![Guenter Roeck](/assets/img/avatar_default.png)
Use device managed functions to simplify error handling, reduce source code size, improve readability, and reduce the likelyhood of bugs. Other improvements as listed below. The conversion was done automatically with coccinelle using the following semantic patches. The semantic patches and the scripts used to generate this commit log are available at https://github.com/groeck/coccinelle-patches - Drop assignments to otherwise unused variables - Drop empty remove function - Use devm_add_action_or_reset() for calls to clk_disable_unprepare - Introduce local variable 'struct device *dev' and use it instead of dereferencing it repeatedly - Use devm_watchdog_register_driver() to register watchdog device Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
251 lines
5.8 KiB
C
251 lines
5.8 KiB
C
/*
|
|
* PIC32 watchdog driver
|
|
*
|
|
* Joshua Henderson <joshua.henderson@microchip.com>
|
|
* Copyright (c) 2016, Microchip Technology Inc.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
#include <linux/clk.h>
|
|
#include <linux/device.h>
|
|
#include <linux/err.h>
|
|
#include <linux/io.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/of.h>
|
|
#include <linux/of_device.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/pm.h>
|
|
#include <linux/watchdog.h>
|
|
|
|
#include <asm/mach-pic32/pic32.h>
|
|
|
|
/* Watchdog Timer Registers */
|
|
#define WDTCON_REG 0x00
|
|
|
|
/* Watchdog Timer Control Register fields */
|
|
#define WDTCON_WIN_EN BIT(0)
|
|
#define WDTCON_RMCS_MASK 0x0003
|
|
#define WDTCON_RMCS_SHIFT 0x0006
|
|
#define WDTCON_RMPS_MASK 0x001F
|
|
#define WDTCON_RMPS_SHIFT 0x0008
|
|
#define WDTCON_ON BIT(15)
|
|
#define WDTCON_CLR_KEY 0x5743
|
|
|
|
/* Reset Control Register fields for watchdog */
|
|
#define RESETCON_TIMEOUT_IDLE BIT(2)
|
|
#define RESETCON_TIMEOUT_SLEEP BIT(3)
|
|
#define RESETCON_WDT_TIMEOUT BIT(4)
|
|
|
|
struct pic32_wdt {
|
|
void __iomem *regs;
|
|
void __iomem *rst_base;
|
|
struct clk *clk;
|
|
};
|
|
|
|
static inline bool pic32_wdt_is_win_enabled(struct pic32_wdt *wdt)
|
|
{
|
|
return !!(readl(wdt->regs + WDTCON_REG) & WDTCON_WIN_EN);
|
|
}
|
|
|
|
static inline u32 pic32_wdt_get_post_scaler(struct pic32_wdt *wdt)
|
|
{
|
|
u32 v = readl(wdt->regs + WDTCON_REG);
|
|
|
|
return (v >> WDTCON_RMPS_SHIFT) & WDTCON_RMPS_MASK;
|
|
}
|
|
|
|
static inline u32 pic32_wdt_get_clk_id(struct pic32_wdt *wdt)
|
|
{
|
|
u32 v = readl(wdt->regs + WDTCON_REG);
|
|
|
|
return (v >> WDTCON_RMCS_SHIFT) & WDTCON_RMCS_MASK;
|
|
}
|
|
|
|
static int pic32_wdt_bootstatus(struct pic32_wdt *wdt)
|
|
{
|
|
u32 v = readl(wdt->rst_base);
|
|
|
|
writel(RESETCON_WDT_TIMEOUT, PIC32_CLR(wdt->rst_base));
|
|
|
|
return v & RESETCON_WDT_TIMEOUT;
|
|
}
|
|
|
|
static u32 pic32_wdt_get_timeout_secs(struct pic32_wdt *wdt, struct device *dev)
|
|
{
|
|
unsigned long rate;
|
|
u32 period, ps, terminal;
|
|
|
|
rate = clk_get_rate(wdt->clk);
|
|
|
|
dev_dbg(dev, "wdt: clk_id %d, clk_rate %lu (prescale)\n",
|
|
pic32_wdt_get_clk_id(wdt), rate);
|
|
|
|
/* default, prescaler of 32 (i.e. div-by-32) is implicit. */
|
|
rate >>= 5;
|
|
if (!rate)
|
|
return 0;
|
|
|
|
/* calculate terminal count from postscaler. */
|
|
ps = pic32_wdt_get_post_scaler(wdt);
|
|
terminal = BIT(ps);
|
|
|
|
/* find time taken (in secs) to reach terminal count */
|
|
period = terminal / rate;
|
|
dev_dbg(dev,
|
|
"wdt: clk_rate %lu (postscale) / terminal %d, timeout %dsec\n",
|
|
rate, terminal, period);
|
|
|
|
return period;
|
|
}
|
|
|
|
static void pic32_wdt_keepalive(struct pic32_wdt *wdt)
|
|
{
|
|
/* write key through single half-word */
|
|
writew(WDTCON_CLR_KEY, wdt->regs + WDTCON_REG + 2);
|
|
}
|
|
|
|
static int pic32_wdt_start(struct watchdog_device *wdd)
|
|
{
|
|
struct pic32_wdt *wdt = watchdog_get_drvdata(wdd);
|
|
|
|
writel(WDTCON_ON, PIC32_SET(wdt->regs + WDTCON_REG));
|
|
pic32_wdt_keepalive(wdt);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pic32_wdt_stop(struct watchdog_device *wdd)
|
|
{
|
|
struct pic32_wdt *wdt = watchdog_get_drvdata(wdd);
|
|
|
|
writel(WDTCON_ON, PIC32_CLR(wdt->regs + WDTCON_REG));
|
|
|
|
/*
|
|
* Cannot touch registers in the CPU cycle following clearing the
|
|
* ON bit.
|
|
*/
|
|
nop();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pic32_wdt_ping(struct watchdog_device *wdd)
|
|
{
|
|
struct pic32_wdt *wdt = watchdog_get_drvdata(wdd);
|
|
|
|
pic32_wdt_keepalive(wdt);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct watchdog_ops pic32_wdt_fops = {
|
|
.owner = THIS_MODULE,
|
|
.start = pic32_wdt_start,
|
|
.stop = pic32_wdt_stop,
|
|
.ping = pic32_wdt_ping,
|
|
};
|
|
|
|
static const struct watchdog_info pic32_wdt_ident = {
|
|
.options = WDIOF_KEEPALIVEPING |
|
|
WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
|
|
.identity = "PIC32 Watchdog",
|
|
};
|
|
|
|
static struct watchdog_device pic32_wdd = {
|
|
.info = &pic32_wdt_ident,
|
|
.ops = &pic32_wdt_fops,
|
|
};
|
|
|
|
static const struct of_device_id pic32_wdt_dt_ids[] = {
|
|
{ .compatible = "microchip,pic32mzda-wdt", },
|
|
{ /* sentinel */ }
|
|
};
|
|
MODULE_DEVICE_TABLE(of, pic32_wdt_dt_ids);
|
|
|
|
static void pic32_clk_disable_unprepare(void *data)
|
|
{
|
|
clk_disable_unprepare(data);
|
|
}
|
|
|
|
static int pic32_wdt_drv_probe(struct platform_device *pdev)
|
|
{
|
|
struct device *dev = &pdev->dev;
|
|
int ret;
|
|
struct watchdog_device *wdd = &pic32_wdd;
|
|
struct pic32_wdt *wdt;
|
|
|
|
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
|
|
if (!wdt)
|
|
return -ENOMEM;
|
|
|
|
wdt->regs = devm_platform_ioremap_resource(pdev, 0);
|
|
if (IS_ERR(wdt->regs))
|
|
return PTR_ERR(wdt->regs);
|
|
|
|
wdt->rst_base = devm_ioremap(dev, PIC32_BASE_RESET, 0x10);
|
|
if (!wdt->rst_base)
|
|
return -ENOMEM;
|
|
|
|
wdt->clk = devm_clk_get(dev, NULL);
|
|
if (IS_ERR(wdt->clk)) {
|
|
dev_err(dev, "clk not found\n");
|
|
return PTR_ERR(wdt->clk);
|
|
}
|
|
|
|
ret = clk_prepare_enable(wdt->clk);
|
|
if (ret) {
|
|
dev_err(dev, "clk enable failed\n");
|
|
return ret;
|
|
}
|
|
ret = devm_add_action_or_reset(dev, pic32_clk_disable_unprepare,
|
|
wdt->clk);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (pic32_wdt_is_win_enabled(wdt)) {
|
|
dev_err(dev, "windowed-clear mode is not supported.\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
wdd->timeout = pic32_wdt_get_timeout_secs(wdt, dev);
|
|
if (!wdd->timeout) {
|
|
dev_err(dev, "failed to read watchdog register timeout\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
dev_info(dev, "timeout %d\n", wdd->timeout);
|
|
|
|
wdd->bootstatus = pic32_wdt_bootstatus(wdt) ? WDIOF_CARDRESET : 0;
|
|
|
|
watchdog_set_nowayout(wdd, WATCHDOG_NOWAYOUT);
|
|
watchdog_set_drvdata(wdd, wdt);
|
|
|
|
ret = devm_watchdog_register_device(dev, wdd);
|
|
if (ret) {
|
|
dev_err(dev, "watchdog register failed, err %d\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
platform_set_drvdata(pdev, wdd);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver pic32_wdt_driver = {
|
|
.probe = pic32_wdt_drv_probe,
|
|
.driver = {
|
|
.name = "pic32-wdt",
|
|
.of_match_table = of_match_ptr(pic32_wdt_dt_ids),
|
|
}
|
|
};
|
|
|
|
module_platform_driver(pic32_wdt_driver);
|
|
|
|
MODULE_AUTHOR("Joshua Henderson <joshua.henderson@microchip.com>");
|
|
MODULE_DESCRIPTION("Microchip PIC32 Watchdog Timer");
|
|
MODULE_LICENSE("GPL");
|