watchdog: imx93: add watchdog timer on imx93

The WDOG clocks are sourced from lpo_clk, and lpo_clk is the fixed
32KHz. TOVAL contains the 16-bit value used to set the timeout period of
the watchdog. When the timeout period exceeds 2 seconds, the value
written to the TOVAL register is larger than 16-bit can represent.
Enabling watchdog prescaler can solve this problem.

Two points need to be aware of:
1. watchdog prescaler enables a fixed 256 pre-scaling of watchdog
counter reference clock
2. reconfiguration takes about 55ms on imx93

Reviewed-by: Jacky Bai <ping.bai@nxp.com>
Signed-off-by: Alice Guo <alice.guo@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220825083256.14565-8-alice.guo@oss.nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
This commit is contained in:
Alice Guo 2022-08-25 16:32:56 +08:00 коммит произвёл Wim Van Sebroeck
Родитель cef6bc98d5
Коммит 8ed2dc4855
1 изменённых файлов: 28 добавлений и 5 удалений

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@ -9,6 +9,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/watchdog.h>
@ -52,11 +53,17 @@ module_param(nowayout, bool, 0000);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
struct imx_wdt_hw_feature {
bool prescaler_enable;
u32 wdog_clock_rate;
};
struct imx7ulp_wdt_device {
struct watchdog_device wdd;
void __iomem *base;
struct clk *clk;
bool post_rcs_wait;
const struct imx_wdt_hw_feature *hw;
};
static int imx7ulp_wdt_wait_ulk(void __iomem *base)
@ -179,7 +186,7 @@ static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog,
unsigned int timeout)
{
struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
u32 toval = WDOG_CLOCK_RATE * timeout;
u32 toval = wdt->hw->wdog_clock_rate * timeout;
u32 val;
int ret;
u32 loop = RETRY_MAX;
@ -276,6 +283,9 @@ static int imx7ulp_wdt_init(struct imx7ulp_wdt_device *wdt, unsigned int timeout
int ret;
u32 loop = RETRY_MAX;
if (wdt->hw->prescaler_enable)
val |= WDOG_CS_PRES;
do {
ret = _imx7ulp_wdt_init(wdt, timeout, val);
toval = readl(wdt->base + WDOG_TOVAL);
@ -346,7 +356,9 @@ static int imx7ulp_wdt_probe(struct platform_device *pdev)
watchdog_stop_on_reboot(wdog);
watchdog_stop_on_unregister(wdog);
watchdog_set_drvdata(wdog, imx7ulp_wdt);
ret = imx7ulp_wdt_init(imx7ulp_wdt, wdog->timeout * WDOG_CLOCK_RATE);
imx7ulp_wdt->hw = of_device_get_match_data(dev);
ret = imx7ulp_wdt_init(imx7ulp_wdt, wdog->timeout * imx7ulp_wdt->hw->wdog_clock_rate);
if (ret)
return ret;
@ -368,7 +380,7 @@ static int __maybe_unused imx7ulp_wdt_suspend_noirq(struct device *dev)
static int __maybe_unused imx7ulp_wdt_resume_noirq(struct device *dev)
{
struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);
u32 timeout = imx7ulp_wdt->wdd.timeout * WDOG_CLOCK_RATE;
u32 timeout = imx7ulp_wdt->wdd.timeout * imx7ulp_wdt->hw->wdog_clock_rate;
int ret;
ret = clk_prepare_enable(imx7ulp_wdt->clk);
@ -389,9 +401,20 @@ static const struct dev_pm_ops imx7ulp_wdt_pm_ops = {
imx7ulp_wdt_resume_noirq)
};
static const struct imx_wdt_hw_feature imx7ulp_wdt_hw = {
.prescaler_enable = false,
.wdog_clock_rate = 1000,
};
static const struct imx_wdt_hw_feature imx93_wdt_hw = {
.prescaler_enable = true,
.wdog_clock_rate = 125,
};
static const struct of_device_id imx7ulp_wdt_dt_ids[] = {
{ .compatible = "fsl,imx8ulp-wdt", },
{ .compatible = "fsl,imx7ulp-wdt", },
{ .compatible = "fsl,imx8ulp-wdt", .data = &imx7ulp_wdt_hw, },
{ .compatible = "fsl,imx7ulp-wdt", .data = &imx7ulp_wdt_hw, },
{ .compatible = "fsl,imx93-wdt", .data = &imx93_wdt_hw, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx7ulp_wdt_dt_ids);