early_init.c

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/* SPDX-License-Identifier: GPL-2.0-or-later */
 
#include <arch/io.h>
#include <device/pnp.h>
#include <stdint.h>
#include "nct5104d.h"
 
#define NUVOTON_ENTRY_KEY 0x87
#define NUVOTON_EXIT_KEY 0xAA
 
/* Enable configuration: pass entry key '0x87' into index port dev
 * two times. */
static void pnp_enter_conf_state(pnp_devfn_t dev)
{
        u16 port = dev >> 8;
        outb(NUVOTON_ENTRY_KEY, port);
        outb(NUVOTON_ENTRY_KEY, port);
}
 
/* Disable configuration: pass exit key '0xAA' into index port dev. */
static void pnp_exit_conf_state(pnp_devfn_t dev)
{
        u16 port = dev >> 8;
        outb(NUVOTON_EXIT_KEY, port);
}
 
/* Route UARTD to pins 41-48 */
void nct5104d_enable_uartd(pnp_devfn_t dev)
{
        u8 tmp;
        u16 port = dev >> 8;
        pnp_enter_conf_state(dev);
        outb(0x1c, port);
        tmp = inb(port + 1);
        tmp |= 0x04;
        outb(tmp, port + 1);
        pnp_exit_conf_state(dev);
}