// 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