55 lines
1.3 KiB
C
55 lines
1.3 KiB
C
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/*
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* File : mbox.c
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* Copyright (c) 2006-2018, RT-Thread Development Team
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Change Logs:
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* Date Author Notes
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* 2019-08-29 zdzn first version
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*/
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/* mailbox message buffer */
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#include "mbox.h"
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#include "mmu.h"
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volatile unsigned int *mbox = (volatile unsigned int *) MBOX_ADDR;
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/**
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* Make a mailbox call. Returns 0 on failure, non-zero on success
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*/
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void init_mbox_mmu_map()
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{
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rt_hw_change_mmu_table(MBOX_ADDR, 96, MBOX_ADDR, STRONG_ORDER_MEM);
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}
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int mbox_call(unsigned char ch, int mmu_enable)
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{
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unsigned int r = (((MBOX_ADDR)&~0xF) | (ch&0xF));
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if (mmu_enable)
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r = BUS_ADDRESS(r);
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/* wait until we can write to the mailbox */
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do
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{
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asm volatile("nop");
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} while (*MBOX_STATUS & MBOX_FULL);
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/* write the address of our message to the mailbox with channel identifier */
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*MBOX_WRITE = r;
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/* now wait for the response */
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while (1)
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{
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/* is there a response? */
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do
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{
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asm volatile("nop");
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}
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while (*MBOX_STATUS & MBOX_EMPTY);
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/* is it a response to our message? */
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if (r == *MBOX_READ)
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{
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/* is it a valid successful response? */
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return mbox[1] == MBOX_RESPONSE;
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}
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}
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return 0;
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}
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