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