1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (c) 2017 Intel Corporation
4 */
5#include <common.h>
6#include <dm.h>
7#include <log.h>
8#include <wdt.h>
9#include <div64.h>
10#include <asm/scu.h>
11
12/* Hardware timeout in seconds */
13#define WDT_PRETIMEOUT		15
14#define WDT_TIMEOUT_MIN		(1 + WDT_PRETIMEOUT)
15#define WDT_TIMEOUT_MAX		170
16
17/*
18 * Note, firmware chooses 90 seconds as a default timeout for watchdog on
19 * Intel Tangier SoC. It means that without handling it in the running code
20 * the reboot will happen.
21 */
22
23enum {
24	SCU_WATCHDOG_START			= 0,
25	SCU_WATCHDOG_STOP			= 1,
26	SCU_WATCHDOG_KEEPALIVE			= 2,
27	SCU_WATCHDOG_SET_ACTION_ON_TIMEOUT	= 3,
28};
29
30static int tangier_wdt_reset(struct udevice *dev)
31{
32	scu_ipc_simple_command(IPCMSG_WATCHDOG_TIMER, SCU_WATCHDOG_KEEPALIVE);
33	return 0;
34}
35
36static int tangier_wdt_stop(struct udevice *dev)
37{
38	return scu_ipc_simple_command(IPCMSG_WATCHDOG_TIMER, SCU_WATCHDOG_STOP);
39}
40
41static int tangier_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
42{
43	u32 timeout_sec;
44	int in_size;
45	struct ipc_wd_start {
46		u32 pretimeout;
47		u32 timeout;
48	} ipc_wd_start;
49
50	/* Calculate timeout in seconds and restrict to min and max value */
51	do_div(timeout_ms, 1000);
52	timeout_sec = clamp_t(u32, timeout_ms, WDT_TIMEOUT_MIN, WDT_TIMEOUT_MAX);
53
54	/* Update values in the IPC request */
55	ipc_wd_start.pretimeout = timeout_sec - WDT_PRETIMEOUT;
56	ipc_wd_start.timeout = timeout_sec;
57
58	/*
59	 * SCU expects the input size for watchdog IPC
60	 * to be based on 4 bytes
61	 */
62	in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4);
63
64	scu_ipc_command(IPCMSG_WATCHDOG_TIMER, SCU_WATCHDOG_START,
65			(u32 *)&ipc_wd_start, in_size, NULL, 0);
66
67	return 0;
68}
69
70static const struct wdt_ops tangier_wdt_ops = {
71	.reset = tangier_wdt_reset,
72	.start = tangier_wdt_start,
73	.stop = tangier_wdt_stop,
74};
75
76static const struct udevice_id tangier_wdt_ids[] = {
77	{ .compatible = "intel,tangier-wdt" },
78	{ /* sentinel */ }
79};
80
81static int tangier_wdt_probe(struct udevice *dev)
82{
83	debug("%s: Probing wdt%u\n", __func__, dev_seq(dev));
84	return 0;
85}
86
87U_BOOT_DRIVER(wdt_tangier) = {
88	.name = "wdt_tangier",
89	.id = UCLASS_WDT,
90	.of_match = tangier_wdt_ids,
91	.ops = &tangier_wdt_ops,
92	.probe = tangier_wdt_probe,
93};
94