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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 | // SPDX-License-Identifier: GPL-2.0+ /* * Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk> * Copyright (C) 2023 Etienne Dublé (CNRS) <etienne.duble@imag.fr> * * This code is mostly derived from the linux driver. */ #include <dm.h> #include <wdt.h> #include <asm/io.h> #include <linux/delay.h> #define PM_RSTC 0x1c #define PM_WDOG 0x24 #define PM_PASSWORD 0x5a000000 /* The hardware supports a maximum timeout value of 0xfffff ticks * (just below 16 seconds). */ #define PM_WDOG_MAX_TICKS 0x000fffff #define PM_RSTC_WRCFG_CLR 0xffffffcf #define PM_RSTC_WRCFG_FULL_RESET 0x00000020 #define PM_RSTC_RESET 0x00000102 #define MS_TO_WDOG_TICKS(x) (((x) << 16) / 1000) struct bcm2835_wdt_priv { void __iomem *base; u64 timeout_ticks; }; static int bcm2835_wdt_start_ticks(struct udevice *dev, u64 timeout_ticks, ulong flags) { struct bcm2835_wdt_priv *priv = dev_get_priv(dev); void __iomem *base = priv->base; u32 cur; writel(PM_PASSWORD | timeout_ticks, base + PM_WDOG); cur = readl(base + PM_RSTC); writel(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) | PM_RSTC_WRCFG_FULL_RESET, base + PM_RSTC); return 0; } static int bcm2835_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags) { struct bcm2835_wdt_priv *priv = dev_get_priv(dev); priv->timeout_ticks = MS_TO_WDOG_TICKS(timeout_ms); if (priv->timeout_ticks > PM_WDOG_MAX_TICKS) { printf("bcm2835_wdt: the timeout value is too high, using ~16s instead.\n"); priv->timeout_ticks = PM_WDOG_MAX_TICKS; } return bcm2835_wdt_start_ticks(dev, priv->timeout_ticks, flags); } static int bcm2835_wdt_reset(struct udevice *dev) { struct bcm2835_wdt_priv *priv = dev_get_priv(dev); /* restart the timer with the value of priv->timeout_ticks * saved from the last bcm2835_wdt_start() call. */ return bcm2835_wdt_start_ticks(dev, priv->timeout_ticks, 0); } static int bcm2835_wdt_stop(struct udevice *dev) { struct bcm2835_wdt_priv *priv = dev_get_priv(dev); void __iomem *base = priv->base; writel(PM_PASSWORD | PM_RSTC_RESET, base + PM_RSTC); return 0; } static int bcm2835_wdt_expire_now(struct udevice *dev, ulong flags) { int ret; /* use a timeout of 10 ticks (~150us) */ ret = bcm2835_wdt_start_ticks(dev, 10, flags); if (ret) return ret; mdelay(500); return 0; } static const struct wdt_ops bcm2835_wdt_ops = { .reset = bcm2835_wdt_reset, .start = bcm2835_wdt_start, .stop = bcm2835_wdt_stop, .expire_now = bcm2835_wdt_expire_now, }; static const struct udevice_id bcm2835_wdt_ids[] = { { .compatible = "brcm,bcm2835-pm" }, { .compatible = "brcm,bcm2835-pm-wdt" }, { /* sentinel */ } }; static int bcm2835_wdt_probe(struct udevice *dev) { struct bcm2835_wdt_priv *priv = dev_get_priv(dev); priv->base = dev_remap_addr(dev); if (!priv->base) return -EINVAL; priv->timeout_ticks = PM_WDOG_MAX_TICKS; bcm2835_wdt_stop(dev); return 0; } U_BOOT_DRIVER(bcm2835_wdt) = { .name = "bcm2835_wdt", .id = UCLASS_WDT, .of_match = bcm2835_wdt_ids, .probe = bcm2835_wdt_probe, .priv_auto = sizeof(struct bcm2835_wdt_priv), .ops = &bcm2835_wdt_ops, }; |