// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <asm/proc-fns.h>
#include <asm/system_misc.h>

#include "regs-ost.h"
#include "reset.h"
#include "smemc.h"
#include "generic.h"

static void do_hw_reset(void);

static int reset_gpio = -1;

int init_gpio_reset(int gpio, int output, int level)
{
        int rc;

        rc = gpio_request(gpio, "reset generator");
        if (rc) {
                printk(KERN_ERR "Can't request reset_gpio\n");
                goto out;
        }

        if (output)
                rc = gpio_direction_output(gpio, level);
        else
                rc = gpio_direction_input(gpio);
        if (rc) {
                printk(KERN_ERR "Can't configure reset_gpio\n");
                gpio_free(gpio);
                goto out;
        }

out:
        if (!rc)
                reset_gpio = gpio;

        return rc;
}

/*
 * Trigger GPIO reset.
 * This covers various types of logic connecting gpio pin
 * to RESET pins (nRESET or GPIO_RESET):
 */
static void do_gpio_reset(void)
{
        BUG_ON(reset_gpio == -1);

        /* drive it low */
        gpio_direction_output(reset_gpio, 0);
        mdelay(2);
        /* rising edge or drive high */
        gpio_set_value(reset_gpio, 1);
        mdelay(2);
        /* falling edge */
        gpio_set_value(reset_gpio, 0);

        /* give it some time */
        mdelay(10);

        WARN_ON(1);
        /* fallback */
        do_hw_reset();
}

static void do_hw_reset(void)
{
        /* Initialize the watchdog and let it fire */
        writel_relaxed(OWER_WME, OWER);
        writel_relaxed(OSSR_M3, OSSR);
        /* ... in 100 ms */
        writel_relaxed(readl_relaxed(OSCR) + 368640, OSMR3);
        /*
         * SDRAM hangs on watchdog reset on Marvell PXA270 (erratum 71)
         * we put SDRAM into self-refresh to prevent that
         */
        while (1)
                writel_relaxed(MDREFR_SLFRSH, MDREFR);
}

void pxa_restart(enum reboot_mode mode, const char *cmd)
{
        local_irq_disable();
        local_fiq_disable();

        clear_reset_status(RESET_STATUS_ALL);

        switch (mode) {
        case REBOOT_SOFT:
                /* Jump into ROM at address 0 */
                soft_restart(0);
                break;
        case REBOOT_GPIO:
                do_gpio_reset();
                break;
        case REBOOT_HARD:
        default:
                do_hw_reset();
                break;
        }
}