1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright 2018 NXP
4 * Author: Dong Aisheng <aisheng.dong@nxp.com>
5 *
6 * Implementation of the SCU IPC functions using MUs (client side).
7 *
8 */
9
10 #include <linux/err.h>
11 #include <linux/firmware/imx/ipc.h>
12 #include <linux/firmware/imx/sci.h>
13 #include <linux/interrupt.h>
14 #include <linux/irq.h>
15 #include <linux/kernel.h>
16 #include <linux/mailbox_client.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/of.h>
20 #include <linux/of_platform.h>
21 #include <linux/platform_device.h>
22
23 #define SCU_MU_CHAN_NUM 8
24 #define MAX_RX_TIMEOUT (msecs_to_jiffies(3000))
25
26 struct imx_sc_chan {
27 struct imx_sc_ipc *sc_ipc;
28
29 struct mbox_client cl;
30 struct mbox_chan *ch;
31 int idx;
32 struct completion tx_done;
33 };
34
35 struct imx_sc_ipc {
36 /* SCU uses 4 Tx and 4 Rx channels */
37 struct imx_sc_chan chans[SCU_MU_CHAN_NUM];
38 struct device *dev;
39 struct mutex lock;
40 struct completion done;
41 bool fast_ipc;
42
43 /* temporarily store the SCU msg */
44 u32 *msg;
45 u8 rx_size;
46 u8 count;
47 };
48
49 /*
50 * This type is used to indicate error response for most functions.
51 */
52 enum imx_sc_error_codes {
53 IMX_SC_ERR_NONE = 0, /* Success */
54 IMX_SC_ERR_VERSION = 1, /* Incompatible API version */
55 IMX_SC_ERR_CONFIG = 2, /* Configuration error */
56 IMX_SC_ERR_PARM = 3, /* Bad parameter */
57 IMX_SC_ERR_NOACCESS = 4, /* Permission error (no access) */
58 IMX_SC_ERR_LOCKED = 5, /* Permission error (locked) */
59 IMX_SC_ERR_UNAVAILABLE = 6, /* Unavailable (out of resources) */
60 IMX_SC_ERR_NOTFOUND = 7, /* Not found */
61 IMX_SC_ERR_NOPOWER = 8, /* No power */
62 IMX_SC_ERR_IPC = 9, /* Generic IPC error */
63 IMX_SC_ERR_BUSY = 10, /* Resource is currently busy/active */
64 IMX_SC_ERR_FAIL = 11, /* General I/O failure */
65 IMX_SC_ERR_LAST
66 };
67
68 static int imx_sc_linux_errmap[IMX_SC_ERR_LAST] = {
69 0, /* IMX_SC_ERR_NONE */
70 -EINVAL, /* IMX_SC_ERR_VERSION */
71 -EINVAL, /* IMX_SC_ERR_CONFIG */
72 -EINVAL, /* IMX_SC_ERR_PARM */
73 -EACCES, /* IMX_SC_ERR_NOACCESS */
74 -EACCES, /* IMX_SC_ERR_LOCKED */
75 -ERANGE, /* IMX_SC_ERR_UNAVAILABLE */
76 -EEXIST, /* IMX_SC_ERR_NOTFOUND */
77 -EPERM, /* IMX_SC_ERR_NOPOWER */
78 -EPIPE, /* IMX_SC_ERR_IPC */
79 -EBUSY, /* IMX_SC_ERR_BUSY */
80 -EIO, /* IMX_SC_ERR_FAIL */
81 };
82
83 static struct imx_sc_ipc *imx_sc_ipc_handle;
84
imx_sc_to_linux_errno(int errno)85 static inline int imx_sc_to_linux_errno(int errno)
86 {
87 if (errno >= IMX_SC_ERR_NONE && errno < IMX_SC_ERR_LAST)
88 return imx_sc_linux_errmap[errno];
89 return -EIO;
90 }
91
92 /*
93 * Get the default handle used by SCU
94 */
imx_scu_get_handle(struct imx_sc_ipc ** ipc)95 int imx_scu_get_handle(struct imx_sc_ipc **ipc)
96 {
97 if (!imx_sc_ipc_handle)
98 return -EPROBE_DEFER;
99
100 *ipc = imx_sc_ipc_handle;
101 return 0;
102 }
103 EXPORT_SYMBOL(imx_scu_get_handle);
104
105 /* Callback called when the word of a message is ack-ed, eg read by SCU */
imx_scu_tx_done(struct mbox_client * cl,void * mssg,int r)106 static void imx_scu_tx_done(struct mbox_client *cl, void *mssg, int r)
107 {
108 struct imx_sc_chan *sc_chan = container_of(cl, struct imx_sc_chan, cl);
109
110 complete(&sc_chan->tx_done);
111 }
112
imx_scu_rx_callback(struct mbox_client * c,void * msg)113 static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
114 {
115 struct imx_sc_chan *sc_chan = container_of(c, struct imx_sc_chan, cl);
116 struct imx_sc_ipc *sc_ipc = sc_chan->sc_ipc;
117 struct imx_sc_rpc_msg *hdr;
118 u32 *data = msg;
119 int i;
120
121 if (!sc_ipc->msg) {
122 dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
123 sc_chan->idx, *data);
124 return;
125 }
126
127 if (sc_ipc->fast_ipc) {
128 hdr = msg;
129 sc_ipc->rx_size = hdr->size;
130 sc_ipc->msg[0] = *data++;
131
132 for (i = 1; i < sc_ipc->rx_size; i++)
133 sc_ipc->msg[i] = *data++;
134
135 complete(&sc_ipc->done);
136
137 return;
138 }
139
140 if (sc_chan->idx == 0) {
141 hdr = msg;
142 sc_ipc->rx_size = hdr->size;
143 dev_dbg(sc_ipc->dev, "msg rx size %u\n", sc_ipc->rx_size);
144 if (sc_ipc->rx_size > 4)
145 dev_warn(sc_ipc->dev, "RPC does not support receiving over 4 words: %u\n",
146 sc_ipc->rx_size);
147 }
148
149 sc_ipc->msg[sc_chan->idx] = *data;
150 sc_ipc->count++;
151
152 dev_dbg(sc_ipc->dev, "mu %u msg %u 0x%x\n", sc_chan->idx,
153 sc_ipc->count, *data);
154
155 if ((sc_ipc->rx_size != 0) && (sc_ipc->count == sc_ipc->rx_size))
156 complete(&sc_ipc->done);
157 }
158
imx_scu_ipc_write(struct imx_sc_ipc * sc_ipc,void * msg)159 static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
160 {
161 struct imx_sc_rpc_msg hdr = *(struct imx_sc_rpc_msg *)msg;
162 struct imx_sc_chan *sc_chan;
163 u32 *data = msg;
164 int ret;
165 int size;
166 int i;
167
168 /* Check size */
169 if (hdr.size > IMX_SC_RPC_MAX_MSG)
170 return -EINVAL;
171
172 dev_dbg(sc_ipc->dev, "RPC SVC %u FUNC %u SIZE %u\n", hdr.svc,
173 hdr.func, hdr.size);
174
175 size = sc_ipc->fast_ipc ? 1 : hdr.size;
176 for (i = 0; i < size; i++) {
177 sc_chan = &sc_ipc->chans[i % 4];
178
179 /*
180 * SCU requires that all messages words are written
181 * sequentially but linux MU driver implements multiple
182 * independent channels for each register so ordering between
183 * different channels must be ensured by SCU API interface.
184 *
185 * Wait for tx_done before every send to ensure that no
186 * queueing happens at the mailbox channel level.
187 */
188 if (!sc_ipc->fast_ipc) {
189 wait_for_completion(&sc_chan->tx_done);
190 reinit_completion(&sc_chan->tx_done);
191 }
192
193 ret = mbox_send_message(sc_chan->ch, &data[i]);
194 if (ret < 0)
195 return ret;
196 }
197
198 return 0;
199 }
200
201 /*
202 * RPC command/response
203 */
imx_scu_call_rpc(struct imx_sc_ipc * sc_ipc,void * msg,bool have_resp)204 int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
205 {
206 uint8_t saved_svc, saved_func;
207 struct imx_sc_rpc_msg *hdr;
208 int ret;
209
210 if (WARN_ON(!sc_ipc || !msg))
211 return -EINVAL;
212
213 mutex_lock(&sc_ipc->lock);
214 reinit_completion(&sc_ipc->done);
215
216 if (have_resp) {
217 sc_ipc->msg = msg;
218 saved_svc = ((struct imx_sc_rpc_msg *)msg)->svc;
219 saved_func = ((struct imx_sc_rpc_msg *)msg)->func;
220 }
221 sc_ipc->count = 0;
222 ret = imx_scu_ipc_write(sc_ipc, msg);
223 if (ret < 0) {
224 dev_err(sc_ipc->dev, "RPC send msg failed: %d\n", ret);
225 goto out;
226 }
227
228 if (have_resp) {
229 if (!wait_for_completion_timeout(&sc_ipc->done,
230 MAX_RX_TIMEOUT)) {
231 dev_err(sc_ipc->dev, "RPC send msg timeout\n");
232 mutex_unlock(&sc_ipc->lock);
233 return -ETIMEDOUT;
234 }
235
236 /* response status is stored in hdr->func field */
237 hdr = msg;
238 ret = hdr->func;
239 /*
240 * Some special SCU firmware APIs do NOT have return value
241 * in hdr->func, but they do have response data, those special
242 * APIs are defined as void function in SCU firmware, so they
243 * should be treated as return success always.
244 */
245 if ((saved_svc == IMX_SC_RPC_SVC_MISC) &&
246 (saved_func == IMX_SC_MISC_FUNC_UNIQUE_ID ||
247 saved_func == IMX_SC_MISC_FUNC_GET_BUTTON_STATUS))
248 ret = 0;
249 }
250
251 out:
252 sc_ipc->msg = NULL;
253 mutex_unlock(&sc_ipc->lock);
254
255 dev_dbg(sc_ipc->dev, "RPC SVC done\n");
256
257 return imx_sc_to_linux_errno(ret);
258 }
259 EXPORT_SYMBOL(imx_scu_call_rpc);
260
imx_scu_probe(struct platform_device * pdev)261 static int imx_scu_probe(struct platform_device *pdev)
262 {
263 struct device *dev = &pdev->dev;
264 struct imx_sc_ipc *sc_ipc;
265 struct imx_sc_chan *sc_chan;
266 struct mbox_client *cl;
267 char *chan_name;
268 struct of_phandle_args args;
269 int num_channel;
270 int ret;
271 int i;
272
273 sc_ipc = devm_kzalloc(dev, sizeof(*sc_ipc), GFP_KERNEL);
274 if (!sc_ipc)
275 return -ENOMEM;
276
277 ret = of_parse_phandle_with_args(pdev->dev.of_node, "mboxes",
278 "#mbox-cells", 0, &args);
279 if (ret)
280 return ret;
281
282 sc_ipc->fast_ipc = of_device_is_compatible(args.np, "fsl,imx8-mu-scu");
283
284 num_channel = sc_ipc->fast_ipc ? 2 : SCU_MU_CHAN_NUM;
285 for (i = 0; i < num_channel; i++) {
286 if (i < num_channel / 2)
287 chan_name = kasprintf(GFP_KERNEL, "tx%d", i);
288 else
289 chan_name = kasprintf(GFP_KERNEL, "rx%d",
290 i - num_channel / 2);
291
292 if (!chan_name)
293 return -ENOMEM;
294
295 sc_chan = &sc_ipc->chans[i];
296 cl = &sc_chan->cl;
297 cl->dev = dev;
298 cl->tx_block = false;
299 cl->knows_txdone = true;
300 cl->rx_callback = imx_scu_rx_callback;
301
302 if (!sc_ipc->fast_ipc) {
303 /* Initial tx_done completion as "done" */
304 cl->tx_done = imx_scu_tx_done;
305 init_completion(&sc_chan->tx_done);
306 complete(&sc_chan->tx_done);
307 }
308
309 sc_chan->sc_ipc = sc_ipc;
310 sc_chan->idx = i % (num_channel / 2);
311 sc_chan->ch = mbox_request_channel_byname(cl, chan_name);
312 if (IS_ERR(sc_chan->ch)) {
313 ret = PTR_ERR(sc_chan->ch);
314 dev_err_probe(dev, ret, "Failed to request mbox chan %s\n",
315 chan_name);
316 kfree(chan_name);
317 return ret;
318 }
319
320 dev_dbg(dev, "request mbox chan %s\n", chan_name);
321 /* chan_name is not used anymore by framework */
322 kfree(chan_name);
323 }
324
325 sc_ipc->dev = dev;
326 mutex_init(&sc_ipc->lock);
327 init_completion(&sc_ipc->done);
328
329 imx_sc_ipc_handle = sc_ipc;
330
331 ret = imx_scu_soc_init(dev);
332 if (ret)
333 dev_warn(dev, "failed to initialize SoC info: %d\n", ret);
334
335 ret = imx_scu_enable_general_irq_channel(dev);
336 if (ret)
337 dev_warn(dev,
338 "failed to enable general irq channel: %d\n", ret);
339
340 dev_info(dev, "NXP i.MX SCU Initialized\n");
341
342 return devm_of_platform_populate(dev);
343 }
344
345 static const struct of_device_id imx_scu_match[] = {
346 { .compatible = "fsl,imx-scu", },
347 { /* Sentinel */ }
348 };
349
350 static struct platform_driver imx_scu_driver = {
351 .driver = {
352 .name = "imx-scu",
353 .of_match_table = imx_scu_match,
354 },
355 .probe = imx_scu_probe,
356 };
357
imx_scu_driver_init(void)358 static int __init imx_scu_driver_init(void)
359 {
360 return platform_driver_register(&imx_scu_driver);
361 }
362 subsys_initcall_sync(imx_scu_driver_init);
363
364 MODULE_AUTHOR("Dong Aisheng <aisheng.dong@nxp.com>");
365 MODULE_DESCRIPTION("IMX SCU firmware protocol driver");
366 MODULE_LICENSE("GPL v2");
367