Re: [PATCH v1 2/2] watchdog: imx2_wdt: add set_pretimeout interface
From: Guenter Roeck
Date: Mon Nov 02 2015 - 23:19:20 EST
On 11/02/2015 07:29 PM, Robin Gong wrote:
Enable set_pretimeout interface and trigger the pretimeout interrupt before
watchdog timeout event happen.
Signed-off-by: Robin Gong <b38343@xxxxxxxxxxxxx>
---
drivers/watchdog/imx2_wdt.c | 67 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 66 insertions(+), 1 deletion(-)
diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
index 0bb1a1d..d3c6b07 100644
--- a/drivers/watchdog/imx2_wdt.c
+++ b/drivers/watchdog/imx2_wdt.c
@@ -24,7 +24,9 @@
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
+#include <linux/interrupt.h>
#include <linux/io.h>
+#include <linux/irq.h>
Are those two new includes both needed ?
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -52,12 +54,18 @@
#define IMX2_WDT_WRSR 0x04 /* Reset Status Register */
#define IMX2_WDT_WRSR_TOUT (1 << 1) /* -> Reset due to Timeout */
+#define IMX2_WDT_WICR 0x06 /*Interrupt Control Register*/
+#define IMX2_WDT_WICR_WIE (1 << 15) /* -> Interrupt Enable */
+#define IMX2_WDT_WICR_WTIS (1 << 14) /* -> Interrupt Status */
+#define IMX2_WDT_WICR_WICT (0xFF << 0) /* Watchdog Interrupt Timeout */
+
"<< 0" doesn't really add any value here.
#define IMX2_WDT_WMCR 0x08 /* Misc Register */
#define IMX2_WDT_MAX_TIME 128
#define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */
#define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8)
+#define WDOG_SEC_TO_PRECOUNT(s) (s * 2) /* set WDOG pre timeout count*/
((s) * 2)
Ah yes, WDOG_SEC_TO_COUNT should also use (s).
struct imx2_wdt_device {
struct clk *clk;
@@ -80,7 +88,8 @@ MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
static const struct watchdog_info imx2_wdt_info = {
.identity = "imx2+ watchdog",
- .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+ .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
+ | WDIOF_PRETIMEOUT,
};
static int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
@@ -207,12 +216,59 @@ static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
}
}
+static int imx2_wdt_check_pretimeout_set(struct imx2_wdt_device *wdev)
+{
+ u32 val;
+
+ regmap_read(wdev->regmap, IMX2_WDT_WICR, &val);
+ return (val & IMX2_WDT_WICR_WIE) ? 1 : 0;
I don't understand the point of this function.
You check if IMX2_WDT_WICR_WIE is set,
+}
+
+static int imx2_wdt_set_pretimeout(struct watchdog_device *wdog,
+ unsigned int new_timeout)
+{
+ struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+ u32 val;
+
+ regmap_read(wdev->regmap, IMX2_WDT_WICR, &val);
+ /* set the new pre-timeout value in the WSR */
+ val &= ~IMX2_WDT_WICR_WICT;
+ val |= WDOG_SEC_TO_PRECOUNT(new_timeout);
+
What is the time here ? Is pretimeout the number of seconds
until the interrupt occurs, or the number of seconds before the actual
timeout (as per API) ?
+ if (!imx2_wdt_check_pretimeout_set(wdev))
+ val |= IMX2_WDT_WICR_WIE; /*enable*/
if IMX2_WDT_WICR_WIE is not set, you set it,
+
+ regmap_write(wdev->regmap, IMX2_WDT_WICR, val);
+
and write the result unconditionally. Unless I am missing something,
regmap_write, wdev->regmap, IMX2_WDT_WICR, val | IMX2_WDT_WICR_WIE);
would accomplish exactly the same.
+ wdog->pretimeout = new_timeout;
+
+ return 0;
+}
+
+static irqreturn_t imx2_wdt_isr(int irq, void *dev_id)
+{
+ struct platform_device *pdev = dev_id;
+ struct watchdog_device *wdog = platform_get_drvdata(pdev);
+ struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+ u32 val;
+
+ regmap_read(wdev->regmap, IMX2_WDT_WICR, &val);
+ if (val & IMX2_WDT_WICR_WTIS) {
+ /*clear interrupt status bit*/
+ regmap_write(wdev->regmap, IMX2_WDT_WICR, val);
+ dev_warn(&pdev->dev, "pre-timeout:%d, %d Seconds remained\n",
+ wdog->pretimeout, wdog->timeout - wdog->pretimeout);
The idea here is that this should trigger a panic.
+ }
+ return IRQ_HANDLED;
+}
+
static const struct watchdog_ops imx2_wdt_ops = {
.owner = THIS_MODULE,
.start = imx2_wdt_start,
.stop = imx2_wdt_stop,
.ping = imx2_wdt_ping,
.set_timeout = imx2_wdt_set_timeout,
+ .set_pretimeout = imx2_wdt_set_pretimeout,
};
static const struct regmap_config imx2_wdt_regmap_config = {
@@ -229,6 +285,7 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
struct resource *res;
void __iomem *base;
int ret;
+ int irq;
u32 val;
wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
@@ -253,6 +310,14 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
return PTR_ERR(wdev->clk);
}
+ irq = platform_get_irq(pdev, 0);
This makes the irq mandatory. What if a platform doesn't have one configured ?
+ ret = devm_request_irq(&pdev->dev, irq, imx2_wdt_isr, 0,
+ dev_name(&pdev->dev), pdev);
+ if (ret) {
+ dev_err(&pdev->dev, "can't get irq %d\n", irq);
You got it, but you could not request it.
This is also a bit early, as the interrupt handler uses variables which are not yet
initialized.
+ return ret;
+ }
+
wdog = &wdev->wdog;
wdog->info = &imx2_wdt_info;
wdog->ops = &imx2_wdt_ops;
--
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