237 lines
6.1 KiB
C
237 lines
6.1 KiB
C
/*
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* Meson Watchdog Driver
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*
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* Copyright (c) 2014 Carlo Caione
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/types.h>
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#include <linux/watchdog.h>
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#define DRV_NAME "meson_wdt"
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#define MESON_WDT_TC 0x00
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#define MESON_WDT_DC_RESET (3 << 24)
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#define MESON_WDT_RESET 0x04
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#define MESON_WDT_TIMEOUT 30
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#define MESON_WDT_MIN_TIMEOUT 1
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#define MESON_SEC_TO_TC(s, c) ((s) * (c))
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static bool nowayout = WATCHDOG_NOWAYOUT;
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static unsigned int timeout;
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struct meson_wdt_data {
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unsigned int enable;
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unsigned int terminal_count_mask;
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unsigned int count_unit;
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};
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static struct meson_wdt_data meson6_wdt_data = {
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.enable = BIT(22),
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.terminal_count_mask = 0x3fffff,
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.count_unit = 100000, /* 10 us */
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};
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static struct meson_wdt_data meson8b_wdt_data = {
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.enable = BIT(19),
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.terminal_count_mask = 0xffff,
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.count_unit = 7812, /* 128 us */
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};
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struct meson_wdt_dev {
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struct watchdog_device wdt_dev;
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void __iomem *wdt_base;
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const struct meson_wdt_data *data;
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};
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static int meson_wdt_restart(struct watchdog_device *wdt_dev,
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unsigned long action, void *data)
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{
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struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
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u32 tc_reboot = MESON_WDT_DC_RESET;
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tc_reboot |= meson_wdt->data->enable;
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while (1) {
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writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
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mdelay(5);
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}
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return 0;
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}
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static int meson_wdt_ping(struct watchdog_device *wdt_dev)
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{
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struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
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writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);
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return 0;
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}
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static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
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unsigned int timeout)
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{
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struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
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u32 reg;
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reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
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reg &= ~meson_wdt->data->terminal_count_mask;
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reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit);
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writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
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}
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static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,
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unsigned int timeout)
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{
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wdt_dev->timeout = timeout;
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meson_wdt_change_timeout(wdt_dev, timeout);
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meson_wdt_ping(wdt_dev);
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return 0;
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}
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static int meson_wdt_stop(struct watchdog_device *wdt_dev)
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{
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struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
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u32 reg;
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reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
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reg &= ~meson_wdt->data->enable;
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writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
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return 0;
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}
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static int meson_wdt_start(struct watchdog_device *wdt_dev)
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{
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struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
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u32 reg;
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meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
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meson_wdt_ping(wdt_dev);
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reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
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reg |= meson_wdt->data->enable;
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writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
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return 0;
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}
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static const struct watchdog_info meson_wdt_info = {
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.identity = DRV_NAME,
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.options = WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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};
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static const struct watchdog_ops meson_wdt_ops = {
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.owner = THIS_MODULE,
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.start = meson_wdt_start,
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.stop = meson_wdt_stop,
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.ping = meson_wdt_ping,
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.set_timeout = meson_wdt_set_timeout,
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.restart = meson_wdt_restart,
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};
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static const struct of_device_id meson_wdt_dt_ids[] = {
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{ .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data },
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{ .compatible = "amlogic,meson8-wdt", .data = &meson6_wdt_data },
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{ .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data },
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{ .compatible = "amlogic,meson8m2-wdt", .data = &meson8b_wdt_data },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
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static int meson_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct meson_wdt_dev *meson_wdt;
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const struct of_device_id *of_id;
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int err;
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meson_wdt = devm_kzalloc(dev, sizeof(*meson_wdt), GFP_KERNEL);
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if (!meson_wdt)
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return -ENOMEM;
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meson_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(meson_wdt->wdt_base))
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return PTR_ERR(meson_wdt->wdt_base);
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of_id = of_match_device(meson_wdt_dt_ids, dev);
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if (!of_id) {
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dev_err(dev, "Unable to initialize WDT data\n");
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return -ENODEV;
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}
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meson_wdt->data = of_id->data;
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meson_wdt->wdt_dev.parent = dev;
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meson_wdt->wdt_dev.info = &meson_wdt_info;
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meson_wdt->wdt_dev.ops = &meson_wdt_ops;
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meson_wdt->wdt_dev.max_timeout =
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meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit;
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meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
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meson_wdt->wdt_dev.timeout = min_t(unsigned int,
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MESON_WDT_TIMEOUT,
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meson_wdt->wdt_dev.max_timeout);
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watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);
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watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, dev);
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watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);
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watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128);
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meson_wdt_stop(&meson_wdt->wdt_dev);
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watchdog_stop_on_reboot(&meson_wdt->wdt_dev);
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err = devm_watchdog_register_device(dev, &meson_wdt->wdt_dev);
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if (err)
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return err;
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dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
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meson_wdt->wdt_dev.timeout, nowayout);
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return 0;
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}
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static struct platform_driver meson_wdt_driver = {
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.probe = meson_wdt_probe,
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.driver = {
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.name = DRV_NAME,
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.of_match_table = meson_wdt_dt_ids,
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},
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};
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module_platform_driver(meson_wdt_driver);
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module_param(timeout, uint, 0);
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MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
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MODULE_DESCRIPTION("Meson Watchdog Timer Driver");
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