/* Copyright (c) 2010, Code Aurora Forum. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and * only version 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301, USA. */ #include <linux/slab.h> #include <linux/io.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/errno.h> #include <linux/err.h> #include <asm/cacheflush.h> #include "scm.h" /* Cache line size for msm8x60 */ #define CACHELINESIZE 32 #define SCM_ENOMEM -5 #define SCM_EOPNOTSUPP -4 #define SCM_EINVAL_ADDR -3 #define SCM_EINVAL_ARG -2 #define SCM_ERROR -1 #define SCM_INTERRUPTED 1 static DEFINE_MUTEX(scm_lock); /** * struct scm_command - one SCM command buffer * @len: total available memory for command and response * @buf_offset: start of command buffer * @resp_hdr_offset: start of response buffer * @id: command to be executed * @buf: buffer returned from scm_get_command_buffer() * * An SCM command is laid out in memory as follows: * * ------------------- <--- struct scm_command * | command header | * ------------------- <--- scm_get_command_buffer() * | command buffer | * ------------------- <--- struct scm_response and * | response header | scm_command_to_response() * ------------------- <--- scm_get_response_buffer() * | response buffer | * ------------------- * * There can be arbitrary padding between the headers and buffers so * you should always use the appropriate scm_get_*_buffer() routines * to access the buffers in a safe manner. */ struct scm_command { u32 len; u32 buf_offset; u32 resp_hdr_offset; u32 id; u32 buf[0]; }; /** * struct scm_response - one SCM response buffer * @len: total available memory for response * @buf_offset: start of response data relative to start of scm_response * @is_complete: indicates if the command has finished processing */ struct scm_response { u32 len; u32 buf_offset; u32 is_complete; }; /** * alloc_scm_command() - Allocate an SCM command * @cmd_size: size of the command buffer * @resp_size: size of the response buffer * * Allocate an SCM command, including enough room for the command * and response headers as well as the command and response buffers. * * Returns a valid &scm_command on success or %NULL if the allocation fails. */ static struct scm_command *alloc_scm_command(size_t cmd_size, size_t resp_size) { struct scm_command *cmd; size_t len = sizeof(*cmd) + sizeof(struct scm_response) + cmd_size + resp_size; cmd = kzalloc(PAGE_ALIGN(len), GFP_KERNEL); if (cmd) { cmd->len = len; cmd->buf_offset = offsetof(struct scm_command, buf); cmd->resp_hdr_offset = cmd->buf_offset + cmd_size; } return cmd; } /** * free_scm_command() - Free an SCM command * @cmd: command to free * * Free an SCM command. */ static inline void free_scm_command(struct scm_command *cmd) { kfree(cmd); } /** * scm_command_to_response() - Get a pointer to a scm_response * @cmd: command * * Returns a pointer to a response for a command. */ static inline struct scm_response *scm_command_to_response( const struct scm_command *cmd) { return (void *)cmd + cmd->resp_hdr_offset; } /** * scm_get_command_buffer() - Get a pointer to a command buffer * @cmd: command * * Returns a pointer to the command buffer of a command. */ static inline void *scm_get_command_buffer(const struct scm_command *cmd) { return (void *)cmd->buf; } /** * scm_get_response_buffer() - Get a pointer to a response buffer * @rsp: response * * Returns a pointer to a response buffer of a response. */ static inline void *scm_get_response_buffer(const struct scm_response *rsp) { return (void *)rsp + rsp->buf_offset; } static int scm_remap_error(int err) { switch (err) { case SCM_ERROR: return -EIO; case SCM_EINVAL_ADDR: case SCM_EINVAL_ARG: return -EINVAL; case SCM_EOPNOTSUPP: return -EOPNOTSUPP; case SCM_ENOMEM: return -ENOMEM; } return -EINVAL; } static u32 smc(u32 cmd_addr) { int context_id; register u32 r0 asm("r0") = 1; register u32 r1 asm("r1") = (u32)&context_id; register u32 r2 asm("r2") = cmd_addr; do { asm volatile( __asmeq("%0", "r0") __asmeq("%1", "r0") __asmeq("%2", "r1") __asmeq("%3", "r2") #ifdef REQUIRES_SEC ".arch_extension sec\n" #endif "smc #0 @ switch to secure world\n" : "=r" (r0) : "r" (r0), "r" (r1), "r" (r2) : "r3"); } while (r0 == SCM_INTERRUPTED); return r0; } static int __scm_call(const struct scm_command *cmd) { int ret; u32 cmd_addr = virt_to_phys(cmd); /* * Flush the entire cache here so callers don't have to remember * to flush the cache when passing physical addresses to the secure * side in the buffer. */ flush_cache_all(); ret = smc(cmd_addr); if (ret < 0) ret = scm_remap_error(ret); return ret; } /** * scm_call() - Send an SCM command * @svc_id: service identifier * @cmd_id: command identifier * @cmd_buf: command buffer * @cmd_len: length of the command buffer * @resp_buf: response buffer * @resp_len: length of the response buffer * * Sends a command to the SCM and waits for the command to finish processing. */ int scm_call(u32 svc_id, u32 cmd_id, const void *cmd_buf, size_t cmd_len, void *resp_buf, size_t resp_len) { int ret; struct scm_command *cmd; struct scm_response *rsp; cmd = alloc_scm_command(cmd_len, resp_len); if (!cmd) return -ENOMEM; cmd->id = (svc_id << 10) | cmd_id; if (cmd_buf) memcpy(scm_get_command_buffer(cmd), cmd_buf, cmd_len); mutex_lock(&scm_lock); ret = __scm_call(cmd); mutex_unlock(&scm_lock); if (ret) goto out; rsp = scm_command_to_response(cmd); do { u32 start = (u32)rsp; u32 end = (u32)scm_get_response_buffer(rsp) + resp_len; start &= ~(CACHELINESIZE - 1); while (start < end) { asm ("mcr p15, 0, %0, c7, c6, 1" : : "r" (start) : "memory"); start += CACHELINESIZE; } } while (!rsp->is_complete); if (resp_buf) memcpy(resp_buf, scm_get_response_buffer(rsp), resp_len); out: free_scm_command(cmd); return ret; } EXPORT_SYMBOL(scm_call); u32 scm_get_version(void) { int context_id; static u32 version = -1; register u32 r0 asm("r0"); register u32 r1 asm("r1"); if (version != -1) return version; mutex_lock(&scm_lock); r0 = 0x1 << 8; r1 = (u32)&context_id; do { asm volatile( __asmeq("%0", "r0") __asmeq("%1", "r1") __asmeq("%2", "r0") __asmeq("%3", "r1") "smc #0 @ switch to secure world\n" : "=r" (r0), "=r" (r1) : "r" (r0), "r" (r1) : "r2", "r3"); } while (r0 == SCM_INTERRUPTED); version = r1; mutex_unlock(&scm_lock); return version; } EXPORT_SYMBOL(scm_get_version);