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