// SPDX-License-Identifier: GPL-2.0
/*
* Watchdog driver for the K3 RTI module
*
* (c) Copyright 2019-2020 Texas Instruments Inc.
* All rights reserved.
*/
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#define DEFAULT_HEARTBEAT 60
/* Max heartbeat is calculated at 32kHz source clock */
#define MAX_HEARTBEAT 1000
/* Timer register set definition */
#define RTIDWDCTRL 0x90
#define RTIDWDPRLD 0x94
#define RTIWDSTATUS 0x98
#define RTIWDKEY 0x9c
#define RTIDWDCNTR 0xa0
#define RTIWWDRXCTRL 0xa4
#define RTIWWDSIZECTRL 0xa8
#define RTIWWDRX_NMI 0xa
#define RTIWWDSIZE_50P 0x50
#define WDENABLE_KEY 0xa98559da
#define WDKEY_SEQ0 0xe51a
#define WDKEY_SEQ1 0xa35c
#define WDT_PRELOAD_SHIFT 13
#define WDT_PRELOAD_MAX 0xfff
#define DWDST BIT(1)
static int heartbeat;
/*
* struct to hold data for each WDT device
* @base - base io address of WD device
* @freq - source clock frequency of WDT
* @wdd - hold watchdog device as is in WDT core
*/
struct rti_wdt_device {
void __iomem *base;
unsigned long freq;
struct watchdog_device wdd;
};
static int rti_wdt_start(struct watchdog_device *wdd)
{
u32 timer_margin;
struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
/* set timeout period */
timer_margin = (u64)wdd->timeout * wdt->freq;
timer_margin >>= WDT_PRELOAD_SHIFT;
if (timer_margin > WDT_PRELOAD_MAX)
timer_margin = WDT_PRELOAD_MAX;
writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
/*
* RTI only supports a windowed mode, where the watchdog can only
* be petted during the open window; not too early or not too late.
* The HW configuration options only allow for the open window size
* to be 50% or less than that; we obviouly want to configure the open
* window as large as possible so we select the 50% option. To avoid
* any glitches, we accommodate 5% safety margin also, so we setup
* the min_hw_hearbeat at 55% of the timeout period.
*/
wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
/* Generate NMI when wdt expires */
writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
/* Open window size 50%; this is the largest window size available */
writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
readl_relaxed(wdt->base + RTIWWDSIZECTRL);
/* enable watchdog */
writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
return 0;
}
static int rti_wdt_ping(struct watchdog_device *wdd)
{
struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
/* put watchdog in service state */
writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
/* put watchdog in active state */
writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
return 0;
}
static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
{
u64 timer_counter;
u32 val;
struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
/* if timeout has occurred then return 0 */
val = readl_relaxed(wdt->base + RTIWDSTATUS);
if (val & DWDST)
return 0;
timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
do_div(timer_counter, wdt->freq);
return timer_counter;
}
static const struct watchdog_info rti_wdt_info = {
.options = WDIOF_KEEPALIVEPING,
.identity = "K3 RTI Watchdog",
};
static const struct watchdog_ops rti_wdt_ops = {
.owner = THIS_MODULE,
.start = rti_wdt_start,
.ping = rti_wdt_ping,
.get_timeleft = rti_wdt_get_timeleft,
};
static int rti_wdt_probe(struct platform_device *pdev)
{
int ret = 0;
struct device *dev = &pdev->dev;
struct resource *wdt_mem;
struct watchdog_device *wdd;
struct rti_wdt_device *wdt;
struct clk *clk;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
clk = clk_get(dev, NULL);
if (IS_ERR(clk)) {
if (PTR_ERR(clk) != -EPROBE_DEFER)
dev_err(dev, "failed to get clock\n");
return PTR_ERR(clk);
}
wdt->freq = clk_get_rate(clk);
clk_put(clk);
if (!wdt->freq) {
dev_err(dev, "Failed to get fck rate.\n");
return -EINVAL;
}
pm_runtime_enable(dev);
ret = pm_runtime_get_sync(dev);
if (ret) {
if (ret != -EPROBE_DEFER)
dev_err(&pdev->dev, "runtime pm failed\n");
return ret;
}
platform_set_drvdata(pdev, wdt);
wdd = &wdt->wdd;
wdd->info = &rti_wdt_info;
wdd->ops = &rti_wdt_ops;
wdd->min_timeout = 1;
wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
wdt->freq * 1000;
wdd->timeout = DEFAULT_HEARTBEAT;
wdd->parent = dev;
watchdog_init_timeout(wdd, heartbeat, dev);
watchdog_set_drvdata(wdd, wdt);
watchdog_set_nowayout(wdd, 1);
watchdog_set_restart_priority(wdd, 128);
wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
wdt->base = devm_ioremap_resource(dev, wdt_mem);
if (IS_ERR(wdt->base)) {
ret = PTR_ERR(wdt->base);
goto err_iomap;
}
ret = watchdog_register_device(wdd);
if (ret) {
dev_err(dev, "cannot register watchdog device\n");
goto err_iomap;
}
return 0;
err_iomap:
pm_runtime_put_sync(&pdev->dev);
return ret;
}
static int rti_wdt_remove(struct platform_device *pdev)
{
struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
watchdog_unregister_device(&wdt->wdd);
pm_runtime_put(&pdev->dev);
return 0;
}
static const struct of_device_id rti_wdt_of_match[] = {
{ .compatible = "ti,j7-rti-wdt", },
{},
};
MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
static struct platform_driver rti_wdt_driver = {
.driver = {
.name = "rti-wdt",
.of_match_table = rti_wdt_of_match,
},
.probe = rti_wdt_probe,
.remove = rti_wdt_remove,
};
module_platform_driver(rti_wdt_driver);
MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:rti-wdt");
