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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Nuvoton Technology corporation.
// Copyright (c) 2018 IBM Corp.
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/watchdog.h>
#define NPCM_WTCR 0x1C
#define NPCM_WTCLK (BIT(10) | BIT(11)) /* Clock divider */
#define NPCM_WTE BIT(7) /* Enable */
#define NPCM_WTIE BIT(6) /* Enable irq */
#define NPCM_WTIS (BIT(4) | BIT(5)) /* Interval selection */
#define NPCM_WTIF BIT(3) /* Interrupt flag*/
#define NPCM_WTRF BIT(2) /* Reset flag */
#define NPCM_WTRE BIT(1) /* Reset enable */
#define NPCM_WTR BIT(0) /* Reset counter */
/*
* Watchdog timeouts
*
* 170 msec: WTCLK=01 WTIS=00 VAL= 0x400
* 670 msec: WTCLK=01 WTIS=01 VAL= 0x410
* 1360 msec: WTCLK=10 WTIS=00 VAL= 0x800
* 2700 msec: WTCLK=01 WTIS=10 VAL= 0x420
* 5360 msec: WTCLK=10 WTIS=01 VAL= 0x810
* 10700 msec: WTCLK=01 WTIS=11 VAL= 0x430
* 21600 msec: WTCLK=10 WTIS=10 VAL= 0x820
* 43000 msec: WTCLK=11 WTIS=00 VAL= 0xC00
* 85600 msec: WTCLK=10 WTIS=11 VAL= 0x830
* 172000 msec: WTCLK=11 WTIS=01 VAL= 0xC10
* 687000 msec: WTCLK=11 WTIS=10 VAL= 0xC20
* 2750000 msec: WTCLK=11 WTIS=11 VAL= 0xC30
*/
struct npcm_wdt {
struct watchdog_device wdd;
void __iomem *reg;
};
static inline struct npcm_wdt *to_npcm_wdt(struct watchdog_device *wdd)
{
return container_of(wdd, struct npcm_wdt, wdd);
}
static int npcm_wdt_ping(struct watchdog_device *wdd)
{
struct npcm_wdt *wdt = to_npcm_wdt(wdd);
u32 val;
val = readl(wdt->reg);
writel(val | NPCM_WTR, wdt->reg);
return 0;
}
static int npcm_wdt_start(struct watchdog_device *wdd)
{
struct npcm_wdt *wdt = to_npcm_wdt(wdd);
u32 val;
if (wdd->timeout < 2)
val = 0x800;
else if (wdd->timeout < 3)
val = 0x420;
else if (wdd->timeout < 6)
val = 0x810;
else if (wdd->timeout < 11)
val = 0x430;
else if (wdd->timeout < 22)
val = 0x820;
else if (wdd->timeout < 44)
val = 0xC00;
else if (wdd->timeout < 87)
val = 0x830;
else if (wdd->timeout < 173)
val = 0xC10;
else if (wdd->timeout < 688)
val = 0xC20;
else
val = 0xC30;
val |= NPCM_WTRE | NPCM_WTE | NPCM_WTR | NPCM_WTIE;
writel(val, wdt->reg);
return 0;
}
static int npcm_wdt_stop(struct watchdog_device *wdd)
{
struct npcm_wdt *wdt = to_npcm_wdt(wdd);
writel(0, wdt->reg);
return 0;
}
static int npcm_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
if (timeout < 2)
wdd->timeout = 1;
else if (timeout < 3)
wdd->timeout = 2;
else if (timeout < 6)
wdd->timeout = 5;
else if (timeout < 11)
wdd->timeout = 10;
else if (timeout < 22)
wdd->timeout = 21;
else if (timeout < 44)
wdd->timeout = 43;
else if (timeout < 87)
wdd->timeout = 86;
else if (timeout < 173)
wdd->timeout = 172;
else if (timeout < 688)
wdd->timeout = 687;
else
wdd->timeout = 2750;
if (watchdog_active(wdd))
npcm_wdt_start(wdd);
return 0;
}
static irqreturn_t npcm_wdt_interrupt(int irq, void *data)
{
struct npcm_wdt *wdt = data;
watchdog_notify_pretimeout(&wdt->wdd);
return IRQ_HANDLED;
}
static int npcm_wdt_restart(struct watchdog_device *wdd,
unsigned long action, void *data)
{
struct npcm_wdt *wdt = to_npcm_wdt(wdd);
writel(NPCM_WTR | NPCM_WTRE | NPCM_WTE, wdt->reg);
udelay(1000);
return 0;
}
static bool npcm_is_running(struct watchdog_device *wdd)
{
struct npcm_wdt *wdt = to_npcm_wdt(wdd);
return readl(wdt->reg) & NPCM_WTE;
}
static const struct watchdog_info npcm_wdt_info = {
.identity = KBUILD_MODNAME,
.options = WDIOF_SETTIMEOUT
| WDIOF_KEEPALIVEPING
| WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops npcm_wdt_ops = {
.owner = THIS_MODULE,
.start = npcm_wdt_start,
.stop = npcm_wdt_stop,
.ping = npcm_wdt_ping,
.set_timeout = npcm_wdt_set_timeout,
.restart = npcm_wdt_restart,
};
static int npcm_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct npcm_wdt *wdt;
int irq;
int ret;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdt->reg = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(wdt->reg))
return PTR_ERR(wdt->reg);
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
wdt->wdd.info = &npcm_wdt_info;
wdt->wdd.ops = &npcm_wdt_ops;
wdt->wdd.min_timeout = 1;
wdt->wdd.max_timeout = 2750;
wdt->wdd.parent = dev;
wdt->wdd.timeout = 86;
watchdog_init_timeout(&wdt->wdd, 0, dev);
/* Ensure timeout is able to be represented by the hardware */
npcm_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout);
if (npcm_is_running(&wdt->wdd)) {
/* Restart with the default or device-tree specified timeout */
npcm_wdt_start(&wdt->wdd);
set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
}
ret = devm_request_irq(dev, irq, npcm_wdt_interrupt, 0, "watchdog",
wdt);
if (ret)
return ret;
ret = devm_watchdog_register_device(dev, &wdt->wdd);
if (ret) {
dev_err(dev, "failed to register watchdog\n");
return ret;
}
dev_info(dev, "NPCM watchdog driver enabled\n");
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id npcm_wdt_match[] = {
{.compatible = "nuvoton,npcm750-wdt"},
{},
};
MODULE_DEVICE_TABLE(of, npcm_wdt_match);
#endif
static struct platform_driver npcm_wdt_driver = {
.probe = npcm_wdt_probe,
.driver = {
.name = "npcm-wdt",
.of_match_table = of_match_ptr(npcm_wdt_match),
},
};
module_platform_driver(npcm_wdt_driver);
MODULE_AUTHOR("Joel Stanley");
MODULE_DESCRIPTION("Watchdog driver for NPCM");
MODULE_LICENSE("GPL v2");
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