cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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stmp_device.c (1953B)

      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);