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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
43enum altera_mbox_msg {
44 MBOX_CMD = 0,
45 MBOX_PTR,
46};
47
48#define MBOX_POLLING_MS 5
49
50struct altera_mbox {
51 bool is_sender;
52 bool intr_mode;
53 int irq;
54 void __iomem *mbox_base;
55 struct device *dev;
56 struct mbox_controller controller;
57
58
59 struct timer_list rxpoll_timer;
60};
61
62static 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
70static 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
78static 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
86static 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
98static 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
110static bool altera_mbox_is_sender(struct altera_mbox *mbox)
111{
112 u32 reg;
113
114
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
121 writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG);
122 return true;
123 }
124 return false;
125}
126
127static 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
141static 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
152static 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
163static 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
171static 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
190static 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;
201 }
202
203 altera_mbox_rx_intmask(mbox, true);
204 return 0;
205 }
206
207polling:
208
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
217static 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
234 if (mbox->intr_mode)
235 altera_mbox_tx_intmask(mbox, true);
236
237
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
244static bool altera_mbox_last_tx_done(struct mbox_chan *chan)
245{
246 struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
247
248
249 return altera_mbox_full(mbox) ? false : true;
250}
251
252static 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
259static 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
275static 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
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
288static 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
296static 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
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
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
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);
351err:
352 return ret;
353}
354
355static 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
367static const struct of_device_id altera_mbox_match[] = {
368 { .compatible = "altr,mailbox-1.0" },
369 { }
370};
371
372MODULE_DEVICE_TABLE(of, altera_mbox_match);
373
374static 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
383module_platform_driver(altera_mbox_driver);
384
385MODULE_LICENSE("GPL v2");
386MODULE_DESCRIPTION("Altera mailbox specific functions");
387MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
388MODULE_ALIAS("platform:altera-mailbox");
389
