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/arch/arm/mach-msm/scm.c

https://github.com/AICP/kernel_asus_grouper
C | 293 lines | 164 code | 32 blank | 97 comment | 15 complexity | 5621813ed1a2a4a27bf6abd9b9df1e64 MD5 | raw file
  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
 39static 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 *
 49 * An SCM command is laid out in memory as follows:
 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 */
 65struct 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 */
 79struct 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 */
 95static 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 */
116static 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 */
127static 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 */
139static 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 */
150static inline void *scm_get_response_buffer(const struct scm_response *rsp)
151{
152	return (void *)rsp + rsp->buf_offset;
153}
154
155static 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
171static 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;
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
189	return r0;
190}
191
192static 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();
203	ret = smc(cmd_addr);
204	if (ret < 0)
205		ret = scm_remap_error(ret);
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 */
221int 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);
256out:
257	free_scm_command(cmd);
258	return ret;
259}
260EXPORT_SYMBOL(scm_call);
261
262u32 scm_get_version(void)
263{
264	int context_id;
265	static u32 version = -1;
266	register u32 r0 asm("r0");
267	register u32 r1 asm("r1");
268
269	if (version != -1)
270		return version;
271
272	mutex_lock(&scm_lock);
273
274	r0 = 0x1 << 8;
275	r1 = (u32)&context_id;
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
288	version = r1;
289	mutex_unlock(&scm_lock);
290
291	return version;
292}
293EXPORT_SYMBOL(scm_get_version);