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
32enum altera_mbox_msg {
33 MBOX_CMD = 0,
34 MBOX_PTR,
35};
36
37#define MBOX_POLLING_MS 5 /* polling interval 5ms */
38
39struct 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
52static 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
60static 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
68static 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
76static 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
88static 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
100static 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
117static 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, data: (void *)data);
128 }
129}
130
131static 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(chan: mbox->chan);
136
137 mod_timer(timer: &mbox->rxpoll_timer,
138 expires: jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
139}
140
141static 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, enable: false);
147 mbox_chan_txdone(chan, r: 0);
148
149 return IRQ_HANDLED;
150}
151
152static 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
160static 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(irq: mbox->irq, handler: altera_mbox_tx_interrupt, flags: 0,
167 DRIVER_NAME, dev: 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
179static 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(irq: mbox->irq, handler: altera_mbox_rx_interrupt, flags: 0,
186 DRIVER_NAME, dev: 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, enable: true);
193 return 0;
194 }
195
196polling:
197 /* Setup polling timer */
198 mbox->chan = chan;
199 timer_setup(&mbox->rxpoll_timer, altera_mbox_poll_rx, 0);
200 mod_timer(timer: &mbox->rxpoll_timer,
201 expires: jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
202
203 return 0;
204}
205
206static 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, enable: 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
233static 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
241static 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
248static 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
264static 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(timer: &mbox->rxpoll_timer);
274 }
275}
276
277static 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
285static 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(dev: &pdev->dev, size: sizeof(*mbox),
292 GFP_KERNEL);
293 if (!mbox)
294 return -ENOMEM;
295
296 /* Allocated one channel */
297 chans = devm_kzalloc(dev: &pdev->dev, size: sizeof(*chans), GFP_KERNEL);
298 if (!chans)
299 return -ENOMEM;
300
301 mbox->mbox_base = devm_platform_ioremap_resource(pdev, index: 0);
302 if (IS_ERR(ptr: mbox->mbox_base))
303 return PTR_ERR(ptr: 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(dev: &pdev->dev, mbox: &mbox->controller);
331 if (ret) {
332 dev_err(&pdev->dev, "Register mailbox failed\n");
333 goto err;
334 }
335
336 platform_set_drvdata(pdev, data: mbox);
337err:
338 return ret;
339}
340
341static const struct of_device_id altera_mbox_match[] = {
342 { .compatible = "altr,mailbox-1.0" },
343 { /* Sentinel */ }
344};
345
346MODULE_DEVICE_TABLE(of, altera_mbox_match);
347
348static 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
356module_platform_driver(altera_mbox_driver);
357
358MODULE_LICENSE("GPL v2");
359MODULE_DESCRIPTION("Altera mailbox specific functions");
360MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
361MODULE_ALIAS("platform:altera-mailbox");
362

source code of linux/drivers/mailbox/mailbox-altera.c