// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 1999 ARM Limited
 * Copyright (C) 2000 Deep Blue Solutions Ltd
 * Copyright 2006-2007,2010 Freescale Semiconductor, Inc. All Rights Reserved.
 * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
 * Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, yanok@emcraft.com
 * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
 */

#include <linux/io.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/compiler.h>
#include <linux/export.h>
#include <linux/stmp_device.h>

#define STMP_MODULE_CLKGATE     (1 << 30)
#define STMP_MODULE_SFTRST      (1 << 31)

/*
 * Clear the bit and poll it cleared.  This is usually called with
 * a reset address and mask being either SFTRST(bit 31) or CLKGATE
 * (bit 30).
 */
static int stmp_clear_poll_bit(void __iomem *addr, u32 mask)
{
        int timeout = 0x400;

        writel(mask, addr + STMP_OFFSET_REG_CLR);
        udelay(1);
        while ((readl(addr) & mask) && --timeout)
                /* nothing */;

        return !timeout;
}

int stmp_reset_block(void __iomem *reset_addr)
{
        int ret;
        int timeout = 0x400;

        /* clear and poll SFTRST */
        ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
        if (unlikely(ret))
                goto error;

        /* clear CLKGATE */
        writel(STMP_MODULE_CLKGATE, reset_addr + STMP_OFFSET_REG_CLR);

        /* set SFTRST to reset the block */
        writel(STMP_MODULE_SFTRST, reset_addr + STMP_OFFSET_REG_SET);
        udelay(1);

        /* poll CLKGATE becoming set */
        while ((!(readl(reset_addr) & STMP_MODULE_CLKGATE)) && --timeout)
                /* nothing */;
        if (unlikely(!timeout))
                goto error;

        /* clear and poll SFTRST */
        ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
        if (unlikely(ret))
                goto error;

        /* clear and poll CLKGATE */
        ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_CLKGATE);
        if (unlikely(ret))
                goto error;

        return 0;

error:
        pr_err("%s(%p): module reset timeout\n", __func__, reset_addr);
        return -ETIMEDOUT;
}
EXPORT_SYMBOL(stmp_reset_block);