1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright Altera Corporation (C) 2013-2014. All rights reserved
4 */
5
6 #include <linux/device.h>
7 #include <linux/interrupt.h>
8 #include <linux/io.h>
9 #include <linux/kernel.h>
10 #include <linux/mailbox_controller.h>
11 #include <linux/module.h>
12 #include <linux/of.h>
13 #include <linux/platform_device.h>
14
15 #define DRIVER_NAME "altera-mailbox"
16
17 #define MAILBOX_CMD_REG 0x00
18 #define MAILBOX_PTR_REG 0x04
19 #define MAILBOX_STS_REG 0x08
20 #define MAILBOX_INTMASK_REG 0x0C
21
22 #define INT_PENDING_MSK 0x1
23 #define INT_SPACE_MSK 0x2
24
25 #define STS_PENDING_MSK 0x1
26 #define STS_FULL_MSK 0x2
27 #define STS_FULL_OFT 0x1
28
29 #define MBOX_PENDING(status) (((status) & STS_PENDING_MSK))
30 #define MBOX_FULL(status) (((status) & STS_FULL_MSK) >> STS_FULL_OFT)
31
32 enum altera_mbox_msg {
33 MBOX_CMD = 0,
34 MBOX_PTR,
35 };
36
37 #define MBOX_POLLING_MS 5 /* polling interval 5ms */
38
39 struct altera_mbox {
40 bool is_sender; /* 1-sender, 0-receiver */
41 bool intr_mode;
42 int irq;
43 void __iomem *mbox_base;
44 struct device *dev;
45 struct mbox_controller controller;
46
47 /* If the controller supports only RX polling mode */
48 struct timer_list rxpoll_timer;
49 struct mbox_chan *chan;
50 };
51
mbox_chan_to_altera_mbox(struct mbox_chan * chan)52 static struct altera_mbox *mbox_chan_to_altera_mbox(struct mbox_chan *chan)
53 {
54 if (!chan || !chan->con_priv)
55 return NULL;
56
57 return (struct altera_mbox *)chan->con_priv;
58 }
59
altera_mbox_full(struct altera_mbox * mbox)60 static inline int altera_mbox_full(struct altera_mbox *mbox)
61 {
62 u32 status;
63
64 status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
65 return MBOX_FULL(status);
66 }
67
altera_mbox_pending(struct altera_mbox * mbox)68 static inline int altera_mbox_pending(struct altera_mbox *mbox)
69 {
70 u32 status;
71
72 status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
73 return MBOX_PENDING(status);
74 }
75
altera_mbox_rx_intmask(struct altera_mbox * mbox,bool enable)76 static void altera_mbox_rx_intmask(struct altera_mbox *mbox, bool enable)
77 {
78 u32 mask;
79
80 mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
81 if (enable)
82 mask |= INT_PENDING_MSK;
83 else
84 mask &= ~INT_PENDING_MSK;
85 writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
86 }
87
altera_mbox_tx_intmask(struct altera_mbox * mbox,bool enable)88 static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable)
89 {
90 u32 mask;
91
92 mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
93 if (enable)
94 mask |= INT_SPACE_MSK;
95 else
96 mask &= ~INT_SPACE_MSK;
97 writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
98 }
99
altera_mbox_is_sender(struct altera_mbox * mbox)100 static bool altera_mbox_is_sender(struct altera_mbox *mbox)
101 {
102 u32 reg;
103 /* Write a magic number to PTR register and read back this register.
104 * This register is read-write if it is a sender.
105 */
106 #define MBOX_MAGIC 0xA5A5AA55
107 writel_relaxed(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG);
108 reg = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
109 if (reg == MBOX_MAGIC) {
110 /* Clear to 0 */
111 writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG);
112 return true;
113 }
114 return false;
115 }
116
altera_mbox_rx_data(struct mbox_chan * chan)117 static void altera_mbox_rx_data(struct mbox_chan *chan)
118 {
119 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
120 u32 data[2];
121
122 if (altera_mbox_pending(mbox)) {
123 data[MBOX_PTR] =
124 readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
125 data[MBOX_CMD] =
126 readl_relaxed(mbox->mbox_base + MAILBOX_CMD_REG);
127 mbox_chan_received_data(chan, (void *)data);
128 }
129 }
130
altera_mbox_poll_rx(struct timer_list * t)131 static void altera_mbox_poll_rx(struct timer_list *t)
132 {
133 struct altera_mbox *mbox = from_timer(mbox, t, rxpoll_timer);
134
135 altera_mbox_rx_data(mbox->chan);
136
137 mod_timer(&mbox->rxpoll_timer,
138 jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
139 }
140
altera_mbox_tx_interrupt(int irq,void * p)141 static irqreturn_t altera_mbox_tx_interrupt(int irq, void *p)
142 {
143 struct mbox_chan *chan = (struct mbox_chan *)p;
144 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
145
146 altera_mbox_tx_intmask(mbox, false);
147 mbox_chan_txdone(chan, 0);
148
149 return IRQ_HANDLED;
150 }
151
altera_mbox_rx_interrupt(int irq,void * p)152 static irqreturn_t altera_mbox_rx_interrupt(int irq, void *p)
153 {
154 struct mbox_chan *chan = (struct mbox_chan *)p;
155
156 altera_mbox_rx_data(chan);
157 return IRQ_HANDLED;
158 }
159
altera_mbox_startup_sender(struct mbox_chan * chan)160 static int altera_mbox_startup_sender(struct mbox_chan *chan)
161 {
162 int ret;
163 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
164
165 if (mbox->intr_mode) {
166 ret = request_irq(mbox->irq, altera_mbox_tx_interrupt, 0,
167 DRIVER_NAME, chan);
168 if (unlikely(ret)) {
169 dev_err(mbox->dev,
170 "failed to register mailbox interrupt:%d\n",
171 ret);
172 return ret;
173 }
174 }
175
176 return 0;
177 }
178
altera_mbox_startup_receiver(struct mbox_chan * chan)179 static int altera_mbox_startup_receiver(struct mbox_chan *chan)
180 {
181 int ret;
182 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
183
184 if (mbox->intr_mode) {
185 ret = request_irq(mbox->irq, altera_mbox_rx_interrupt, 0,
186 DRIVER_NAME, chan);
187 if (unlikely(ret)) {
188 mbox->intr_mode = false;
189 goto polling; /* use polling if failed */
190 }
191
192 altera_mbox_rx_intmask(mbox, true);
193 return 0;
194 }
195
196 polling:
197 /* Setup polling timer */
198 mbox->chan = chan;
199 timer_setup(&mbox->rxpoll_timer, altera_mbox_poll_rx, 0);
200 mod_timer(&mbox->rxpoll_timer,
201 jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
202
203 return 0;
204 }
205
altera_mbox_send_data(struct mbox_chan * chan,void * data)206 static int altera_mbox_send_data(struct mbox_chan *chan, void *data)
207 {
208 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
209 u32 *udata = (u32 *)data;
210
211 if (!mbox || !data)
212 return -EINVAL;
213 if (!mbox->is_sender) {
214 dev_warn(mbox->dev,
215 "failed to send. This is receiver mailbox.\n");
216 return -EINVAL;
217 }
218
219 if (altera_mbox_full(mbox))
220 return -EBUSY;
221
222 /* Enable interrupt before send */
223 if (mbox->intr_mode)
224 altera_mbox_tx_intmask(mbox, true);
225
226 /* Pointer register must write before command register */
227 writel_relaxed(udata[MBOX_PTR], mbox->mbox_base + MAILBOX_PTR_REG);
228 writel_relaxed(udata[MBOX_CMD], mbox->mbox_base + MAILBOX_CMD_REG);
229
230 return 0;
231 }
232
altera_mbox_last_tx_done(struct mbox_chan * chan)233 static bool altera_mbox_last_tx_done(struct mbox_chan *chan)
234 {
235 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
236
237 /* Return false if mailbox is full */
238 return altera_mbox_full(mbox) ? false : true;
239 }
240
altera_mbox_peek_data(struct mbox_chan * chan)241 static bool altera_mbox_peek_data(struct mbox_chan *chan)
242 {
243 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
244
245 return altera_mbox_pending(mbox) ? true : false;
246 }
247
altera_mbox_startup(struct mbox_chan * chan)248 static int altera_mbox_startup(struct mbox_chan *chan)
249 {
250 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
251 int ret = 0;
252
253 if (!mbox)
254 return -EINVAL;
255
256 if (mbox->is_sender)
257 ret = altera_mbox_startup_sender(chan);
258 else
259 ret = altera_mbox_startup_receiver(chan);
260
261 return ret;
262 }
263
altera_mbox_shutdown(struct mbox_chan * chan)264 static void altera_mbox_shutdown(struct mbox_chan *chan)
265 {
266 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
267
268 if (mbox->intr_mode) {
269 /* Unmask all interrupt masks */
270 writel_relaxed(~0, mbox->mbox_base + MAILBOX_INTMASK_REG);
271 free_irq(mbox->irq, chan);
272 } else if (!mbox->is_sender) {
273 del_timer_sync(&mbox->rxpoll_timer);
274 }
275 }
276
277 static const struct mbox_chan_ops altera_mbox_ops = {
278 .send_data = altera_mbox_send_data,
279 .startup = altera_mbox_startup,
280 .shutdown = altera_mbox_shutdown,
281 .last_tx_done = altera_mbox_last_tx_done,
282 .peek_data = altera_mbox_peek_data,
283 };
284
altera_mbox_probe(struct platform_device * pdev)285 static int altera_mbox_probe(struct platform_device *pdev)
286 {
287 struct altera_mbox *mbox;
288 struct mbox_chan *chans;
289 int ret;
290
291 mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox),
292 GFP_KERNEL);
293 if (!mbox)
294 return -ENOMEM;
295
296 /* Allocated one channel */
297 chans = devm_kzalloc(&pdev->dev, sizeof(*chans), GFP_KERNEL);
298 if (!chans)
299 return -ENOMEM;
300
301 mbox->mbox_base = devm_platform_ioremap_resource(pdev, 0);
302 if (IS_ERR(mbox->mbox_base))
303 return PTR_ERR(mbox->mbox_base);
304
305 /* Check is it a sender or receiver? */
306 mbox->is_sender = altera_mbox_is_sender(mbox);
307
308 mbox->irq = platform_get_irq(pdev, 0);
309 if (mbox->irq >= 0)
310 mbox->intr_mode = true;
311
312 mbox->dev = &pdev->dev;
313
314 /* Hardware supports only one channel. */
315 chans[0].con_priv = mbox;
316 mbox->controller.dev = mbox->dev;
317 mbox->controller.num_chans = 1;
318 mbox->controller.chans = chans;
319 mbox->controller.ops = &altera_mbox_ops;
320
321 if (mbox->is_sender) {
322 if (mbox->intr_mode) {
323 mbox->controller.txdone_irq = true;
324 } else {
325 mbox->controller.txdone_poll = true;
326 mbox->controller.txpoll_period = MBOX_POLLING_MS;
327 }
328 }
329
330 ret = devm_mbox_controller_register(&pdev->dev, &mbox->controller);
331 if (ret) {
332 dev_err(&pdev->dev, "Register mailbox failed\n");
333 goto err;
334 }
335
336 platform_set_drvdata(pdev, mbox);
337 err:
338 return ret;
339 }
340
341 static const struct of_device_id altera_mbox_match[] = {
342 { .compatible = "altr,mailbox-1.0" },
343 { /* Sentinel */ }
344 };
345
346 MODULE_DEVICE_TABLE(of, altera_mbox_match);
347
348 static struct platform_driver altera_mbox_driver = {
349 .probe = altera_mbox_probe,
350 .driver = {
351 .name = DRIVER_NAME,
352 .of_match_table = altera_mbox_match,
353 },
354 };
355
356 module_platform_driver(altera_mbox_driver);
357
358 MODULE_LICENSE("GPL v2");
359 MODULE_DESCRIPTION("Altera mailbox specific functions");
360 MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
361 MODULE_ALIAS("platform:altera-mailbox");
362