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 struct mbox_chan *chan;
61 };
62
mbox_chan_to_altera_mbox(struct mbox_chan * chan)63 static struct altera_mbox *mbox_chan_to_altera_mbox(struct mbox_chan *chan)
64 {
65 if (!chan || !chan->con_priv)
66 return NULL;
67
68 return (struct altera_mbox *)chan->con_priv;
69 }
70
altera_mbox_full(struct altera_mbox * mbox)71 static inline int altera_mbox_full(struct altera_mbox *mbox)
72 {
73 u32 status;
74
75 status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
76 return MBOX_FULL(status);
77 }
78
altera_mbox_pending(struct altera_mbox * mbox)79 static inline int altera_mbox_pending(struct altera_mbox *mbox)
80 {
81 u32 status;
82
83 status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
84 return MBOX_PENDING(status);
85 }
86
altera_mbox_rx_intmask(struct altera_mbox * mbox,bool enable)87 static void altera_mbox_rx_intmask(struct altera_mbox *mbox, bool enable)
88 {
89 u32 mask;
90
91 mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
92 if (enable)
93 mask |= INT_PENDING_MSK;
94 else
95 mask &= ~INT_PENDING_MSK;
96 writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
97 }
98
altera_mbox_tx_intmask(struct altera_mbox * mbox,bool enable)99 static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable)
100 {
101 u32 mask;
102
103 mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
104 if (enable)
105 mask |= INT_SPACE_MSK;
106 else
107 mask &= ~INT_SPACE_MSK;
108 writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
109 }
110
altera_mbox_is_sender(struct altera_mbox * mbox)111 static bool altera_mbox_is_sender(struct altera_mbox *mbox)
112 {
113 u32 reg;
114 /* Write a magic number to PTR register and read back this register.
115 * This register is read-write if it is a sender.
116 */
117 #define MBOX_MAGIC 0xA5A5AA55
118 writel_relaxed(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG);
119 reg = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
120 if (reg == MBOX_MAGIC) {
121 /* Clear to 0 */
122 writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG);
123 return true;
124 }
125 return false;
126 }
127
altera_mbox_rx_data(struct mbox_chan * chan)128 static void altera_mbox_rx_data(struct mbox_chan *chan)
129 {
130 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
131 u32 data[2];
132
133 if (altera_mbox_pending(mbox)) {
134 data[MBOX_PTR] =
135 readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
136 data[MBOX_CMD] =
137 readl_relaxed(mbox->mbox_base + MAILBOX_CMD_REG);
138 mbox_chan_received_data(chan, (void *)data);
139 }
140 }
141
altera_mbox_poll_rx(struct timer_list * t)142 static void altera_mbox_poll_rx(struct timer_list *t)
143 {
144 struct altera_mbox *mbox = from_timer(mbox, t, rxpoll_timer);
145
146 altera_mbox_rx_data(mbox->chan);
147
148 mod_timer(&mbox->rxpoll_timer,
149 jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
150 }
151
altera_mbox_tx_interrupt(int irq,void * p)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
altera_mbox_rx_interrupt(int irq,void * p)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
altera_mbox_startup_sender(struct mbox_chan * chan)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
altera_mbox_startup_receiver(struct mbox_chan * chan)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 mbox->chan = chan;
210 timer_setup(&mbox->rxpoll_timer, altera_mbox_poll_rx, 0);
211 mod_timer(&mbox->rxpoll_timer,
212 jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
213
214 return 0;
215 }
216
altera_mbox_send_data(struct mbox_chan * chan,void * data)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
altera_mbox_last_tx_done(struct mbox_chan * chan)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
altera_mbox_peek_data(struct mbox_chan * chan)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
altera_mbox_startup(struct mbox_chan * chan)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
altera_mbox_shutdown(struct mbox_chan * chan)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 const 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
altera_mbox_probe(struct platform_device * pdev)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
altera_mbox_remove(struct platform_device * pdev)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");
389
