xref: /openbmc/linux/drivers/firmware/imx/imx-scu.c (revision 5b45759c)
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