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21a0a29d | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 | 2 | /* |
f30c2269 | 3 | * drivers/char/watchdog/ixp4xx_wdt.c |
1da177e4 LT |
4 | * |
5 | * Watchdog driver for Intel IXP4xx network processors | |
6 | * | |
7 | * Author: Deepak Saxena <dsaxena@plexity.net> | |
21a0a29d | 8 | * Author: Linus Walleij <linus.walleij@linaro.org> |
1da177e4 LT |
9 | * |
10 | * Copyright 2004 (c) MontaVista, Software, Inc. | |
11 | * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> | |
1da177e4 LT |
12 | */ |
13 | ||
1da177e4 | 14 | #include <linux/module.h> |
1da177e4 LT |
15 | #include <linux/types.h> |
16 | #include <linux/kernel.h> | |
1da177e4 | 17 | #include <linux/watchdog.h> |
21a0a29d LW |
18 | #include <linux/bits.h> |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/clk.h> | |
21 | #include <linux/soc/ixp4xx/cpu.h> | |
22 | ||
23 | struct ixp4xx_wdt { | |
24 | struct watchdog_device wdd; | |
25 | void __iomem *base; | |
26 | unsigned long rate; | |
27 | }; | |
1da177e4 | 28 | |
21a0a29d LW |
29 | /* Fallback if we do not have a clock for this */ |
30 | #define IXP4XX_TIMER_FREQ 66666000 | |
1da177e4 | 31 | |
21a0a29d LW |
32 | /* Registers after the timer registers */ |
33 | #define IXP4XX_OSWT_OFFSET 0x14 /* Watchdog Timer */ | |
34 | #define IXP4XX_OSWE_OFFSET 0x18 /* Watchdog Enable */ | |
35 | #define IXP4XX_OSWK_OFFSET 0x1C /* Watchdog Key */ | |
36 | #define IXP4XX_OSST_OFFSET 0x20 /* Timer Status */ | |
1da177e4 | 37 | |
21a0a29d LW |
38 | #define IXP4XX_OSST_TIMER_WDOG_PEND 0x00000008 |
39 | #define IXP4XX_OSST_TIMER_WARM_RESET 0x00000010 | |
40 | #define IXP4XX_WDT_KEY 0x0000482E | |
41 | #define IXP4XX_WDT_RESET_ENABLE 0x00000001 | |
42 | #define IXP4XX_WDT_IRQ_ENABLE 0x00000002 | |
43 | #define IXP4XX_WDT_COUNT_ENABLE 0x00000004 | |
1da177e4 | 44 | |
21a0a29d LW |
45 | static inline |
46 | struct ixp4xx_wdt *to_ixp4xx_wdt(struct watchdog_device *wdd) | |
1da177e4 | 47 | { |
21a0a29d | 48 | return container_of(wdd, struct ixp4xx_wdt, wdd); |
1da177e4 LT |
49 | } |
50 | ||
21a0a29d | 51 | static int ixp4xx_wdt_start(struct watchdog_device *wdd) |
1da177e4 | 52 | { |
21a0a29d | 53 | struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd); |
1da177e4 | 54 | |
21a0a29d LW |
55 | __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET); |
56 | __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET); | |
57 | __raw_writel(wdd->timeout * iwdt->rate, | |
58 | iwdt->base + IXP4XX_OSWT_OFFSET); | |
59 | __raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE, | |
60 | iwdt->base + IXP4XX_OSWE_OFFSET); | |
61 | __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET); | |
1da177e4 | 62 | |
21a0a29d | 63 | return 0; |
1da177e4 LT |
64 | } |
65 | ||
21a0a29d | 66 | static int ixp4xx_wdt_stop(struct watchdog_device *wdd) |
1da177e4 | 67 | { |
21a0a29d | 68 | struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd); |
1da177e4 | 69 | |
21a0a29d LW |
70 | __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET); |
71 | __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET); | |
72 | __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET); | |
1da177e4 | 73 | |
21a0a29d | 74 | return 0; |
1da177e4 LT |
75 | } |
76 | ||
21a0a29d LW |
77 | static int ixp4xx_wdt_set_timeout(struct watchdog_device *wdd, |
78 | unsigned int timeout) | |
1da177e4 | 79 | { |
21a0a29d LW |
80 | wdd->timeout = timeout; |
81 | if (watchdog_active(wdd)) | |
82 | ixp4xx_wdt_start(wdd); | |
1da177e4 LT |
83 | |
84 | return 0; | |
85 | } | |
86 | ||
21a0a29d LW |
87 | static const struct watchdog_ops ixp4xx_wdt_ops = { |
88 | .start = ixp4xx_wdt_start, | |
89 | .stop = ixp4xx_wdt_stop, | |
90 | .set_timeout = ixp4xx_wdt_set_timeout, | |
91 | .owner = THIS_MODULE, | |
1da177e4 LT |
92 | }; |
93 | ||
21a0a29d LW |
94 | static const struct watchdog_info ixp4xx_wdt_info = { |
95 | .options = WDIOF_KEEPALIVEPING | |
96 | | WDIOF_MAGICCLOSE | |
97 | | WDIOF_SETTIMEOUT, | |
98 | .identity = KBUILD_MODNAME, | |
1da177e4 LT |
99 | }; |
100 | ||
21a0a29d LW |
101 | /* Devres-handled clock disablement */ |
102 | static void ixp4xx_clock_action(void *d) | |
103 | { | |
104 | clk_disable_unprepare(d); | |
105 | } | |
106 | ||
107 | static int ixp4xx_wdt_probe(struct platform_device *pdev) | |
1da177e4 | 108 | { |
21a0a29d LW |
109 | struct device *dev = &pdev->dev; |
110 | struct ixp4xx_wdt *iwdt; | |
111 | struct clk *clk; | |
1da177e4 | 112 | int ret; |
1da177e4 | 113 | |
0ba8b9b2 | 114 | if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) { |
21a0a29d | 115 | dev_err(dev, "Rev. A0 IXP42x CPU detected - watchdog disabled\n"); |
1da177e4 LT |
116 | return -ENODEV; |
117 | } | |
1da177e4 | 118 | |
21a0a29d LW |
119 | iwdt = devm_kzalloc(dev, sizeof(*iwdt), GFP_KERNEL); |
120 | if (!iwdt) | |
121 | return -ENOMEM; | |
abd1c6ad | 122 | iwdt->base = (void __iomem *)dev->platform_data; |
1da177e4 | 123 | |
21a0a29d LW |
124 | /* |
125 | * Retrieve rate from a fixed clock from the device tree if | |
126 | * the parent has that, else use the default clock rate. | |
127 | */ | |
128 | clk = devm_clk_get(dev->parent, NULL); | |
129 | if (!IS_ERR(clk)) { | |
130 | ret = clk_prepare_enable(clk); | |
131 | if (ret) | |
132 | return ret; | |
133 | ret = devm_add_action_or_reset(dev, ixp4xx_clock_action, clk); | |
134 | if (ret) | |
135 | return ret; | |
136 | iwdt->rate = clk_get_rate(clk); | |
137 | } | |
138 | if (!iwdt->rate) | |
139 | iwdt->rate = IXP4XX_TIMER_FREQ; | |
1da177e4 | 140 | |
21a0a29d LW |
141 | iwdt->wdd.info = &ixp4xx_wdt_info; |
142 | iwdt->wdd.ops = &ixp4xx_wdt_ops; | |
143 | iwdt->wdd.min_timeout = 1; | |
144 | iwdt->wdd.max_timeout = U32_MAX / iwdt->rate; | |
145 | iwdt->wdd.parent = dev; | |
146 | /* Default to 60 seconds */ | |
147 | iwdt->wdd.timeout = 60U; | |
148 | watchdog_init_timeout(&iwdt->wdd, 0, dev); | |
1da177e4 | 149 | |
21a0a29d LW |
150 | if (__raw_readl(iwdt->base + IXP4XX_OSST_OFFSET) & |
151 | IXP4XX_OSST_TIMER_WARM_RESET) | |
152 | iwdt->wdd.bootstatus = WDIOF_CARDRESET; | |
153 | ||
154 | ret = devm_watchdog_register_device(dev, &iwdt->wdd); | |
155 | if (ret) | |
156 | return ret; | |
157 | ||
158 | dev_info(dev, "IXP4xx watchdog available\n"); | |
1da177e4 | 159 | |
21a0a29d LW |
160 | return 0; |
161 | } | |
1da177e4 | 162 | |
21a0a29d LW |
163 | static struct platform_driver ixp4xx_wdt_driver = { |
164 | .probe = ixp4xx_wdt_probe, | |
165 | .driver = { | |
166 | .name = "ixp4xx-watchdog", | |
167 | }, | |
168 | }; | |
169 | module_platform_driver(ixp4xx_wdt_driver); | |
1da177e4 | 170 | |
21a0a29d LW |
171 | MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); |
172 | MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog"); | |
1da177e4 | 173 | MODULE_LICENSE("GPL"); |