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