1 /* 2 * Copyright (C) 1999 ARM Limited 3 * Copyright (C) 2000 Deep Blue Solutions Ltd 4 * Copyright 2006-2007,2010 Freescale Semiconductor, Inc. All Rights Reserved. 5 * Copyright 2008 Juergen Beisert, kernel@pengutronix.de 6 * Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, yanok@emcraft.com 7 * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K. 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 2 of the License, or 12 * (at your option) any later version. 13 */ 14 15 #include <linux/io.h> 16 #include <linux/errno.h> 17 #include <linux/delay.h> 18 #include <linux/module.h> 19 #include <linux/stmp_device.h> 20 21 #define STMP_MODULE_CLKGATE (1 << 30) 22 #define STMP_MODULE_SFTRST (1 << 31) 23 24 /* 25 * Clear the bit and poll it cleared. This is usually called with 26 * a reset address and mask being either SFTRST(bit 31) or CLKGATE 27 * (bit 30). 28 */ 29 static int stmp_clear_poll_bit(void __iomem *addr, u32 mask) 30 { 31 int timeout = 0x400; 32 33 writel(mask, addr + STMP_OFFSET_REG_CLR); 34 udelay(1); 35 while ((readl(addr) & mask) && --timeout) 36 /* nothing */; 37 38 return !timeout; 39 } 40 41 int stmp_reset_block(void __iomem *reset_addr) 42 { 43 int ret; 44 int timeout = 0x400; 45 46 /* clear and poll SFTRST */ 47 ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST); 48 if (unlikely(ret)) 49 goto error; 50 51 /* clear CLKGATE */ 52 writel(STMP_MODULE_CLKGATE, reset_addr + STMP_OFFSET_REG_CLR); 53 54 /* set SFTRST to reset the block */ 55 writel(STMP_MODULE_SFTRST, reset_addr + STMP_OFFSET_REG_SET); 56 udelay(1); 57 58 /* poll CLKGATE becoming set */ 59 while ((!(readl(reset_addr) & STMP_MODULE_CLKGATE)) && --timeout) 60 /* nothing */; 61 if (unlikely(!timeout)) 62 goto error; 63 64 /* clear and poll SFTRST */ 65 ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST); 66 if (unlikely(ret)) 67 goto error; 68 69 /* clear and poll CLKGATE */ 70 ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_CLKGATE); 71 if (unlikely(ret)) 72 goto error; 73 74 return 0; 75 76 error: 77 pr_err("%s(%p): module reset timeout\n", __func__, reset_addr); 78 return -ETIMEDOUT; 79 } 80 EXPORT_SYMBOL(stmp_reset_block); 81