1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Amlogic Secure Monitor driver
4  *
5  * Copyright (C) 2016 Endless Mobile, Inc.
6  * Author: Carlo Caione <carlo@endlessm.com>
7  */
8 
9 #define pr_fmt(fmt) "meson-sm: " fmt
10 
11 #include <linux/arm-smccc.h>
12 #include <linux/bug.h>
13 #include <linux/io.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/of_device.h>
17 #include <linux/platform_device.h>
18 #include <linux/printk.h>
19 #include <linux/types.h>
20 #include <linux/sizes.h>
21  #include <linux/slab.h>
22 
23 #include <linux/firmware/meson/meson_sm.h>
24 
25 struct meson_sm_cmd {
26 	unsigned int index;
27 	u32 smc_id;
28 };
29 #define CMD(d, s) { .index = (d), .smc_id = (s), }
30 
31 struct meson_sm_chip {
32 	unsigned int shmem_size;
33 	u32 cmd_shmem_in_base;
34 	u32 cmd_shmem_out_base;
35 	struct meson_sm_cmd cmd[];
36 };
37 
38 static const struct meson_sm_chip gxbb_chip = {
39 	.shmem_size		= SZ_4K,
40 	.cmd_shmem_in_base	= 0x82000020,
41 	.cmd_shmem_out_base	= 0x82000021,
42 	.cmd = {
43 		CMD(SM_EFUSE_READ,	0x82000030),
44 		CMD(SM_EFUSE_WRITE,	0x82000031),
45 		CMD(SM_EFUSE_USER_MAX,	0x82000033),
46 		CMD(SM_GET_CHIP_ID,	0x82000044),
47 		CMD(SM_A1_PWRC_SET,	0x82000093),
48 		CMD(SM_A1_PWRC_GET,	0x82000095),
49 		{ /* sentinel */ },
50 	},
51 };
52 
53 struct meson_sm_firmware {
54 	const struct meson_sm_chip *chip;
55 	void __iomem *sm_shmem_in_base;
56 	void __iomem *sm_shmem_out_base;
57 };
58 
59 static u32 meson_sm_get_cmd(const struct meson_sm_chip *chip,
60 			    unsigned int cmd_index)
61 {
62 	const struct meson_sm_cmd *cmd = chip->cmd;
63 
64 	while (cmd->smc_id && cmd->index != cmd_index)
65 		cmd++;
66 
67 	return cmd->smc_id;
68 }
69 
70 static u32 __meson_sm_call(u32 cmd, u32 arg0, u32 arg1, u32 arg2,
71 			   u32 arg3, u32 arg4)
72 {
73 	struct arm_smccc_res res;
74 
75 	arm_smccc_smc(cmd, arg0, arg1, arg2, arg3, arg4, 0, 0, &res);
76 	return res.a0;
77 }
78 
79 static void __iomem *meson_sm_map_shmem(u32 cmd_shmem, unsigned int size)
80 {
81 	u32 sm_phy_base;
82 
83 	sm_phy_base = __meson_sm_call(cmd_shmem, 0, 0, 0, 0, 0);
84 	if (!sm_phy_base)
85 		return NULL;
86 
87 	return ioremap_cache(sm_phy_base, size);
88 }
89 
90 /**
91  * meson_sm_call - generic SMC32 call to the secure-monitor
92  *
93  * @fw:		Pointer to secure-monitor firmware
94  * @cmd_index:	Index of the SMC32 function ID
95  * @ret:	Returned value
96  * @arg0:	SMC32 Argument 0
97  * @arg1:	SMC32 Argument 1
98  * @arg2:	SMC32 Argument 2
99  * @arg3:	SMC32 Argument 3
100  * @arg4:	SMC32 Argument 4
101  *
102  * Return:	0 on success, a negative value on error
103  */
104 int meson_sm_call(struct meson_sm_firmware *fw, unsigned int cmd_index,
105 		  u32 *ret, u32 arg0, u32 arg1, u32 arg2, u32 arg3, u32 arg4)
106 {
107 	u32 cmd, lret;
108 
109 	if (!fw->chip)
110 		return -ENOENT;
111 
112 	cmd = meson_sm_get_cmd(fw->chip, cmd_index);
113 	if (!cmd)
114 		return -EINVAL;
115 
116 	lret = __meson_sm_call(cmd, arg0, arg1, arg2, arg3, arg4);
117 
118 	if (ret)
119 		*ret = lret;
120 
121 	return 0;
122 }
123 EXPORT_SYMBOL(meson_sm_call);
124 
125 /**
126  * meson_sm_call_read - retrieve data from secure-monitor
127  *
128  * @fw:		Pointer to secure-monitor firmware
129  * @buffer:	Buffer to store the retrieved data
130  * @bsize:	Size of the buffer
131  * @cmd_index:	Index of the SMC32 function ID
132  * @arg0:	SMC32 Argument 0
133  * @arg1:	SMC32 Argument 1
134  * @arg2:	SMC32 Argument 2
135  * @arg3:	SMC32 Argument 3
136  * @arg4:	SMC32 Argument 4
137  *
138  * Return:	size of read data on success, a negative value on error
139  *		When 0 is returned there is no guarantee about the amount of
140  *		data read and bsize bytes are copied in buffer.
141  */
142 int meson_sm_call_read(struct meson_sm_firmware *fw, void *buffer,
143 		       unsigned int bsize, unsigned int cmd_index, u32 arg0,
144 		       u32 arg1, u32 arg2, u32 arg3, u32 arg4)
145 {
146 	u32 size;
147 	int ret;
148 
149 	if (!fw->chip)
150 		return -ENOENT;
151 
152 	if (!fw->chip->cmd_shmem_out_base)
153 		return -EINVAL;
154 
155 	if (bsize > fw->chip->shmem_size)
156 		return -EINVAL;
157 
158 	if (meson_sm_call(fw, cmd_index, &size, arg0, arg1, arg2, arg3, arg4) < 0)
159 		return -EINVAL;
160 
161 	if (size > bsize)
162 		return -EINVAL;
163 
164 	ret = size;
165 
166 	if (!size)
167 		size = bsize;
168 
169 	if (buffer)
170 		memcpy(buffer, fw->sm_shmem_out_base, size);
171 
172 	return ret;
173 }
174 EXPORT_SYMBOL(meson_sm_call_read);
175 
176 /**
177  * meson_sm_call_write - send data to secure-monitor
178  *
179  * @fw:		Pointer to secure-monitor firmware
180  * @buffer:	Buffer containing data to send
181  * @size:	Size of the data to send
182  * @cmd_index:	Index of the SMC32 function ID
183  * @arg0:	SMC32 Argument 0
184  * @arg1:	SMC32 Argument 1
185  * @arg2:	SMC32 Argument 2
186  * @arg3:	SMC32 Argument 3
187  * @arg4:	SMC32 Argument 4
188  *
189  * Return:	size of sent data on success, a negative value on error
190  */
191 int meson_sm_call_write(struct meson_sm_firmware *fw, void *buffer,
192 			unsigned int size, unsigned int cmd_index, u32 arg0,
193 			u32 arg1, u32 arg2, u32 arg3, u32 arg4)
194 {
195 	u32 written;
196 
197 	if (!fw->chip)
198 		return -ENOENT;
199 
200 	if (size > fw->chip->shmem_size)
201 		return -EINVAL;
202 
203 	if (!fw->chip->cmd_shmem_in_base)
204 		return -EINVAL;
205 
206 	memcpy(fw->sm_shmem_in_base, buffer, size);
207 
208 	if (meson_sm_call(fw, cmd_index, &written, arg0, arg1, arg2, arg3, arg4) < 0)
209 		return -EINVAL;
210 
211 	if (!written)
212 		return -EINVAL;
213 
214 	return written;
215 }
216 EXPORT_SYMBOL(meson_sm_call_write);
217 
218 /**
219  * meson_sm_get - get pointer to meson_sm_firmware structure.
220  *
221  * @sm_node:		Pointer to the secure-monitor Device Tree node.
222  *
223  * Return:		NULL is the secure-monitor device is not ready.
224  */
225 struct meson_sm_firmware *meson_sm_get(struct device_node *sm_node)
226 {
227 	struct platform_device *pdev = of_find_device_by_node(sm_node);
228 
229 	if (!pdev)
230 		return NULL;
231 
232 	return platform_get_drvdata(pdev);
233 }
234 EXPORT_SYMBOL_GPL(meson_sm_get);
235 
236 #define SM_CHIP_ID_LENGTH	119
237 #define SM_CHIP_ID_OFFSET	4
238 #define SM_CHIP_ID_SIZE		12
239 
240 static ssize_t serial_show(struct device *dev, struct device_attribute *attr,
241 			 char *buf)
242 {
243 	struct platform_device *pdev = to_platform_device(dev);
244 	struct meson_sm_firmware *fw;
245 	uint8_t *id_buf;
246 	int ret;
247 
248 	fw = platform_get_drvdata(pdev);
249 
250 	id_buf = kmalloc(SM_CHIP_ID_LENGTH, GFP_KERNEL);
251 	if (!id_buf)
252 		return -ENOMEM;
253 
254 	ret = meson_sm_call_read(fw, id_buf, SM_CHIP_ID_LENGTH, SM_GET_CHIP_ID,
255 				 0, 0, 0, 0, 0);
256 	if (ret < 0) {
257 		kfree(id_buf);
258 		return ret;
259 	}
260 
261 	ret = sprintf(buf, "%12phN\n", &id_buf[SM_CHIP_ID_OFFSET]);
262 
263 	kfree(id_buf);
264 
265 	return ret;
266 }
267 
268 static DEVICE_ATTR_RO(serial);
269 
270 static struct attribute *meson_sm_sysfs_attributes[] = {
271 	&dev_attr_serial.attr,
272 	NULL,
273 };
274 
275 static const struct attribute_group meson_sm_sysfs_attr_group = {
276 	.attrs = meson_sm_sysfs_attributes,
277 };
278 
279 static const struct of_device_id meson_sm_ids[] = {
280 	{ .compatible = "amlogic,meson-gxbb-sm", .data = &gxbb_chip },
281 	{ /* sentinel */ },
282 };
283 
284 static int __init meson_sm_probe(struct platform_device *pdev)
285 {
286 	struct device *dev = &pdev->dev;
287 	const struct meson_sm_chip *chip;
288 	struct meson_sm_firmware *fw;
289 
290 	fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
291 	if (!fw)
292 		return -ENOMEM;
293 
294 	chip = of_match_device(meson_sm_ids, dev)->data;
295 
296 	if (chip->cmd_shmem_in_base) {
297 		fw->sm_shmem_in_base = meson_sm_map_shmem(chip->cmd_shmem_in_base,
298 							  chip->shmem_size);
299 		if (WARN_ON(!fw->sm_shmem_in_base))
300 			goto out;
301 	}
302 
303 	if (chip->cmd_shmem_out_base) {
304 		fw->sm_shmem_out_base = meson_sm_map_shmem(chip->cmd_shmem_out_base,
305 							   chip->shmem_size);
306 		if (WARN_ON(!fw->sm_shmem_out_base))
307 			goto out_in_base;
308 	}
309 
310 	fw->chip = chip;
311 
312 	platform_set_drvdata(pdev, fw);
313 
314 	pr_info("secure-monitor enabled\n");
315 
316 	if (sysfs_create_group(&pdev->dev.kobj, &meson_sm_sysfs_attr_group))
317 		goto out_in_base;
318 
319 	return 0;
320 
321 out_in_base:
322 	iounmap(fw->sm_shmem_in_base);
323 out:
324 	return -EINVAL;
325 }
326 
327 static struct platform_driver meson_sm_driver = {
328 	.driver = {
329 		.name = "meson-sm",
330 		.of_match_table = of_match_ptr(meson_sm_ids),
331 	},
332 };
333 module_platform_driver_probe(meson_sm_driver, meson_sm_probe);
334 MODULE_LICENSE("GPL v2");
335