blob: a904656f4fd7c5848155feaf0b0b3b4b50eeb00c
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/compiler.h> |
19 | #include <linux/export.h> |
20 | #include <linux/stmp_device.h> |
21 | |
22 | #define STMP_MODULE_CLKGATE (1 << 30) |
23 | #define STMP_MODULE_SFTRST (1 << 31) |
24 | |
25 | /* |
26 | * Clear the bit and poll it cleared. This is usually called with |
27 | * a reset address and mask being either SFTRST(bit 31) or CLKGATE |
28 | * (bit 30). |
29 | */ |
30 | static int stmp_clear_poll_bit(void __iomem *addr, u32 mask) |
31 | { |
32 | int timeout = 0x400; |
33 | |
34 | writel(mask, addr + STMP_OFFSET_REG_CLR); |
35 | udelay(1); |
36 | while ((readl(addr) & mask) && --timeout) |
37 | /* nothing */; |
38 | |
39 | return !timeout; |
40 | } |
41 | |
42 | int stmp_reset_block(void __iomem *reset_addr) |
43 | { |
44 | int ret; |
45 | int timeout = 0x400; |
46 | |
47 | /* clear and poll SFTRST */ |
48 | ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST); |
49 | if (unlikely(ret)) |
50 | goto error; |
51 | |
52 | /* clear CLKGATE */ |
53 | writel(STMP_MODULE_CLKGATE, reset_addr + STMP_OFFSET_REG_CLR); |
54 | |
55 | /* set SFTRST to reset the block */ |
56 | writel(STMP_MODULE_SFTRST, reset_addr + STMP_OFFSET_REG_SET); |
57 | udelay(1); |
58 | |
59 | /* poll CLKGATE becoming set */ |
60 | while ((!(readl(reset_addr) & STMP_MODULE_CLKGATE)) && --timeout) |
61 | /* nothing */; |
62 | if (unlikely(!timeout)) |
63 | goto error; |
64 | |
65 | /* clear and poll SFTRST */ |
66 | ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST); |
67 | if (unlikely(ret)) |
68 | goto error; |
69 | |
70 | /* clear and poll CLKGATE */ |
71 | ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_CLKGATE); |
72 | if (unlikely(ret)) |
73 | goto error; |
74 | |
75 | return 0; |
76 | |
77 | error: |
78 | pr_err("%s(%p): module reset timeout\n", __func__, reset_addr); |
79 | return -ETIMEDOUT; |
80 | } |
81 | EXPORT_SYMBOL(stmp_reset_block); |
82 |