LXR linux/lib/stmp

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright (C) 1999 ARM Limited
   4 * Copyright (C) 2000 Deep Blue Solutions Ltd
   5 * Copyright 2006-2007,2010 Freescale Semiconductor, Inc. All Rights Reserved.
   6 * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
   7 * Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, yanok@emcraft.com
   8 * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
   9 */
  10
  11#include <linux/io.h>
  12#include <linux/errno.h>
  13#include <linux/delay.h>
  14#include <linux/compiler.h>
  15#include <linux/export.h>
  16#include <linux/stmp_device.h>
  17
  18#define STMP_MODULE_CLKGATE     (1 << 30)
  19#define STMP_MODULE_SFTRST      (1 << 31)
  20
  21/*
  22 * Clear the bit and poll it cleared.  This is usually called with
  23 * a reset address and mask being either SFTRST(bit 31) or CLKGATE
  24 * (bit 30).
  25 */
  26static int stmp_clear_poll_bit(void __iomem *addr, u32 mask)
  27{
  28        int timeout = 0x400;
  29
  30        writel(mask, addr + STMP_OFFSET_REG_CLR);
  31        udelay(1);
  32        while ((readl(addr) & mask) && --timeout)
  33                /* nothing */;
  34
  35        return !timeout;
  36}
  37
  38int stmp_reset_block(void __iomem *reset_addr)
  39{
  40        int ret;
  41        int timeout = 0x400;
  42
  43        /* clear and poll SFTRST */
  44        ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
  45        if (unlikely(ret))
  46                goto error;
  47
  48        /* clear CLKGATE */
  49        writel(STMP_MODULE_CLKGATE, reset_addr + STMP_OFFSET_REG_CLR);
  50
  51        /* set SFTRST to reset the block */
  52        writel(STMP_MODULE_SFTRST, reset_addr + STMP_OFFSET_REG_SET);
  53        udelay(1);
  54
  55        /* poll CLKGATE becoming set */
  56        while ((!(readl(reset_addr) & STMP_MODULE_CLKGATE)) && --timeout)
  57                /* nothing */;
  58        if (unlikely(!timeout))
  59                goto error;
  60
  61        /* clear and poll SFTRST */
  62        ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
  63        if (unlikely(ret))
  64                goto error;
  65
  66        /* clear and poll CLKGATE */
  67        ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_CLKGATE);
  68        if (unlikely(ret))
  69                goto error;
  70
  71        return 0;
  72
  73error:
  74        pr_err("%s(%p): module reset timeout\n", __func__, reset_addr);
  75        return -ETIMEDOUT;
  76}
  77EXPORT_SYMBOL(stmp_reset_block);
  78