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 */ 26 static 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 38 int 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 73 error: 74 pr_err("%s(%p): module reset timeout\n", __func__, reset_addr); 75 return -ETIMEDOUT; 76 } 77 EXPORT_SYMBOL(stmp_reset_block); 78