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gerrit.devboardsforandroid.linaro.org / platform / external / u-boot / 1cb1c0fc8d6b797901f68afe5e9dd18c20401c5e / . / drivers / watchdog / rti_wdt.c
blob: ebe29c74091fa02549a93f8b38d5afd255556194 [file] [log] [blame]
Jan Kiszkad388f362020-06-23 13:15:08 +0200[diff] [blame]1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (c) Siemens AG, 2020
4 *
5 * Authors:
6 * Jan Kiszka <jan.kiszka@siemens.com>
7 *
8 * Derived from linux/drivers/watchdog/rti_wdt.c
9 */
10
11#include <common.h>
12#include <clk.h>
13#include <dm.h>
14#include <power-domain.h>
15#include <wdt.h>
16#include <asm/io.h>
17
18/* Timer register set definition */
19#define RTIDWDCTRL 0x90
20#define RTIDWDPRLD 0x94
21#define RTIWDSTATUS 0x98
22#define RTIWDKEY 0x9c
23#define RTIDWDCNTR 0xa0
24#define RTIWWDRXCTRL 0xa4
25#define RTIWWDSIZECTRL 0xa8
26
27#define RTIWWDRX_NMI 0xa
28
29#define RTIWWDSIZE_50P 0x50
30
31#define WDENABLE_KEY 0xa98559da
32
33#define WDKEY_SEQ0 0xe51a
34#define WDKEY_SEQ1 0xa35c
35
36#define WDT_PRELOAD_SHIFT 13
37
38#define WDT_PRELOAD_MAX 0xfff
39
40struct rti_wdt_priv {
41 phys_addr_t regs;
42 unsigned int clk_khz;
43};
44
45static int rti_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
46{
47 struct rti_wdt_priv *priv = dev_get_priv(dev);
48 u32 timer_margin;
49 int ret;
50
51 if (readl(priv->regs + RTIDWDCTRL) == WDENABLE_KEY)
52 return -EBUSY;
53
54 timer_margin = timeout_ms * priv->clk_khz / 1000;
55 timer_margin >>= WDT_PRELOAD_SHIFT;
56 if (timer_margin > WDT_PRELOAD_MAX)
57 timer_margin = WDT_PRELOAD_MAX;
58
59 writel(timer_margin, priv->regs + RTIDWDPRLD);
60 writel(RTIWWDRX_NMI, priv->regs + RTIWWDRXCTRL);
61 writel(RTIWWDSIZE_50P, priv->regs + RTIWWDSIZECTRL);
62
63 readl(priv->regs + RTIWWDSIZECTRL);
64
65 writel(WDENABLE_KEY, priv->regs + RTIDWDCTRL);
66
67 return 0;
68}
69
70static int rti_wdt_reset(struct udevice *dev)
71{
72 struct rti_wdt_priv *priv = dev_get_priv(dev);
73 u32 prld;
74
75 /* Make sure we do not reset too early */
76 prld = readl(priv->regs + RTIDWDPRLD) << WDT_PRELOAD_SHIFT;
77 if (readl(priv->regs + RTIDWDCNTR) >= prld / 2)
78 return -EPERM;
79
80 writel(WDKEY_SEQ0, priv->regs + RTIWDKEY);
81 writel(WDKEY_SEQ1, priv->regs + RTIWDKEY);
82
83 return 0;
84}
85
86static int rti_wdt_probe(struct udevice *dev)
87{
88 struct rti_wdt_priv *priv = dev_get_priv(dev);
89 struct clk clk;
90 int ret;
91
92 priv->regs = devfdt_get_addr(dev);
93 if (!priv->regs)
94 return -EINVAL;
95
96 ret = clk_get_by_index(dev, 0, &clk);
97 if (ret)
98 return ret;
99
100 priv->clk_khz = clk_get_rate(&clk);
101
102 return 0;
103}
104
105static const struct wdt_ops rti_wdt_ops = {
106 .start = rti_wdt_start,
107 .reset = rti_wdt_reset,
108};
109
110static const struct udevice_id rti_wdt_ids[] = {
111 { .compatible = "ti,j7-rti-wdt" },
112 { }
113};
114
115U_BOOT_DRIVER(rti_wdt) = {
116 .name = "rti_wdt",
117 .id = UCLASS_WDT,
118 .of_match = rti_wdt_ids,
119 .ops = &rti_wdt_ops,
120 .probe = rti_wdt_probe,
121 .priv_auto_alloc_size = sizeof(struct rti_wdt_priv),
122 .flags = DM_FLAG_REMOVE_WITH_PD_ON,
123};