mirror of https://gitee.com/openkylin/linux.git
249 lines
6.1 KiB
C
249 lines
6.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Renesas RZ/A Series WDT Driver
|
|
*
|
|
* Copyright (C) 2017 Renesas Electronics America, Inc.
|
|
* Copyright (C) 2017 Chris Brandt
|
|
*/
|
|
|
|
#include <linux/bitops.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/module.h>
|
|
#include <linux/of_address.h>
|
|
#include <linux/of_device.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/watchdog.h>
|
|
|
|
#define DEFAULT_TIMEOUT 30
|
|
|
|
/* Watchdog Timer Registers */
|
|
#define WTCSR 0
|
|
#define WTCSR_MAGIC 0xA500
|
|
#define WTSCR_WT BIT(6)
|
|
#define WTSCR_TME BIT(5)
|
|
#define WTSCR_CKS(i) (i)
|
|
|
|
#define WTCNT 2
|
|
#define WTCNT_MAGIC 0x5A00
|
|
|
|
#define WRCSR 4
|
|
#define WRCSR_MAGIC 0x5A00
|
|
#define WRCSR_RSTE BIT(6)
|
|
#define WRCSR_CLEAR_WOVF 0xA500 /* special value */
|
|
|
|
/* The maximum CKS register setting value to get the longest timeout */
|
|
#define CKS_3BIT 0x7
|
|
#define CKS_4BIT 0xF
|
|
|
|
#define DIVIDER_3BIT 16384 /* Clock divider when CKS = 0x7 */
|
|
#define DIVIDER_4BIT 4194304 /* Clock divider when CKS = 0xF */
|
|
|
|
struct rza_wdt {
|
|
struct watchdog_device wdev;
|
|
void __iomem *base;
|
|
struct clk *clk;
|
|
u8 count;
|
|
u8 cks;
|
|
};
|
|
|
|
static void rza_wdt_calc_timeout(struct rza_wdt *priv, int timeout)
|
|
{
|
|
unsigned long rate = clk_get_rate(priv->clk);
|
|
unsigned int ticks;
|
|
|
|
if (priv->cks == CKS_4BIT) {
|
|
ticks = DIV_ROUND_UP(timeout * rate, DIVIDER_4BIT);
|
|
|
|
/*
|
|
* Since max_timeout was set in probe, we know that the timeout
|
|
* value passed will never calculate to a tick value greater
|
|
* than 256.
|
|
*/
|
|
priv->count = 256 - ticks;
|
|
|
|
} else {
|
|
/* Start timer with longest timeout */
|
|
priv->count = 0;
|
|
}
|
|
|
|
pr_debug("%s: timeout set to %u (WTCNT=%d)\n", __func__,
|
|
timeout, priv->count);
|
|
}
|
|
|
|
static int rza_wdt_start(struct watchdog_device *wdev)
|
|
{
|
|
struct rza_wdt *priv = watchdog_get_drvdata(wdev);
|
|
|
|
/* Stop timer */
|
|
writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
|
|
|
|
/* Must dummy read WRCSR:WOVF at least once before clearing */
|
|
readb(priv->base + WRCSR);
|
|
writew(WRCSR_CLEAR_WOVF, priv->base + WRCSR);
|
|
|
|
rza_wdt_calc_timeout(priv, wdev->timeout);
|
|
|
|
writew(WRCSR_MAGIC | WRCSR_RSTE, priv->base + WRCSR);
|
|
writew(WTCNT_MAGIC | priv->count, priv->base + WTCNT);
|
|
writew(WTCSR_MAGIC | WTSCR_WT | WTSCR_TME |
|
|
WTSCR_CKS(priv->cks), priv->base + WTCSR);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int rza_wdt_stop(struct watchdog_device *wdev)
|
|
{
|
|
struct rza_wdt *priv = watchdog_get_drvdata(wdev);
|
|
|
|
writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int rza_wdt_ping(struct watchdog_device *wdev)
|
|
{
|
|
struct rza_wdt *priv = watchdog_get_drvdata(wdev);
|
|
|
|
writew(WTCNT_MAGIC | priv->count, priv->base + WTCNT);
|
|
|
|
pr_debug("%s: timeout = %u\n", __func__, wdev->timeout);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int rza_set_timeout(struct watchdog_device *wdev, unsigned int timeout)
|
|
{
|
|
wdev->timeout = timeout;
|
|
rza_wdt_start(wdev);
|
|
return 0;
|
|
}
|
|
|
|
static int rza_wdt_restart(struct watchdog_device *wdev, unsigned long action,
|
|
void *data)
|
|
{
|
|
struct rza_wdt *priv = watchdog_get_drvdata(wdev);
|
|
|
|
/* Stop timer */
|
|
writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
|
|
|
|
/* Must dummy read WRCSR:WOVF at least once before clearing */
|
|
readb(priv->base + WRCSR);
|
|
writew(WRCSR_CLEAR_WOVF, priv->base + WRCSR);
|
|
|
|
/*
|
|
* Start timer with fastest clock source and only 1 clock left before
|
|
* overflow with reset option enabled.
|
|
*/
|
|
writew(WRCSR_MAGIC | WRCSR_RSTE, priv->base + WRCSR);
|
|
writew(WTCNT_MAGIC | 255, priv->base + WTCNT);
|
|
writew(WTCSR_MAGIC | WTSCR_WT | WTSCR_TME, priv->base + WTCSR);
|
|
|
|
/*
|
|
* Actually make sure the above sequence hits hardware before sleeping.
|
|
*/
|
|
wmb();
|
|
|
|
/* Wait for WDT overflow (reset) */
|
|
udelay(20);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct watchdog_info rza_wdt_ident = {
|
|
.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
|
|
.identity = "Renesas RZ/A WDT Watchdog",
|
|
};
|
|
|
|
static const struct watchdog_ops rza_wdt_ops = {
|
|
.owner = THIS_MODULE,
|
|
.start = rza_wdt_start,
|
|
.stop = rza_wdt_stop,
|
|
.ping = rza_wdt_ping,
|
|
.set_timeout = rza_set_timeout,
|
|
.restart = rza_wdt_restart,
|
|
};
|
|
|
|
static int rza_wdt_probe(struct platform_device *pdev)
|
|
{
|
|
struct rza_wdt *priv;
|
|
struct resource *res;
|
|
unsigned long rate;
|
|
int ret;
|
|
|
|
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
|
|
if (!priv)
|
|
return -ENOMEM;
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
priv->base = devm_ioremap_resource(&pdev->dev, res);
|
|
if (IS_ERR(priv->base))
|
|
return PTR_ERR(priv->base);
|
|
|
|
priv->clk = devm_clk_get(&pdev->dev, NULL);
|
|
if (IS_ERR(priv->clk))
|
|
return PTR_ERR(priv->clk);
|
|
|
|
rate = clk_get_rate(priv->clk);
|
|
if (rate < 16384) {
|
|
dev_err(&pdev->dev, "invalid clock rate (%ld)\n", rate);
|
|
return -ENOENT;
|
|
}
|
|
|
|
priv->wdev.info = &rza_wdt_ident,
|
|
priv->wdev.ops = &rza_wdt_ops,
|
|
priv->wdev.parent = &pdev->dev;
|
|
|
|
priv->cks = (u8)(uintptr_t)of_device_get_match_data(&pdev->dev);
|
|
if (priv->cks == CKS_4BIT) {
|
|
/* Assume slowest clock rate possible (CKS=0xF) */
|
|
priv->wdev.max_timeout = (DIVIDER_4BIT * U8_MAX) / rate;
|
|
|
|
} else if (priv->cks == CKS_3BIT) {
|
|
/* Assume slowest clock rate possible (CKS=7) */
|
|
rate /= DIVIDER_3BIT;
|
|
|
|
/*
|
|
* Since the max possible timeout of our 8-bit count
|
|
* register is less than a second, we must use
|
|
* max_hw_heartbeat_ms.
|
|
*/
|
|
priv->wdev.max_hw_heartbeat_ms = (1000 * U8_MAX) / rate;
|
|
dev_dbg(&pdev->dev, "max hw timeout of %dms\n",
|
|
priv->wdev.max_hw_heartbeat_ms);
|
|
}
|
|
|
|
priv->wdev.min_timeout = 1;
|
|
priv->wdev.timeout = DEFAULT_TIMEOUT;
|
|
|
|
watchdog_init_timeout(&priv->wdev, 0, &pdev->dev);
|
|
watchdog_set_drvdata(&priv->wdev, priv);
|
|
|
|
ret = devm_watchdog_register_device(&pdev->dev, &priv->wdev);
|
|
if (ret)
|
|
dev_err(&pdev->dev, "Cannot register watchdog device\n");
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const struct of_device_id rza_wdt_of_match[] = {
|
|
{ .compatible = "renesas,r7s9210-wdt", .data = (void *)CKS_4BIT, },
|
|
{ .compatible = "renesas,rza-wdt", .data = (void *)CKS_3BIT, },
|
|
{ /* sentinel */ }
|
|
};
|
|
MODULE_DEVICE_TABLE(of, rza_wdt_of_match);
|
|
|
|
static struct platform_driver rza_wdt_driver = {
|
|
.probe = rza_wdt_probe,
|
|
.driver = {
|
|
.name = "rza_wdt",
|
|
.of_match_table = rza_wdt_of_match,
|
|
},
|
|
};
|
|
|
|
module_platform_driver(rza_wdt_driver);
|
|
|
|
MODULE_DESCRIPTION("Renesas RZ/A WDT Driver");
|
|
MODULE_AUTHOR("Chris Brandt <chris.brandt@renesas.com>");
|
|
MODULE_LICENSE("GPL v2");
|