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