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/* Copyright 2012 The ChromiumOS Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Shared memory module for Chrome EC */
#include "common.h"
#include "console.h"
#include "link_defs.h"
#include "shared_mem.h"
#include "system.h"
#include "util.h"
static int buf_in_use;
static int max_used;
/* 1 MB buffer for fake shared memory implementation */
STATIC_IF(CONFIG_FAKE_SHMEM) char fake_shmem_buf[BIT(20)];
int shared_mem_size(void)
{
if (IS_ENABLED(CONFIG_FAKE_SHMEM))
return sizeof(fake_shmem_buf);
/*
* Use all the RAM we can. The shared memory buffer is the last thing
* allocated from the start of RAM, so we can use everything up to the
* jump data at the end of RAM.
*/
return system_usable_ram_end() - (uintptr_t)__shared_mem_buf;
}
int shared_mem_acquire(int size, char **dest_ptr)
{
if (size > shared_mem_size() || size <= 0)
return EC_ERROR_INVAL;
if (buf_in_use)
return EC_ERROR_BUSY;
/*
* We could guard buf_in_use with a mutex, but since shared memory is
* currently only used by debug commands, that's overkill.
*/
buf_in_use = size;
if (IS_ENABLED(CONFIG_FAKE_SHMEM))
*dest_ptr = fake_shmem_buf;
else
*dest_ptr = __shared_mem_buf;
if (max_used < size)
max_used = size;
return EC_SUCCESS;
}
void shared_mem_release(void *ptr)
{
buf_in_use = 0;
}
#ifdef CONFIG_CMD_SHMEM
static int command_shmem(int argc, char **argv)
{
ccprintf("Size:%6d\n", shared_mem_size());
ccprintf("Used:%6d\n", buf_in_use);
ccprintf("Max: %6d\n", max_used);
return EC_SUCCESS;
}
DECLARE_SAFE_CONSOLE_COMMAND(shmem, command_shmem,
NULL,
"Print shared memory stats");
#endif
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