1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Spreadtrum mailbox driver
4 *
5 * Copyright (c) 2020 Spreadtrum Communications Inc.
6 */
7
8 #include <linux/delay.h>
9 #include <linux/err.h>
10 #include <linux/interrupt.h>
11 #include <linux/io.h>
12 #include <linux/mailbox_controller.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/clk.h>
16
17 #define SPRD_MBOX_ID 0x0
18 #define SPRD_MBOX_MSG_LOW 0x4
19 #define SPRD_MBOX_MSG_HIGH 0x8
20 #define SPRD_MBOX_TRIGGER 0xc
21 #define SPRD_MBOX_FIFO_RST 0x10
22 #define SPRD_MBOX_FIFO_STS 0x14
23 #define SPRD_MBOX_IRQ_STS 0x18
24 #define SPRD_MBOX_IRQ_MSK 0x1c
25 #define SPRD_MBOX_LOCK 0x20
26 #define SPRD_MBOX_FIFO_DEPTH 0x24
27
28 /* Bit and mask definiation for inbox's SPRD_MBOX_FIFO_STS register */
29 #define SPRD_INBOX_FIFO_DELIVER_MASK GENMASK(23, 16)
30 #define SPRD_INBOX_FIFO_OVERLOW_MASK GENMASK(15, 8)
31 #define SPRD_INBOX_FIFO_DELIVER_SHIFT 16
32 #define SPRD_INBOX_FIFO_BUSY_MASK GENMASK(7, 0)
33
34 /* Bit and mask definiation for SPRD_MBOX_IRQ_STS register */
35 #define SPRD_MBOX_IRQ_CLR BIT(0)
36
37 /* Bit and mask definiation for outbox's SPRD_MBOX_FIFO_STS register */
38 #define SPRD_OUTBOX_FIFO_FULL BIT(0)
39 #define SPRD_OUTBOX_FIFO_WR_SHIFT 16
40 #define SPRD_OUTBOX_FIFO_RD_SHIFT 24
41 #define SPRD_OUTBOX_FIFO_POS_MASK GENMASK(7, 0)
42
43 /* Bit and mask definiation for inbox's SPRD_MBOX_IRQ_MSK register */
44 #define SPRD_INBOX_FIFO_BLOCK_IRQ BIT(0)
45 #define SPRD_INBOX_FIFO_OVERFLOW_IRQ BIT(1)
46 #define SPRD_INBOX_FIFO_DELIVER_IRQ BIT(2)
47 #define SPRD_INBOX_FIFO_IRQ_MASK GENMASK(2, 0)
48
49 /* Bit and mask definiation for outbox's SPRD_MBOX_IRQ_MSK register */
50 #define SPRD_OUTBOX_FIFO_NOT_EMPTY_IRQ BIT(0)
51 #define SPRD_OUTBOX_FIFO_IRQ_MASK GENMASK(4, 0)
52
53 #define SPRD_MBOX_CHAN_MAX 8
54
55 struct sprd_mbox_priv {
56 struct mbox_controller mbox;
57 struct device *dev;
58 void __iomem *inbox_base;
59 void __iomem *outbox_base;
60 struct clk *clk;
61 u32 outbox_fifo_depth;
62
63 struct mbox_chan chan[SPRD_MBOX_CHAN_MAX];
64 };
65
to_sprd_mbox_priv(struct mbox_controller * mbox)66 static struct sprd_mbox_priv *to_sprd_mbox_priv(struct mbox_controller *mbox)
67 {
68 return container_of(mbox, struct sprd_mbox_priv, mbox);
69 }
70
sprd_mbox_get_fifo_len(struct sprd_mbox_priv * priv,u32 fifo_sts)71 static u32 sprd_mbox_get_fifo_len(struct sprd_mbox_priv *priv, u32 fifo_sts)
72 {
73 u32 wr_pos = (fifo_sts >> SPRD_OUTBOX_FIFO_WR_SHIFT) &
74 SPRD_OUTBOX_FIFO_POS_MASK;
75 u32 rd_pos = (fifo_sts >> SPRD_OUTBOX_FIFO_RD_SHIFT) &
76 SPRD_OUTBOX_FIFO_POS_MASK;
77 u32 fifo_len;
78
79 /*
80 * If the read pointer is equal with write pointer, which means the fifo
81 * is full or empty.
82 */
83 if (wr_pos == rd_pos) {
84 if (fifo_sts & SPRD_OUTBOX_FIFO_FULL)
85 fifo_len = priv->outbox_fifo_depth;
86 else
87 fifo_len = 0;
88 } else if (wr_pos > rd_pos) {
89 fifo_len = wr_pos - rd_pos;
90 } else {
91 fifo_len = priv->outbox_fifo_depth - rd_pos + wr_pos;
92 }
93
94 return fifo_len;
95 }
96
sprd_mbox_outbox_isr(int irq,void * data)97 static irqreturn_t sprd_mbox_outbox_isr(int irq, void *data)
98 {
99 struct sprd_mbox_priv *priv = data;
100 struct mbox_chan *chan;
101 u32 fifo_sts, fifo_len, msg[2];
102 int i, id;
103
104 fifo_sts = readl(priv->outbox_base + SPRD_MBOX_FIFO_STS);
105
106 fifo_len = sprd_mbox_get_fifo_len(priv, fifo_sts);
107 if (!fifo_len) {
108 dev_warn_ratelimited(priv->dev, "spurious outbox interrupt\n");
109 return IRQ_NONE;
110 }
111
112 for (i = 0; i < fifo_len; i++) {
113 msg[0] = readl(priv->outbox_base + SPRD_MBOX_MSG_LOW);
114 msg[1] = readl(priv->outbox_base + SPRD_MBOX_MSG_HIGH);
115 id = readl(priv->outbox_base + SPRD_MBOX_ID);
116
117 chan = &priv->chan[id];
118 mbox_chan_received_data(chan, (void *)msg);
119
120 /* Trigger to update outbox FIFO pointer */
121 writel(0x1, priv->outbox_base + SPRD_MBOX_TRIGGER);
122 }
123
124 /* Clear irq status after reading all message. */
125 writel(SPRD_MBOX_IRQ_CLR, priv->outbox_base + SPRD_MBOX_IRQ_STS);
126
127 return IRQ_HANDLED;
128 }
129
sprd_mbox_inbox_isr(int irq,void * data)130 static irqreturn_t sprd_mbox_inbox_isr(int irq, void *data)
131 {
132 struct sprd_mbox_priv *priv = data;
133 struct mbox_chan *chan;
134 u32 fifo_sts, send_sts, busy, id;
135
136 fifo_sts = readl(priv->inbox_base + SPRD_MBOX_FIFO_STS);
137
138 /* Get the inbox data delivery status */
139 send_sts = (fifo_sts & SPRD_INBOX_FIFO_DELIVER_MASK) >>
140 SPRD_INBOX_FIFO_DELIVER_SHIFT;
141 if (!send_sts) {
142 dev_warn_ratelimited(priv->dev, "spurious inbox interrupt\n");
143 return IRQ_NONE;
144 }
145
146 while (send_sts) {
147 id = __ffs(send_sts);
148 send_sts &= (send_sts - 1);
149
150 chan = &priv->chan[id];
151
152 /*
153 * Check if the message was fetched by remote traget, if yes,
154 * that means the transmission has been completed.
155 */
156 busy = fifo_sts & SPRD_INBOX_FIFO_BUSY_MASK;
157 if (!(busy & BIT(id)))
158 mbox_chan_txdone(chan, 0);
159 }
160
161 /* Clear FIFO delivery and overflow status */
162 writel(fifo_sts &
163 (SPRD_INBOX_FIFO_DELIVER_MASK | SPRD_INBOX_FIFO_OVERLOW_MASK),
164 priv->inbox_base + SPRD_MBOX_FIFO_RST);
165
166 /* Clear irq status */
167 writel(SPRD_MBOX_IRQ_CLR, priv->inbox_base + SPRD_MBOX_IRQ_STS);
168
169 return IRQ_HANDLED;
170 }
171
sprd_mbox_send_data(struct mbox_chan * chan,void * msg)172 static int sprd_mbox_send_data(struct mbox_chan *chan, void *msg)
173 {
174 struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
175 unsigned long id = (unsigned long)chan->con_priv;
176 u32 *data = msg;
177
178 /* Write data into inbox FIFO, and only support 8 bytes every time */
179 writel(data[0], priv->inbox_base + SPRD_MBOX_MSG_LOW);
180 writel(data[1], priv->inbox_base + SPRD_MBOX_MSG_HIGH);
181
182 /* Set target core id */
183 writel(id, priv->inbox_base + SPRD_MBOX_ID);
184
185 /* Trigger remote request */
186 writel(0x1, priv->inbox_base + SPRD_MBOX_TRIGGER);
187
188 return 0;
189 }
190
sprd_mbox_flush(struct mbox_chan * chan,unsigned long timeout)191 static int sprd_mbox_flush(struct mbox_chan *chan, unsigned long timeout)
192 {
193 struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
194 unsigned long id = (unsigned long)chan->con_priv;
195 u32 busy;
196
197 timeout = jiffies + msecs_to_jiffies(timeout);
198
199 while (time_before(jiffies, timeout)) {
200 busy = readl(priv->inbox_base + SPRD_MBOX_FIFO_STS) &
201 SPRD_INBOX_FIFO_BUSY_MASK;
202 if (!(busy & BIT(id))) {
203 mbox_chan_txdone(chan, 0);
204 return 0;
205 }
206
207 udelay(1);
208 }
209
210 return -ETIME;
211 }
212
sprd_mbox_startup(struct mbox_chan * chan)213 static int sprd_mbox_startup(struct mbox_chan *chan)
214 {
215 struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
216 u32 val;
217
218 /* Select outbox FIFO mode and reset the outbox FIFO status */
219 writel(0x0, priv->outbox_base + SPRD_MBOX_FIFO_RST);
220
221 /* Enable inbox FIFO overflow and delivery interrupt */
222 val = readl(priv->inbox_base + SPRD_MBOX_IRQ_MSK);
223 val &= ~(SPRD_INBOX_FIFO_OVERFLOW_IRQ | SPRD_INBOX_FIFO_DELIVER_IRQ);
224 writel(val, priv->inbox_base + SPRD_MBOX_IRQ_MSK);
225
226 /* Enable outbox FIFO not empty interrupt */
227 val = readl(priv->outbox_base + SPRD_MBOX_IRQ_MSK);
228 val &= ~SPRD_OUTBOX_FIFO_NOT_EMPTY_IRQ;
229 writel(val, priv->outbox_base + SPRD_MBOX_IRQ_MSK);
230
231 return 0;
232 }
233
sprd_mbox_shutdown(struct mbox_chan * chan)234 static void sprd_mbox_shutdown(struct mbox_chan *chan)
235 {
236 struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
237
238 /* Disable inbox & outbox interrupt */
239 writel(SPRD_INBOX_FIFO_IRQ_MASK, priv->inbox_base + SPRD_MBOX_IRQ_MSK);
240 writel(SPRD_OUTBOX_FIFO_IRQ_MASK, priv->outbox_base + SPRD_MBOX_IRQ_MSK);
241 }
242
243 static const struct mbox_chan_ops sprd_mbox_ops = {
244 .send_data = sprd_mbox_send_data,
245 .flush = sprd_mbox_flush,
246 .startup = sprd_mbox_startup,
247 .shutdown = sprd_mbox_shutdown,
248 };
249
sprd_mbox_disable(void * data)250 static void sprd_mbox_disable(void *data)
251 {
252 struct sprd_mbox_priv *priv = data;
253
254 clk_disable_unprepare(priv->clk);
255 }
256
sprd_mbox_probe(struct platform_device * pdev)257 static int sprd_mbox_probe(struct platform_device *pdev)
258 {
259 struct device *dev = &pdev->dev;
260 struct sprd_mbox_priv *priv;
261 int ret, inbox_irq, outbox_irq;
262 unsigned long id;
263
264 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
265 if (!priv)
266 return -ENOMEM;
267
268 priv->dev = dev;
269
270 /*
271 * The Spreadtrum mailbox uses an inbox to send messages to the target
272 * core, and uses an outbox to receive messages from other cores.
273 *
274 * Thus the mailbox controller supplies 2 different register addresses
275 * and IRQ numbers for inbox and outbox.
276 */
277 priv->inbox_base = devm_platform_ioremap_resource(pdev, 0);
278 if (IS_ERR(priv->inbox_base))
279 return PTR_ERR(priv->inbox_base);
280
281 priv->outbox_base = devm_platform_ioremap_resource(pdev, 1);
282 if (IS_ERR(priv->outbox_base))
283 return PTR_ERR(priv->outbox_base);
284
285 priv->clk = devm_clk_get(dev, "enable");
286 if (IS_ERR(priv->clk)) {
287 dev_err(dev, "failed to get mailbox clock\n");
288 return PTR_ERR(priv->clk);
289 }
290
291 ret = clk_prepare_enable(priv->clk);
292 if (ret)
293 return ret;
294
295 ret = devm_add_action_or_reset(dev, sprd_mbox_disable, priv);
296 if (ret) {
297 dev_err(dev, "failed to add mailbox disable action\n");
298 return ret;
299 }
300
301 inbox_irq = platform_get_irq(pdev, 0);
302 if (inbox_irq < 0)
303 return inbox_irq;
304
305 ret = devm_request_irq(dev, inbox_irq, sprd_mbox_inbox_isr,
306 IRQF_NO_SUSPEND, dev_name(dev), priv);
307 if (ret) {
308 dev_err(dev, "failed to request inbox IRQ: %d\n", ret);
309 return ret;
310 }
311
312 outbox_irq = platform_get_irq(pdev, 1);
313 if (outbox_irq < 0)
314 return outbox_irq;
315
316 ret = devm_request_irq(dev, outbox_irq, sprd_mbox_outbox_isr,
317 IRQF_NO_SUSPEND, dev_name(dev), priv);
318 if (ret) {
319 dev_err(dev, "failed to request outbox IRQ: %d\n", ret);
320 return ret;
321 }
322
323 /* Get the default outbox FIFO depth */
324 priv->outbox_fifo_depth =
325 readl(priv->outbox_base + SPRD_MBOX_FIFO_DEPTH) + 1;
326 priv->mbox.dev = dev;
327 priv->mbox.chans = &priv->chan[0];
328 priv->mbox.num_chans = SPRD_MBOX_CHAN_MAX;
329 priv->mbox.ops = &sprd_mbox_ops;
330 priv->mbox.txdone_irq = true;
331
332 for (id = 0; id < SPRD_MBOX_CHAN_MAX; id++)
333 priv->chan[id].con_priv = (void *)id;
334
335 ret = devm_mbox_controller_register(dev, &priv->mbox);
336 if (ret) {
337 dev_err(dev, "failed to register mailbox: %d\n", ret);
338 return ret;
339 }
340
341 return 0;
342 }
343
344 static const struct of_device_id sprd_mbox_of_match[] = {
345 { .compatible = "sprd,sc9860-mailbox", },
346 { },
347 };
348 MODULE_DEVICE_TABLE(of, sprd_mbox_of_match);
349
350 static struct platform_driver sprd_mbox_driver = {
351 .driver = {
352 .name = "sprd-mailbox",
353 .of_match_table = sprd_mbox_of_match,
354 },
355 .probe = sprd_mbox_probe,
356 };
357 module_platform_driver(sprd_mbox_driver);
358
359 MODULE_AUTHOR("Baolin Wang <baolin.wang@unisoc.com>");
360 MODULE_DESCRIPTION("Spreadtrum mailbox driver");
361 MODULE_LICENSE("GPL v2");
362
