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f62092f6 LFT |
1 | /* |
2 | * Copyright Altera Corporation (C) 2013-2014. All rights reserved | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms and conditions of the GNU General Public License, | |
6 | * version 2, as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along with | |
14 | * this program. If not, see <http://www.gnu.org/licenses/>. | |
15 | */ | |
16 | ||
17 | #include <linux/device.h> | |
18 | #include <linux/interrupt.h> | |
19 | #include <linux/io.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/mailbox_controller.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/of.h> | |
24 | #include <linux/platform_device.h> | |
25 | ||
26 | #define DRIVER_NAME "altera-mailbox" | |
27 | ||
28 | #define MAILBOX_CMD_REG 0x00 | |
29 | #define MAILBOX_PTR_REG 0x04 | |
30 | #define MAILBOX_STS_REG 0x08 | |
31 | #define MAILBOX_INTMASK_REG 0x0C | |
32 | ||
33 | #define INT_PENDING_MSK 0x1 | |
34 | #define INT_SPACE_MSK 0x2 | |
35 | ||
36 | #define STS_PENDING_MSK 0x1 | |
37 | #define STS_FULL_MSK 0x2 | |
38 | #define STS_FULL_OFT 0x1 | |
39 | ||
40 | #define MBOX_PENDING(status) (((status) & STS_PENDING_MSK)) | |
41 | #define MBOX_FULL(status) (((status) & STS_FULL_MSK) >> STS_FULL_OFT) | |
42 | ||
43 | enum altera_mbox_msg { | |
44 | MBOX_CMD = 0, | |
45 | MBOX_PTR, | |
46 | }; | |
47 | ||
48 | #define MBOX_POLLING_MS 5 /* polling interval 5ms */ | |
49 | ||
50 | struct altera_mbox { | |
51 | bool is_sender; /* 1-sender, 0-receiver */ | |
52 | bool intr_mode; | |
53 | int irq; | |
54 | void __iomem *mbox_base; | |
55 | struct device *dev; | |
56 | struct mbox_controller controller; | |
57 | ||
58 | /* If the controller supports only RX polling mode */ | |
59 | struct timer_list rxpoll_timer; | |
60 | }; | |
61 | ||
62 | static struct altera_mbox *mbox_chan_to_altera_mbox(struct mbox_chan *chan) | |
63 | { | |
64 | if (!chan || !chan->con_priv) | |
65 | return NULL; | |
66 | ||
67 | return (struct altera_mbox *)chan->con_priv; | |
68 | } | |
69 | ||
70 | static inline int altera_mbox_full(struct altera_mbox *mbox) | |
71 | { | |
72 | u32 status; | |
73 | ||
74 | status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG); | |
75 | return MBOX_FULL(status); | |
76 | } | |
77 | ||
78 | static inline int altera_mbox_pending(struct altera_mbox *mbox) | |
79 | { | |
80 | u32 status; | |
81 | ||
82 | status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG); | |
83 | return MBOX_PENDING(status); | |
84 | } | |
85 | ||
86 | static void altera_mbox_rx_intmask(struct altera_mbox *mbox, bool enable) | |
87 | { | |
88 | u32 mask; | |
89 | ||
90 | mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG); | |
91 | if (enable) | |
92 | mask |= INT_PENDING_MSK; | |
93 | else | |
94 | mask &= ~INT_PENDING_MSK; | |
95 | writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG); | |
96 | } | |
97 | ||
98 | static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable) | |
99 | { | |
100 | u32 mask; | |
101 | ||
102 | mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG); | |
103 | if (enable) | |
104 | mask |= INT_SPACE_MSK; | |
105 | else | |
106 | mask &= ~INT_SPACE_MSK; | |
107 | writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG); | |
108 | } | |
109 | ||
110 | static bool altera_mbox_is_sender(struct altera_mbox *mbox) | |
111 | { | |
112 | u32 reg; | |
113 | /* Write a magic number to PTR register and read back this register. | |
114 | * This register is read-write if it is a sender. | |
115 | */ | |
116 | #define MBOX_MAGIC 0xA5A5AA55 | |
117 | writel_relaxed(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG); | |
118 | reg = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG); | |
119 | if (reg == MBOX_MAGIC) { | |
120 | /* Clear to 0 */ | |
121 | writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG); | |
122 | return true; | |
123 | } | |
124 | return false; | |
125 | } | |
126 | ||
127 | static void altera_mbox_rx_data(struct mbox_chan *chan) | |
128 | { | |
129 | struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); | |
130 | u32 data[2]; | |
131 | ||
132 | if (altera_mbox_pending(mbox)) { | |
133 | data[MBOX_PTR] = | |
134 | readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG); | |
135 | data[MBOX_CMD] = | |
136 | readl_relaxed(mbox->mbox_base + MAILBOX_CMD_REG); | |
137 | mbox_chan_received_data(chan, (void *)data); | |
138 | } | |
139 | } | |
140 | ||
141 | static void altera_mbox_poll_rx(unsigned long data) | |
142 | { | |
143 | struct mbox_chan *chan = (struct mbox_chan *)data; | |
144 | struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); | |
145 | ||
146 | altera_mbox_rx_data(chan); | |
147 | ||
148 | mod_timer(&mbox->rxpoll_timer, | |
149 | jiffies + msecs_to_jiffies(MBOX_POLLING_MS)); | |
150 | } | |
151 | ||
152 | static irqreturn_t altera_mbox_tx_interrupt(int irq, void *p) | |
153 | { | |
154 | struct mbox_chan *chan = (struct mbox_chan *)p; | |
155 | struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); | |
156 | ||
157 | altera_mbox_tx_intmask(mbox, false); | |
158 | mbox_chan_txdone(chan, 0); | |
159 | ||
160 | return IRQ_HANDLED; | |
161 | } | |
162 | ||
163 | static irqreturn_t altera_mbox_rx_interrupt(int irq, void *p) | |
164 | { | |
165 | struct mbox_chan *chan = (struct mbox_chan *)p; | |
166 | ||
167 | altera_mbox_rx_data(chan); | |
168 | return IRQ_HANDLED; | |
169 | } | |
170 | ||
171 | static int altera_mbox_startup_sender(struct mbox_chan *chan) | |
172 | { | |
173 | int ret; | |
174 | struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); | |
175 | ||
176 | if (mbox->intr_mode) { | |
177 | ret = request_irq(mbox->irq, altera_mbox_tx_interrupt, 0, | |
178 | DRIVER_NAME, chan); | |
179 | if (unlikely(ret)) { | |
180 | dev_err(mbox->dev, | |
181 | "failed to register mailbox interrupt:%d\n", | |
182 | ret); | |
183 | return ret; | |
184 | } | |
185 | } | |
186 | ||
187 | return 0; | |
188 | } | |
189 | ||
190 | static int altera_mbox_startup_receiver(struct mbox_chan *chan) | |
191 | { | |
192 | int ret; | |
193 | struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); | |
194 | ||
195 | if (mbox->intr_mode) { | |
196 | ret = request_irq(mbox->irq, altera_mbox_rx_interrupt, 0, | |
197 | DRIVER_NAME, chan); | |
198 | if (unlikely(ret)) { | |
199 | mbox->intr_mode = false; | |
200 | goto polling; /* use polling if failed */ | |
201 | } | |
202 | ||
203 | altera_mbox_rx_intmask(mbox, true); | |
204 | return 0; | |
205 | } | |
206 | ||
207 | polling: | |
208 | /* Setup polling timer */ | |
209 | setup_timer(&mbox->rxpoll_timer, altera_mbox_poll_rx, | |
210 | (unsigned long)chan); | |
211 | mod_timer(&mbox->rxpoll_timer, | |
212 | jiffies + msecs_to_jiffies(MBOX_POLLING_MS)); | |
213 | ||
214 | return 0; | |
215 | } | |
216 | ||
217 | static int altera_mbox_send_data(struct mbox_chan *chan, void *data) | |
218 | { | |
219 | struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); | |
220 | u32 *udata = (u32 *)data; | |
221 | ||
222 | if (!mbox || !data) | |
223 | return -EINVAL; | |
224 | if (!mbox->is_sender) { | |
225 | dev_warn(mbox->dev, | |
226 | "failed to send. This is receiver mailbox.\n"); | |
227 | return -EINVAL; | |
228 | } | |
229 | ||
230 | if (altera_mbox_full(mbox)) | |
231 | return -EBUSY; | |
232 | ||
233 | /* Enable interrupt before send */ | |
234 | if (mbox->intr_mode) | |
235 | altera_mbox_tx_intmask(mbox, true); | |
236 | ||
237 | /* Pointer register must write before command register */ | |
238 | writel_relaxed(udata[MBOX_PTR], mbox->mbox_base + MAILBOX_PTR_REG); | |
239 | writel_relaxed(udata[MBOX_CMD], mbox->mbox_base + MAILBOX_CMD_REG); | |
240 | ||
241 | return 0; | |
242 | } | |
243 | ||
244 | static bool altera_mbox_last_tx_done(struct mbox_chan *chan) | |
245 | { | |
246 | struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); | |
247 | ||
248 | /* Return false if mailbox is full */ | |
249 | return altera_mbox_full(mbox) ? false : true; | |
250 | } | |
251 | ||
252 | static bool altera_mbox_peek_data(struct mbox_chan *chan) | |
253 | { | |
254 | struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); | |
255 | ||
256 | return altera_mbox_pending(mbox) ? true : false; | |
257 | } | |
258 | ||
259 | static int altera_mbox_startup(struct mbox_chan *chan) | |
260 | { | |
261 | struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); | |
262 | int ret = 0; | |
263 | ||
264 | if (!mbox) | |
265 | return -EINVAL; | |
266 | ||
267 | if (mbox->is_sender) | |
268 | ret = altera_mbox_startup_sender(chan); | |
269 | else | |
270 | ret = altera_mbox_startup_receiver(chan); | |
271 | ||
272 | return ret; | |
273 | } | |
274 | ||
275 | static void altera_mbox_shutdown(struct mbox_chan *chan) | |
276 | { | |
277 | struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan); | |
278 | ||
279 | if (mbox->intr_mode) { | |
280 | /* Unmask all interrupt masks */ | |
281 | writel_relaxed(~0, mbox->mbox_base + MAILBOX_INTMASK_REG); | |
282 | free_irq(mbox->irq, chan); | |
283 | } else if (!mbox->is_sender) { | |
284 | del_timer_sync(&mbox->rxpoll_timer); | |
285 | } | |
286 | } | |
287 | ||
288 | static struct mbox_chan_ops altera_mbox_ops = { | |
289 | .send_data = altera_mbox_send_data, | |
290 | .startup = altera_mbox_startup, | |
291 | .shutdown = altera_mbox_shutdown, | |
292 | .last_tx_done = altera_mbox_last_tx_done, | |
293 | .peek_data = altera_mbox_peek_data, | |
294 | }; | |
295 | ||
296 | static int altera_mbox_probe(struct platform_device *pdev) | |
297 | { | |
298 | struct altera_mbox *mbox; | |
299 | struct resource *regs; | |
300 | struct mbox_chan *chans; | |
301 | int ret; | |
302 | ||
303 | mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), | |
304 | GFP_KERNEL); | |
305 | if (!mbox) | |
306 | return -ENOMEM; | |
307 | ||
308 | /* Allocated one channel */ | |
309 | chans = devm_kzalloc(&pdev->dev, sizeof(*chans), GFP_KERNEL); | |
310 | if (!chans) | |
311 | return -ENOMEM; | |
312 | ||
313 | regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
314 | ||
315 | mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs); | |
316 | if (IS_ERR(mbox->mbox_base)) | |
317 | return PTR_ERR(mbox->mbox_base); | |
318 | ||
319 | /* Check is it a sender or receiver? */ | |
320 | mbox->is_sender = altera_mbox_is_sender(mbox); | |
321 | ||
322 | mbox->irq = platform_get_irq(pdev, 0); | |
323 | if (mbox->irq >= 0) | |
324 | mbox->intr_mode = true; | |
325 | ||
326 | mbox->dev = &pdev->dev; | |
327 | ||
328 | /* Hardware supports only one channel. */ | |
329 | chans[0].con_priv = mbox; | |
330 | mbox->controller.dev = mbox->dev; | |
331 | mbox->controller.num_chans = 1; | |
332 | mbox->controller.chans = chans; | |
333 | mbox->controller.ops = &altera_mbox_ops; | |
334 | ||
335 | if (mbox->is_sender) { | |
336 | if (mbox->intr_mode) { | |
337 | mbox->controller.txdone_irq = true; | |
338 | } else { | |
339 | mbox->controller.txdone_poll = true; | |
340 | mbox->controller.txpoll_period = MBOX_POLLING_MS; | |
341 | } | |
342 | } | |
343 | ||
344 | ret = mbox_controller_register(&mbox->controller); | |
345 | if (ret) { | |
346 | dev_err(&pdev->dev, "Register mailbox failed\n"); | |
347 | goto err; | |
348 | } | |
349 | ||
350 | platform_set_drvdata(pdev, mbox); | |
351 | err: | |
352 | return ret; | |
353 | } | |
354 | ||
355 | static int altera_mbox_remove(struct platform_device *pdev) | |
356 | { | |
357 | struct altera_mbox *mbox = platform_get_drvdata(pdev); | |
358 | ||
359 | if (!mbox) | |
360 | return -EINVAL; | |
361 | ||
362 | mbox_controller_unregister(&mbox->controller); | |
363 | ||
364 | return 0; | |
365 | } | |
366 | ||
367 | static const struct of_device_id altera_mbox_match[] = { | |
368 | { .compatible = "altr,mailbox-1.0" }, | |
369 | { /* Sentinel */ } | |
370 | }; | |
371 | ||
372 | MODULE_DEVICE_TABLE(of, altera_mbox_match); | |
373 | ||
374 | static struct platform_driver altera_mbox_driver = { | |
375 | .probe = altera_mbox_probe, | |
376 | .remove = altera_mbox_remove, | |
377 | .driver = { | |
378 | .name = DRIVER_NAME, | |
379 | .of_match_table = altera_mbox_match, | |
380 | }, | |
381 | }; | |
382 | ||
383 | module_platform_driver(altera_mbox_driver); | |
384 | ||
385 | MODULE_LICENSE("GPL v2"); | |
386 | MODULE_DESCRIPTION("Altera mailbox specific functions"); | |
387 | MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>"); | |
388 | MODULE_ALIAS("platform:altera-mailbox"); |