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2f58b8d0 JC |
1 | /* |
2 | * This program is free software; you can redistribute it and/or modify it | |
3 | * under the terms of the GNU General Public License version 2 as published | |
4 | * by the Free Software Foundation. | |
5 | * | |
f3519a66 | 6 | * Copyright (C) 2010 John Crispin <john@phrozen.org> |
710322ba | 7 | * Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de> |
2f58b8d0 JC |
8 | * Based on EP93xx wdt driver |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
1f59f8af | 12 | #include <linux/bitops.h> |
2f58b8d0 | 13 | #include <linux/watchdog.h> |
cdb86121 | 14 | #include <linux/of_platform.h> |
2f58b8d0 JC |
15 | #include <linux/uaccess.h> |
16 | #include <linux/clk.h> | |
17 | #include <linux/io.h> | |
710322ba HM |
18 | #include <linux/regmap.h> |
19 | #include <linux/mfd/syscon.h> | |
2f58b8d0 | 20 | |
cdb86121 | 21 | #include <lantiq_soc.h> |
2f58b8d0 | 22 | |
710322ba HM |
23 | #define LTQ_XRX_RCU_RST_STAT 0x0014 |
24 | #define LTQ_XRX_RCU_RST_STAT_WDT BIT(31) | |
25 | ||
26 | /* CPU0 Reset Source Register */ | |
27 | #define LTQ_FALCON_SYS1_CPU0RS 0x0060 | |
28 | /* reset cause mask */ | |
29 | #define LTQ_FALCON_SYS1_CPU0RS_MASK 0x0007 | |
30 | #define LTQ_FALCON_SYS1_CPU0RS_WDT 0x02 | |
31 | ||
cdb86121 JC |
32 | /* |
33 | * Section 3.4 of the datasheet | |
2f58b8d0 JC |
34 | * The password sequence protects the WDT control register from unintended |
35 | * write actions, which might cause malfunction of the WDT. | |
36 | * | |
37 | * essentially the following two magic passwords need to be written to allow | |
38 | * IO access to the WDT core | |
39 | */ | |
1f59f8af HM |
40 | #define LTQ_WDT_CR_PW1 0x00BE0000 |
41 | #define LTQ_WDT_CR_PW2 0x00DC0000 | |
42 | ||
43 | #define LTQ_WDT_CR 0x0 /* watchdog control register */ | |
44 | #define LTQ_WDT_CR_GEN BIT(31) /* enable bit */ | |
45 | /* Pre-warning limit set to 1/16 of max WDT period */ | |
46 | #define LTQ_WDT_CR_PWL (0x3 << 26) | |
47 | /* set clock divider to 0x40000 */ | |
48 | #define LTQ_WDT_CR_CLKDIV (0x3 << 24) | |
49 | #define LTQ_WDT_CR_PW_MASK GENMASK(23, 16) /* Password field */ | |
50 | #define LTQ_WDT_CR_MAX_TIMEOUT ((1 << 16) - 1) /* The reload field is 16 bit */ | |
dcd7e04e HM |
51 | #define LTQ_WDT_SR 0x8 /* watchdog status register */ |
52 | #define LTQ_WDT_SR_EN BIT(31) /* Enable */ | |
2f58b8d0 | 53 | |
2f58b8d0 | 54 | #define LTQ_WDT_DIVIDER 0x40000 |
2f58b8d0 | 55 | |
86a1e189 | 56 | static bool nowayout = WATCHDOG_NOWAYOUT; |
2f58b8d0 | 57 | |
dcd7e04e HM |
58 | struct ltq_wdt_hw { |
59 | int (*bootstatus_get)(struct device *dev); | |
60 | }; | |
2f58b8d0 | 61 | |
dcd7e04e HM |
62 | struct ltq_wdt_priv { |
63 | struct watchdog_device wdt; | |
64 | void __iomem *membase; | |
65 | unsigned long clk_rate; | |
66 | }; | |
2f58b8d0 | 67 | |
dcd7e04e | 68 | static u32 ltq_wdt_r32(struct ltq_wdt_priv *priv, u32 offset) |
2f58b8d0 | 69 | { |
dcd7e04e | 70 | return __raw_readl(priv->membase + offset); |
2f58b8d0 JC |
71 | } |
72 | ||
dcd7e04e | 73 | static void ltq_wdt_w32(struct ltq_wdt_priv *priv, u32 val, u32 offset) |
2f58b8d0 | 74 | { |
dcd7e04e | 75 | __raw_writel(val, priv->membase + offset); |
2f58b8d0 JC |
76 | } |
77 | ||
dcd7e04e HM |
78 | static void ltq_wdt_mask(struct ltq_wdt_priv *priv, u32 clear, u32 set, |
79 | u32 offset) | |
2f58b8d0 | 80 | { |
dcd7e04e HM |
81 | u32 val = ltq_wdt_r32(priv, offset); |
82 | ||
83 | val &= ~(clear); | |
84 | val |= set; | |
85 | ltq_wdt_w32(priv, val, offset); | |
86 | } | |
2f58b8d0 | 87 | |
dcd7e04e HM |
88 | static struct ltq_wdt_priv *ltq_wdt_get_priv(struct watchdog_device *wdt) |
89 | { | |
90 | return container_of(wdt, struct ltq_wdt_priv, wdt); | |
2f58b8d0 JC |
91 | } |
92 | ||
dcd7e04e | 93 | static struct watchdog_info ltq_wdt_info = { |
2f58b8d0 | 94 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
dcd7e04e | 95 | WDIOF_CARDRESET, |
2f58b8d0 JC |
96 | .identity = "ltq_wdt", |
97 | }; | |
98 | ||
dcd7e04e | 99 | static int ltq_wdt_start(struct watchdog_device *wdt) |
2f58b8d0 | 100 | { |
dcd7e04e HM |
101 | struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt); |
102 | u32 timeout; | |
103 | ||
104 | timeout = wdt->timeout * priv->clk_rate; | |
105 | ||
106 | ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK, LTQ_WDT_CR_PW1, LTQ_WDT_CR); | |
107 | /* write the second magic plus the configuration and new timeout */ | |
108 | ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK | LTQ_WDT_CR_MAX_TIMEOUT, | |
109 | LTQ_WDT_CR_GEN | LTQ_WDT_CR_PWL | LTQ_WDT_CR_CLKDIV | | |
110 | LTQ_WDT_CR_PW2 | timeout, | |
111 | LTQ_WDT_CR); | |
112 | ||
113 | return 0; | |
2f58b8d0 JC |
114 | } |
115 | ||
dcd7e04e | 116 | static int ltq_wdt_stop(struct watchdog_device *wdt) |
2f58b8d0 | 117 | { |
dcd7e04e HM |
118 | struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt); |
119 | ||
120 | ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK, LTQ_WDT_CR_PW1, LTQ_WDT_CR); | |
121 | ltq_wdt_mask(priv, LTQ_WDT_CR_GEN | LTQ_WDT_CR_PW_MASK, | |
122 | LTQ_WDT_CR_PW2, LTQ_WDT_CR); | |
2f58b8d0 | 123 | |
dcd7e04e | 124 | return 0; |
2f58b8d0 JC |
125 | } |
126 | ||
dcd7e04e | 127 | static int ltq_wdt_ping(struct watchdog_device *wdt) |
2f58b8d0 | 128 | { |
dcd7e04e HM |
129 | struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt); |
130 | u32 timeout; | |
131 | ||
132 | timeout = wdt->timeout * priv->clk_rate; | |
133 | ||
134 | ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK, LTQ_WDT_CR_PW1, LTQ_WDT_CR); | |
135 | /* write the second magic plus the configuration and new timeout */ | |
136 | ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK | LTQ_WDT_CR_MAX_TIMEOUT, | |
137 | LTQ_WDT_CR_PW2 | timeout, LTQ_WDT_CR); | |
2f58b8d0 JC |
138 | |
139 | return 0; | |
140 | } | |
141 | ||
dcd7e04e | 142 | static const struct watchdog_ops ltq_wdt_ops = { |
2f58b8d0 | 143 | .owner = THIS_MODULE, |
dcd7e04e HM |
144 | .start = ltq_wdt_start, |
145 | .stop = ltq_wdt_stop, | |
146 | .ping = ltq_wdt_ping, | |
2f58b8d0 JC |
147 | }; |
148 | ||
dcd7e04e | 149 | static int ltq_wdt_xrx_bootstatus_get(struct device *dev) |
710322ba | 150 | { |
710322ba HM |
151 | struct regmap *rcu_regmap; |
152 | u32 val; | |
153 | int err; | |
154 | ||
155 | rcu_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap"); | |
156 | if (IS_ERR(rcu_regmap)) | |
157 | return PTR_ERR(rcu_regmap); | |
158 | ||
159 | err = regmap_read(rcu_regmap, LTQ_XRX_RCU_RST_STAT, &val); | |
160 | if (err) | |
161 | return err; | |
162 | ||
163 | if (val & LTQ_XRX_RCU_RST_STAT_WDT) | |
dcd7e04e | 164 | return WDIOF_CARDRESET; |
710322ba HM |
165 | |
166 | return 0; | |
167 | } | |
168 | ||
dcd7e04e | 169 | static int ltq_wdt_falcon_bootstatus_get(struct device *dev) |
710322ba | 170 | { |
710322ba HM |
171 | struct regmap *rcu_regmap; |
172 | u32 val; | |
173 | int err; | |
174 | ||
175 | rcu_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, | |
176 | "lantiq,rcu"); | |
177 | if (IS_ERR(rcu_regmap)) | |
178 | return PTR_ERR(rcu_regmap); | |
179 | ||
180 | err = regmap_read(rcu_regmap, LTQ_FALCON_SYS1_CPU0RS, &val); | |
181 | if (err) | |
182 | return err; | |
183 | ||
184 | if ((val & LTQ_FALCON_SYS1_CPU0RS_MASK) == LTQ_FALCON_SYS1_CPU0RS_WDT) | |
dcd7e04e | 185 | return WDIOF_CARDRESET; |
710322ba HM |
186 | |
187 | return 0; | |
188 | } | |
189 | ||
dcd7e04e | 190 | static int ltq_wdt_probe(struct platform_device *pdev) |
2f58b8d0 | 191 | { |
dcd7e04e HM |
192 | struct device *dev = &pdev->dev; |
193 | struct ltq_wdt_priv *priv; | |
194 | struct watchdog_device *wdt; | |
195 | struct resource *res; | |
2f58b8d0 | 196 | struct clk *clk; |
dcd7e04e | 197 | const struct ltq_wdt_hw *ltq_wdt_hw; |
710322ba | 198 | int ret; |
dcd7e04e | 199 | u32 status; |
2f58b8d0 | 200 | |
dcd7e04e HM |
201 | priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); |
202 | if (!priv) | |
203 | return -ENOMEM; | |
2f58b8d0 | 204 | |
dcd7e04e HM |
205 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
206 | priv->membase = devm_ioremap_resource(dev, res); | |
207 | if (IS_ERR(priv->membase)) | |
208 | return PTR_ERR(priv->membase); | |
710322ba | 209 | |
2f58b8d0 | 210 | /* we do not need to enable the clock as it is always running */ |
cdb86121 | 211 | clk = clk_get_io(); |
dcd7e04e HM |
212 | priv->clk_rate = clk_get_rate(clk) / LTQ_WDT_DIVIDER; |
213 | if (!priv->clk_rate) { | |
214 | dev_err(dev, "clock rate less than divider %i\n", | |
215 | LTQ_WDT_DIVIDER); | |
216 | return -EINVAL; | |
cdb86121 | 217 | } |
2f58b8d0 | 218 | |
dcd7e04e HM |
219 | wdt = &priv->wdt; |
220 | wdt->info = <q_wdt_info; | |
221 | wdt->ops = <q_wdt_ops; | |
222 | wdt->min_timeout = 1; | |
223 | wdt->max_timeout = LTQ_WDT_CR_MAX_TIMEOUT / priv->clk_rate; | |
224 | wdt->timeout = wdt->max_timeout; | |
225 | wdt->parent = dev; | |
226 | ||
227 | ltq_wdt_hw = of_device_get_match_data(dev); | |
228 | if (ltq_wdt_hw && ltq_wdt_hw->bootstatus_get) { | |
229 | ret = ltq_wdt_hw->bootstatus_get(dev); | |
230 | if (ret >= 0) | |
231 | wdt->bootstatus = ret; | |
232 | } | |
2f58b8d0 | 233 | |
dcd7e04e HM |
234 | watchdog_set_nowayout(wdt, nowayout); |
235 | watchdog_init_timeout(wdt, 0, dev); | |
236 | ||
237 | status = ltq_wdt_r32(priv, LTQ_WDT_SR); | |
238 | if (status & LTQ_WDT_SR_EN) { | |
239 | /* | |
240 | * If the watchdog is already running overwrite it with our | |
241 | * new settings. Stop is not needed as the start call will | |
242 | * replace all settings anyway. | |
243 | */ | |
244 | ltq_wdt_start(wdt); | |
245 | set_bit(WDOG_HW_RUNNING, &wdt->status); | |
246 | } | |
2f58b8d0 | 247 | |
dcd7e04e | 248 | return devm_watchdog_register_device(dev, wdt); |
2f58b8d0 JC |
249 | } |
250 | ||
dcd7e04e HM |
251 | static const struct ltq_wdt_hw ltq_wdt_xrx100 = { |
252 | .bootstatus_get = ltq_wdt_xrx_bootstatus_get, | |
253 | }; | |
254 | ||
255 | static const struct ltq_wdt_hw ltq_wdt_falcon = { | |
256 | .bootstatus_get = ltq_wdt_falcon_bootstatus_get, | |
257 | }; | |
258 | ||
cdb86121 | 259 | static const struct of_device_id ltq_wdt_match[] = { |
dcd7e04e HM |
260 | { .compatible = "lantiq,wdt", .data = NULL }, |
261 | { .compatible = "lantiq,xrx100-wdt", .data = <q_wdt_xrx100 }, | |
262 | { .compatible = "lantiq,falcon-wdt", .data = <q_wdt_falcon }, | |
cdb86121 JC |
263 | {}, |
264 | }; | |
265 | MODULE_DEVICE_TABLE(of, ltq_wdt_match); | |
2f58b8d0 JC |
266 | |
267 | static struct platform_driver ltq_wdt_driver = { | |
cdb86121 | 268 | .probe = ltq_wdt_probe, |
2f58b8d0 | 269 | .driver = { |
cdb86121 | 270 | .name = "wdt", |
cdb86121 | 271 | .of_match_table = ltq_wdt_match, |
2f58b8d0 JC |
272 | }, |
273 | }; | |
274 | ||
cdb86121 | 275 | module_platform_driver(ltq_wdt_driver); |
2f58b8d0 | 276 | |
86a1e189 | 277 | module_param(nowayout, bool, 0); |
2f58b8d0 | 278 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
f3519a66 | 279 | MODULE_AUTHOR("John Crispin <john@phrozen.org>"); |
2f58b8d0 JC |
280 | MODULE_DESCRIPTION("Lantiq SoC Watchdog"); |
281 | MODULE_LICENSE("GPL"); |