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1 | /* Copyright (c) 2010, Code Aurora Forum. All rights reserved. |
2 | * | |
3 | * This program is free software; you can redistribute it and/or modify | |
4 | * it under the terms of the GNU General Public License version 2 and | |
5 | * only version 2 as published by the Free Software Foundation. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, | |
8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | * GNU General Public License for more details. | |
11 | * | |
12 | * You should have received a copy of the GNU General Public License | |
13 | * along with this program; if not, write to the Free Software | |
14 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
15 | * 02110-1301, USA. | |
16 | */ | |
17 | ||
18 | #include <linux/slab.h> | |
19 | #include <linux/io.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/mutex.h> | |
22 | #include <linux/errno.h> | |
23 | #include <linux/err.h> | |
24 | ||
25 | #include <asm/cacheflush.h> | |
26 | ||
27 | #include "scm.h" | |
28 | ||
29 | /* Cache line size for msm8x60 */ | |
30 | #define CACHELINESIZE 32 | |
31 | ||
32 | #define SCM_ENOMEM -5 | |
33 | #define SCM_EOPNOTSUPP -4 | |
34 | #define SCM_EINVAL_ADDR -3 | |
35 | #define SCM_EINVAL_ARG -2 | |
36 | #define SCM_ERROR -1 | |
37 | #define SCM_INTERRUPTED 1 | |
38 | ||
39 | static DEFINE_MUTEX(scm_lock); | |
40 | ||
41 | /** | |
42 | * struct scm_command - one SCM command buffer | |
43 | * @len: total available memory for command and response | |
44 | * @buf_offset: start of command buffer | |
45 | * @resp_hdr_offset: start of response buffer | |
46 | * @id: command to be executed | |
47 | * @buf: buffer returned from scm_get_command_buffer() | |
48 | * | |
25985edc | 49 | * An SCM command is laid out in memory as follows: |
2a1eb58a SB |
50 | * |
51 | * ------------------- <--- struct scm_command | |
52 | * | command header | | |
53 | * ------------------- <--- scm_get_command_buffer() | |
54 | * | command buffer | | |
55 | * ------------------- <--- struct scm_response and | |
56 | * | response header | scm_command_to_response() | |
57 | * ------------------- <--- scm_get_response_buffer() | |
58 | * | response buffer | | |
59 | * ------------------- | |
60 | * | |
61 | * There can be arbitrary padding between the headers and buffers so | |
62 | * you should always use the appropriate scm_get_*_buffer() routines | |
63 | * to access the buffers in a safe manner. | |
64 | */ | |
65 | struct scm_command { | |
66 | u32 len; | |
67 | u32 buf_offset; | |
68 | u32 resp_hdr_offset; | |
69 | u32 id; | |
70 | u32 buf[0]; | |
71 | }; | |
72 | ||
73 | /** | |
74 | * struct scm_response - one SCM response buffer | |
75 | * @len: total available memory for response | |
76 | * @buf_offset: start of response data relative to start of scm_response | |
77 | * @is_complete: indicates if the command has finished processing | |
78 | */ | |
79 | struct scm_response { | |
80 | u32 len; | |
81 | u32 buf_offset; | |
82 | u32 is_complete; | |
83 | }; | |
84 | ||
85 | /** | |
86 | * alloc_scm_command() - Allocate an SCM command | |
87 | * @cmd_size: size of the command buffer | |
88 | * @resp_size: size of the response buffer | |
89 | * | |
90 | * Allocate an SCM command, including enough room for the command | |
91 | * and response headers as well as the command and response buffers. | |
92 | * | |
93 | * Returns a valid &scm_command on success or %NULL if the allocation fails. | |
94 | */ | |
95 | static struct scm_command *alloc_scm_command(size_t cmd_size, size_t resp_size) | |
96 | { | |
97 | struct scm_command *cmd; | |
98 | size_t len = sizeof(*cmd) + sizeof(struct scm_response) + cmd_size + | |
99 | resp_size; | |
100 | ||
101 | cmd = kzalloc(PAGE_ALIGN(len), GFP_KERNEL); | |
102 | if (cmd) { | |
103 | cmd->len = len; | |
104 | cmd->buf_offset = offsetof(struct scm_command, buf); | |
105 | cmd->resp_hdr_offset = cmd->buf_offset + cmd_size; | |
106 | } | |
107 | return cmd; | |
108 | } | |
109 | ||
110 | /** | |
111 | * free_scm_command() - Free an SCM command | |
112 | * @cmd: command to free | |
113 | * | |
114 | * Free an SCM command. | |
115 | */ | |
116 | static inline void free_scm_command(struct scm_command *cmd) | |
117 | { | |
118 | kfree(cmd); | |
119 | } | |
120 | ||
121 | /** | |
122 | * scm_command_to_response() - Get a pointer to a scm_response | |
123 | * @cmd: command | |
124 | * | |
125 | * Returns a pointer to a response for a command. | |
126 | */ | |
127 | static inline struct scm_response *scm_command_to_response( | |
128 | const struct scm_command *cmd) | |
129 | { | |
130 | return (void *)cmd + cmd->resp_hdr_offset; | |
131 | } | |
132 | ||
133 | /** | |
134 | * scm_get_command_buffer() - Get a pointer to a command buffer | |
135 | * @cmd: command | |
136 | * | |
137 | * Returns a pointer to the command buffer of a command. | |
138 | */ | |
139 | static inline void *scm_get_command_buffer(const struct scm_command *cmd) | |
140 | { | |
141 | return (void *)cmd->buf; | |
142 | } | |
143 | ||
144 | /** | |
145 | * scm_get_response_buffer() - Get a pointer to a response buffer | |
146 | * @rsp: response | |
147 | * | |
148 | * Returns a pointer to a response buffer of a response. | |
149 | */ | |
150 | static inline void *scm_get_response_buffer(const struct scm_response *rsp) | |
151 | { | |
152 | return (void *)rsp + rsp->buf_offset; | |
153 | } | |
154 | ||
155 | static int scm_remap_error(int err) | |
156 | { | |
157 | switch (err) { | |
158 | case SCM_ERROR: | |
159 | return -EIO; | |
160 | case SCM_EINVAL_ADDR: | |
161 | case SCM_EINVAL_ARG: | |
162 | return -EINVAL; | |
163 | case SCM_EOPNOTSUPP: | |
164 | return -EOPNOTSUPP; | |
165 | case SCM_ENOMEM: | |
166 | return -ENOMEM; | |
167 | } | |
168 | return -EINVAL; | |
169 | } | |
170 | ||
171 | static u32 smc(u32 cmd_addr) | |
172 | { | |
173 | int context_id; | |
174 | register u32 r0 asm("r0") = 1; | |
175 | register u32 r1 asm("r1") = (u32)&context_id; | |
176 | register u32 r2 asm("r2") = cmd_addr; | |
8e76a809 SB |
177 | do { |
178 | asm volatile( | |
179 | __asmeq("%0", "r0") | |
180 | __asmeq("%1", "r0") | |
181 | __asmeq("%2", "r1") | |
182 | __asmeq("%3", "r2") | |
183 | "smc #0 @ switch to secure world\n" | |
184 | : "=r" (r0) | |
185 | : "r" (r0), "r" (r1), "r" (r2) | |
186 | : "r3"); | |
187 | } while (r0 == SCM_INTERRUPTED); | |
188 | ||
2a1eb58a SB |
189 | return r0; |
190 | } | |
191 | ||
192 | static int __scm_call(const struct scm_command *cmd) | |
193 | { | |
194 | int ret; | |
195 | u32 cmd_addr = virt_to_phys(cmd); | |
196 | ||
197 | /* | |
198 | * Flush the entire cache here so callers don't have to remember | |
199 | * to flush the cache when passing physical addresses to the secure | |
200 | * side in the buffer. | |
201 | */ | |
202 | flush_cache_all(); | |
8e76a809 SB |
203 | ret = smc(cmd_addr); |
204 | if (ret < 0) | |
205 | ret = scm_remap_error(ret); | |
2a1eb58a SB |
206 | |
207 | return ret; | |
208 | } | |
209 | ||
210 | /** | |
211 | * scm_call() - Send an SCM command | |
212 | * @svc_id: service identifier | |
213 | * @cmd_id: command identifier | |
214 | * @cmd_buf: command buffer | |
215 | * @cmd_len: length of the command buffer | |
216 | * @resp_buf: response buffer | |
217 | * @resp_len: length of the response buffer | |
218 | * | |
219 | * Sends a command to the SCM and waits for the command to finish processing. | |
220 | */ | |
221 | int scm_call(u32 svc_id, u32 cmd_id, const void *cmd_buf, size_t cmd_len, | |
222 | void *resp_buf, size_t resp_len) | |
223 | { | |
224 | int ret; | |
225 | struct scm_command *cmd; | |
226 | struct scm_response *rsp; | |
227 | ||
228 | cmd = alloc_scm_command(cmd_len, resp_len); | |
229 | if (!cmd) | |
230 | return -ENOMEM; | |
231 | ||
232 | cmd->id = (svc_id << 10) | cmd_id; | |
233 | if (cmd_buf) | |
234 | memcpy(scm_get_command_buffer(cmd), cmd_buf, cmd_len); | |
235 | ||
236 | mutex_lock(&scm_lock); | |
237 | ret = __scm_call(cmd); | |
238 | mutex_unlock(&scm_lock); | |
239 | if (ret) | |
240 | goto out; | |
241 | ||
242 | rsp = scm_command_to_response(cmd); | |
243 | do { | |
244 | u32 start = (u32)rsp; | |
245 | u32 end = (u32)scm_get_response_buffer(rsp) + resp_len; | |
246 | start &= ~(CACHELINESIZE - 1); | |
247 | while (start < end) { | |
248 | asm ("mcr p15, 0, %0, c7, c6, 1" : : "r" (start) | |
249 | : "memory"); | |
250 | start += CACHELINESIZE; | |
251 | } | |
252 | } while (!rsp->is_complete); | |
253 | ||
254 | if (resp_buf) | |
255 | memcpy(resp_buf, scm_get_response_buffer(rsp), resp_len); | |
256 | out: | |
257 | free_scm_command(cmd); | |
258 | return ret; | |
259 | } | |
260 | EXPORT_SYMBOL(scm_call); | |
261 | ||
262 | u32 scm_get_version(void) | |
263 | { | |
264 | int context_id; | |
265 | static u32 version = -1; | |
98d4ded6 SB |
266 | register u32 r0 asm("r0"); |
267 | register u32 r1 asm("r1"); | |
2a1eb58a SB |
268 | |
269 | if (version != -1) | |
270 | return version; | |
271 | ||
272 | mutex_lock(&scm_lock); | |
98d4ded6 SB |
273 | |
274 | r0 = 0x1 << 8; | |
275 | r1 = (u32)&context_id; | |
8e76a809 SB |
276 | do { |
277 | asm volatile( | |
278 | __asmeq("%0", "r0") | |
279 | __asmeq("%1", "r1") | |
280 | __asmeq("%2", "r0") | |
281 | __asmeq("%3", "r1") | |
282 | "smc #0 @ switch to secure world\n" | |
283 | : "=r" (r0), "=r" (r1) | |
284 | : "r" (r0), "r" (r1) | |
285 | : "r2", "r3"); | |
286 | } while (r0 == SCM_INTERRUPTED); | |
287 | ||
2a1eb58a SB |
288 | version = r1; |
289 | mutex_unlock(&scm_lock); | |
290 | ||
291 | return version; | |
292 | } | |
293 | EXPORT_SYMBOL(scm_get_version); |