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
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