1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2017-2018 HiSilicon Limited.
3 // Copyright (c) 2017-2018 Linaro Limited.
4
5 #include <linux/bitops.h>
6 #include <linux/delay.h>
7 #include <linux/device.h>
8 #include <linux/err.h>
9 #include <linux/interrupt.h>
10 #include <linux/io.h>
11 #include <linux/iopoll.h>
12 #include <linux/mailbox_controller.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/slab.h>
16
17 #include "mailbox.h"
18
19 #define MBOX_CHAN_MAX 32
20
21 #define MBOX_RX 0x0
22 #define MBOX_TX 0x1
23
24 #define MBOX_BASE(mbox, ch) ((mbox)->base + ((ch) * 0x40))
25 #define MBOX_SRC_REG 0x00
26 #define MBOX_DST_REG 0x04
27 #define MBOX_DCLR_REG 0x08
28 #define MBOX_DSTAT_REG 0x0c
29 #define MBOX_MODE_REG 0x10
30 #define MBOX_IMASK_REG 0x14
31 #define MBOX_ICLR_REG 0x18
32 #define MBOX_SEND_REG 0x1c
33 #define MBOX_DATA_REG 0x20
34
35 #define MBOX_IPC_LOCK_REG 0xa00
36 #define MBOX_IPC_UNLOCK 0x1acce551
37
38 #define MBOX_AUTOMATIC_ACK 1
39
40 #define MBOX_STATE_IDLE BIT(4)
41 #define MBOX_STATE_READY BIT(5)
42 #define MBOX_STATE_ACK BIT(7)
43
44 #define MBOX_MSG_LEN 8
45
46 /**
47 * Hi3660 mailbox channel information
48 *
49 * A channel can be used for TX or RX, it can trigger remote
50 * processor interrupt to notify remote processor and can receive
51 * interrupt if has incoming message.
52 *
53 * @dst_irq: Interrupt vector for remote processor
54 * @ack_irq: Interrupt vector for local processor
55 */
56 struct hi3660_chan_info {
57 unsigned int dst_irq;
58 unsigned int ack_irq;
59 };
60
61 /**
62 * Hi3660 mailbox controller data
63 *
64 * Mailbox controller includes 32 channels and can allocate
65 * channel for message transferring.
66 *
67 * @dev: Device to which it is attached
68 * @base: Base address of the register mapping region
69 * @chan: Representation of channels in mailbox controller
70 * @mchan: Representation of channel info
71 * @controller: Representation of a communication channel controller
72 */
73 struct hi3660_mbox {
74 struct device *dev;
75 void __iomem *base;
76 struct mbox_chan chan[MBOX_CHAN_MAX];
77 struct hi3660_chan_info mchan[MBOX_CHAN_MAX];
78 struct mbox_controller controller;
79 };
80
to_hi3660_mbox(struct mbox_controller * mbox)81 static struct hi3660_mbox *to_hi3660_mbox(struct mbox_controller *mbox)
82 {
83 return container_of(mbox, struct hi3660_mbox, controller);
84 }
85
hi3660_mbox_check_state(struct mbox_chan * chan)86 static int hi3660_mbox_check_state(struct mbox_chan *chan)
87 {
88 unsigned long ch = (unsigned long)chan->con_priv;
89 struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
90 struct hi3660_chan_info *mchan = &mbox->mchan[ch];
91 void __iomem *base = MBOX_BASE(mbox, ch);
92 unsigned long val;
93 unsigned int ret;
94
95 /* Mailbox is ready to use */
96 if (readl(base + MBOX_MODE_REG) & MBOX_STATE_READY)
97 return 0;
98
99 /* Wait for acknowledge from remote */
100 ret = readx_poll_timeout_atomic(readl, base + MBOX_MODE_REG,
101 val, (val & MBOX_STATE_ACK), 1000, 300000);
102 if (ret) {
103 dev_err(mbox->dev, "%s: timeout for receiving ack\n", __func__);
104 return ret;
105 }
106
107 /* clear ack state, mailbox will get back to ready state */
108 writel(BIT(mchan->ack_irq), base + MBOX_ICLR_REG);
109
110 return 0;
111 }
112
hi3660_mbox_unlock(struct mbox_chan * chan)113 static int hi3660_mbox_unlock(struct mbox_chan *chan)
114 {
115 struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
116 unsigned int val, retry = 3;
117
118 do {
119 writel(MBOX_IPC_UNLOCK, mbox->base + MBOX_IPC_LOCK_REG);
120
121 val = readl(mbox->base + MBOX_IPC_LOCK_REG);
122 if (!val)
123 break;
124
125 udelay(10);
126 } while (retry--);
127
128 if (val)
129 dev_err(mbox->dev, "%s: failed to unlock mailbox\n", __func__);
130
131 return (!val) ? 0 : -ETIMEDOUT;
132 }
133
hi3660_mbox_acquire_channel(struct mbox_chan * chan)134 static int hi3660_mbox_acquire_channel(struct mbox_chan *chan)
135 {
136 unsigned long ch = (unsigned long)chan->con_priv;
137 struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
138 struct hi3660_chan_info *mchan = &mbox->mchan[ch];
139 void __iomem *base = MBOX_BASE(mbox, ch);
140 unsigned int val, retry;
141
142 for (retry = 10; retry; retry--) {
143 /* Check if channel is in idle state */
144 if (readl(base + MBOX_MODE_REG) & MBOX_STATE_IDLE) {
145 writel(BIT(mchan->ack_irq), base + MBOX_SRC_REG);
146
147 /* Check ack bit has been set successfully */
148 val = readl(base + MBOX_SRC_REG);
149 if (val & BIT(mchan->ack_irq))
150 break;
151 }
152 }
153
154 if (!retry)
155 dev_err(mbox->dev, "%s: failed to acquire channel\n", __func__);
156
157 return retry ? 0 : -ETIMEDOUT;
158 }
159
hi3660_mbox_startup(struct mbox_chan * chan)160 static int hi3660_mbox_startup(struct mbox_chan *chan)
161 {
162 int ret;
163
164 ret = hi3660_mbox_unlock(chan);
165 if (ret)
166 return ret;
167
168 ret = hi3660_mbox_acquire_channel(chan);
169 if (ret)
170 return ret;
171
172 return 0;
173 }
174
hi3660_mbox_send_data(struct mbox_chan * chan,void * msg)175 static int hi3660_mbox_send_data(struct mbox_chan *chan, void *msg)
176 {
177 unsigned long ch = (unsigned long)chan->con_priv;
178 struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
179 struct hi3660_chan_info *mchan = &mbox->mchan[ch];
180 void __iomem *base = MBOX_BASE(mbox, ch);
181 u32 *buf = msg;
182 unsigned int i;
183 int ret;
184
185 ret = hi3660_mbox_check_state(chan);
186 if (ret)
187 return ret;
188
189 /* Clear mask for destination interrupt */
190 writel_relaxed(~BIT(mchan->dst_irq), base + MBOX_IMASK_REG);
191
192 /* Config destination for interrupt vector */
193 writel_relaxed(BIT(mchan->dst_irq), base + MBOX_DST_REG);
194
195 /* Automatic acknowledge mode */
196 writel_relaxed(MBOX_AUTOMATIC_ACK, base + MBOX_MODE_REG);
197
198 /* Fill message data */
199 for (i = 0; i < MBOX_MSG_LEN; i++)
200 writel_relaxed(buf[i], base + MBOX_DATA_REG + i * 4);
201
202 /* Trigger data transferring */
203 writel(BIT(mchan->ack_irq), base + MBOX_SEND_REG);
204 return 0;
205 }
206
207 static const struct mbox_chan_ops hi3660_mbox_ops = {
208 .startup = hi3660_mbox_startup,
209 .send_data = hi3660_mbox_send_data,
210 };
211
hi3660_mbox_xlate(struct mbox_controller * controller,const struct of_phandle_args * spec)212 static struct mbox_chan *hi3660_mbox_xlate(struct mbox_controller *controller,
213 const struct of_phandle_args *spec)
214 {
215 struct hi3660_mbox *mbox = to_hi3660_mbox(controller);
216 struct hi3660_chan_info *mchan;
217 unsigned int ch = spec->args[0];
218
219 if (ch >= MBOX_CHAN_MAX) {
220 dev_err(mbox->dev, "Invalid channel idx %d\n", ch);
221 return ERR_PTR(-EINVAL);
222 }
223
224 mchan = &mbox->mchan[ch];
225 mchan->dst_irq = spec->args[1];
226 mchan->ack_irq = spec->args[2];
227
228 return &mbox->chan[ch];
229 }
230
231 static const struct of_device_id hi3660_mbox_of_match[] = {
232 { .compatible = "hisilicon,hi3660-mbox", },
233 {},
234 };
235
236 MODULE_DEVICE_TABLE(of, hi3660_mbox_of_match);
237
hi3660_mbox_probe(struct platform_device * pdev)238 static int hi3660_mbox_probe(struct platform_device *pdev)
239 {
240 struct device *dev = &pdev->dev;
241 struct hi3660_mbox *mbox;
242 struct mbox_chan *chan;
243 unsigned long ch;
244 int err;
245
246 mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
247 if (!mbox)
248 return -ENOMEM;
249
250 mbox->base = devm_platform_ioremap_resource(pdev, 0);
251 if (IS_ERR(mbox->base))
252 return PTR_ERR(mbox->base);
253
254 mbox->dev = dev;
255 mbox->controller.dev = dev;
256 mbox->controller.chans = mbox->chan;
257 mbox->controller.num_chans = MBOX_CHAN_MAX;
258 mbox->controller.ops = &hi3660_mbox_ops;
259 mbox->controller.of_xlate = hi3660_mbox_xlate;
260
261 /* Initialize mailbox channel data */
262 chan = mbox->chan;
263 for (ch = 0; ch < MBOX_CHAN_MAX; ch++)
264 chan[ch].con_priv = (void *)ch;
265
266 err = devm_mbox_controller_register(dev, &mbox->controller);
267 if (err) {
268 dev_err(dev, "Failed to register mailbox %d\n", err);
269 return err;
270 }
271
272 platform_set_drvdata(pdev, mbox);
273 dev_info(dev, "Mailbox enabled\n");
274 return 0;
275 }
276
277 static struct platform_driver hi3660_mbox_driver = {
278 .probe = hi3660_mbox_probe,
279 .driver = {
280 .name = "hi3660-mbox",
281 .of_match_table = hi3660_mbox_of_match,
282 },
283 };
284
hi3660_mbox_init(void)285 static int __init hi3660_mbox_init(void)
286 {
287 return platform_driver_register(&hi3660_mbox_driver);
288 }
289 core_initcall(hi3660_mbox_init);
290
hi3660_mbox_exit(void)291 static void __exit hi3660_mbox_exit(void)
292 {
293 platform_driver_unregister(&hi3660_mbox_driver);
294 }
295 module_exit(hi3660_mbox_exit);
296
297 MODULE_LICENSE("GPL");
298 MODULE_DESCRIPTION("Hisilicon Hi3660 Mailbox Controller");
299 MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");
300