| Jan Kiszka | ddf21d5 | 2020-06-23 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 | |
| 40 | struct rti_wdt_priv { |
| 41 | phys_addr_t regs; |
| 42 | unsigned int clk_khz; |
| 43 | }; |
| 44 | |
| 45 | static 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 | |
| 70 | static 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 | |
| 86 | static 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 | |
| 105 | static const struct wdt_ops rti_wdt_ops = { |
| 106 | .start = rti_wdt_start, |
| 107 | .reset = rti_wdt_reset, |
| 108 | }; |
| 109 | |
| 110 | static const struct udevice_id rti_wdt_ids[] = { |
| 111 | { .compatible = "ti,j7-rti-wdt" }, |
| 112 | { } |
| 113 | }; |
| 114 | |
| 115 | U_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, |
| Simon Glass | 8a2b47f | 2020-12-03 16:55:17 -0700 | [diff] [blame] | 121 | .priv_auto = sizeof(struct rti_wdt_priv), |
| Jan Kiszka | ddf21d5 | 2020-06-23 13:15:08 +0200 | [diff] [blame] | 122 | .flags = DM_FLAG_REMOVE_WITH_PD_ON, |
| 123 | }; |