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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * intel-mid_wdt: generic Intel MID SCU watchdog driver
4 *
5 * Platforms supported so far:
6 * - Merrifield only
7 *
8 * Copyright (C) 2014 Intel Corporation. All rights reserved.
9 * Contact: David Cohen <david.a.cohen@linux.intel.com>
10 */
11
12#include <linux/interrupt.h>
13#include <linux/module.h>
14#include <linux/nmi.h>
15#include <linux/platform_device.h>
16#include <linux/watchdog.h>
17#include <linux/platform_data/intel-mid_wdt.h>
18
19#include <asm/intel_scu_ipc.h>
20#include <asm/intel-mid.h>
21
22#define IPC_WATCHDOG 0xf8
23
24#define MID_WDT_PRETIMEOUT 15
25#define MID_WDT_TIMEOUT_MIN (1 + MID_WDT_PRETIMEOUT)
26#define MID_WDT_TIMEOUT_MAX 170
27#define MID_WDT_DEFAULT_TIMEOUT 90
28
29/* SCU watchdog messages */
30enum {
31 SCU_WATCHDOG_START = 0,
32 SCU_WATCHDOG_STOP,
33 SCU_WATCHDOG_KEEPALIVE,
34};
35
36struct mid_wdt {
37 struct watchdog_device wd;
38 struct device *dev;
39 struct intel_scu_ipc_dev *scu;
40};
41
42static inline int
43wdt_command(struct mid_wdt *mid, int sub, const void *in, size_t inlen, size_t size)
44{
45 struct intel_scu_ipc_dev *scu = mid->scu;
46
47 return intel_scu_ipc_dev_command_with_size(scu, IPC_WATCHDOG, sub, in,
48 inlen, size, NULL, 0);
49}
50
51static int wdt_start(struct watchdog_device *wd)
52{
53 struct mid_wdt *mid = watchdog_get_drvdata(wd);
54 int ret, in_size;
55 int timeout = wd->timeout;
56 struct ipc_wd_start {
57 u32 pretimeout;
58 u32 timeout;
59 } ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout };
60
61 /*
62 * SCU expects the input size for watchdog IPC to be 2 which is the
63 * size of the structure in dwords. SCU IPC normally takes bytes
64 * but this is a special case where we specify size to be different
65 * than inlen.
66 */
67 in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4);
68
69 ret = wdt_command(mid, SCU_WATCHDOG_START, &ipc_wd_start,
70 sizeof(ipc_wd_start), in_size);
71 if (ret)
72 dev_crit(mid->dev, "error starting watchdog: %d\n", ret);
73
74 return ret;
75}
76
77static int wdt_ping(struct watchdog_device *wd)
78{
79 struct mid_wdt *mid = watchdog_get_drvdata(wd);
80 int ret;
81
82 ret = wdt_command(mid, SCU_WATCHDOG_KEEPALIVE, NULL, 0, 0);
83 if (ret)
84 dev_crit(mid->dev, "Error executing keepalive: %d\n", ret);
85
86 return ret;
87}
88
89static int wdt_stop(struct watchdog_device *wd)
90{
91 struct mid_wdt *mid = watchdog_get_drvdata(wd);
92 int ret;
93
94 ret = wdt_command(mid, SCU_WATCHDOG_STOP, NULL, 0, 0);
95 if (ret)
96 dev_crit(mid->dev, "Error stopping watchdog: %d\n", ret);
97
98 return ret;
99}
100
101static irqreturn_t mid_wdt_irq(int irq, void *dev_id)
102{
103 panic("Kernel Watchdog");
104
105 /* This code should not be reached */
106 return IRQ_HANDLED;
107}
108
109static const struct watchdog_info mid_wdt_info = {
110 .identity = "Intel MID SCU watchdog",
111 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
112};
113
114static const struct watchdog_ops mid_wdt_ops = {
115 .owner = THIS_MODULE,
116 .start = wdt_start,
117 .stop = wdt_stop,
118 .ping = wdt_ping,
119};
120
121static int mid_wdt_probe(struct platform_device *pdev)
122{
123 struct device *dev = &pdev->dev;
124 struct watchdog_device *wdt_dev;
125 struct intel_mid_wdt_pdata *pdata = dev->platform_data;
126 struct mid_wdt *mid;
127 int ret;
128
129 if (!pdata) {
130 dev_err(dev, "missing platform data\n");
131 return -EINVAL;
132 }
133
134 if (pdata->probe) {
135 ret = pdata->probe(pdev);
136 if (ret)
137 return ret;
138 }
139
140 mid = devm_kzalloc(dev, sizeof(*mid), GFP_KERNEL);
141 if (!mid)
142 return -ENOMEM;
143
144 mid->dev = dev;
145 wdt_dev = &mid->wd;
146
147 wdt_dev->info = &mid_wdt_info;
148 wdt_dev->ops = &mid_wdt_ops;
149 wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN;
150 wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX;
151 wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT;
152 wdt_dev->parent = dev;
153
154 watchdog_set_nowayout(wdt_dev, WATCHDOG_NOWAYOUT);
155 watchdog_set_drvdata(wdt_dev, mid);
156
157 mid->scu = devm_intel_scu_ipc_dev_get(dev);
158 if (!mid->scu)
159 return -EPROBE_DEFER;
160
161 ret = devm_request_irq(dev, pdata->irq, mid_wdt_irq,
162 IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog",
163 wdt_dev);
164 if (ret) {
165 dev_err(dev, "error requesting warning irq %d\n", pdata->irq);
166 return ret;
167 }
168
169 /*
170 * The firmware followed by U-Boot leaves the watchdog running
171 * with the default threshold which may vary. When we get here
172 * we should make a decision to prevent any side effects before
173 * user space daemon will take care of it. The best option,
174 * taking into consideration that there is no way to read values
175 * back from hardware, is to enforce watchdog being run with
176 * deterministic values.
177 */
178 ret = wdt_start(wdt_dev);
179 if (ret)
180 return ret;
181
182 /* Make sure the watchdog is serviced */
183 set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
184
185 ret = devm_watchdog_register_device(dev, wdt_dev);
186 if (ret)
187 return ret;
188
189 dev_info(dev, "Intel MID watchdog device probed\n");
190
191 return 0;
192}
193
194static struct platform_driver mid_wdt_driver = {
195 .probe = mid_wdt_probe,
196 .driver = {
197 .name = "intel_mid_wdt",
198 },
199};
200
201module_platform_driver(mid_wdt_driver);
202
203MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>");
204MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform");
205MODULE_LICENSE("GPL");
206MODULE_ALIAS("platform:intel_mid_wdt");
1/*
2 * intel-mid_wdt: generic Intel MID SCU watchdog driver
3 *
4 * Platforms supported so far:
5 * - Merrifield only
6 *
7 * Copyright (C) 2014 Intel Corporation. All rights reserved.
8 * Contact: David Cohen <david.a.cohen@linux.intel.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of version 2 of the GNU General
12 * Public License as published by the Free Software Foundation.
13 */
14
15#include <linux/interrupt.h>
16#include <linux/module.h>
17#include <linux/nmi.h>
18#include <linux/platform_device.h>
19#include <linux/watchdog.h>
20#include <linux/platform_data/intel-mid_wdt.h>
21
22#include <asm/intel_scu_ipc.h>
23#include <asm/intel-mid.h>
24
25#define IPC_WATCHDOG 0xf8
26
27#define MID_WDT_PRETIMEOUT 15
28#define MID_WDT_TIMEOUT_MIN (1 + MID_WDT_PRETIMEOUT)
29#define MID_WDT_TIMEOUT_MAX 170
30#define MID_WDT_DEFAULT_TIMEOUT 90
31
32/* SCU watchdog messages */
33enum {
34 SCU_WATCHDOG_START = 0,
35 SCU_WATCHDOG_STOP,
36 SCU_WATCHDOG_KEEPALIVE,
37};
38
39static inline int wdt_command(int sub, u32 *in, int inlen)
40{
41 return intel_scu_ipc_command(IPC_WATCHDOG, sub, in, inlen, NULL, 0);
42}
43
44static int wdt_start(struct watchdog_device *wd)
45{
46 struct device *dev = watchdog_get_drvdata(wd);
47 int ret, in_size;
48 int timeout = wd->timeout;
49 struct ipc_wd_start {
50 u32 pretimeout;
51 u32 timeout;
52 } ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout };
53
54 /*
55 * SCU expects the input size for watchdog IPC to
56 * be based on 4 bytes
57 */
58 in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4);
59
60 ret = wdt_command(SCU_WATCHDOG_START, (u32 *)&ipc_wd_start, in_size);
61 if (ret)
62 dev_crit(dev, "error starting watchdog: %d\n", ret);
63
64 return ret;
65}
66
67static int wdt_ping(struct watchdog_device *wd)
68{
69 struct device *dev = watchdog_get_drvdata(wd);
70 int ret;
71
72 ret = wdt_command(SCU_WATCHDOG_KEEPALIVE, NULL, 0);
73 if (ret)
74 dev_crit(dev, "Error executing keepalive: %d\n", ret);
75
76 return ret;
77}
78
79static int wdt_stop(struct watchdog_device *wd)
80{
81 struct device *dev = watchdog_get_drvdata(wd);
82 int ret;
83
84 ret = wdt_command(SCU_WATCHDOG_STOP, NULL, 0);
85 if (ret)
86 dev_crit(dev, "Error stopping watchdog: %d\n", ret);
87
88 return ret;
89}
90
91static irqreturn_t mid_wdt_irq(int irq, void *dev_id)
92{
93 panic("Kernel Watchdog");
94
95 /* This code should not be reached */
96 return IRQ_HANDLED;
97}
98
99static const struct watchdog_info mid_wdt_info = {
100 .identity = "Intel MID SCU watchdog",
101 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
102};
103
104static const struct watchdog_ops mid_wdt_ops = {
105 .owner = THIS_MODULE,
106 .start = wdt_start,
107 .stop = wdt_stop,
108 .ping = wdt_ping,
109};
110
111static int mid_wdt_probe(struct platform_device *pdev)
112{
113 struct watchdog_device *wdt_dev;
114 struct intel_mid_wdt_pdata *pdata = pdev->dev.platform_data;
115 int ret;
116
117 if (!pdata) {
118 dev_err(&pdev->dev, "missing platform data\n");
119 return -EINVAL;
120 }
121
122 if (pdata->probe) {
123 ret = pdata->probe(pdev);
124 if (ret)
125 return ret;
126 }
127
128 wdt_dev = devm_kzalloc(&pdev->dev, sizeof(*wdt_dev), GFP_KERNEL);
129 if (!wdt_dev)
130 return -ENOMEM;
131
132 wdt_dev->info = &mid_wdt_info;
133 wdt_dev->ops = &mid_wdt_ops;
134 wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN;
135 wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX;
136 wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT;
137 wdt_dev->parent = &pdev->dev;
138
139 watchdog_set_drvdata(wdt_dev, &pdev->dev);
140
141 ret = devm_request_irq(&pdev->dev, pdata->irq, mid_wdt_irq,
142 IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog",
143 wdt_dev);
144 if (ret) {
145 dev_err(&pdev->dev, "error requesting warning irq %d\n",
146 pdata->irq);
147 return ret;
148 }
149
150 /*
151 * The firmware followed by U-Boot leaves the watchdog running
152 * with the default threshold which may vary. When we get here
153 * we should make a decision to prevent any side effects before
154 * user space daemon will take care of it. The best option,
155 * taking into consideration that there is no way to read values
156 * back from hardware, is to enforce watchdog being run with
157 * deterministic values.
158 */
159 ret = wdt_start(wdt_dev);
160 if (ret)
161 return ret;
162
163 /* Make sure the watchdog is serviced */
164 set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
165
166 ret = devm_watchdog_register_device(&pdev->dev, wdt_dev);
167 if (ret) {
168 dev_err(&pdev->dev, "error registering watchdog device\n");
169 return ret;
170 }
171
172 dev_info(&pdev->dev, "Intel MID watchdog device probed\n");
173
174 return 0;
175}
176
177static struct platform_driver mid_wdt_driver = {
178 .probe = mid_wdt_probe,
179 .driver = {
180 .name = "intel_mid_wdt",
181 },
182};
183
184module_platform_driver(mid_wdt_driver);
185
186MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>");
187MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform");
188MODULE_LICENSE("GPL");