riscv-openocd/contrib/loaders/flash/at91sam7x/dcc.c

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