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// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#define MASK_WDGCS_ENABLE 0x01
#define MASK_WDGCS_RELOAD 0x04
#define MASK_WDGCS_NMIEN 0x08
#define MASK_WDGCS_WARN 0x80
#define WDT_MAX_TIMEOUT_MS 655350
#define WDT_DEFAULT_TIMEOUT 30
#define SECS_TO_WDOG_TICKS(x) ((x) * 100)
#define WDOG_TICKS_TO_SECS(x) ((x) / 100)
#define GXP_WDT_CNT_OFS 0x10
#define GXP_WDT_CTRL_OFS 0x16
struct gxp_wdt {
void __iomem *base;
struct watchdog_device wdd;
};
static void gxp_wdt_enable_reload(struct gxp_wdt *drvdata)
{
u8 val;
val = readb(drvdata->base + GXP_WDT_CTRL_OFS);
val |= (MASK_WDGCS_ENABLE | MASK_WDGCS_RELOAD);
writeb(val, drvdata->base + GXP_WDT_CTRL_OFS);
}
static int gxp_wdt_start(struct watchdog_device *wdd)
{
struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
writew(SECS_TO_WDOG_TICKS(wdd->timeout), drvdata->base + GXP_WDT_CNT_OFS);
gxp_wdt_enable_reload(drvdata);
return 0;
}
static int gxp_wdt_stop(struct watchdog_device *wdd)
{
struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
u8 val;
val = readb_relaxed(drvdata->base + GXP_WDT_CTRL_OFS);
val &= ~MASK_WDGCS_ENABLE;
writeb(val, drvdata->base + GXP_WDT_CTRL_OFS);
return 0;
}
static int gxp_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
u32 actual;
wdd->timeout = timeout;
actual = min(timeout * 100, wdd->max_hw_heartbeat_ms / 10);
writew(actual, drvdata->base + GXP_WDT_CNT_OFS);
return 0;
}
static unsigned int gxp_wdt_get_timeleft(struct watchdog_device *wdd)
{
struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
u32 val = readw(drvdata->base + GXP_WDT_CNT_OFS);
return WDOG_TICKS_TO_SECS(val);
}
static int gxp_wdt_ping(struct watchdog_device *wdd)
{
struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
gxp_wdt_enable_reload(drvdata);
return 0;
}
static int gxp_restart(struct watchdog_device *wdd, unsigned long action,
void *data)
{
struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
writew(1, drvdata->base + GXP_WDT_CNT_OFS);
gxp_wdt_enable_reload(drvdata);
mdelay(100);
return 0;
}
static const struct watchdog_ops gxp_wdt_ops = {
.owner = THIS_MODULE,
.start = gxp_wdt_start,
.stop = gxp_wdt_stop,
.ping = gxp_wdt_ping,
.set_timeout = gxp_wdt_set_timeout,
.get_timeleft = gxp_wdt_get_timeleft,
.restart = gxp_restart,
};
static const struct watchdog_info gxp_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
.identity = "HPE GXP Watchdog timer",
};
static int gxp_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct gxp_wdt *drvdata;
int err;
u8 val;
drvdata = devm_kzalloc(dev, sizeof(struct gxp_wdt), GFP_KERNEL);
if (!drvdata)
return -ENOMEM;
/*
* The register area where the timer and watchdog reside is disarranged.
* Hence mapping individual register blocks for the timer and watchdog
* is not recommended as they would have access to each others
* registers. Based on feedback the watchdog is no longer part of the
* device tree file and the timer driver now creates the watchdog as a
* child device. During the watchdogs creation, the timer driver passes
* the base address to the watchdog over the private interface.
*/
drvdata->base = (void __iomem *)dev->platform_data;
drvdata->wdd.info = &gxp_wdt_info;
drvdata->wdd.ops = &gxp_wdt_ops;
drvdata->wdd.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT_MS;
drvdata->wdd.parent = dev;
drvdata->wdd.timeout = WDT_DEFAULT_TIMEOUT;
watchdog_set_drvdata(&drvdata->wdd, drvdata);
watchdog_set_nowayout(&drvdata->wdd, WATCHDOG_NOWAYOUT);
val = readb(drvdata->base + GXP_WDT_CTRL_OFS);
if (val & MASK_WDGCS_ENABLE)
set_bit(WDOG_HW_RUNNING, &drvdata->wdd.status);
watchdog_set_restart_priority(&drvdata->wdd, 128);
watchdog_stop_on_reboot(&drvdata->wdd);
err = devm_watchdog_register_device(dev, &drvdata->wdd);
if (err) {
dev_err(dev, "Failed to register watchdog device");
return err;
}
dev_info(dev, "HPE GXP watchdog timer");
return 0;
}
static struct platform_driver gxp_wdt_driver = {
.probe = gxp_wdt_probe,
.driver = {
.name = "gxp-wdt",
},
};
module_platform_driver(gxp_wdt_driver);
MODULE_AUTHOR("Nick Hawkins <nick.hawkins@hpe.com>");
MODULE_AUTHOR("Jean-Marie Verdun <verdun@hpe.com>");
MODULE_DESCRIPTION("Driver for GXP watchdog timer");
MODULE_LICENSE("GPL");
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