1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs |
4 | * |
5 | * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp> |
6 | */ |
7 | |
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
9 | |
10 | #include <linux/module.h> |
11 | #include <linux/moduleparam.h> |
12 | #include <linux/types.h> |
13 | #include <linux/watchdog.h> |
14 | #include <linux/init.h> |
15 | #include <linux/platform_device.h> |
16 | #include <linux/clk.h> |
17 | #include <linux/err.h> |
18 | #include <linux/io.h> |
19 | #include <asm/txx9tmr.h> |
20 | |
21 | #define WD_TIMER_CCD 7 /* 1/256 */ |
22 | #define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD)) |
23 | #define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK) |
24 | #define TIMER_MARGIN 60 /* Default is 60 seconds */ |
25 | |
26 | static unsigned int timeout = TIMER_MARGIN; /* in seconds */ |
27 | module_param(timeout, uint, 0); |
28 | MODULE_PARM_DESC(timeout, |
29 | "Watchdog timeout in seconds. " |
30 | "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), " |
31 | "default=" __MODULE_STRING(TIMER_MARGIN) ")" ); |
32 | |
33 | static bool nowayout = WATCHDOG_NOWAYOUT; |
34 | module_param(nowayout, bool, 0); |
35 | MODULE_PARM_DESC(nowayout, |
36 | "Watchdog cannot be stopped once started " |
37 | "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
38 | |
39 | static struct txx9_tmr_reg __iomem *txx9wdt_reg; |
40 | static struct clk *txx9_imclk; |
41 | static DEFINE_SPINLOCK(txx9_lock); |
42 | |
43 | static int txx9wdt_ping(struct watchdog_device *wdt_dev) |
44 | { |
45 | spin_lock(lock: &txx9_lock); |
46 | __raw_writel(val: TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, addr: &txx9wdt_reg->wtmr); |
47 | spin_unlock(lock: &txx9_lock); |
48 | return 0; |
49 | } |
50 | |
51 | static int txx9wdt_start(struct watchdog_device *wdt_dev) |
52 | { |
53 | spin_lock(lock: &txx9_lock); |
54 | __raw_writel(WD_TIMER_CLK * wdt_dev->timeout, addr: &txx9wdt_reg->cpra); |
55 | __raw_writel(WD_TIMER_CCD, addr: &txx9wdt_reg->ccdr); |
56 | __raw_writel(val: 0, addr: &txx9wdt_reg->tisr); /* clear pending interrupt */ |
57 | __raw_writel(val: TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG, |
58 | addr: &txx9wdt_reg->tcr); |
59 | __raw_writel(val: TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, addr: &txx9wdt_reg->wtmr); |
60 | spin_unlock(lock: &txx9_lock); |
61 | return 0; |
62 | } |
63 | |
64 | static int txx9wdt_stop(struct watchdog_device *wdt_dev) |
65 | { |
66 | spin_lock(lock: &txx9_lock); |
67 | __raw_writel(val: TXx9_TMWTMR_WDIS, addr: &txx9wdt_reg->wtmr); |
68 | __raw_writel(__raw_readl(addr: &txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE, |
69 | addr: &txx9wdt_reg->tcr); |
70 | spin_unlock(lock: &txx9_lock); |
71 | return 0; |
72 | } |
73 | |
74 | static int txx9wdt_set_timeout(struct watchdog_device *wdt_dev, |
75 | unsigned int new_timeout) |
76 | { |
77 | wdt_dev->timeout = new_timeout; |
78 | txx9wdt_stop(wdt_dev); |
79 | txx9wdt_start(wdt_dev); |
80 | return 0; |
81 | } |
82 | |
83 | static const struct watchdog_info txx9wdt_info = { |
84 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
85 | .identity = "Hardware Watchdog for TXx9" , |
86 | }; |
87 | |
88 | static const struct watchdog_ops txx9wdt_ops = { |
89 | .owner = THIS_MODULE, |
90 | .start = txx9wdt_start, |
91 | .stop = txx9wdt_stop, |
92 | .ping = txx9wdt_ping, |
93 | .set_timeout = txx9wdt_set_timeout, |
94 | }; |
95 | |
96 | static struct watchdog_device txx9wdt = { |
97 | .info = &txx9wdt_info, |
98 | .ops = &txx9wdt_ops, |
99 | }; |
100 | |
101 | static int __init txx9wdt_probe(struct platform_device *dev) |
102 | { |
103 | int ret; |
104 | |
105 | txx9_imclk = clk_get(NULL, id: "imbus_clk" ); |
106 | if (IS_ERR(ptr: txx9_imclk)) { |
107 | ret = PTR_ERR(ptr: txx9_imclk); |
108 | txx9_imclk = NULL; |
109 | goto exit; |
110 | } |
111 | ret = clk_prepare_enable(clk: txx9_imclk); |
112 | if (ret) { |
113 | clk_put(clk: txx9_imclk); |
114 | txx9_imclk = NULL; |
115 | goto exit; |
116 | } |
117 | |
118 | txx9wdt_reg = devm_platform_ioremap_resource(pdev: dev, index: 0); |
119 | if (IS_ERR(ptr: txx9wdt_reg)) { |
120 | ret = PTR_ERR(ptr: txx9wdt_reg); |
121 | goto exit; |
122 | } |
123 | |
124 | if (timeout < 1 || timeout > WD_MAX_TIMEOUT) |
125 | timeout = TIMER_MARGIN; |
126 | txx9wdt.timeout = timeout; |
127 | txx9wdt.min_timeout = 1; |
128 | txx9wdt.max_timeout = WD_MAX_TIMEOUT; |
129 | txx9wdt.parent = &dev->dev; |
130 | watchdog_set_nowayout(wdd: &txx9wdt, nowayout); |
131 | |
132 | ret = watchdog_register_device(&txx9wdt); |
133 | if (ret) |
134 | goto exit; |
135 | |
136 | pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n" , |
137 | timeout, WD_MAX_TIMEOUT, nowayout); |
138 | |
139 | return 0; |
140 | exit: |
141 | if (txx9_imclk) { |
142 | clk_disable_unprepare(clk: txx9_imclk); |
143 | clk_put(clk: txx9_imclk); |
144 | } |
145 | return ret; |
146 | } |
147 | |
148 | static int __exit txx9wdt_remove(struct platform_device *dev) |
149 | { |
150 | watchdog_unregister_device(&txx9wdt); |
151 | clk_disable_unprepare(clk: txx9_imclk); |
152 | clk_put(clk: txx9_imclk); |
153 | return 0; |
154 | } |
155 | |
156 | static void txx9wdt_shutdown(struct platform_device *dev) |
157 | { |
158 | txx9wdt_stop(wdt_dev: &txx9wdt); |
159 | } |
160 | |
161 | static struct platform_driver txx9wdt_driver = { |
162 | .remove = __exit_p(txx9wdt_remove), |
163 | .shutdown = txx9wdt_shutdown, |
164 | .driver = { |
165 | .name = "txx9wdt" , |
166 | }, |
167 | }; |
168 | |
169 | module_platform_driver_probe(txx9wdt_driver, txx9wdt_probe); |
170 | |
171 | MODULE_DESCRIPTION("TXx9 Watchdog Driver" ); |
172 | MODULE_LICENSE("GPL" ); |
173 | MODULE_ALIAS("platform:txx9wdt" ); |
174 | |