projects/linux·blob v6.1 · refs

77 lines · 1.9 KiB

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, [email protected]
7 * Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, [email protected]
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);