1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Watchdog driver for the K3 RTI module
4 *
5 * (c) Copyright 2019-2020 Texas Instruments Inc.
6 * All rights reserved.
7 */
8
9#include <linux/clk.h>
10#include <linux/device.h>
11#include <linux/err.h>
12#include <linux/io.h>
13#include <linux/kernel.h>
14#include <linux/mod_devicetable.h>
15#include <linux/module.h>
16#include <linux/moduleparam.h>
17#include <linux/of.h>
18#include <linux/of_address.h>
19#include <linux/platform_device.h>
20#include <linux/pm_runtime.h>
21#include <linux/types.h>
22#include <linux/watchdog.h>
23
24#define DEFAULT_HEARTBEAT 60
25
26/* Max heartbeat is calculated at 32kHz source clock */
27#define MAX_HEARTBEAT 1000
28
29/* Timer register set definition */
30#define RTIDWDCTRL 0x90
31#define RTIDWDPRLD 0x94
32#define RTIWDSTATUS 0x98
33#define RTIWDKEY 0x9c
34#define RTIDWDCNTR 0xa0
35#define RTIWWDRXCTRL 0xa4
36#define RTIWWDSIZECTRL 0xa8
37
38#define RTIWWDRX_NMI 0xa
39
40#define RTIWWDSIZE_50P 0x50
41#define RTIWWDSIZE_25P 0x500
42#define RTIWWDSIZE_12P5 0x5000
43#define RTIWWDSIZE_6P25 0x50000
44#define RTIWWDSIZE_3P125 0x500000
45
46#define WDENABLE_KEY 0xa98559da
47
48#define WDKEY_SEQ0 0xe51a
49#define WDKEY_SEQ1 0xa35c
50
51#define WDT_PRELOAD_SHIFT 13
52
53#define WDT_PRELOAD_MAX 0xfff
54
55#define DWDST BIT(1)
56
57#define PON_REASON_SOF_NUM 0xBBBBCCCC
58#define PON_REASON_MAGIC_NUM 0xDDDDDDDD
59#define PON_REASON_EOF_NUM 0xCCCCBBBB
60#define RESERVED_MEM_MIN_SIZE 12
61
62static int heartbeat = DEFAULT_HEARTBEAT;
63
64/*
65 * struct to hold data for each WDT device
66 * @base - base io address of WD device
67 * @freq - source clock frequency of WDT
68 * @wdd - hold watchdog device as is in WDT core
69 */
70struct rti_wdt_device {
71 void __iomem *base;
72 unsigned long freq;
73 struct watchdog_device wdd;
74};
75
76static int rti_wdt_start(struct watchdog_device *wdd)
77{
78 u32 timer_margin;
79 struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
80
81 /* set timeout period */
82 timer_margin = (u64)wdd->timeout * wdt->freq;
83 timer_margin >>= WDT_PRELOAD_SHIFT;
84 if (timer_margin > WDT_PRELOAD_MAX)
85 timer_margin = WDT_PRELOAD_MAX;
86 writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
87
88 /*
89 * RTI only supports a windowed mode, where the watchdog can only
90 * be petted during the open window; not too early or not too late.
91 * The HW configuration options only allow for the open window size
92 * to be 50% or less than that; we obviouly want to configure the open
93 * window as large as possible so we select the 50% option.
94 */
95 wdd->min_hw_heartbeat_ms = 500 * wdd->timeout;
96
97 /* Generate NMI when wdt expires */
98 writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
99
100 /* Open window size 50%; this is the largest window size available */
101 writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
102
103 readl_relaxed(wdt->base + RTIWWDSIZECTRL);
104
105 /* enable watchdog */
106 writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
107 return 0;
108}
109
110static int rti_wdt_ping(struct watchdog_device *wdd)
111{
112 struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
113
114 /* put watchdog in service state */
115 writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
116 /* put watchdog in active state */
117 writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
118
119 return 0;
120}
121
122static int rti_wdt_setup_hw_hb(struct watchdog_device *wdd, u32 wsize)
123{
124 /*
125 * RTI only supports a windowed mode, where the watchdog can only
126 * be petted during the open window; not too early or not too late.
127 * The HW configuration options only allow for the open window size
128 * to be 50% or less than that.
129 */
130 switch (wsize) {
131 case RTIWWDSIZE_50P:
132 /* 50% open window => 50% min heartbeat */
133 wdd->min_hw_heartbeat_ms = 500 * heartbeat;
134 break;
135
136 case RTIWWDSIZE_25P:
137 /* 25% open window => 75% min heartbeat */
138 wdd->min_hw_heartbeat_ms = 750 * heartbeat;
139 break;
140
141 case RTIWWDSIZE_12P5:
142 /* 12.5% open window => 87.5% min heartbeat */
143 wdd->min_hw_heartbeat_ms = 875 * heartbeat;
144 break;
145
146 case RTIWWDSIZE_6P25:
147 /* 6.5% open window => 93.5% min heartbeat */
148 wdd->min_hw_heartbeat_ms = 935 * heartbeat;
149 break;
150
151 case RTIWWDSIZE_3P125:
152 /* 3.125% open window => 96.9% min heartbeat */
153 wdd->min_hw_heartbeat_ms = 969 * heartbeat;
154 break;
155
156 default:
157 return -EINVAL;
158 }
159
160 return 0;
161}
162
163static unsigned int rti_wdt_get_timeleft_ms(struct watchdog_device *wdd)
164{
165 u64 timer_counter;
166 u32 val;
167 struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
168
169 /* if timeout has occurred then return 0 */
170 val = readl_relaxed(wdt->base + RTIWDSTATUS);
171 if (val & DWDST)
172 return 0;
173
174 timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
175
176 timer_counter *= 1000;
177
178 do_div(timer_counter, wdt->freq);
179
180 return timer_counter;
181}
182
183static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
184{
185 return rti_wdt_get_timeleft_ms(wdd) / 1000;
186}
187
188static const struct watchdog_info rti_wdt_info = {
189 .options = WDIOF_KEEPALIVEPING,
190 .identity = "K3 RTI Watchdog",
191};
192
193static const struct watchdog_ops rti_wdt_ops = {
194 .owner = THIS_MODULE,
195 .start = rti_wdt_start,
196 .ping = rti_wdt_ping,
197 .get_timeleft = rti_wdt_get_timeleft,
198};
199
200static int rti_wdt_probe(struct platform_device *pdev)
201{
202 int ret = 0;
203 struct device *dev = &pdev->dev;
204 struct watchdog_device *wdd;
205 struct rti_wdt_device *wdt;
206 struct clk *clk;
207 u32 last_ping = 0;
208 struct device_node *node;
209 u32 reserved_mem_size;
210 struct resource res;
211 u32 *vaddr;
212 u64 paddr;
213
214 wdt = devm_kzalloc(dev, size: sizeof(*wdt), GFP_KERNEL);
215 if (!wdt)
216 return -ENOMEM;
217
218 clk = clk_get(dev, NULL);
219 if (IS_ERR(ptr: clk))
220 return dev_err_probe(dev, err: PTR_ERR(ptr: clk), fmt: "failed to get clock\n");
221
222 wdt->freq = clk_get_rate(clk);
223
224 clk_put(clk);
225
226 if (!wdt->freq) {
227 dev_err(dev, "Failed to get fck rate.\n");
228 return -EINVAL;
229 }
230
231 /*
232 * If watchdog is running at 32k clock, it is not accurate.
233 * Adjust frequency down in this case so that we don't pet
234 * the watchdog too often.
235 */
236 if (wdt->freq < 32768)
237 wdt->freq = wdt->freq * 9 / 10;
238
239 pm_runtime_enable(dev);
240 ret = pm_runtime_resume_and_get(dev);
241 if (ret < 0) {
242 pm_runtime_disable(dev: &pdev->dev);
243 return dev_err_probe(dev, err: ret, fmt: "runtime pm failed\n");
244 }
245
246 platform_set_drvdata(pdev, data: wdt);
247
248 wdd = &wdt->wdd;
249 wdd->info = &rti_wdt_info;
250 wdd->ops = &rti_wdt_ops;
251 wdd->min_timeout = 1;
252 wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
253 wdt->freq * 1000;
254 wdd->parent = dev;
255
256 watchdog_set_drvdata(wdd, data: wdt);
257 watchdog_set_nowayout(wdd, nowayout: 1);
258 watchdog_set_restart_priority(wdd, priority: 128);
259
260 wdt->base = devm_platform_ioremap_resource(pdev, index: 0);
261 if (IS_ERR(ptr: wdt->base)) {
262 ret = PTR_ERR(ptr: wdt->base);
263 goto err_iomap;
264 }
265
266 if (readl(addr: wdt->base + RTIDWDCTRL) == WDENABLE_KEY) {
267 int preset_heartbeat;
268 u32 time_left_ms;
269 u64 heartbeat_ms;
270 u32 wsize;
271
272 set_bit(WDOG_HW_RUNNING, addr: &wdd->status);
273 time_left_ms = rti_wdt_get_timeleft_ms(wdd);
274 heartbeat_ms = readl(addr: wdt->base + RTIDWDPRLD);
275 heartbeat_ms <<= WDT_PRELOAD_SHIFT;
276 heartbeat_ms *= 1000;
277 do_div(heartbeat_ms, wdt->freq);
278 preset_heartbeat = heartbeat_ms + 500;
279 preset_heartbeat /= 1000;
280 if (preset_heartbeat != heartbeat)
281 dev_warn(dev, "watchdog already running, ignoring heartbeat config!\n");
282
283 heartbeat = preset_heartbeat;
284
285 wsize = readl(addr: wdt->base + RTIWWDSIZECTRL);
286 ret = rti_wdt_setup_hw_hb(wdd, wsize);
287 if (ret) {
288 dev_err(dev, "bad window size.\n");
289 goto err_iomap;
290 }
291
292 last_ping = heartbeat_ms - time_left_ms;
293 if (time_left_ms > heartbeat_ms) {
294 dev_warn(dev, "time_left > heartbeat? Assuming last ping just before now.\n");
295 last_ping = 0;
296 }
297 }
298
299 node = of_parse_phandle(np: pdev->dev.of_node, phandle_name: "memory-region", index: 0);
300 if (node) {
301 ret = of_address_to_resource(dev: node, index: 0, r: &res);
302 if (ret) {
303 dev_err(dev, "No memory address assigned to the region.\n");
304 goto err_iomap;
305 }
306
307 /*
308 * If reserved memory is defined for watchdog reset cause.
309 * Readout the Power-on(PON) reason and pass to bootstatus.
310 */
311 paddr = res.start;
312 reserved_mem_size = resource_size(res: &res);
313 if (reserved_mem_size < RESERVED_MEM_MIN_SIZE) {
314 dev_err(dev, "The size of reserved memory is too small.\n");
315 ret = -EINVAL;
316 goto err_iomap;
317 }
318
319 vaddr = memremap(offset: paddr, size: reserved_mem_size, flags: MEMREMAP_WB);
320 if (!vaddr) {
321 dev_err(dev, "Failed to map memory-region.\n");
322 ret = -ENOMEM;
323 goto err_iomap;
324 }
325
326 if (vaddr[0] == PON_REASON_SOF_NUM &&
327 vaddr[1] == PON_REASON_MAGIC_NUM &&
328 vaddr[2] == PON_REASON_EOF_NUM) {
329 wdd->bootstatus |= WDIOF_CARDRESET;
330 }
331 memset(vaddr, 0, reserved_mem_size);
332 memunmap(addr: vaddr);
333 }
334
335 watchdog_init_timeout(wdd, timeout_parm: heartbeat, dev);
336
337 ret = watchdog_register_device(wdd);
338 if (ret) {
339 dev_err(dev, "cannot register watchdog device\n");
340 goto err_iomap;
341 }
342
343 if (last_ping)
344 watchdog_set_last_hw_keepalive(wdd, last_ping);
345
346 return 0;
347
348err_iomap:
349 pm_runtime_put_sync(dev: &pdev->dev);
350 pm_runtime_disable(dev: &pdev->dev);
351
352 return ret;
353}
354
355static void rti_wdt_remove(struct platform_device *pdev)
356{
357 struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
358
359 watchdog_unregister_device(&wdt->wdd);
360 pm_runtime_put(dev: &pdev->dev);
361 pm_runtime_disable(dev: &pdev->dev);
362}
363
364static const struct of_device_id rti_wdt_of_match[] = {
365 { .compatible = "ti,j7-rti-wdt", },
366 {},
367};
368MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
369
370static struct platform_driver rti_wdt_driver = {
371 .driver = {
372 .name = "rti-wdt",
373 .of_match_table = rti_wdt_of_match,
374 },
375 .probe = rti_wdt_probe,
376 .remove_new = rti_wdt_remove,
377};
378
379module_platform_driver(rti_wdt_driver);
380
381MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
382MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
383
384module_param(heartbeat, int, 0);
385MODULE_PARM_DESC(heartbeat,
386 "Watchdog heartbeat period in seconds from 1 to "
387 __MODULE_STRING(MAX_HEARTBEAT) ", default "
388 __MODULE_STRING(DEFAULT_HEARTBEAT));
389
390MODULE_LICENSE("GPL");
391MODULE_ALIAS("platform:rti-wdt");
392

source code of linux/drivers/watchdog/rti_wdt.c