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 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 */
18
19 #include <linux/kernel.h>
20 #include <linux/clk.h>
21 #include <linux/io.h>
22 #include <linux/err.h>
23 #include <linux/delay.h>
24 #include <linux/init.h>
25 #include <linux/module.h>
26
27 #include <asm/proc-fns.h>
28 #include <asm/system_misc.h>
29
30 #include <mach/mxs.h>
31 #include <mach/common.h>
32
33 #define MX23_CLKCTRL_RESET_OFFSET 0x120
34 #define MX28_CLKCTRL_RESET_OFFSET 0x1e0
35 #define MXS_CLKCTRL_RESET_CHIP (1 << 1)
36
37 #define MXS_MODULE_CLKGATE (1 << 30)
38 #define MXS_MODULE_SFTRST (1 << 31)
39
40 #define CLKCTRL_TIMEOUT 10 /* 10 ms */
41
42 static void __iomem *mxs_clkctrl_reset_addr;
43
44 /*
45 * Reset the system. It is called by machine_restart().
46 */
mxs_restart(char mode,const char * cmd)47 void mxs_restart(char mode, const char *cmd)
48 {
49 /* reset the chip */
50 __mxs_setl(MXS_CLKCTRL_RESET_CHIP, mxs_clkctrl_reset_addr);
51
52 pr_err("Failed to assert the chip reset\n");
53
54 /* Delay to allow the serial port to show the message */
55 mdelay(50);
56
57 /* We'll take a jump through zero as a poor second */
58 soft_restart(0);
59 }
60
mxs_arch_reset_init(void)61 static int __init mxs_arch_reset_init(void)
62 {
63 struct clk *clk;
64
65 mxs_clkctrl_reset_addr = MXS_IO_ADDRESS(MXS_CLKCTRL_BASE_ADDR) +
66 (cpu_is_mx23() ? MX23_CLKCTRL_RESET_OFFSET :
67 MX28_CLKCTRL_RESET_OFFSET);
68
69 clk = clk_get_sys("rtc", NULL);
70 if (!IS_ERR(clk))
71 clk_prepare_enable(clk);
72
73 return 0;
74 }
75 core_initcall(mxs_arch_reset_init);
76
77 /*
78 * Clear the bit and poll it cleared. This is usually called with
79 * a reset address and mask being either SFTRST(bit 31) or CLKGATE
80 * (bit 30).
81 */
clear_poll_bit(void __iomem * addr,u32 mask)82 static int clear_poll_bit(void __iomem *addr, u32 mask)
83 {
84 int timeout = 0x400;
85
86 /* clear the bit */
87 __mxs_clrl(mask, addr);
88
89 /*
90 * SFTRST needs 3 GPMI clocks to settle, the reference manual
91 * recommends to wait 1us.
92 */
93 udelay(1);
94
95 /* poll the bit becoming clear */
96 while ((__raw_readl(addr) & mask) && --timeout)
97 /* nothing */;
98
99 return !timeout;
100 }
101
mxs_reset_block(void __iomem * reset_addr)102 int mxs_reset_block(void __iomem *reset_addr)
103 {
104 int ret;
105 int timeout = 0x400;
106
107 /* clear and poll SFTRST */
108 ret = clear_poll_bit(reset_addr, MXS_MODULE_SFTRST);
109 if (unlikely(ret))
110 goto error;
111
112 /* clear CLKGATE */
113 __mxs_clrl(MXS_MODULE_CLKGATE, reset_addr);
114
115 /* set SFTRST to reset the block */
116 __mxs_setl(MXS_MODULE_SFTRST, reset_addr);
117 udelay(1);
118
119 /* poll CLKGATE becoming set */
120 while ((!(__raw_readl(reset_addr) & MXS_MODULE_CLKGATE)) && --timeout)
121 /* nothing */;
122 if (unlikely(!timeout))
123 goto error;
124
125 /* clear and poll SFTRST */
126 ret = clear_poll_bit(reset_addr, MXS_MODULE_SFTRST);
127 if (unlikely(ret))
128 goto error;
129
130 /* clear and poll CLKGATE */
131 ret = clear_poll_bit(reset_addr, MXS_MODULE_CLKGATE);
132 if (unlikely(ret))
133 goto error;
134
135 return 0;
136
137 error:
138 pr_err("%s(%p): module reset timeout\n", __func__, reset_addr);
139 return -ETIMEDOUT;
140 }
141 EXPORT_SYMBOL(mxs_reset_block);
142
mxs_clkctrl_timeout(unsigned int reg_offset,unsigned int mask)143 int mxs_clkctrl_timeout(unsigned int reg_offset, unsigned int mask)
144 {
145 unsigned long timeout = jiffies + msecs_to_jiffies(CLKCTRL_TIMEOUT);
146 while (readl_relaxed(MXS_IO_ADDRESS(MXS_CLKCTRL_BASE_ADDR)
147 + reg_offset) & mask) {
148 if (time_after(jiffies, timeout)) {
149 pr_err("Timeout at CLKCTRL + 0x%x\n", reg_offset);
150 return -ETIMEDOUT;
151 }
152 }
153
154 return 0;
155 }
156