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/*
* Watchdog driver for Cortina Systems Gemini SoC
*
* Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
*
* Inspired by the out-of-tree drivers from OpenWRT:
* Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/watchdog.h>
#define GEMINI_WDCOUNTER 0x0
#define GEMINI_WDLOAD 0x4
#define GEMINI_WDRESTART 0x8
#define GEMINI_WDCR 0xC
#define WDRESTART_MAGIC 0x5AB9
#define WDCR_CLOCK_5MHZ BIT(4)
#define WDCR_SYS_RST BIT(1)
#define WDCR_ENABLE BIT(0)
#define WDT_CLOCK 5000000 /* 5 MHz */
struct gemini_wdt {
struct watchdog_device wdd;
struct device *dev;
void __iomem *base;
};
static inline
struct gemini_wdt *to_gemini_wdt(struct watchdog_device *wdd)
{
return container_of(wdd, struct gemini_wdt, wdd);
}
static int gemini_wdt_start(struct watchdog_device *wdd)
{
struct gemini_wdt *gwdt = to_gemini_wdt(wdd);
writel(wdd->timeout * WDT_CLOCK, gwdt->base + GEMINI_WDLOAD);
writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART);
/* set clock before enabling */
writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST,
gwdt->base + GEMINI_WDCR);
writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE,
gwdt->base + GEMINI_WDCR);
return 0;
}
static int gemini_wdt_stop(struct watchdog_device *wdd)
{
struct gemini_wdt *gwdt = to_gemini_wdt(wdd);
writel(0, gwdt->base + GEMINI_WDCR);
return 0;
}
static int gemini_wdt_ping(struct watchdog_device *wdd)
{
struct gemini_wdt *gwdt = to_gemini_wdt(wdd);
writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART);
return 0;
}
static int gemini_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
wdd->timeout = timeout;
if (watchdog_active(wdd))
gemini_wdt_start(wdd);
return 0;
}
static irqreturn_t gemini_wdt_interrupt(int irq, void *data)
{
struct gemini_wdt *gwdt = data;
watchdog_notify_pretimeout(&gwdt->wdd);
return IRQ_HANDLED;
}
static const struct watchdog_ops gemini_wdt_ops = {
.start = gemini_wdt_start,
.stop = gemini_wdt_stop,
.ping = gemini_wdt_ping,
.set_timeout = gemini_wdt_set_timeout,
.owner = THIS_MODULE,
};
static const struct watchdog_info gemini_wdt_info = {
.options = WDIOF_KEEPALIVEPING
| WDIOF_MAGICCLOSE
| WDIOF_SETTIMEOUT,
.identity = KBUILD_MODNAME,
};
static int gemini_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct resource *res;
struct gemini_wdt *gwdt;
unsigned int reg;
int irq;
int ret;
gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
if (!gwdt)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
gwdt->base = devm_ioremap_resource(dev, res);
if (IS_ERR(gwdt->base))
return PTR_ERR(gwdt->base);
irq = platform_get_irq(pdev, 0);
if (!irq)
return -EINVAL;
gwdt->dev = dev;
gwdt->wdd.info = &gemini_wdt_info;
gwdt->wdd.ops = &gemini_wdt_ops;
gwdt->wdd.min_timeout = 1;
gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK;
gwdt->wdd.parent = dev;
/*
* If 'timeout-sec' unspecified in devicetree, assume a 13 second
* default.
*/
gwdt->wdd.timeout = 13U;
watchdog_init_timeout(&gwdt->wdd, 0, dev);
reg = readw(gwdt->base + GEMINI_WDCR);
if (reg & WDCR_ENABLE) {
/* Watchdog was enabled by the bootloader, disable it. */
reg &= ~WDCR_ENABLE;
writel(reg, gwdt->base + GEMINI_WDCR);
}
ret = devm_request_irq(dev, irq, gemini_wdt_interrupt, 0,
"watchdog bark", gwdt);
if (ret)
return ret;
ret = devm_watchdog_register_device(dev, &gwdt->wdd);
if (ret) {
dev_err(&pdev->dev, "failed to register watchdog\n");
return ret;
}
/* Set up platform driver data */
platform_set_drvdata(pdev, gwdt);
dev_info(dev, "Gemini watchdog driver enabled\n");
return 0;
}
static int __maybe_unused gemini_wdt_suspend(struct device *dev)
{
struct gemini_wdt *gwdt = dev_get_drvdata(dev);
unsigned int reg;
reg = readw(gwdt->base + GEMINI_WDCR);
reg &= ~WDCR_ENABLE;
writel(reg, gwdt->base + GEMINI_WDCR);
return 0;
}
static int __maybe_unused gemini_wdt_resume(struct device *dev)
{
struct gemini_wdt *gwdt = dev_get_drvdata(dev);
unsigned int reg;
if (watchdog_active(&gwdt->wdd)) {
reg = readw(gwdt->base + GEMINI_WDCR);
reg |= WDCR_ENABLE;
writel(reg, gwdt->base + GEMINI_WDCR);
}
return 0;
}
static const struct dev_pm_ops gemini_wdt_dev_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(gemini_wdt_suspend,
gemini_wdt_resume)
};
#ifdef CONFIG_OF
static const struct of_device_id gemini_wdt_match[] = {
{ .compatible = "cortina,gemini-watchdog" },
{},
};
MODULE_DEVICE_TABLE(of, gemini_wdt_match);
#endif
static struct platform_driver gemini_wdt_driver = {
.probe = gemini_wdt_probe,
.driver = {
.name = "gemini-wdt",
.of_match_table = of_match_ptr(gemini_wdt_match),
.pm = &gemini_wdt_dev_pm_ops,
},
};
module_platform_driver(gemini_wdt_driver);
MODULE_AUTHOR("Linus Walleij");
MODULE_DESCRIPTION("Watchdog driver for Gemini");
MODULE_LICENSE("GPL");
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