39 lines
1.0 KiB
C
39 lines
1.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/***************************************************************************
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* Copyright (C) 2007 by Pavel Chromy *
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* chromy@asix.cz *
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***************************************************************************/
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#include "dcc.h"
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/* debug channel read (debugger->MCU) */
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uint32 dcc_rd(void)
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{
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volatile uint32 dcc_reg;
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do {
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asm volatile ("mrc p14, 0, %0, C0, C0" : "=r" (dcc_reg) :);
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} while ((dcc_reg&1) == 0);
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asm volatile ("mrc p14, 0, %0, C1, C0" : "=r" (dcc_reg) :);
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return dcc_reg;
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}
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/* debug channel write (MCU->debugger) */
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int dcc_wr(uint32 data)
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{
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volatile uint32 dcc_reg;
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do {
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asm volatile ("mrc p14, 0, %0, C0, C0" : "=r" (dcc_reg) :);
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/* operation controlled by master, cancel operation
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upon reception of data for immediate response */
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if (dcc_reg&1) return -1;
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} while (dcc_reg&2);
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asm volatile ("mcr p14, 0, %0, C1, C0" : : "r" (data));
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return 0;
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}
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