hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
linux-sg2042/drivers/watchdog/asm9260_wdt.c

395 lines
8.9 KiB
C
Raw Blame History

/*
* Watchdog driver for Alphascale ASM9260.
*
* Copyright (c) 2014 Oleksij Rempel <linux@rempel-privat.de>
*
* Licensed under GPLv2 or later.
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/watchdog.h>
#define CLOCK_FREQ 1000000
/* Watchdog Mode register */
#define HW_WDMOD 0x00
/* Wake interrupt. Set by HW, can't be cleared. */
#define BM_MOD_WDINT BIT(3)
/* This bit set if timeout reached. Cleared by SW. */
#define BM_MOD_WDTOF BIT(2)
/* HW Reset on timeout */
#define BM_MOD_WDRESET BIT(1)
/* WD enable */
#define BM_MOD_WDEN BIT(0)
/*
* Watchdog Timer Constant register
* Minimal value is 0xff, the meaning of this value
* depends on used clock: T = WDCLK * (0xff + 1) * 4
*/
#define HW_WDTC 0x04
#define BM_WDTC_MAX(freq) (0x7fffffff / (freq))
/* Watchdog Feed register */
#define HW_WDFEED 0x08
/* Watchdog Timer Value register */
#define HW_WDTV 0x0c
#define ASM9260_WDT_DEFAULT_TIMEOUT 30
enum asm9260_wdt_mode {
HW_RESET,
SW_RESET,
DEBUG,
};
struct asm9260_wdt_priv {
struct device *dev;
struct watchdog_device wdd;
struct clk *clk;
struct clk *clk_ahb;
struct reset_control *rst;
void __iomem *iobase;
int irq;
unsigned long wdt_freq;
enum asm9260_wdt_mode mode;
};
static int asm9260_wdt_feed(struct watchdog_device *wdd)
{
struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
iowrite32(0xaa, priv->iobase + HW_WDFEED);
iowrite32(0x55, priv->iobase + HW_WDFEED);
return 0;
}
static unsigned int asm9260_wdt_gettimeleft(struct watchdog_device *wdd)
{
struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
u32 counter;
counter = ioread32(priv->iobase + HW_WDTV);
return counter / priv->wdt_freq;
}
static int asm9260_wdt_updatetimeout(struct watchdog_device *wdd)
{
struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
u32 counter;
counter = wdd->timeout * priv->wdt_freq;
iowrite32(counter, priv->iobase + HW_WDTC);
return 0;
}
static int asm9260_wdt_enable(struct watchdog_device *wdd)
{
struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
u32 mode = 0;
if (priv->mode == HW_RESET)
mode = BM_MOD_WDRESET;
iowrite32(BM_MOD_WDEN | mode, priv->iobase + HW_WDMOD);
asm9260_wdt_updatetimeout(wdd);
asm9260_wdt_feed(wdd);
return 0;
}
static int asm9260_wdt_disable(struct watchdog_device *wdd)
{
struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
/* The only way to disable WD is to reset it. */
reset_control_assert(priv->rst);
reset_control_deassert(priv->rst);
return 0;
}
static int asm9260_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
{
wdd->timeout = to;
asm9260_wdt_updatetimeout(wdd);
return 0;
}
static void asm9260_wdt_sys_reset(struct asm9260_wdt_priv *priv)
{
/* init WD if it was not started */
iowrite32(BM_MOD_WDEN | BM_MOD_WDRESET, priv->iobase + HW_WDMOD);
iowrite32(0xff, priv->iobase + HW_WDTC);
/* first pass correct sequence */
asm9260_wdt_feed(&priv->wdd);
/*
* Then write wrong pattern to the feed to trigger reset
* ASAP.
*/
iowrite32(0xff, priv->iobase + HW_WDFEED);
mdelay(1000);
}
static irqreturn_t asm9260_wdt_irq(int irq, void *devid)
{
struct asm9260_wdt_priv *priv = devid;
u32 stat;
stat = ioread32(priv->iobase + HW_WDMOD);
if (!(stat & BM_MOD_WDINT))
return IRQ_NONE;
if (priv->mode == DEBUG) {
dev_info(priv->dev, "Watchdog Timeout. Do nothing.\n");
} else {
dev_info(priv->dev, "Watchdog Timeout. Doing SW Reset.\n");
asm9260_wdt_sys_reset(priv);
}
return IRQ_HANDLED;
}
static int asm9260_restart(struct watchdog_device *wdd, unsigned long action,
void *data)
{
struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
asm9260_wdt_sys_reset(priv);
return 0;
}
static const struct watchdog_info asm9260_wdt_ident = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
| WDIOF_MAGICCLOSE,
.identity = "Alphascale asm9260 Watchdog",
};
static const struct watchdog_ops asm9260_wdt_ops = {
.owner = THIS_MODULE,
.start = asm9260_wdt_enable,
.stop = asm9260_wdt_disable,
.get_timeleft = asm9260_wdt_gettimeleft,
.ping = asm9260_wdt_feed,
.set_timeout = asm9260_wdt_settimeout,
.restart = asm9260_restart,
};
static int asm9260_wdt_get_dt_clks(struct asm9260_wdt_priv *priv)
{
int err;
unsigned long clk;
priv->clk = devm_clk_get(priv->dev, "mod");
if (IS_ERR(priv->clk)) {
dev_err(priv->dev, "Failed to get \"mod\" clk\n");
return PTR_ERR(priv->clk);
}
/* configure AHB clock */
priv->clk_ahb = devm_clk_get(priv->dev, "ahb");
if (IS_ERR(priv->clk_ahb)) {
dev_err(priv->dev, "Failed to get \"ahb\" clk\n");
return PTR_ERR(priv->clk_ahb);
}
err = clk_prepare_enable(priv->clk_ahb);
if (err) {
dev_err(priv->dev, "Failed to enable ahb_clk!\n");
return err;
}
err = clk_set_rate(priv->clk, CLOCK_FREQ);
if (err) {
clk_disable_unprepare(priv->clk_ahb);
dev_err(priv->dev, "Failed to set rate!\n");
return err;
}
err = clk_prepare_enable(priv->clk);
if (err) {
clk_disable_unprepare(priv->clk_ahb);
dev_err(priv->dev, "Failed to enable clk!\n");
return err;
}
/* wdt has internal divider */
clk = clk_get_rate(priv->clk);
if (!clk) {
clk_disable_unprepare(priv->clk);
clk_disable_unprepare(priv->clk_ahb);
dev_err(priv->dev, "Failed, clk is 0!\n");
return -EINVAL;
}
priv->wdt_freq = clk / 2;
return 0;
}
static void asm9260_wdt_get_dt_mode(struct asm9260_wdt_priv *priv)
{
const char *tmp;
int ret;
/* default mode */
priv->mode = HW_RESET;
ret = of_property_read_string(priv->dev->of_node,
"alphascale,mode", &tmp);
if (ret < 0)
return;
if (!strcmp(tmp, "hw"))
priv->mode = HW_RESET;
else if (!strcmp(tmp, "sw"))
priv->mode = SW_RESET;
else if (!strcmp(tmp, "debug"))
priv->mode = DEBUG;
else
dev_warn(priv->dev, "unknown reset-type: %s. Using default \"hw\" mode.",
tmp);
}
static int asm9260_wdt_probe(struct platform_device *pdev)
{
struct asm9260_wdt_priv *priv;
struct watchdog_device *wdd;
struct resource *res;
int ret;
static const char * const mode_name[] = { "hw", "sw", "debug", };
priv = devm_kzalloc(&pdev->dev, sizeof(struct asm9260_wdt_priv),
GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->dev = &pdev->dev;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->iobase = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv->iobase))
return PTR_ERR(priv->iobase);
priv->rst = devm_reset_control_get_exclusive(&pdev->dev, "wdt_rst");
if (IS_ERR(priv->rst))
return PTR_ERR(priv->rst);
ret = asm9260_wdt_get_dt_clks(priv);
if (ret)
return ret;
wdd = &priv->wdd;
wdd->info = &asm9260_wdt_ident;
wdd->ops = &asm9260_wdt_ops;
wdd->min_timeout = 1;
wdd->max_timeout = BM_WDTC_MAX(priv->wdt_freq);
wdd->parent = &pdev->dev;
watchdog_set_drvdata(wdd, priv);
/*
* 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.
*/
wdd->timeout = ASM9260_WDT_DEFAULT_TIMEOUT;
watchdog_init_timeout(wdd, 0, &pdev->dev);
asm9260_wdt_get_dt_mode(priv);
if (priv->mode != HW_RESET)
priv->irq = platform_get_irq(pdev, 0);
if (priv->irq > 0) {
/*
* Not all supported platforms specify an interrupt for the
* watchdog, so let's make it optional.
*/
ret = devm_request_irq(&pdev->dev, priv->irq,
asm9260_wdt_irq, 0, pdev->name, priv);
if (ret < 0)
dev_warn(&pdev->dev, "failed to request IRQ\n");
}
watchdog_set_restart_priority(wdd, 128);
ret = watchdog_register_device(wdd);
if (ret)
goto clk_off;
platform_set_drvdata(pdev, priv);
dev_info(&pdev->dev, "Watchdog enabled (timeout: %d sec, mode: %s)\n",
wdd->timeout, mode_name[priv->mode]);
return 0;
clk_off:
clk_disable_unprepare(priv->clk);
clk_disable_unprepare(priv->clk_ahb);
return ret;
}
static void asm9260_wdt_shutdown(struct platform_device *pdev)
{
struct asm9260_wdt_priv *priv = platform_get_drvdata(pdev);
asm9260_wdt_disable(&priv->wdd);
}
static int asm9260_wdt_remove(struct platform_device *pdev)
{
struct asm9260_wdt_priv *priv = platform_get_drvdata(pdev);
asm9260_wdt_disable(&priv->wdd);
watchdog_unregister_device(&priv->wdd);
clk_disable_unprepare(priv->clk);
clk_disable_unprepare(priv->clk_ahb);
return 0;
}
static const struct of_device_id asm9260_wdt_of_match[] = {
{ .compatible = "alphascale,asm9260-wdt"},
{},
};
MODULE_DEVICE_TABLE(of, asm9260_wdt_of_match);
static struct platform_driver asm9260_wdt_driver = {
.driver = {
.name = "asm9260-wdt",
.of_match_table = asm9260_wdt_of_match,
},
.probe = asm9260_wdt_probe,
.remove = asm9260_wdt_remove,
.shutdown = asm9260_wdt_shutdown,
};
module_platform_driver(asm9260_wdt_driver);
MODULE_DESCRIPTION("asm9260 WatchDog Timer Driver");
MODULE_AUTHOR("Oleksij Rempel <linux@rempel-privat.de>");
MODULE_LICENSE("GPL");
Reference in New Issue View Git Blame Copy Permalink