https://github.com/torvalds/linux
Tip revision: 46cf053efec6a3a5f343fead837777efe8252a46 authored by Linus Torvalds on 23 December 2019, 01:02:23 UTC
Linux 5.5-rc3
Linux 5.5-rc3
Tip revision: 46cf053
qcom-wdt.c
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
*/
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/of_device.h>
enum wdt_reg {
WDT_RST,
WDT_EN,
WDT_STS,
WDT_BARK_TIME,
WDT_BITE_TIME,
};
#define QCOM_WDT_ENABLE BIT(0)
#define QCOM_WDT_ENABLE_IRQ BIT(1)
static const u32 reg_offset_data_apcs_tmr[] = {
[WDT_RST] = 0x38,
[WDT_EN] = 0x40,
[WDT_STS] = 0x44,
[WDT_BARK_TIME] = 0x4C,
[WDT_BITE_TIME] = 0x5C,
};
static const u32 reg_offset_data_kpss[] = {
[WDT_RST] = 0x4,
[WDT_EN] = 0x8,
[WDT_STS] = 0xC,
[WDT_BARK_TIME] = 0x10,
[WDT_BITE_TIME] = 0x14,
};
struct qcom_wdt {
struct watchdog_device wdd;
unsigned long rate;
void __iomem *base;
const u32 *layout;
};
static void __iomem *wdt_addr(struct qcom_wdt *wdt, enum wdt_reg reg)
{
return wdt->base + wdt->layout[reg];
}
static inline
struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
{
return container_of(wdd, struct qcom_wdt, wdd);
}
static inline int qcom_get_enable(struct watchdog_device *wdd)
{
int enable = QCOM_WDT_ENABLE;
if (wdd->pretimeout)
enable |= QCOM_WDT_ENABLE_IRQ;
return enable;
}
static irqreturn_t qcom_wdt_isr(int irq, void *arg)
{
struct watchdog_device *wdd = arg;
watchdog_notify_pretimeout(wdd);
return IRQ_HANDLED;
}
static int qcom_wdt_start(struct watchdog_device *wdd)
{
struct qcom_wdt *wdt = to_qcom_wdt(wdd);
unsigned int bark = wdd->timeout - wdd->pretimeout;
writel(0, wdt_addr(wdt, WDT_EN));
writel(1, wdt_addr(wdt, WDT_RST));
writel(bark * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
writel(qcom_get_enable(wdd), wdt_addr(wdt, WDT_EN));
return 0;
}
static int qcom_wdt_stop(struct watchdog_device *wdd)
{
struct qcom_wdt *wdt = to_qcom_wdt(wdd);
writel(0, wdt_addr(wdt, WDT_EN));
return 0;
}
static int qcom_wdt_ping(struct watchdog_device *wdd)
{
struct qcom_wdt *wdt = to_qcom_wdt(wdd);
writel(1, wdt_addr(wdt, WDT_RST));
return 0;
}
static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
wdd->timeout = timeout;
return qcom_wdt_start(wdd);
}
static int qcom_wdt_set_pretimeout(struct watchdog_device *wdd,
unsigned int timeout)
{
wdd->pretimeout = timeout;
return qcom_wdt_start(wdd);
}
static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
void *data)
{
struct qcom_wdt *wdt = to_qcom_wdt(wdd);
u32 timeout;
/*
* Trigger watchdog bite:
* Setup BITE_TIME to be 128ms, and enable WDT.
*/
timeout = 128 * wdt->rate / 1000;
writel(0, wdt_addr(wdt, WDT_EN));
writel(1, wdt_addr(wdt, WDT_RST));
writel(timeout, wdt_addr(wdt, WDT_BARK_TIME));
writel(timeout, wdt_addr(wdt, WDT_BITE_TIME));
writel(QCOM_WDT_ENABLE, wdt_addr(wdt, WDT_EN));
/*
* Actually make sure the above sequence hits hardware before sleeping.
*/
wmb();
msleep(150);
return 0;
}
static const struct watchdog_ops qcom_wdt_ops = {
.start = qcom_wdt_start,
.stop = qcom_wdt_stop,
.ping = qcom_wdt_ping,
.set_timeout = qcom_wdt_set_timeout,
.set_pretimeout = qcom_wdt_set_pretimeout,
.restart = qcom_wdt_restart,
.owner = THIS_MODULE,
};
static const struct watchdog_info qcom_wdt_info = {
.options = WDIOF_KEEPALIVEPING
| WDIOF_MAGICCLOSE
| WDIOF_SETTIMEOUT
| WDIOF_CARDRESET,
.identity = KBUILD_MODNAME,
};
static const struct watchdog_info qcom_wdt_pt_info = {
.options = WDIOF_KEEPALIVEPING
| WDIOF_MAGICCLOSE
| WDIOF_SETTIMEOUT
| WDIOF_PRETIMEOUT
| WDIOF_CARDRESET,
.identity = KBUILD_MODNAME,
};
static void qcom_clk_disable_unprepare(void *data)
{
clk_disable_unprepare(data);
}
static int qcom_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct qcom_wdt *wdt;
struct resource *res;
struct device_node *np = dev->of_node;
const u32 *regs;
u32 percpu_offset;
int irq, ret;
struct clk *clk;
regs = of_device_get_match_data(dev);
if (!regs) {
dev_err(dev, "Unsupported QCOM WDT module\n");
return -ENODEV;
}
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENOMEM;
/* We use CPU0's DGT for the watchdog */
if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
percpu_offset = 0;
res->start += percpu_offset;
res->end += percpu_offset;
wdt->base = devm_ioremap_resource(dev, res);
if (IS_ERR(wdt->base))
return PTR_ERR(wdt->base);
clk = devm_clk_get(dev, NULL);
if (IS_ERR(clk)) {
dev_err(dev, "failed to get input clock\n");
return PTR_ERR(clk);
}
ret = clk_prepare_enable(clk);
if (ret) {
dev_err(dev, "failed to setup clock\n");
return ret;
}
ret = devm_add_action_or_reset(dev, qcom_clk_disable_unprepare, clk);
if (ret)
return ret;
/*
* We use the clock rate to calculate the max timeout, so ensure it's
* not zero to avoid a divide-by-zero exception.
*
* WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
* that it would bite before a second elapses it's usefulness is
* limited. Bail if this is the case.
*/
wdt->rate = clk_get_rate(clk);
if (wdt->rate == 0 ||
wdt->rate > 0x10000000U) {
dev_err(dev, "invalid clock rate\n");
return -EINVAL;
}
/* check if there is pretimeout support */
irq = platform_get_irq(pdev, 0);
if (irq > 0) {
ret = devm_request_irq(dev, irq, qcom_wdt_isr,
IRQF_TRIGGER_RISING,
"wdt_bark", &wdt->wdd);
if (ret)
return ret;
wdt->wdd.info = &qcom_wdt_pt_info;
wdt->wdd.pretimeout = 1;
} else {
if (irq == -EPROBE_DEFER)
return -EPROBE_DEFER;
wdt->wdd.info = &qcom_wdt_info;
}
wdt->wdd.ops = &qcom_wdt_ops;
wdt->wdd.min_timeout = 1;
wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
wdt->wdd.parent = dev;
wdt->layout = regs;
if (readl(wdt_addr(wdt, WDT_STS)) & 1)
wdt->wdd.bootstatus = WDIOF_CARDRESET;
/*
* If 'timeout-sec' unspecified in devicetree, assume a 30 second
* default, unless the max timeout is less than 30 seconds, then use
* the max instead.
*/
wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
watchdog_init_timeout(&wdt->wdd, 0, dev);
ret = devm_watchdog_register_device(dev, &wdt->wdd);
if (ret)
return ret;
platform_set_drvdata(pdev, wdt);
return 0;
}
static int __maybe_unused qcom_wdt_suspend(struct device *dev)
{
struct qcom_wdt *wdt = dev_get_drvdata(dev);
if (watchdog_active(&wdt->wdd))
qcom_wdt_stop(&wdt->wdd);
return 0;
}
static int __maybe_unused qcom_wdt_resume(struct device *dev)
{
struct qcom_wdt *wdt = dev_get_drvdata(dev);
if (watchdog_active(&wdt->wdd))
qcom_wdt_start(&wdt->wdd);
return 0;
}
static SIMPLE_DEV_PM_OPS(qcom_wdt_pm_ops, qcom_wdt_suspend, qcom_wdt_resume);
static const struct of_device_id qcom_wdt_of_table[] = {
{ .compatible = "qcom,kpss-timer", .data = reg_offset_data_apcs_tmr },
{ .compatible = "qcom,scss-timer", .data = reg_offset_data_apcs_tmr },
{ .compatible = "qcom,kpss-wdt", .data = reg_offset_data_kpss },
{ },
};
MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);
static struct platform_driver qcom_watchdog_driver = {
.probe = qcom_wdt_probe,
.driver = {
.name = KBUILD_MODNAME,
.of_match_table = qcom_wdt_of_table,
.pm = &qcom_wdt_pm_ops,
},
};
module_platform_driver(qcom_watchdog_driver);
MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
MODULE_LICENSE("GPL v2");