/*
* Imagination Technologies PowerDown Controller Watchdog Timer.
*
* Copyright (c) 2014 Imagination Technologies Ltd.
*
* 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.
*
* Based on drivers/watchdog/sunxi_wdt.c Copyright (c) 2013 Carlo Caione
* 2012 Henrik Nordstrom
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/log2.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/watchdog.h>
/* registers */
#define PDC_WDT_SOFT_RESET 0x00
#define PDC_WDT_CONFIG 0x04
#define PDC_WDT_CONFIG_ENABLE BIT(31)
#define PDC_WDT_CONFIG_DELAY_MASK 0x1f
#define PDC_WDT_TICKLE1 0x08
#define PDC_WDT_TICKLE1_MAGIC 0xabcd1234
#define PDC_WDT_TICKLE2 0x0c
#define PDC_WDT_TICKLE2_MAGIC 0x4321dcba
#define PDC_WDT_TICKLE_STATUS_MASK 0x7
#define PDC_WDT_TICKLE_STATUS_SHIFT 0
#define PDC_WDT_TICKLE_STATUS_HRESET 0x0 /* Hard reset */
#define PDC_WDT_TICKLE_STATUS_TIMEOUT 0x1 /* Timeout */
#define PDC_WDT_TICKLE_STATUS_TICKLE 0x2 /* Tickled incorrectly */
#define PDC_WDT_TICKLE_STATUS_SRESET 0x3 /* Soft reset */
#define PDC_WDT_TICKLE_STATUS_USER 0x4 /* User reset */
/* Timeout values are in seconds */
#define PDC_WDT_MIN_TIMEOUT 1
#define PDC_WDT_DEF_TIMEOUT 64
static int heartbeat = PDC_WDT_DEF_TIMEOUT;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds "
"(default=" __MODULE_STRING(PDC_WDT_DEF_TIMEOUT) ")");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
struct pdc_wdt_dev {
struct watchdog_device wdt_dev;
struct clk *wdt_clk;
struct clk *sys_clk;
void __iomem *base;
};
static int pdc_wdt_keepalive(struct watchdog_device *wdt_dev)
{
struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
writel(PDC_WDT_TICKLE1_MAGIC, wdt->base + PDC_WDT_TICKLE1);
writel(PDC_WDT_TICKLE2_MAGIC, wdt->base + PDC_WDT_TICKLE2);
return 0;
}
static int pdc_wdt_stop(struct watchdog_device *wdt_dev)
{
unsigned int val;
struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
val = readl(wdt->base + PDC_WDT_CONFIG);
val &= ~PDC_WDT_CONFIG_ENABLE;
writel(val, wdt->base + PDC_WDT_CONFIG);
/* Must tickle to finish the stop */
pdc_wdt_keepalive(wdt_dev);
return 0;
}
static int pdc_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int new_timeout)
{
unsigned int val;
struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
unsigned long clk_rate = clk_get_rate(wdt->wdt_clk);
wdt->wdt_dev.timeout = new_timeout;
val = readl(wdt->base + PDC_WDT_CONFIG) & ~PDC_WDT_CONFIG_DELAY_MASK;
val |= order_base_2(new_timeout * clk_rate) - 1;
writel(val, wdt->base + PDC_WDT_CONFIG);
return 0;
}
/* Start the watchdog timer (delay should already be set) */
static int pdc_wdt_start(struct watchdog_device *wdt_dev)
{
unsigned int val;
struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
val = readl(wdt->base + PDC_WDT_CONFIG);
val |= PDC_WDT_CONFIG_ENABLE;
writel(val, wdt->base + PDC_WDT_CONFIG);
return 0;
}
static struct watchdog_info pdc_wdt_info = {
.identity = "IMG PDC Watchdog",
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops pdc_wdt_ops = {
.owner = THIS_MODULE,
.start = pdc_wdt_start,
.stop = pdc_wdt_stop,
.ping = pdc_wdt_keepalive,
.set_timeout = pdc_wdt_set_timeout,
};
static int pdc_wdt_probe(struct platform_device *pdev)
{
int ret, val;
unsigned long clk_rate;
struct resource *res;
struct pdc_wdt_dev *pdc_wdt;
pdc_wdt = devm_kzalloc(&pdev->dev, sizeof(*pdc_wdt), GFP_KERNEL);
if (!pdc_wdt)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
pdc_wdt->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(pdc_wdt->base))
return PTR_ERR(pdc_wdt->base);
pdc_wdt->sys_clk = devm_clk_get(&pdev->dev, "sys");
if (IS_ERR(pdc_wdt->sys_clk)) {
dev_err(&pdev->dev, "failed to get the sys clock\n");
return PTR_ERR(pdc_wdt->sys_clk);
}
pdc_wdt->wdt_clk = devm_clk_get(&pdev->dev, "wdt");
if (IS_ERR(pdc_wdt->wdt_clk)) {
dev_err(&pdev->dev, "failed to get the wdt clock\n");
return PTR_ERR(pdc_wdt->wdt_clk);
}
ret = clk_prepare_enable(pdc_wdt->sys_clk);
if (ret) {
dev_err(&pdev->dev, "could not prepare or enable sys clock\n");
return ret;
}
ret = clk_prepare_enable(pdc_wdt->wdt_clk);
if (ret) {
dev_err(&pdev->dev, "could not prepare or enable wdt clock\n");
goto disable_sys_clk;
}
/* We use the clock rate to calculate the max timeout */
clk_rate = clk_get_rate(pdc_wdt->wdt_clk);
if (clk_rate == 0) {
dev_err(&pdev->dev, "failed to get clock rate\n");
ret = -EINVAL;
goto disable_wdt_clk;
}
if (order_base_2(clk_rate) > PDC_WDT_CONFIG_DELAY_MASK + 1) {
dev_err(&pdev->dev, "invalid clock rate\n");
ret = -EINVAL;
goto disable_wdt_clk;
}
if (order_base_2(clk_rate) == 0)
pdc_wdt->wdt_dev.min_timeout = PDC_WDT_MIN_TIMEOUT + 1;
else
pdc_wdt->wdt_dev.min_timeout = PDC_WDT_MIN_TIMEOUT;
pdc_wdt->wdt_dev.info = &pdc_wdt_info;
pdc_wdt->wdt_dev.ops = &pdc_wdt_ops;
pdc_wdt->wdt_dev.max_timeout = 1 << PDC_WDT_CONFIG_DELAY_MASK;
pdc_wdt->wdt_dev.parent = &pdev->dev;
watchdog_set_drvdata(&pdc_wdt->wdt_dev, pdc_wdt);
ret = watchdog_init_timeout(&pdc_wdt->wdt_dev, heartbeat, &pdev->dev);
if (ret < 0) {
pdc_wdt->wdt_dev.timeout = pdc_wdt->wdt_dev.max_timeout;
dev_warn(&pdev->dev,
"Initial timeout out of range! setting max timeout\n");
}
pdc_wdt_stop(&pdc_wdt->wdt_dev);
/* Find what caused the last reset */
val = readl(pdc_wdt->base + PDC_WDT_TICKLE1);
val = (val & PDC_WDT_TICKLE_STATUS_MASK) >> PDC_WDT_TICKLE_STATUS_SHIFT;
switch (val) {
case PDC_WDT_TICKLE_STATUS_TICKLE:
case PDC_WDT_TICKLE_STATUS_TIMEOUT:
pdc_wdt->wdt_dev.bootstatus |= WDIOF_CARDRESET;
dev_info(&pdev->dev,
"watchdog module last reset due to timeout\n");
break;
case PDC_WDT_TICKLE_STATUS_HRESET:
dev_info(&pdev->dev,
"watchdog module last reset due to hard reset\n");
break;
case PDC_WDT_TICKLE_STATUS_SRESET:
dev_info(&pdev->dev,
"watchdog module last reset due to soft reset\n");
break;
case PDC_WDT_TICKLE_STATUS_USER:
dev_info(&pdev->dev,
"watchdog module last reset due to user reset\n");
break;
default:
dev_info(&pdev->dev,
"contains an illegal status code (%08x)\n", val);
break;
}
watchdog_set_nowayout(&pdc_wdt->wdt_dev, nowayout);
platform_set_drvdata(pdev, pdc_wdt);
ret = watchdog_register_device(&pdc_wdt->wdt_dev);
if (ret)
goto disable_wdt_clk;
return 0;
disable_wdt_clk:
clk_disable_unprepare(pdc_wdt->wdt_clk);
disable_sys_clk:
clk_disable_unprepare(pdc_wdt->sys_clk);
return ret;
}
static void pdc_wdt_shutdown(struct platform_device *pdev)
{
struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(pdev);
pdc_wdt_stop(&pdc_wdt->wdt_dev);
}
static int pdc_wdt_remove(struct platform_device *pdev)
{
struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(pdev);
pdc_wdt_stop(&pdc_wdt->wdt_dev);
watchdog_unregister_device(&pdc_wdt->wdt_dev);
clk_disable_unprepare(pdc_wdt->wdt_clk);
clk_disable_unprepare(pdc_wdt->sys_clk);
return 0;
}
static const struct of_device_id pdc_wdt_match[] = {
{ .compatible = "img,pdc-wdt" },
{}
};
MODULE_DEVICE_TABLE(of, pdc_wdt_match);
static struct platform_driver pdc_wdt_driver = {
.driver = {
.name = "imgpdc-wdt",
.of_match_table = pdc_wdt_match,
},
.probe = pdc_wdt_probe,
.remove = pdc_wdt_remove,
.shutdown = pdc_wdt_shutdown,
};
module_platform_driver(pdc_wdt_driver);
MODULE_AUTHOR("Jude Abraham <Jude.Abraham@imgtec.com>");
MODULE_AUTHOR("Naidu Tellapati <Naidu.Tellapati@imgtec.com>");
MODULE_DESCRIPTION("Imagination Technologies PDC Watchdog Timer Driver");
MODULE_LICENSE("GPL v2");
