 | } |
477 | |
478 | dev_info(&pdev->dev, "%s: Registered Tx/Rx Mailbox\n" , mdev->name); |
479 | |
480 | return 0; |
481 | } |
482 | |
483 | static struct platform_driver sti_mbox_driver = { |
484 | .probe = sti_mbox_probe, |
485 | .driver = { |
486 | .name = "sti-mailbox" , |
487 | .of_match_table = sti_mailbox_match, |
488 | }, |
489 | }; |
490 | module_platform_driver(sti_mbox_driver); |
491 | |
492 | MODULE_LICENSE("GPL" ); |
493 | MODULE_DESCRIPTION("STMicroelectronics Mailbox Controller" ); |
494 | MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org" ); |
495 | MODULE_ALIAS("platform:mailbox-sti" ); |
496 | |