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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2004-2007 ARM Limited.
* Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
* Copyright (C) 2015 - 2016 Xilinx, Inc, Michal Simek
*
* As a special exception, if other files instantiate templates or use macros
* or inline functions from this file, or you compile this file and link it
* with other works to produce a work based on this file, this file does not
* by itself cause the resulting work to be covered by the GNU General Public
* License. However the source code for this file must still be made available
* in accordance with section (3) of the GNU General Public License.
* This exception does not invalidate any other reasons why a work based on
* this file might be covered by the GNU General Public License.
*/
#include <common.h>
#include <dm.h>
#include <serial.h>
#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V7A) || defined(CONFIG_CPU_V7R)
/*
* ARMV6 & ARMV7
*/
#define DCC_RBIT (1 << 30)
#define DCC_WBIT (1 << 29)
#define write_dcc(x) \
__asm__ volatile ("mcr p14, 0, %0, c0, c5, 0\n" : : "r" (x))
#define read_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c0, c5, 0\n" : "=r" (x))
#define status_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c0, c1, 0\n" : "=r" (x))
#elif defined(CONFIG_CPU_XSCALE)
/*
* XSCALE
*/
#define DCC_RBIT (1 << 31)
#define DCC_WBIT (1 << 28)
#define write_dcc(x) \
__asm__ volatile ("mcr p14, 0, %0, c8, c0, 0\n" : : "r" (x))
#define read_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c9, c0, 0\n" : "=r" (x))
#define status_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c14, c0, 0\n" : "=r" (x))
#elif defined(CONFIG_ARM64)
/*
* ARMV8
*/
#define DCC_RBIT (1 << 30)
#define DCC_WBIT (1 << 29)
#define write_dcc(x) \
__asm__ volatile ("msr dbgdtrtx_el0, %0\n" : : "r" (x))
#define read_dcc(x) \
__asm__ volatile ("mrs %0, dbgdtrrx_el0\n" : "=r" (x))
#define status_dcc(x) \
__asm__ volatile ("mrs %0, mdccsr_el0\n" : "=r" (x))
#else
#define DCC_RBIT (1 << 0)
#define DCC_WBIT (1 << 1)
#define write_dcc(x) \
__asm__ volatile ("mcr p14, 0, %0, c1, c0, 0\n" : : "r" (x))
#define read_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c1, c0, 0\n" : "=r" (x))
#define status_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c0, c0, 0\n" : "=r" (x))
#endif
#define can_read_dcc(x) do { \
status_dcc(x); \
x &= DCC_RBIT; \
} while (0);
#define can_write_dcc(x) do { \
status_dcc(x); \
x &= DCC_WBIT; \
x = (x == 0); \
} while (0);
#define TIMEOUT_COUNT 0x4000000
static int arm_dcc_getc(struct udevice *dev)
{
int ch;
register unsigned int reg;
do {
can_read_dcc(reg);
} while (!reg);
read_dcc(ch);
return ch;
}
static int arm_dcc_putc(struct udevice *dev, char ch)
{
register unsigned int reg;
unsigned int timeout_count = TIMEOUT_COUNT;
while (--timeout_count) {
can_write_dcc(reg);
if (reg)
break;
}
if (timeout_count == 0)
return -EAGAIN;
else
write_dcc(ch);
return 0;
}
static int arm_dcc_pending(struct udevice *dev, bool input)
{
register unsigned int reg;
if (input) {
can_read_dcc(reg);
} else {
can_write_dcc(reg);
}
return reg;
}
static const struct dm_serial_ops arm_dcc_ops = {
.putc = arm_dcc_putc,
.pending = arm_dcc_pending,
.getc = arm_dcc_getc,
};
static const struct udevice_id arm_dcc_ids[] = {
{ .compatible = "arm,dcc", },
{ }
};
U_BOOT_DRIVER(serial_dcc) = {
.name = "arm_dcc",
.id = UCLASS_SERIAL,
.of_match = arm_dcc_ids,
.ops = &arm_dcc_ops,
};
#ifdef CONFIG_DEBUG_UART_ARM_DCC
#include <debug_uart.h>
static inline void _debug_uart_init(void)
{
}
static inline void _debug_uart_putc(int ch)
{
arm_dcc_putc(NULL, ch);
}
DEBUG_UART_FUNCS
#endif
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