| /* Copyright (c) 2010-2011, 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. |
| */ |
| |
| #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 <linux/init.h> |
| |
| #include <asm/cacheflush.h> |
| |
| #include <mach/scm.h> |
| |
| #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") |
| "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; |
| } |
| |
| static u32 cacheline_size; |
| |
| static void scm_inv_range(unsigned long start, unsigned long end) |
| { |
| start = round_down(start, cacheline_size); |
| end = round_up(end, cacheline_size); |
| while (start < end) { |
| asm ("mcr p15, 0, %0, c7, c6, 1" : : "r" (start) |
| : "memory"); |
| start += cacheline_size; |
| } |
| dsb(); |
| isb(); |
| } |
| |
| /** |
| * 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; |
| unsigned long start, end; |
| |
| 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); |
| start = (unsigned long)rsp; |
| |
| do { |
| scm_inv_range(start, start + sizeof(*rsp)); |
| } while (!rsp->is_complete); |
| |
| end = (unsigned long)scm_get_response_buffer(rsp) + resp_len; |
| scm_inv_range(start, end); |
| |
| 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); |
| |
| static int scm_init(void) |
| { |
| u32 ctr; |
| |
| asm volatile("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr)); |
| cacheline_size = 4 << ((ctr >> 16) & 0xf); |
| |
| return 0; |
| } |
| early_initcall(scm_init); |