1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Hisilicon's Hi6220 mailbox driver
4  *
5  * Copyright (c) 2015 HiSilicon Limited.
6  * Copyright (c) 2015 Linaro Limited.
7  *
8  * Author: Leo Yan <leo.yan@linaro.org>
9  */
10 
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/interrupt.h>
14 #include <linux/io.h>
15 #include <linux/kfifo.h>
16 #include <linux/mailbox_controller.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/slab.h>
21 
22 #define MBOX_CHAN_MAX			32
23 
24 #define MBOX_TX				0x1
25 
26 /* Mailbox message length: 8 words */
27 #define MBOX_MSG_LEN			8
28 
29 /* Mailbox Registers */
30 #define MBOX_OFF(m)			(0x40 * (m))
31 #define MBOX_MODE_REG(m)		(MBOX_OFF(m) + 0x0)
32 #define MBOX_DATA_REG(m)		(MBOX_OFF(m) + 0x4)
33 
34 #define MBOX_STATE_MASK			(0xF << 4)
35 #define MBOX_STATE_IDLE			(0x1 << 4)
36 #define MBOX_STATE_TX			(0x2 << 4)
37 #define MBOX_STATE_RX			(0x4 << 4)
38 #define MBOX_STATE_ACK			(0x8 << 4)
39 #define MBOX_ACK_CONFIG_MASK		(0x1 << 0)
40 #define MBOX_ACK_AUTOMATIC		(0x1 << 0)
41 #define MBOX_ACK_IRQ			(0x0 << 0)
42 
43 /* IPC registers */
44 #define ACK_INT_RAW_REG(i)		((i) + 0x400)
45 #define ACK_INT_MSK_REG(i)		((i) + 0x404)
46 #define ACK_INT_STAT_REG(i)		((i) + 0x408)
47 #define ACK_INT_CLR_REG(i)		((i) + 0x40c)
48 #define ACK_INT_ENA_REG(i)		((i) + 0x500)
49 #define ACK_INT_DIS_REG(i)		((i) + 0x504)
50 #define DST_INT_RAW_REG(i)		((i) + 0x420)
51 
52 
53 struct hi6220_mbox_chan {
54 
55 	/*
56 	 * Description for channel's hardware info:
57 	 *  - direction: tx or rx
58 	 *  - dst irq: peer core's irq number
59 	 *  - ack irq: local irq number
60 	 *  - slot number
61 	 */
62 	unsigned int dir, dst_irq, ack_irq;
63 	unsigned int slot;
64 
65 	struct hi6220_mbox *parent;
66 };
67 
68 struct hi6220_mbox {
69 	struct device *dev;
70 
71 	int irq;
72 
73 	/* flag of enabling tx's irq mode */
74 	bool tx_irq_mode;
75 
76 	/* region for ipc event */
77 	void __iomem *ipc;
78 
79 	/* region for mailbox */
80 	void __iomem *base;
81 
82 	unsigned int chan_num;
83 	struct hi6220_mbox_chan *mchan;
84 
85 	void *irq_map_chan[MBOX_CHAN_MAX];
86 	struct mbox_chan *chan;
87 	struct mbox_controller controller;
88 };
89 
90 static void mbox_set_state(struct hi6220_mbox *mbox,
91 			   unsigned int slot, u32 val)
92 {
93 	u32 status;
94 
95 	status = readl(mbox->base + MBOX_MODE_REG(slot));
96 	status = (status & ~MBOX_STATE_MASK) | val;
97 	writel(status, mbox->base + MBOX_MODE_REG(slot));
98 }
99 
100 static void mbox_set_mode(struct hi6220_mbox *mbox,
101 			  unsigned int slot, u32 val)
102 {
103 	u32 mode;
104 
105 	mode = readl(mbox->base + MBOX_MODE_REG(slot));
106 	mode = (mode & ~MBOX_ACK_CONFIG_MASK) | val;
107 	writel(mode, mbox->base + MBOX_MODE_REG(slot));
108 }
109 
110 static bool hi6220_mbox_last_tx_done(struct mbox_chan *chan)
111 {
112 	struct hi6220_mbox_chan *mchan = chan->con_priv;
113 	struct hi6220_mbox *mbox = mchan->parent;
114 	u32 state;
115 
116 	/* Only set idle state for polling mode */
117 	BUG_ON(mbox->tx_irq_mode);
118 
119 	state = readl(mbox->base + MBOX_MODE_REG(mchan->slot));
120 	return ((state & MBOX_STATE_MASK) == MBOX_STATE_IDLE);
121 }
122 
123 static int hi6220_mbox_send_data(struct mbox_chan *chan, void *msg)
124 {
125 	struct hi6220_mbox_chan *mchan = chan->con_priv;
126 	struct hi6220_mbox *mbox = mchan->parent;
127 	unsigned int slot = mchan->slot;
128 	u32 *buf = msg;
129 	int i;
130 
131 	/* indicate as a TX channel */
132 	mchan->dir = MBOX_TX;
133 
134 	mbox_set_state(mbox, slot, MBOX_STATE_TX);
135 
136 	if (mbox->tx_irq_mode)
137 		mbox_set_mode(mbox, slot, MBOX_ACK_IRQ);
138 	else
139 		mbox_set_mode(mbox, slot, MBOX_ACK_AUTOMATIC);
140 
141 	for (i = 0; i < MBOX_MSG_LEN; i++)
142 		writel(buf[i], mbox->base + MBOX_DATA_REG(slot) + i * 4);
143 
144 	/* trigger remote request */
145 	writel(BIT(mchan->dst_irq), DST_INT_RAW_REG(mbox->ipc));
146 	return 0;
147 }
148 
149 static irqreturn_t hi6220_mbox_interrupt(int irq, void *p)
150 {
151 	struct hi6220_mbox *mbox = p;
152 	struct hi6220_mbox_chan *mchan;
153 	struct mbox_chan *chan;
154 	unsigned int state, intr_bit, i;
155 	u32 msg[MBOX_MSG_LEN];
156 
157 	state = readl(ACK_INT_STAT_REG(mbox->ipc));
158 	if (!state) {
159 		dev_warn(mbox->dev, "%s: spurious interrupt\n",
160 			 __func__);
161 		return IRQ_HANDLED;
162 	}
163 
164 	while (state) {
165 		intr_bit = __ffs(state);
166 		state &= (state - 1);
167 
168 		chan = mbox->irq_map_chan[intr_bit];
169 		if (!chan) {
170 			dev_warn(mbox->dev, "%s: unexpected irq vector %d\n",
171 				 __func__, intr_bit);
172 			continue;
173 		}
174 
175 		mchan = chan->con_priv;
176 		if (mchan->dir == MBOX_TX)
177 			mbox_chan_txdone(chan, 0);
178 		else {
179 			for (i = 0; i < MBOX_MSG_LEN; i++)
180 				msg[i] = readl(mbox->base +
181 					MBOX_DATA_REG(mchan->slot) + i * 4);
182 
183 			mbox_chan_received_data(chan, (void *)msg);
184 		}
185 
186 		/* clear IRQ source */
187 		writel(BIT(mchan->ack_irq), ACK_INT_CLR_REG(mbox->ipc));
188 		mbox_set_state(mbox, mchan->slot, MBOX_STATE_IDLE);
189 	}
190 
191 	return IRQ_HANDLED;
192 }
193 
194 static int hi6220_mbox_startup(struct mbox_chan *chan)
195 {
196 	struct hi6220_mbox_chan *mchan = chan->con_priv;
197 	struct hi6220_mbox *mbox = mchan->parent;
198 
199 	mchan->dir = 0;
200 
201 	/* enable interrupt */
202 	writel(BIT(mchan->ack_irq), ACK_INT_ENA_REG(mbox->ipc));
203 	return 0;
204 }
205 
206 static void hi6220_mbox_shutdown(struct mbox_chan *chan)
207 {
208 	struct hi6220_mbox_chan *mchan = chan->con_priv;
209 	struct hi6220_mbox *mbox = mchan->parent;
210 
211 	/* disable interrupt */
212 	writel(BIT(mchan->ack_irq), ACK_INT_DIS_REG(mbox->ipc));
213 	mbox->irq_map_chan[mchan->ack_irq] = NULL;
214 }
215 
216 static const struct mbox_chan_ops hi6220_mbox_ops = {
217 	.send_data    = hi6220_mbox_send_data,
218 	.startup      = hi6220_mbox_startup,
219 	.shutdown     = hi6220_mbox_shutdown,
220 	.last_tx_done = hi6220_mbox_last_tx_done,
221 };
222 
223 static struct mbox_chan *hi6220_mbox_xlate(struct mbox_controller *controller,
224 					   const struct of_phandle_args *spec)
225 {
226 	struct hi6220_mbox *mbox = dev_get_drvdata(controller->dev);
227 	struct hi6220_mbox_chan *mchan;
228 	struct mbox_chan *chan;
229 	unsigned int i = spec->args[0];
230 	unsigned int dst_irq = spec->args[1];
231 	unsigned int ack_irq = spec->args[2];
232 
233 	/* Bounds checking */
234 	if (i >= mbox->chan_num || dst_irq >= mbox->chan_num ||
235 	    ack_irq >= mbox->chan_num) {
236 		dev_err(mbox->dev,
237 			"Invalid channel idx %d dst_irq %d ack_irq %d\n",
238 			i, dst_irq, ack_irq);
239 		return ERR_PTR(-EINVAL);
240 	}
241 
242 	/* Is requested channel free? */
243 	chan = &mbox->chan[i];
244 	if (mbox->irq_map_chan[ack_irq] == (void *)chan) {
245 		dev_err(mbox->dev, "Channel in use\n");
246 		return ERR_PTR(-EBUSY);
247 	}
248 
249 	mchan = chan->con_priv;
250 	mchan->dst_irq = dst_irq;
251 	mchan->ack_irq = ack_irq;
252 
253 	mbox->irq_map_chan[ack_irq] = (void *)chan;
254 	return chan;
255 }
256 
257 static const struct of_device_id hi6220_mbox_of_match[] = {
258 	{ .compatible = "hisilicon,hi6220-mbox", },
259 	{},
260 };
261 MODULE_DEVICE_TABLE(of, hi6220_mbox_of_match);
262 
263 static int hi6220_mbox_probe(struct platform_device *pdev)
264 {
265 	struct device_node *node = pdev->dev.of_node;
266 	struct device *dev = &pdev->dev;
267 	struct hi6220_mbox *mbox;
268 	int i, err;
269 
270 	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
271 	if (!mbox)
272 		return -ENOMEM;
273 
274 	mbox->dev = dev;
275 	mbox->chan_num = MBOX_CHAN_MAX;
276 	mbox->mchan = devm_kcalloc(dev,
277 		mbox->chan_num, sizeof(*mbox->mchan), GFP_KERNEL);
278 	if (!mbox->mchan)
279 		return -ENOMEM;
280 
281 	mbox->chan = devm_kcalloc(dev,
282 		mbox->chan_num, sizeof(*mbox->chan), GFP_KERNEL);
283 	if (!mbox->chan)
284 		return -ENOMEM;
285 
286 	mbox->irq = platform_get_irq(pdev, 0);
287 	if (mbox->irq < 0)
288 		return mbox->irq;
289 
290 	mbox->ipc = devm_platform_ioremap_resource(pdev, 0);
291 	if (IS_ERR(mbox->ipc)) {
292 		dev_err(dev, "ioremap ipc failed\n");
293 		return PTR_ERR(mbox->ipc);
294 	}
295 
296 	mbox->base = devm_platform_ioremap_resource(pdev, 1);
297 	if (IS_ERR(mbox->base)) {
298 		dev_err(dev, "ioremap buffer failed\n");
299 		return PTR_ERR(mbox->base);
300 	}
301 
302 	err = devm_request_irq(dev, mbox->irq, hi6220_mbox_interrupt, 0,
303 			dev_name(dev), mbox);
304 	if (err) {
305 		dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n",
306 			err);
307 		return -ENODEV;
308 	}
309 
310 	mbox->controller.dev = dev;
311 	mbox->controller.chans = &mbox->chan[0];
312 	mbox->controller.num_chans = mbox->chan_num;
313 	mbox->controller.ops = &hi6220_mbox_ops;
314 	mbox->controller.of_xlate = hi6220_mbox_xlate;
315 
316 	for (i = 0; i < mbox->chan_num; i++) {
317 		mbox->chan[i].con_priv = &mbox->mchan[i];
318 		mbox->irq_map_chan[i] = NULL;
319 
320 		mbox->mchan[i].parent = mbox;
321 		mbox->mchan[i].slot   = i;
322 	}
323 
324 	/* mask and clear all interrupt vectors */
325 	writel(0x0,  ACK_INT_MSK_REG(mbox->ipc));
326 	writel(~0x0, ACK_INT_CLR_REG(mbox->ipc));
327 
328 	/* use interrupt for tx's ack */
329 	mbox->tx_irq_mode = !of_property_read_bool(node, "hi6220,mbox-tx-noirq");
330 
331 	if (mbox->tx_irq_mode)
332 		mbox->controller.txdone_irq = true;
333 	else {
334 		mbox->controller.txdone_poll = true;
335 		mbox->controller.txpoll_period = 5;
336 	}
337 
338 	err = devm_mbox_controller_register(dev, &mbox->controller);
339 	if (err) {
340 		dev_err(dev, "Failed to register mailbox %d\n", err);
341 		return err;
342 	}
343 
344 	platform_set_drvdata(pdev, mbox);
345 	dev_info(dev, "Mailbox enabled\n");
346 	return 0;
347 }
348 
349 static struct platform_driver hi6220_mbox_driver = {
350 	.driver = {
351 		.name = "hi6220-mbox",
352 		.of_match_table = hi6220_mbox_of_match,
353 	},
354 	.probe	= hi6220_mbox_probe,
355 };
356 
357 static int __init hi6220_mbox_init(void)
358 {
359 	return platform_driver_register(&hi6220_mbox_driver);
360 }
361 core_initcall(hi6220_mbox_init);
362 
363 static void __exit hi6220_mbox_exit(void)
364 {
365 	platform_driver_unregister(&hi6220_mbox_driver);
366 }
367 module_exit(hi6220_mbox_exit);
368 
369 MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");
370 MODULE_DESCRIPTION("Hi6220 mailbox driver");
371 MODULE_LICENSE("GPL v2");
372