89c4fecd9b
This driver supports the bcm2835 watchdog found on Raspberry Pi boards. It is derived from the Linux driver and was tested on two Raspberry Pi board versions (B+ and 3B+). Signed-off-by: Etienne Dublé <etienne.duble@imag.fr> Reviewed-by: Stefan Roese <sr@denx.de>
133 lines
3.0 KiB
C
133 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk>
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* Copyright (C) 2023 Etienne Dublé (CNRS) <etienne.duble@imag.fr>
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*
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* This code is mostly derived from the linux driver.
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*/
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#include <dm.h>
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#include <wdt.h>
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#include <asm/io.h>
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#include <linux/delay.h>
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#define PM_RSTC 0x1c
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#define PM_WDOG 0x24
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#define PM_PASSWORD 0x5a000000
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/* The hardware supports a maximum timeout value of 0xfffff ticks
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* (just below 16 seconds).
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*/
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#define PM_WDOG_MAX_TICKS 0x000fffff
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#define PM_RSTC_WRCFG_CLR 0xffffffcf
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#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
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#define PM_RSTC_RESET 0x00000102
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#define MS_TO_WDOG_TICKS(x) (((x) << 16) / 1000)
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struct bcm2835_wdt_priv {
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void __iomem *base;
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u64 timeout_ticks;
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};
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static int bcm2835_wdt_start_ticks(struct udevice *dev,
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u64 timeout_ticks, ulong flags)
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{
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struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
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void __iomem *base = priv->base;
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u32 cur;
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writel(PM_PASSWORD | timeout_ticks, base + PM_WDOG);
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cur = readl(base + PM_RSTC);
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writel(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) | PM_RSTC_WRCFG_FULL_RESET,
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base + PM_RSTC);
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return 0;
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}
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static int bcm2835_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
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{
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struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
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priv->timeout_ticks = MS_TO_WDOG_TICKS(timeout_ms);
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if (priv->timeout_ticks > PM_WDOG_MAX_TICKS) {
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printf("bcm2835_wdt: the timeout value is too high, using ~16s instead.\n");
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priv->timeout_ticks = PM_WDOG_MAX_TICKS;
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}
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return bcm2835_wdt_start_ticks(dev, priv->timeout_ticks, flags);
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}
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static int bcm2835_wdt_reset(struct udevice *dev)
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{
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struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
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/* restart the timer with the value of priv->timeout_ticks
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* saved from the last bcm2835_wdt_start() call.
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*/
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return bcm2835_wdt_start_ticks(dev, priv->timeout_ticks, 0);
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}
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static int bcm2835_wdt_stop(struct udevice *dev)
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{
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struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
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void __iomem *base = priv->base;
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writel(PM_PASSWORD | PM_RSTC_RESET, base + PM_RSTC);
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return 0;
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}
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static int bcm2835_wdt_expire_now(struct udevice *dev, ulong flags)
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{
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int ret;
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/* use a timeout of 10 ticks (~150us) */
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ret = bcm2835_wdt_start_ticks(dev, 10, flags);
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if (ret)
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return ret;
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mdelay(500);
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return 0;
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}
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static const struct wdt_ops bcm2835_wdt_ops = {
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.reset = bcm2835_wdt_reset,
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.start = bcm2835_wdt_start,
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.stop = bcm2835_wdt_stop,
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.expire_now = bcm2835_wdt_expire_now,
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};
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static const struct udevice_id bcm2835_wdt_ids[] = {
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{ .compatible = "brcm,bcm2835-pm" },
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{ .compatible = "brcm,bcm2835-pm-wdt" },
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{ /* sentinel */ }
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};
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static int bcm2835_wdt_probe(struct udevice *dev)
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{
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struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
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priv->base = dev_remap_addr(dev);
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if (!priv->base)
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return -EINVAL;
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priv->timeout_ticks = PM_WDOG_MAX_TICKS;
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bcm2835_wdt_stop(dev);
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return 0;
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}
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U_BOOT_DRIVER(bcm2835_wdt) = {
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.name = "bcm2835_wdt",
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.id = UCLASS_WDT,
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.of_match = bcm2835_wdt_ids,
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.probe = bcm2835_wdt_probe,
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.priv_auto = sizeof(struct bcm2835_wdt_priv),
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.ops = &bcm2835_wdt_ops,
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};
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