Watchdog: introdouce ARM SBSA watchdog driver

From: Fu Wei <[email protected]>

The sbsa-gwdt.txt documentation in devicetree/bindings/watchdog is for introducing SBSA(Server Base System Architecture) Generic Watchdog device node info into FDT

Signed-off-by Fu Wei <[email protected]>

Quoted 7 lines · On Friday 15 May 2015 19:08:05 [email protected]…

From: Fu Wei <[email protected]>

The sbsa-gwdt.txt documentation in devicetree/bindings/watchdog is for introducing SBSA(Server Base System Architecture) Generic Watchdog device node info into FDT

Signed-off-by Fu Wei <[email protected]>

Looks good, just one minor comment:

Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt line 24

Quoted 3 lines

Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt new file +3 -0

+Optional properties
+- timeout-sec : Watchdog pre-timeout and timeout values (in seconds).
+     The first is timeout values, then pre-timeout.

Please update Documentation/watchdog/watchdog-kernel-api.txt as well, to mention the second number in the timeout-sec property.

Arnd

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Quoted 7 lines · On Friday 15 May 2015 19:08:05 [email protected]…

From: Fu Wei <[email protected]>

The sbsa-gwdt.txt documentation in devicetree/bindings/watchdog is for introducing SBSA(Server Base System Architecture) Generic Watchdog device node info into FDT

Signed-off-by Fu Wei <[email protected]>

Looks good, just one minor comment:

Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt line 24

Quoted 3 lines

Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt new file +3 -0

+Optional properties
+- timeout-sec : Watchdog pre-timeout and timeout values (in seconds).
+	The first is timeout values, then pre-timeout.

Please update Documentation/watchdog/watchdog-kernel-api.txt as well, to mention the second number in the timeout-sec property.

Arnd

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From: Fu Wei <[email protected]>

This patchset:

(1)Introdouces Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt for FDT info of SBSA Generic Watchdog, and give two examples of adding SBSA Generic Watchdog device node into the dts files:
foundation-v8.dts and amd-seattle-soc.dtsi

(2)Introdouce "pretimeout" into the watchdog framework

(3)Introdouces ARM SBSA watchdog driver
a.Use linux kernel watchdog framework
b.Work with FDT on ARM64
c.Use "pretimeout" in watchdog framework
d.In first timeout(WS0), do panic to save system context e.Support geting timeout and pretimeout from
parameter and FDT at the driver init stage

(4)Parse SBSA Generic Watchdog Structure in GTDT table of ACPI,
and create a platform device with that information This platform device can be used by This Watchdog driver

This patchset has been tested with watchdog daemon (ACPI/FDT, module/build-in) on the following platforms:
(1)ARM Foundation v8 model
(2)AMD Seattle B0

Quoted 19 lines · On Friday 15 May 2015 19:08:04 [email protected]…

From: Fu Wei <[email protected]>

This patchset:

(1)Introdouces Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt for FDT info of SBSA Generic Watchdog, and give two examples of adding SBSA Generic Watchdog device node into the dts files:
foundation-v8.dts and amd-seattle-soc.dtsi

(2)Introdouce "pretimeout" into the watchdog framework

(3)Introdouces ARM SBSA watchdog driver
a.Use linux kernel watchdog framework
b.Work with FDT on ARM64
c.Use "pretimeout" in watchdog framework
d.In first timeout(WS0), do panic to save system context e.Support geting timeout and pretimeout from
parameter and FDT at the driver init stage

Quoted 10 lines

(4)Parse SBSA Generic Watchdog Structure in GTDT table of ACPI,
and create a platform device with that information This platform device can be used by This Watchdog driver

This patchset has been tested with watchdog daemon (ACPI/FDT, module/build-in) on the following platforms:
(1)ARM Foundation v8 model
(2)AMD Seattle B0

I've had a few very minor comments to the individual patches, otherwise looks good. I have not reviewed the ACPI part of the series, as I have no knowledge of that.

Arnd

From: Fu Wei <[email protected]>

(1)Use linux kernel watchdog framework
(2)Work with FDT on ARM64
(3)Use "pretimeout" in watchdog framework
(4)In first timeout(WS0), do panic to save system context (5)support geting timeout and pretimeout from
parameter and FDT at the driver init stage.

Signed-off-by Fu Wei <[email protected]>

Quoted 9 lines · On Friday 15 May 2015 19:24:49 [email protected]…

From: Fu Wei <[email protected]>

(1)Use linux kernel watchdog framework
(2)Work with FDT on ARM64
(3)Use "pretimeout" in watchdog framework
(4)In first timeout(WS0), do panic to save system context (5)support geting timeout and pretimeout from
parameter and FDT at the driver init stage.

Quoted 1 line

Signed-off-by Fu Wei <[email protected]>

The patch looks good overall. Please try to describe in the patch in full sentences in the changelog, as we normally do.

A few tiny details that I'd do differently, but don't have to change if the watchdog maintainer is fine with your version:

drivers/watchdog/sbsa_gwdt.c line 99

Quoted 10 lines

drivers/watchdog/sbsa_gwdt.c new file +10 -0

+struct sbsa_gwdt {
+	struct watchdog_device	wdd;
+	u32			clk;
+	void __iomem		*refresh_base;
+	void __iomem		*control_base;
+#ifdef CONFIG_PM_SLEEP
+	spinlock_t		lock;
+	u8			pm_status_store;
+#endif
+};

I would drop the #ifdef here, and favor readability over saving a few bytes.

drivers/watchdog/sbsa_gwdt.c line 364

Quoted 9 lines

drivers/watchdog/sbsa_gwdt.c new file +8 -0

+	/*
+	 * Try to determine the frequency from the cp15 interface
+	 */
+	clk = arch_timer_get_cntfrq();
+	if (!clk) {
+		dev_err(dev, "System Counter frequency not available\n");
+		return -EINVAL;
+	}

Is it guaranteed that the same clock feeds the arch timer and the watchdog? Maybe it would be better to use the clk API to read the frequency, so we can avoid this dependency.

Quoted 4 lines

drivers/watchdog/sbsa_gwdt.c new file +3 -0

+
+	pr_debug("sbsa_gwdt: ioremap %s frame 0x%llx(size: %llu)-->%p.\n",
+		 res->name, (unsigned long long)res->start,

drivers/watchdog/sbsa_gwdt.c line 386

Quoted 10 lines

drivers/watchdog/sbsa_gwdt.c new file +10 -0

+		(unsigned long long)(res->end - res->start + 1), rf_base);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "control");
+	cf_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(rf_base))
+		return PTR_ERR(rf_base);
+
+	pr_debug("sbsa_gwdt: ioremap %s frame 0x%llx(size: %llu)-->%p.\n",
+		 res->name, (unsigned long long)res->start,
+		(unsigned long long)(res->end - res->start + 1), cf_base);

I would probably drop the various pr_debug() calls here. Once the driver works fine, they are normally not that useful any more.

Arnd

yes. you are right. According to SBSA doc, the clocksource of SBSA watchdog is System Counter. And System Counter is in (arm_)arch_timer. So I think we should do

depends on ARM_ARCH_TIMER

and use the relevant interface :

	clk = arch_timer_get_rate();

will improve it, thanks for your suggestion!

Quoted 2 lines

I would probably drop the various pr_debug() calls here. Once the driver works fine, they are normally not that useful any more.

yes, for this drive, if it works fine, we can drop it, but I keep these info for some reason:
(1)they can help engineer debug GTDT table or DTS, if the info of watchdog goes wrong.

From: Fu Wei <[email protected]>

(1)Use linux kernel watchdog framework
(2)Work with FDT on ARM64
(3)Use "pretimeout" in watchdog framework
(4)In first timeout(WS0), do panic to save system context (5)support geting timeout and pretimeout from

parameter and FDT at the driver init stage.

Signed-off-by Fu Wei <[email protected]>

---
  drivers/watchdog/Kconfig     |  10 +
  drivers/watchdog/Makefile    |   1 +
  drivers/watchdog/sbsa_gwdt.c | 553 +++++++++++++++++++++++++++++++++++++++++++
  3 files changed, 564 insertions(+)

create mode 100644 drivers/watchdog/sbsa_gwdt.c

drivers/watchdog/Kconfig +0 -0

index e5e7c55..1e1bc8b 100644

drivers/watchdog/Kconfig +3 -0

+	  will reboot your system when the second timeout(WS1) is reached.
+	  More details: DEN0029B - Server Base System Architecture (SBSA)
+
  config AT91RM9200_WATCHDOG
  	tristate "AT91RM9200 watchdog"
  	depends on SOC_AT91RM9200 && MFD_SYSCON

drivers/watchdog/Makefile +1 -0

index 5c19294..471f1b7c 100644
@@ -30,6 +30,7 @@ obj-$(CONFIG_USBPCWATCHDOG) += pcwd_usb.o
 
  # ARM Architecture
  obj-$(CONFIG_ARM_SP805_WATCHDOG) += sp805_wdt.o
+obj-$(CONFIG_ARM_SBSA_WATCHDOG) += sbsa_gwdt.o
  obj-$(CONFIG_AT91RM9200_WATCHDOG) += at91rm9200_wdt.o
  obj-$(CONFIG_AT91SAM9X_WATCHDOG) += at91sam9_wdt.o
  obj-$(CONFIG_CADENCE_WATCHDOG) += cadence_wdt.o

drivers/watchdog/sbsa_gwdt.c new file +9 -0

new file mode 100644
index 0000000..52838b1
@@ -0,0 +1,553 @@
+/*
+ * SBSA(Server Base System Architecture) Generic Watchdog driver
+ *
+ * Copyright (c) 2015, Linaro Ltd.
+ * Author: Fu Wei <[email protected]>
+ *         Suravee Suthikulpanit <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License 2 as published

drivers/watchdog/sbsa_gwdt.c new file +47 -0

+ *       automatically by hardware, when WS0 is triggered.
+ *       This gives a maximum watch period of around 10s at the maximum
+ *       system counter frequency.
+ *       The System Counter shall run at maximum of 400MHz.
+ *       More details: DEN0029B - Server Base System Architecture (SBSA)
+ *
+ * Kernel/API:                         P---------| pretimeout
+ *               |-------------------------------T timeout
+ * SBSA GWDT:                          P--WOR---WS1 pretimeout
+ *               |-------WCV----------WS0~~~~~~~~T timeout
+ */
+
+#include <asm/arch_timer.h>
+
+#include <linux/acpi.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/watchdog.h>
+
+/* SBSA Generic Watchdog register definitions */
+/* refresh frame */
+#define SBSA_GWDT_WRR				0x000
+
+/* control frame */
+#define SBSA_GWDT_WCS				0x000
+#define SBSA_GWDT_WOR				0x008
+#define SBSA_GWDT_WCV_LO			0x010
+#define SBSA_GWDT_WCV_HI			0x014
+
+/* refresh/control frame */
+#define SBSA_GWDT_W_IIDR			0xfcc
+#define SBSA_GWDT_IDR				0xfd0
+
+/* Watchdog Control and Status Register */
+#define SBSA_GWDT_WCS_EN			BIT(0)
+#define SBSA_GWDT_WCS_WS0			BIT(1)
+#define SBSA_GWDT_WCS_WS1			BIT(2)
+
+/* Watchdog Interface Identification Register */
+#define SBSA_GWDT_W_IIDR_PID(x)			((x >> 20) & 0xfff)

drivers/watchdog/sbsa_gwdt.c new file +81 -0

+};
+
+#define to_sbsa_gwdt(e) container_of(e, struct sbsa_gwdt, wdd)
+
+#define DEFAULT_TIMEOUT_WS0	10 /* seconds, the 1st watch period*/
+#define DEFAULT_PRETIMEOUT	5 /* seconds, the 2nd watch period*/
+
+static unsigned int timeout;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout,
+		 "Watchdog timeout in seconds. (>=0, default="
+		 __MODULE_STRING(DEFAULT_TIMEOUT_WS0 + DEFAULT_PRETIMEOUT) ")");
+
+static unsigned int max_timeout = UINT_MAX;
+module_param(max_timeout, uint, 0);
+MODULE_PARM_DESC(max_timeout,
+		 "Watchdog max timeout in seconds. (>=0, default="
+		 __MODULE_STRING(UINT_MAX) ")");
+
+static unsigned int max_pretimeout = U32_MAX;
+module_param(max_pretimeout, uint, 0);
+MODULE_PARM_DESC(max_pretimeout,
+		 "Watchdog max pretimeout in seconds. (>=0, default="
+		 __MODULE_STRING(U32_MAX) ")");
+
+static unsigned int pretimeout;
+module_param(pretimeout, uint, 0);
+MODULE_PARM_DESC(pretimeout,
+		 "Watchdog pretimeout in seconds. (>=0, default="
+		 __MODULE_STRING(DEFAULT_PRETIMEOUT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, S_IRUGO);
+MODULE_PARM_DESC(nowayout,
+		 "Watchdog cannot be stopped once started (default="
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+/*
+ * Architected system timer support.
+ */
+static void sbsa_gwdt_cf_write(unsigned int reg, u32 val,
+			       struct watchdog_device *wdd)
+{
+	struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+
+	writel_relaxed(val, gwdt->control_base + reg);
+}
+
+static void sbsa_gwdt_rf_write(unsigned int reg, u32 val,
+			       struct watchdog_device *wdd)
+{
+	struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+
+	writel_relaxed(val, gwdt->refresh_base + reg);
+}
+
+static u32 sbsa_gwdt_cf_read(unsigned int reg, struct watchdog_device *wdd)
+{
+	struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+
+	return readl_relaxed(gwdt->control_base + reg);
+}
+
+/*
+ * help founctions for accessing 64bit WCV register
+ * mutex_lock must be called prior to calling this function.
+ */
+static u64 sbsa_gwdt_get_wcv(struct watchdog_device *wdd)
+{
+	u32 wcv_lo, wcv_hi;
+
+	do {
+		wcv_hi = sbsa_gwdt_cf_read(SBSA_GWDT_WCV_HI, wdd);
+		wcv_lo = sbsa_gwdt_cf_read(SBSA_GWDT_WCV_LO, wdd);
+	} while (wcv_hi != sbsa_gwdt_cf_read(SBSA_GWDT_WCV_HI, wdd));
+
+	return (((u64)wcv_hi << 32) | wcv_lo);
+}
+
+static void sbsa_gwdt_set_wcv(struct watchdog_device *wdd, u64 value)
+{

drivers/watchdog/sbsa_gwdt.c new file +18 -0

+}
+
+static void reload_timeout_to_wcv(struct watchdog_device *wdd)
+{
+	struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+	u64 wcv;
+
+	wcv = arch_counter_get_cntvct() +
+		(u64)(wdd->timeout - wdd->pretimeout) * gwdt->clk;
+
+	sbsa_gwdt_set_wcv(wdd, wcv);
+}
+
+/*
+ * Use the following function to set the limit of timeout
+ * after updating pretimeout
+ */
+static void sbsa_gwdt_set_timeout_limits(struct sbsa_gwdt *gwdt)

drivers/watchdog/sbsa_gwdt.c new file +12 -0

+}
+
+static int sbsa_gwdt_set_pretimeout(struct watchdog_device *wdd,
+				    unsigned int pretimeout)
+{
+	struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+	u32 wor;
+
+	wdd->pretimeout = pretimeout;
+	sbsa_gwdt_set_timeout_limits(gwdt);
+
+	if (!pretimeout)

drivers/watchdog/sbsa_gwdt.c new file +73 -0

+
+	return 0;
+}
+
+static int sbsa_gwdt_stop(struct watchdog_device *wdd)
+{
+	/* Force refresh */
+	sbsa_gwdt_rf_write(SBSA_GWDT_WRR, 0xc0ffee, wdd);
+	/* writing WCS will cause an explicit watchdog refresh */
+	sbsa_gwdt_cf_write(SBSA_GWDT_WCS, 0, wdd);
+
+	pr_debug("sbsa_gwdt: WCS is %x(%s)\n",
+		 sbsa_gwdt_cf_read(SBSA_GWDT_WCS, wdd), __func__);
+
+	return 0;
+}
+
+static int sbsa_gwdt_keepalive(struct watchdog_device *wdd)
+{
+	/*
+	 * Writing WRR for an explicit watchdog refresh
+	 * You can write anyting(like 0xc0ffee)
+	 */
+	sbsa_gwdt_rf_write(SBSA_GWDT_WRR, 0xc0ffee, wdd);
+
+	reload_timeout_to_wcv(wdd);
+
+	pr_debug("sbsa_gwdt: ping, %us left.\n", sbsa_gwdt_get_timeleft(wdd));
+
+	return 0;
+}
+
+static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id)
+{
+	struct sbsa_gwdt *gwdt = (struct sbsa_gwdt *)dev_id;
+	struct watchdog_device *wdd = &gwdt->wdd;
+	u32 status;
+
+	status = sbsa_gwdt_cf_read(SBSA_GWDT_WCS, wdd);
+
+	pr_debug("sbsa_gwdt: interrupt routine, WCS@%x\n", status);
+
+	if (status & SBSA_GWDT_WCS_WS0) {
+		pr_debug("sbsa_gwdt WS0: trigger WS1 in %ds!\n",
+			 sbsa_gwdt_get_timeleft(wdd));
+		panic("SBSA Watchdog pre-timeout");
+	}
+
+	return IRQ_HANDLED;
+}
+
+static struct watchdog_info sbsa_gwdt_info = {
+	.identity	= "SBSA Generic Watchdog",
+	.options	= WDIOF_SETTIMEOUT |
+			  WDIOF_KEEPALIVEPING |
+			  WDIOF_MAGICCLOSE |
+			  WDIOF_PRETIMEOUT |
+			  WDIOF_CARDRESET,
+};
+
+static struct watchdog_ops sbsa_gwdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= sbsa_gwdt_start,
+	.stop		= sbsa_gwdt_stop,
+	.ping		= sbsa_gwdt_keepalive,
+	.set_timeout	= sbsa_gwdt_set_timeout,
+	.set_pretimeout	= sbsa_gwdt_set_pretimeout,
+	.get_timeleft	= sbsa_gwdt_get_timeleft,
+};
+
+static int sbsa_gwdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;

drivers/watchdog/sbsa_gwdt.c new file +12 -0

+
+	/*
+	 * Try to determine the frequency from the cp15 interface
+	 */
+	clk = arch_timer_get_cntfrq();
+	if (!clk) {
+		dev_err(dev, "System Counter frequency not available\n");
+		return -EINVAL;
+	}
+
+	gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
+	if (!gwdt)

drivers/watchdog/sbsa_gwdt.c new file +29 -0

+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "control");
+	cf_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(rf_base))
+		return PTR_ERR(rf_base);
+
+	pr_debug("sbsa_gwdt: ioremap %s frame 0x%llx(size: %llu)-->%p.\n",
+		 res->name, (unsigned long long)res->start,
+		(unsigned long long)(res->end - res->start + 1), cf_base);
+
+	irq = platform_get_irq_byname(pdev, "ws0");
+	if (irq < 0) {
+		dev_err(dev, "unable to get ws0 interrupt.\n");
+		return irq;
+	}
+
+	pr_debug("sbsa_gwdt: ws0 irq %d.\n", irq);
+
+	gwdt->refresh_base = rf_base;
+	gwdt->control_base = cf_base;
+	gwdt->clk = clk;
+#ifdef CONFIG_PM_SLEEP
+	spin_lock_init(&gwdt->lock);
+#endif
+	platform_set_drvdata(pdev, gwdt);
+
+	pr_debug("sbsa_gwdt: hw clk: %uHz--> WOR(32bit) max timeout is %us.\n",
+		 gwdt->clk, U32_MAX / clk);
+

drivers/watchdog/sbsa_gwdt.c new file +10 -0

+			 status, sbsa_gwdt_get_wcv(wdd));
+		wdd->bootstatus |= WDIOF_CARDRESET;
+	}
+	/* Check if watchdog is already enabled */
+	if (status & SBSA_GWDT_WCS_EN) {
+		dev_warn(dev, "already enabled!\n");
+		sbsa_gwdt_keepalive(wdd);
+	}
+
+	pr_debug("sbsa_gwdt: WCS: %x(%s)\n", status, __func__);

drivers/watchdog/sbsa_gwdt.c new file +12 -0

+	}
+	sbsa_gwdt_set_timeout(wdd, wdd->timeout);
+
+	ret = devm_request_irq(dev, irq, sbsa_gwdt_interrupt, IRQF_TIMER,
+			       pdev->name, gwdt);
+	if (ret) {
+		dev_err(dev, "unable to request IRQ %d\n", irq);
+		return ret;
+	}
+
+	ret = watchdog_register_device(wdd);
+	if (ret)

drivers/watchdog/sbsa_gwdt.c new file +18 -0

+
+	dev_info(dev, "Initialized with %ds timeout, %ds pretimeout @ %uHz\n",
+		 wdd->timeout, wdd->pretimeout, gwdt->clk);
+
+	return 0;
+}
+
+static void sbsa_gwdt_shutdown(struct platform_device *pdev)
+{
+	struct sbsa_gwdt *gwdt = platform_get_drvdata(pdev);
+
+	sbsa_gwdt_stop(&gwdt->wdd);
+}
+
+static int sbsa_gwdt_remove(struct platform_device *pdev)
+{
+	struct sbsa_gwdt *gwdt = platform_get_drvdata(pdev);
+	int ret = 0;

drivers/watchdog/sbsa_gwdt.c new file +5 -0

+
+	return 0;
+}
+
+/* Enable watchdog and configure it if necessary */

drivers/watchdog/sbsa_gwdt.c new file +22 -0

+	spin_unlock(&gwdt->lock);
+
+	return 0;
+}
+#endif
+
+static const struct of_device_id sbsa_gwdt_of_match[] = {
+	{ .compatible = "arm,sbsa-gwdt", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sbsa_gwdt_of_match);
+
+static const struct dev_pm_ops sbsa_gwdt_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(sbsa_gwdt_suspend, sbsa_gwdt_resume)
+};
+
+static struct platform_driver sbsa_gwdt_driver = {
+	.driver = {
+		.name = "sbsa-gwdt",
+		.pm = &sbsa_gwdt_pm_ops,
+		.of_match_table = sbsa_gwdt_of_match,
+	},

Quoted 8 lines · On 05/15/2015 04:24 AM, [email protected] wrote:

From: Fu Wei <[email protected]>

(1)Use linux kernel watchdog framework
(2)Work with FDT on ARM64
(3)Use "pretimeout" in watchdog framework
(4)In first timeout(WS0), do panic to save system context (5)support geting timeout and pretimeout from

getting

Quoted 1 line

parameter and FDT at the driver init stage.

Subject: s/introdouce/introduce/

Please find a better description.

Also, please provide revisions numbers for your patch sets, and list the changes from one revision to the next.

Quoted 26 lines

Signed-off-by Fu Wei <[email protected]>

---
  drivers/watchdog/Kconfig     |  10 +
  drivers/watchdog/Makefile    |   1 +
  drivers/watchdog/sbsa_gwdt.c | 553
+++++++++++++++++++++++++++++++++++++++++++
  3 files changed, 564 insertions(+)

create mode 100644 drivers/watchdog/sbsa_gwdt.c

drivers/watchdog/Kconfig +0 -0

index e5e7c55..1e1bc8b 100644
@@ -152,6 +152,16 @@ config ARM_SP805_WATCHDOG
          ARM Primecell SP805 Watchdog timer. This will reboot your system

when
the timeout is reached.

drivers/watchdog/Kconfig +6 -0

+config ARM_SBSA_WATCHDOG
+       tristate "ARM SBSA Generic Watchdog"
+       depends on ARM || ARM64 || COMPILE_TEST
+       select WATCHDOG_CORE
+       help
+         ARM SBSA Generic Watchdog timer. This has two Watchdog

Quoted 1 line

Signal(WS0/WS1),

signals

Quoted 2 lines

+ will trigger a warnning interrupt(do panic) in the first
timeout(WS0);

warning

Quoted 40 lines

drivers/watchdog/Kconfig +3 -0

+         will reboot your system when the second timeout(WS1) is reached.
+         More details: DEN0029B - Server Base System Architecture (SBSA)
+
  config AT91RM9200_WATCHDOG
        tristate "AT91RM9200 watchdog"
        depends on SOC_AT91RM9200 && MFD_SYSCON

drivers/watchdog/Makefile +1 -0

index 5c19294..471f1b7c 100644
@@ -30,6 +30,7 @@ obj-$(CONFIG_USBPCWATCHDOG) += pcwd_usb.o
 
  # ARM Architecture
  obj-$(CONFIG_ARM_SP805_WATCHDOG) += sp805_wdt.o
+obj-$(CONFIG_ARM_SBSA_WATCHDOG) += sbsa_gwdt.o
  obj-$(CONFIG_AT91RM9200_WATCHDOG) += at91rm9200_wdt.o
  obj-$(CONFIG_AT91SAM9X_WATCHDOG) += at91sam9_wdt.o
  obj-$(CONFIG_CADENCE_WATCHDOG) += cadence_wdt.o

drivers/watchdog/sbsa_gwdt.c new file +14 -0

new file mode 100644
index 0000000..52838b1
@@ -0,0 +1,553 @@
+/*
+ * SBSA(Server Base System Architecture) Generic Watchdog driver
+ *
+ * Copyright (c) 2015, Linaro Ltd.
+ * Author: Fu Wei <[email protected]>
+ *         Suravee Suthikulpanit <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

drivers/watchdog/sbsa_gwdt.c line 19

Quoted 5 lines

drivers/watchdog/sbsa_gwdt.c new file +5 -0

+ * GNU General Public License for more details.
+ *
+ * Note: This SBSA Generic watchdog driver is compatible with
+ *       the pretimeout concept of Linux kernel.
+ *       But timeout and pretimeout are set by the different REGs.

Why "But" ?

Quoted 6 lines

drivers/watchdog/sbsa_gwdt.c new file +4 -0

+ *       The first watch period is set by writing WCV directly,
+ *       that can support more than 10s timeout at the maximum
+ *       system counter frequency.
+ *       And the second watch period is set by WOR(32bit) which will be

loaded

s/And the/The/

Quoted 55 lines

+ *       automatically by hardware, when WS0 is triggered.
+ *       This gives a maximum watch period of around 10s at the maximum
+ *       system counter frequency.
+ *       The System Counter shall run at maximum of 400MHz.
+ *       More details: DEN0029B - Server Base System Architecture (SBSA)

+ *
+ * Kernel/API: P---------| pretimeout
+ * |-------------------------------T timeout
+ * SBSA GWDT: P--WOR---WS1 pretimeout
+ * |-------WCV----------WS0~~~~~~~~T timeout
+ */

drivers/watchdog/sbsa_gwdt.c new file +36 -0

+
+#include <asm/arch_timer.h>
+
+#include <linux/acpi.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/watchdog.h>
+
+/* SBSA Generic Watchdog register definitions */
+/* refresh frame */
+#define SBSA_GWDT_WRR                          0x000
+
+/* control frame */
+#define SBSA_GWDT_WCS                          0x000
+#define SBSA_GWDT_WOR                          0x008
+#define SBSA_GWDT_WCV_LO                       0x010
+#define SBSA_GWDT_WCV_HI                       0x014
+
+/* refresh/control frame */
+#define SBSA_GWDT_W_IIDR                       0xfcc
+#define SBSA_GWDT_IDR                          0xfd0
+
+/* Watchdog Control and Status Register */
+#define SBSA_GWDT_WCS_EN                       BIT(0)
+#define SBSA_GWDT_WCS_WS0                      BIT(1)
+#define SBSA_GWDT_WCS_WS1                      BIT(2)
+
+/* Watchdog Interface Identification Register */
+#define SBSA_GWDT_W_IIDR_PID(x)                        ((x >> 20) &

0xfff)

drivers/watchdog/sbsa_gwdt.c new file +5 -0

+#define SBSA_GWDT_W_IIDR_ARCH_VER(x)           ((x >> 16) & 0xf)
+#define SBSA_GWDT_W_IIDR_REV(x)                        ((x >> 12) & 0xf)
+#define SBSA_GWDT_W_IIDR_IMPLEMENTER(x)                (x & 0xfff)
+#define SBSA_GWDT_W_IIDR_VID_BANK(x)           ((x >> 8) & 0xf)
+#define SBSA_GWDT_W_IIDR_VID(x)                        (x & 0x7f)

drivers/watchdog/sbsa_gwdt.c line 80

Quoted 5 lines

drivers/watchdog/sbsa_gwdt.c new file +5 -0

+
+/* Watchdog Identification Register */
+#define SBSA_GWDT_IDR_W_PIDR2                  0xfe8
+#define SBSA_GWDT_IDR_W_PIDR2_ARCH_VER(x)      ((x >> 4) & 0xf)
+

(x) for all the above macros, please.

Quoted 7 lines

+/**
+ * struct sbsa_gwdt - Internal representation of the SBSA GWDT

+ * @wdd:               kernel watchdog_device structure
+ * @clk:               store the System Counter clock frequency, in Hz.
+ * @refresh_base:      VA of the watchdog refresh frame
+ * @control_base:      VA of the watchdog control frame

Please spell out "Virtual address".

drivers/watchdog/sbsa_gwdt.c line 98

Quoted 13 lines

+ * @lock: struct sbsa_gwdt spinlock
+ * @pm_status_store: store the PM info of WDT
+ */

drivers/watchdog/sbsa_gwdt.c new file +9 -0

+struct sbsa_gwdt {
+       struct watchdog_device  wdd;
+       u32                     clk;
+       void __iomem            *refresh_base;
+       void __iomem            *control_base;
+#ifdef CONFIG_PM_SLEEP
+       spinlock_t              lock;
+       u8                      pm_status_store;
+#endif

Please avoid the #ifdef

Quoted 90 lines

drivers/watchdog/sbsa_gwdt.c new file +12 -0

+};
+
+#define to_sbsa_gwdt(e) container_of(e, struct sbsa_gwdt, wdd)
+
+#define DEFAULT_TIMEOUT_WS0    10 /* seconds, the 1st watch period*/
+#define DEFAULT_PRETIMEOUT     5 /* seconds, the 2nd watch period*/
+
+static unsigned int timeout;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout,
+                "Watchdog timeout in seconds. (>=0, default="
+                __MODULE_STRING(DEFAULT_TIMEOUT_WS0 + DEFAULT_PRETIMEOUT)

")");

drivers/watchdog/sbsa_gwdt.c new file +45 -0

+
+static unsigned int max_timeout = UINT_MAX;
+module_param(max_timeout, uint, 0);
+MODULE_PARM_DESC(max_timeout,
+                "Watchdog max timeout in seconds. (>=0, default="
+                __MODULE_STRING(UINT_MAX) ")");
+
+static unsigned int max_pretimeout = U32_MAX;
+module_param(max_pretimeout, uint, 0);
+MODULE_PARM_DESC(max_pretimeout,
+                "Watchdog max pretimeout in seconds. (>=0, default="
+                __MODULE_STRING(U32_MAX) ")");
+
+static unsigned int pretimeout;
+module_param(pretimeout, uint, 0);
+MODULE_PARM_DESC(pretimeout,
+                "Watchdog pretimeout in seconds. (>=0, default="
+                __MODULE_STRING(DEFAULT_PRETIMEOUT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, S_IRUGO);
+MODULE_PARM_DESC(nowayout,
+                "Watchdog cannot be stopped once started (default="
+                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+/*
+ * Architected system timer support.
+ */
+static void sbsa_gwdt_cf_write(unsigned int reg, u32 val,
+                              struct watchdog_device *wdd)
+{
+       struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+
+       writel_relaxed(val, gwdt->control_base + reg);
+}
+
+static void sbsa_gwdt_rf_write(unsigned int reg, u32 val,
+                              struct watchdog_device *wdd)
+{
+       struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+
+       writel_relaxed(val, gwdt->refresh_base + reg);
+}
+
+static u32 sbsa_gwdt_cf_read(unsigned int reg, struct watchdog_device

*wdd)

drivers/watchdog/sbsa_gwdt.c new file +29 -0

+{
+       struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+
+       return readl_relaxed(gwdt->control_base + reg);
+}
+
+/*
+ * help founctions for accessing 64bit WCV register
+ * mutex_lock must be called prior to calling this function.
+ */
+static u64 sbsa_gwdt_get_wcv(struct watchdog_device *wdd)
+{
+       u32 wcv_lo, wcv_hi;
+
+       do {
+               wcv_hi = sbsa_gwdt_cf_read(SBSA_GWDT_WCV_HI, wdd);
+               wcv_lo = sbsa_gwdt_cf_read(SBSA_GWDT_WCV_LO, wdd);
+       } while (wcv_hi != sbsa_gwdt_cf_read(SBSA_GWDT_WCV_HI, wdd));
+
+       return (((u64)wcv_hi << 32) | wcv_lo);
+}
+
+static void sbsa_gwdt_set_wcv(struct watchdog_device *wdd, u64 value)
+{
+       u32 wcv_lo, wcv_hi;
+
+       wcv_lo = value & U32_MAX;
+       wcv_hi = (value >> 32) & U32_MAX;
+

drivers/watchdog/sbsa_gwdt.c line 189

Quoted 5 lines

drivers/watchdog/sbsa_gwdt.c new file +5 -0

+       sbsa_gwdt_cf_write(SBSA_GWDT_WCV_HI, wcv_hi, wdd);
+       sbsa_gwdt_cf_write(SBSA_GWDT_WCV_LO, wcv_lo, wdd);
+
+       pr_debug("sbsa_gwdt: set WCV to %llu, result: %llu\n",
+                value, sbsa_gwdt_get_wcv(wdd));

Is this pr_debug still necessary ?

Quoted 26 lines

drivers/watchdog/sbsa_gwdt.c new file +24 -0

+}
+
+static void reload_timeout_to_wcv(struct watchdog_device *wdd)
+{
+       struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+       u64 wcv;
+
+       wcv = arch_counter_get_cntvct() +
+               (u64)(wdd->timeout - wdd->pretimeout) * gwdt->clk;
+
+       sbsa_gwdt_set_wcv(wdd, wcv);
+}
+
+/*
+ * Use the following function to set the limit of timeout
+ * after updating pretimeout
+ */
+static void sbsa_gwdt_set_timeout_limits(struct sbsa_gwdt *gwdt)
+{
+       unsigned int first_period_max = (U64_MAX / gwdt->clk);
+       struct watchdog_device *wdd = &gwdt->wdd;
+
+       wdd->min_timeout = wdd->pretimeout + 1;
+       wdd->max_timeout = min(wdd->pretimeout + first_period_max,

drivers/watchdog/sbsa_gwdt.c line 217

Quoted 5 lines

max_timeout);

drivers/watchdog/sbsa_gwdt.c new file +4 -0

+
+       pr_debug("sbsa_gwdt: timeout (%u-%u), pretimeout (%u-%u)\n",
+                wdd->min_timeout, wdd->max_timeout,
+                wdd->min_pretimeout, wdd->max_pretimeout);

Is this still necessary ?

drivers/watchdog/sbsa_gwdt.c line 226

Quoted 10 lines

drivers/watchdog/sbsa_gwdt.c new file +9 -0

+}
+
+static int sbsa_gwdt_set_timeout(struct watchdog_device *wdd,
+                                unsigned int timeout)
+{
+       wdd->timeout = timeout;
+
+       return 0;
+       /* watchdog framework will trigger a ping, after this call */

Unnecessary comment.

Quoted 19 lines

drivers/watchdog/sbsa_gwdt.c new file +18 -0

+}
+
+static int sbsa_gwdt_set_pretimeout(struct watchdog_device *wdd,
+                                   unsigned int pretimeout)
+{
+       struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+       u32 wor;
+
+       wdd->pretimeout = pretimeout;
+       sbsa_gwdt_set_timeout_limits(gwdt);
+
+       if (!pretimeout)
+               /* gives sbsa_gwdt_start a chance to setup timeout */
+               wor = gwdt->clk;
+       else
+               wor = pretimeout * gwdt->clk;
+
+       /* refresh the WOR, that will cause an explicit watchdog refresh

drivers/watchdog/sbsa_gwdt.c line 248

Quoted 5 lines

*/

drivers/watchdog/sbsa_gwdt.c new file +4 -0

+       sbsa_gwdt_cf_write(SBSA_GWDT_WOR, wor, wdd);
+
+       pr_debug("sbsa_gwdt: set WOR to %x(%us), result: %x\n",
+                wor, pretimeout, sbsa_gwdt_cf_read(SBSA_GWDT_WOR, wdd));

Is this still necessary ?

drivers/watchdog/sbsa_gwdt.c line 226

Quoted 4 lines

drivers/watchdog/sbsa_gwdt.c new file +3 -0

+
+       return 0;
+       /* watchdog framework will trigger a ping, after this call */

Unnecessary comment.

drivers/watchdog/sbsa_gwdt.c line 259

Quoted 9 lines

drivers/watchdog/sbsa_gwdt.c new file +8 -0

+}
+
+static unsigned int sbsa_gwdt_get_timeleft(struct watchdog_device *wdd)
+{
+       struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+       u64 timeleft = sbsa_gwdt_get_wcv(wdd) - arch_counter_get_cntvct();
+
+       return timeleft / gwdt->clk;

Will this ever be built on a 32 bit target ? That may cause a link error due to the 64 bit divide operation.

Quoted 12 lines

drivers/watchdog/sbsa_gwdt.c new file +11 -0

+}
+
+static int sbsa_gwdt_start(struct watchdog_device *wdd)
+{
+       /* Force refresh */
+       sbsa_gwdt_rf_write(SBSA_GWDT_WRR, 0xc0ffee, wdd);
+       /* writing WCS will cause an explicit watchdog refresh */
+       sbsa_gwdt_cf_write(SBSA_GWDT_WCS, SBSA_GWDT_WCS_EN, wdd);
+
+       reload_timeout_to_wcv(wdd);
+

drivers/watchdog/sbsa_gwdt.c

Quoted 2 lines

drivers/watchdog/sbsa_gwdt.c new file +2 -0

+       pr_debug("sbsa_gwdt: WCS is %x(%s)\n",
+                sbsa_gwdt_cf_read(SBSA_GWDT_WCS, wdd), __func__);

Another one. If you think you need to keep those, can you at least use dev_dbg ?
I won't comment on the debug messages further, but I really think that even for debug messages this is a bit noisy.

Quoted 81 lines

drivers/watchdog/sbsa_gwdt.c new file +28 -0

+
+       return 0;
+}
+
+static int sbsa_gwdt_stop(struct watchdog_device *wdd)
+{
+       /* Force refresh */
+       sbsa_gwdt_rf_write(SBSA_GWDT_WRR, 0xc0ffee, wdd);
+       /* writing WCS will cause an explicit watchdog refresh */
+       sbsa_gwdt_cf_write(SBSA_GWDT_WCS, 0, wdd);
+
+       pr_debug("sbsa_gwdt: WCS is %x(%s)\n",
+                sbsa_gwdt_cf_read(SBSA_GWDT_WCS, wdd), __func__);
+
+       return 0;
+}
+
+static int sbsa_gwdt_keepalive(struct watchdog_device *wdd)
+{
+       /*
+        * Writing WRR for an explicit watchdog refresh
+        * You can write anyting(like 0xc0ffee)
+        */
+       sbsa_gwdt_rf_write(SBSA_GWDT_WRR, 0xc0ffee, wdd);
+
+       reload_timeout_to_wcv(wdd);
+
+       pr_debug("sbsa_gwdt: ping, %us left.\n",

sbsa_gwdt_get_timeleft(wdd));

drivers/watchdog/sbsa_gwdt.c new file +50 -0

+
+       return 0;
+}
+
+static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id)
+{
+       struct sbsa_gwdt *gwdt = (struct sbsa_gwdt *)dev_id;
+       struct watchdog_device *wdd = &gwdt->wdd;
+       u32 status;
+
+       status = sbsa_gwdt_cf_read(SBSA_GWDT_WCS, wdd);
+
+       pr_debug("sbsa_gwdt: interrupt routine, WCS@%x\n", status);
+
+       if (status & SBSA_GWDT_WCS_WS0) {
+               pr_debug("sbsa_gwdt WS0: trigger WS1 in %ds!\n",
+                        sbsa_gwdt_get_timeleft(wdd));
+               panic("SBSA Watchdog pre-timeout");
+       }
+
+       return IRQ_HANDLED;
+}
+
+static struct watchdog_info sbsa_gwdt_info = {
+       .identity       = "SBSA Generic Watchdog",
+       .options        = WDIOF_SETTIMEOUT |
+                         WDIOF_KEEPALIVEPING |
+                         WDIOF_MAGICCLOSE |
+                         WDIOF_PRETIMEOUT |
+                         WDIOF_CARDRESET,
+};
+
+static struct watchdog_ops sbsa_gwdt_ops = {
+       .owner          = THIS_MODULE,
+       .start          = sbsa_gwdt_start,
+       .stop           = sbsa_gwdt_stop,
+       .ping           = sbsa_gwdt_keepalive,
+       .set_timeout    = sbsa_gwdt_set_timeout,
+       .set_pretimeout = sbsa_gwdt_set_pretimeout,
+       .get_timeleft   = sbsa_gwdt_get_timeleft,
+};
+
+static int sbsa_gwdt_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+
+       struct sbsa_gwdt *gwdt;
+       struct watchdog_device *wdd;
+
+       struct resource *res;

drivers/watchdog/sbsa_gwdt.c line 355

Quoted 5 lines

drivers/watchdog/sbsa_gwdt.c new file +5 -0

+       void *rf_base, *cf_base;
+       int irq;
+       u32 clk, status, w_iidr;
+
+       int ret = 0;

Please drop the empty lines above.

Quoted 19 lines

drivers/watchdog/sbsa_gwdt.c new file +15 -0

+
+       /*
+        * Try to determine the frequency from the cp15 interface
+        */
+       clk = arch_timer_get_cntfrq();
+       if (!clk) {
+               dev_err(dev, "System Counter frequency not available\n");
+               return -EINVAL;
+       }
+
+       gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
+       if (!gwdt)
+               return -ENOMEM;
+
+       res = platform_get_resource_byname(pdev, IORESOURCE_MEM,

"refresh");

drivers/watchdog/sbsa_gwdt.c new file +2 -0

+       rf_base = devm_ioremap_resource(dev, res);
+       if (IS_ERR(rf_base))

drivers/watchdog/sbsa_gwdt.c line 377

Quoted 5 lines

drivers/watchdog/sbsa_gwdt.c new file +5 -0

+               return PTR_ERR(rf_base);
+
+       pr_debug("sbsa_gwdt: ioremap %s frame 0x%llx(size: %llu)-->%p.\n",
+                res->name, (unsigned long long)res->start,
+               (unsigned long long)(res->end - res->start + 1), rf_base);

If you think you need to keep those messages, please at least use %pR.

Quoted 40 lines

drivers/watchdog/sbsa_gwdt.c new file +2 -0

+
+       res = platform_get_resource_byname(pdev, IORESOURCE_MEM,

"control");

drivers/watchdog/sbsa_gwdt.c new file +25 -0

+       cf_base = devm_ioremap_resource(dev, res);
+       if (IS_ERR(rf_base))
+               return PTR_ERR(rf_base);
+
+       pr_debug("sbsa_gwdt: ioremap %s frame 0x%llx(size: %llu)-->%p.\n",
+                res->name, (unsigned long long)res->start,
+               (unsigned long long)(res->end - res->start + 1), cf_base);
+
+       irq = platform_get_irq_byname(pdev, "ws0");
+       if (irq < 0) {
+               dev_err(dev, "unable to get ws0 interrupt.\n");
+               return irq;
+       }
+
+       pr_debug("sbsa_gwdt: ws0 irq %d.\n", irq);
+
+       gwdt->refresh_base = rf_base;
+       gwdt->control_base = cf_base;
+       gwdt->clk = clk;
+#ifdef CONFIG_PM_SLEEP
+       spin_lock_init(&gwdt->lock);
+#endif
+       platform_set_drvdata(pdev, gwdt);
+
+       pr_debug("sbsa_gwdt: hw clk: %uHz--> WOR(32bit) max timeout is

%us.\n",

drivers/watchdog/sbsa_gwdt.c new file +9 -0

+                gwdt->clk, U32_MAX / clk);
+
+       wdd = &gwdt->wdd;
+       wdd->parent = dev;
+       wdd->info = &sbsa_gwdt_info;
+       wdd->ops = &sbsa_gwdt_ops;
+       watchdog_set_drvdata(wdd, gwdt);
+       watchdog_set_nowayout(wdd, nowayout);
+

Quoted 4 lines

drivers/watchdog/sbsa_gwdt.c new file +3 -0

+       status = sbsa_gwdt_cf_read(SBSA_GWDT_WCS, wdd);
+       if (status & SBSA_GWDT_WCS_WS1) {
+               dev_warn(dev, "System was reseted by WDT(WCS: %x, WCV:

%llx)\n",

"was reseted" is kind of odd. Can you use just "reset" or maybe "restarted" ?

Quoted 20 lines

drivers/watchdog/sbsa_gwdt.c new file +19 -0

+                        status, sbsa_gwdt_get_wcv(wdd));
+               wdd->bootstatus |= WDIOF_CARDRESET;
+       }
+       /* Check if watchdog is already enabled */
+       if (status & SBSA_GWDT_WCS_EN) {
+               dev_warn(dev, "already enabled!\n");
+               sbsa_gwdt_keepalive(wdd);
+       }
+
+       pr_debug("sbsa_gwdt: WCS: %x(%s)\n", status, __func__);
+
+       wdd->min_pretimeout = 0;
+       wdd->max_pretimeout = min(U32_MAX / clk, max_timeout - 1);
+       sbsa_gwdt_set_timeout_limits(gwdt);
+
+       watchdog_init_pretimeout(wdd, pretimeout, dev);
+       if (!wdd->pretimeout) {
+               wdd->pretimeout = DEFAULT_PRETIMEOUT;
+               dev_info(dev, "can't get pretimeout param, set default

Quoted 2 lines

%us.\n",
+ wdd->pretimeout);

Unnecessary message. The pretimeout is printed again below.

Quoted 9 lines

drivers/watchdog/sbsa_gwdt.c new file +7 -0

+       }
+       sbsa_gwdt_set_pretimeout(wdd, wdd->pretimeout);
+
+       watchdog_init_timeout(wdd, timeout, dev);
+       if (!wdd->timeout) {
+               wdd->timeout = wdd->pretimeout + DEFAULT_TIMEOUT_WS0;
+               dev_info(dev, "can't get timeout param, set default:

%us.\n",
+ wdd->timeout);

Same here.

Quoted 17 lines

drivers/watchdog/sbsa_gwdt.c new file +17 -0

+       }
+       sbsa_gwdt_set_timeout(wdd, wdd->timeout);
+
+       ret = devm_request_irq(dev, irq, sbsa_gwdt_interrupt, IRQF_TIMER,
+                              pdev->name, gwdt);
+       if (ret) {
+               dev_err(dev, "unable to request IRQ %d\n", irq);
+               return ret;
+       }
+
+       ret = watchdog_register_device(wdd);
+       if (ret)
+               return ret;
+
+       /* get device information from control frame and display */
+       w_iidr = sbsa_gwdt_cf_read(SBSA_GWDT_W_IIDR, &gwdt->wdd);
+       dev_info(dev, "PID:%u(JEP106 %u-%u), Arch v%u Rev %u.",

drivers/watchdog/sbsa_gwdt.c line 466

Quoted 5 lines

drivers/watchdog/sbsa_gwdt.c new file +5 -0

+                SBSA_GWDT_W_IIDR_PID(w_iidr),
+                SBSA_GWDT_W_IIDR_VID_BANK(w_iidr),
+                SBSA_GWDT_W_IIDR_VID(w_iidr),
+                SBSA_GWDT_W_IIDR_ARCH_VER(w_iidr),
+                SBSA_GWDT_W_IIDR_REV(w_iidr));

Is this valuable information ?

Quoted 27 lines

drivers/watchdog/sbsa_gwdt.c new file +2 -0

+
+       dev_info(dev, "Initialized with %ds timeout, %ds pretimeout @

%uHz\n",

drivers/watchdog/sbsa_gwdt.c new file +22 -0

+                wdd->timeout, wdd->pretimeout, gwdt->clk);
+
+       return 0;
+}
+
+static void sbsa_gwdt_shutdown(struct platform_device *pdev)
+{
+       struct sbsa_gwdt *gwdt = platform_get_drvdata(pdev);
+
+       sbsa_gwdt_stop(&gwdt->wdd);
+}
+
+static int sbsa_gwdt_remove(struct platform_device *pdev)
+{
+       struct sbsa_gwdt *gwdt = platform_get_drvdata(pdev);
+       int ret = 0;
+
+       if (!nowayout)
+               ret = sbsa_gwdt_stop(&gwdt->wdd);
+
+       watchdog_unregister_device(&gwdt->wdd);
+

drivers/watchdog/sbsa_gwdt.c line 494

Quoted 4 lines

drivers/watchdog/sbsa_gwdt.c new file +4 -0

+       return ret;
+}
+
+#ifdef CONFIG_PM_SLEEP

You don't need the #ifdef if you use __maybe_unused with the function declarations.

drivers/watchdog/sbsa_gwdt.c line 506

Quoted 13 lines

drivers/watchdog/sbsa_gwdt.c new file +12 -0

+/* Disable watchdog if it is active during suspend */
+static int sbsa_gwdt_suspend(struct device *dev)
+{
+       struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
+       struct watchdog_device *wdd = &gwdt->wdd;
+
+       spin_lock(&gwdt->lock);
+       gwdt->pm_status_store = sbsa_gwdt_cf_read(SBSA_GWDT_WCS, wdd);
+
+       if (gwdt->pm_status_store & SBSA_GWDT_WCS_EN)
+               sbsa_gwdt_stop(wdd);
+       spin_unlock(&gwdt->lock);

Wonder what this lock is protecting against. Can you explain ? I would assume that suspend and resume are mutually exclusive and don't require locking against each other.

Quoted 10 lines

drivers/watchdog/sbsa_gwdt.c new file +10 -0

+
+       return 0;
+}
+
+/* Enable watchdog and configure it if necessary */
+static int sbsa_gwdt_resume(struct device *dev)
+{
+       struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
+       struct watchdog_device *wdd = &gwdt->wdd;
+

drivers/watchdog/sbsa_gwdt.c line 521

Quoted 5 lines

drivers/watchdog/sbsa_gwdt.c new file +5 -0

+       spin_lock(&gwdt->lock);
+       if (gwdt->pm_status_store & SBSA_GWDT_WCS_EN)
+               sbsa_gwdt_start(wdd);
+       else
+               sbsa_gwdt_stop(wdd);

What is the stop here for ?

Quoted 35 lines

drivers/watchdog/sbsa_gwdt.c new file +32 -0

+       spin_unlock(&gwdt->lock);
+
+       return 0;
+}
+#endif
+
+static const struct of_device_id sbsa_gwdt_of_match[] = {
+       { .compatible = "arm,sbsa-gwdt", },
+       {},
+};
+MODULE_DEVICE_TABLE(of, sbsa_gwdt_of_match);
+
+static const struct dev_pm_ops sbsa_gwdt_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(sbsa_gwdt_suspend, sbsa_gwdt_resume)
+};
+
+static struct platform_driver sbsa_gwdt_driver = {
+       .driver = {
+               .name = "sbsa-gwdt",
+               .pm = &sbsa_gwdt_pm_ops,
+               .of_match_table = sbsa_gwdt_of_match,
+       },
+       .probe = sbsa_gwdt_probe,
+       .remove = sbsa_gwdt_remove,
+       .shutdown = sbsa_gwdt_shutdown,
+};
+
+module_platform_driver(sbsa_gwdt_driver);
+
+MODULE_DESCRIPTION("SBSA Generic Watchdog Driver");
+MODULE_AUTHOR("Fu Wei <[email protected]>");
+MODULE_LICENSE("GPL v2");

From: Fu Wei <[email protected]>

Reasons:
(1)kernel already has two watchdog drivers are using "pretimeout":
drivers/char/ipmi/ipmi_watchdog.c drivers/watchdog/kempld_wdt.c(but the definition is different)
(2)some other dirvers are going to use this: ARM SBSA Generic Watchdog

Signed-off-by Fu Wei <[email protected]>

---
  drivers/watchdog/watchdog_core.c | 66 ++++++++++++++++++++++++++++++++++++++++
  drivers/watchdog/watchdog_dev.c  | 48 +++++++++++++++++++++++++++++
  include/linux/watchdog.h         | 19 ++++++++++++
  3 files changed, 133 insertions(+)

drivers/watchdog/watchdog_core.c +0 -0

index cec9b55..6ca9578 100644
@@ -54,6 +54,14 @@ static void watchdog_check_min_max_timeout(struct watchdog_device *wdd)
  		wdd->min_timeout = 0;

drivers/watchdog/watchdog_core.c +16 -0

  }
 
  /**

@@ -98,6 +106,63 @@ int watchdog_init_timeout(struct watchdog_device *wdd,
  }
  EXPORT_SYMBOL_GPL(watchdog_init_timeout);
 
+static void watchdog_check_min_max_pretimeout(struct watchdog_device *wdd)
+{
+	/*
+	 * Check that we have valid min and max pretimeout values, if
+	 * not reset them both to 0 (=not used or unknown)
+	 */
+	if (wdd->min_pretimeout > wdd->max_pretimeout) {
+		pr_info("Invalid min and max pretimeout, resetting to 0!\n");
+		wdd->min_pretimeout = 0;
+		wdd->max_pretimeout = 0;
+	}
+}
+
+/**
+ * watchdog_init_pretimeout() - initialize the pretimeout field
+ * @pretimeout_parm: pretimeout module parameter

drivers/watchdog/watchdog_core.c +13 -0

+int watchdog_init_pretimeout(struct watchdog_device *wdd,
+			     unsigned int pretimeout_parm, struct device *dev)
+{
+	int ret = 0;
+	u32 timeouts[2];
+
+	watchdog_check_min_max_pretimeout(wdd);
+
+	/* try to get the timeout module parameter first */
+	if (!watchdog_pretimeout_invalid(wdd, pretimeout_parm) &&
+	    pretimeout_parm) {
+		wdd->pretimeout = pretimeout_parm;
+		return ret;

drivers/watchdog/watchdog_core.c +9 -0

+		wdd->pretimeout = timeouts[1];
+	else
+		ret = -EINVAL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(watchdog_init_pretimeout);
+
  /**
   * watchdog_register_device() - register a watchdog device
   * @wdd: watchdog device

@@ -119,6 +184,7 @@ int watchdog_register_device(struct watchdog_device *wdd)
  	if (wdd->ops->start == NULL || wdd->ops->stop == NULL)
  		return -EINVAL;
 
+	watchdog_check_min_max_pretimeout(wdd);
  	watchdog_check_min_max_timeout(wdd);
 
  	/*

drivers/watchdog/watchdog_dev.c +32 -0

index 6aaefba..b519257 100644
@@ -218,6 +218,38 @@ out_timeout:
  }
 
  /*
+ *	watchdog_set_pretimeout: set the watchdog timer pretimeout
+ *	@wddev: the watchdog device to set the timeout for
+ *	@pretimeout: pretimeout to set in seconds
+ */
+
+static int watchdog_set_pretimeout(struct watchdog_device *wddev,
+				   unsigned int pretimeout)
+{
+	int err;
+
+	if (!wddev->ops->set_pretimeout ||
+	    !(wddev->info->options & WDIOF_PRETIMEOUT))
+		return -EOPNOTSUPP;
+
+	if (watchdog_pretimeout_invalid(wddev, pretimeout))
+		return -EINVAL;
+
+	mutex_lock(&wddev->lock);
+
+	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+		err = -ENODEV;
+		goto out_pretimeout;
+	}
+
+	err = wddev->ops->set_pretimeout(wddev, pretimeout);
+
+out_pretimeout:
+	mutex_unlock(&wddev->lock);
+	return err;
+}
+
+/*
   *	watchdog_get_timeleft: wrapper to get the time left before a reboot
   *	@wddev: the watchdog device to get the remaining time from
   *	@timeleft: the time that's left

@@ -388,6 +420,22 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
  		if (wdd->timeout == 0)

drivers/watchdog/watchdog_dev.c +7 -0

+		watchdog_ping(wdd);
+		/* Fall */
+	case WDIOC_GETPRETIMEOUT:
+		/* timeout == 0 means that we don't use the pretimeout */
+		if (wdd->pretimeout == 0)
+			return -EOPNOTSUPP;
+		return put_user(wdd->pretimeout, p);
  	case WDIOC_GETTIMELEFT:
  		err = watchdog_get_timeleft(wdd, &val);
  		if (err)

include/linux/watchdog.h +16 -0

index a746bf5..f0a3c5b 100644
@@ -25,6 +25,7 @@ struct watchdog_device;
   * @ping:	The routine that sends a keepalive ping to the watchdog device.
   * @status:	The routine that shows the status of the watchdog device.
   * @set_timeout:The routine for setting the watchdog devices timeout value.
+ * @set_pretimeout:The routine for setting the watchdog devices pretimeout value
   * @get_timeleft:The routine that get's the time that's left before a reset.
   * @ref:	The ref operation for dyn. allocated watchdog_device structs
   * @unref:	The unref operation for dyn. allocated watchdog_device structs

@@ -44,6 +45,7 @@ struct watchdog_ops {
  	int (*ping)(struct watchdog_device *);
  	unsigned int (*status)(struct watchdog_device *);
  	int (*set_timeout)(struct watchdog_device *, unsigned int);
+	int (*set_pretimeout)(struct watchdog_device *, unsigned int);
  	unsigned int (*get_timeleft)(struct watchdog_device *);
  	void (*ref)(struct watchdog_device *);
  	void (*unref)(struct watchdog_device *);

@@ -62,6 +64,9 @@ struct watchdog_ops {
   * @timeout:	The watchdog devices timeout value.
   * @min_timeout:The watchdog devices minimum timeout value.
   * @max_timeout:The watchdog devices maximum timeout value.
+ * @pretimeout:	The watchdog devices pretimeout value.
+ * @min_pretimeout:The watchdog devices minimum pretimeout value.
+ * @max_pretimeout:The watchdog devices maximum pretimeout value.
   * @driver-data:Pointer to the drivers private data.
   * @lock:	Lock for watchdog core internal use only.
   * @status:	Field that contains the devices internal status bits.

@@ -86,6 +91,9 @@ struct watchdog_device {
  	unsigned int timeout;
  	unsigned int min_timeout;
  	unsigned int max_timeout;
+	unsigned int pretimeout;
+	unsigned int min_pretimeout;
+	unsigned int max_pretimeout;
  	void *driver_data;
  	struct mutex lock;
  	unsigned long status;

@@ -120,6 +128,14 @@ static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigne
  		(t < wdd->min_timeout || t > wdd->max_timeout));
  }
 
+/* Use the following function to check if a pretimeout value is invalid */
+static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd,
+					       unsigned int t)
+{
+	return ((wdd->max_pretimeout != 0) &&
+		(t < wdd->min_pretimeout || t > wdd->max_pretimeout));
+}
+
  /* Use the following functions to manipulate watchdog driver specific data */
  static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
  {

Quoted 38 lines · On 05/15/2015 04:24 AM, [email protected] wrote:

From: Fu Wei <[email protected]>

Reasons:
(1)kernel already has two watchdog drivers are using "pretimeout":
drivers/char/ipmi/ipmi_watchdog.c drivers/watchdog/kempld_wdt.c(but the definition is different)
(2)some other dirvers are going to use this: ARM SBSA Generic Watchdog

Signed-off-by Fu Wei <[email protected]>

---
  drivers/watchdog/watchdog_core.c | 66
++++++++++++++++++++++++++++++++++++++++
  drivers/watchdog/watchdog_dev.c  | 48 +++++++++++++++++++++++++++++
  include/linux/watchdog.h         | 19 ++++++++++++
  3 files changed, 133 insertions(+)

drivers/watchdog/watchdog_core.c +5 -0

index cec9b55..6ca9578 100644
@@ -54,6 +54,14 @@ static void watchdog_check_min_max_timeout(struct
 watchdog_device *wdd)
                wdd->min_timeout = 0;
                wdd->max_timeout = 0;
        }
+       if (wdd->min_pretimeout && wdd->min_timeout < wdd->min_pretimeout)
 {
+               pr_info("Invalid min timeout, resetting to min
 pretimeout!\n");
+               wdd->min_timeout = wdd->min_pretimeout;
+       }
+       if (wdd->max_pretimeout && wdd->max_timeout < wdd->max_pretimeout)

{
+ pr_info("Invalid max timeout, resetting to max
pretimeout!\n");
+ wdd->max_timeout = wdd->max_pretimeout;

Quoted 1 line

+ }

I am a bit concerned about the context dependency introduced here. If someone calls
_init_pretimeout after calling init_timeout, this may result in still invalid timeout
values.

Quoted 37 lines

  }

/**

drivers/watchdog/watchdog_core.c +19 -0

@@ -98,6 +106,63 @@ int watchdog_init_timeout(struct watchdog_device *wdd,
  }
  EXPORT_SYMBOL_GPL(watchdog_init_timeout);
 
+static void watchdog_check_min_max_pretimeout(struct watchdog_device
 *wdd)
+{
+       /*
+        * Check that we have valid min and max pretimeout values, if
+        * not reset them both to 0 (=not used or unknown)
+        */
+       if (wdd->min_pretimeout > wdd->max_pretimeout) {
+               pr_info("Invalid min and max pretimeout, resetting to
 0!\n");
+               wdd->min_pretimeout = 0;
+               wdd->max_pretimeout = 0;
+       }
+}
+
+/**
+ * watchdog_init_pretimeout() - initialize the pretimeout field
+ * @pretimeout_parm: pretimeout module parameter
+ * @dev: Device that stores the timeout-sec property
+ *
+ * Initialize the pretimeout field of the watchdog_device struct with

either
+ * the pretimeout module parameter (if it is valid value) or the timeout-sec
+ * property (only if it is a valid value and the timeout_parm is out of bounds).
+ * If none of them are valid then we keep the old value (which should normally

Quoted 4 lines

+ * be the default pretimeout value.
+ *
+ * A zero is returned on success and -EINVAL for failure.
+ */

The new API function also needs to be documented in Documentation/watchdog/watchdog-kernel-api.txt.

Quoted 21 lines

drivers/watchdog/watchdog_core.c +2 -0

+int watchdog_init_pretimeout(struct watchdog_device *wdd,
+                            unsigned int pretimeout_parm, struct device

*dev)

drivers/watchdog/watchdog_core.c +17 -0

+{
+       int ret = 0;
+       u32 timeouts[2];
+
+       watchdog_check_min_max_pretimeout(wdd);
+
+       /* try to get the timeout module parameter first */
+       if (!watchdog_pretimeout_invalid(wdd, pretimeout_parm) &&
+           pretimeout_parm) {
+               wdd->pretimeout = pretimeout_parm;
+               return ret;
+       }
+       if (pretimeout_parm)
+               ret = -EINVAL;
+
+       /* try to get the timeout_sec property */
+       if (!dev || !dev->of_node)

drivers/watchdog/watchdog_core.c int watchdog_init_timeout(struct watchdog_device *wdd, · line 157

Quoted 4 lines

drivers/watchdog/watchdog_core.c +4 -0

+               return ret;
+       ret = of_property_read_u32_array(dev->of_node,
+                                        "timeout-sec", timeouts, 2);
+       if (!watchdog_pretimeout_invalid(wdd, timeouts[1]) && timeouts[1])

Guess we are still waiting for feedback from the devicetree maintainers on this.

Both the above synchronization concern and this makes me wonder if we should introduce
watchdog_init_timeouts() instead, which would take pretimeout as additional parameter.
What do you think about that ?

Quoted 75 lines

drivers/watchdog/watchdog_core.c +9 -0

+               wdd->pretimeout = timeouts[1];
+       else
+               ret = -EINVAL;
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(watchdog_init_pretimeout);
+
  /**
   * watchdog_register_device() - register a watchdog device
   * @wdd: watchdog device

@@ -119,6 +184,7 @@ int watchdog_register_device(struct watchdog_device
 *wdd)
        if (wdd->ops->start == NULL || wdd->ops->stop == NULL)
                return -EINVAL;
 
+       watchdog_check_min_max_pretimeout(wdd);
        watchdog_check_min_max_timeout(wdd);
 

        /*

drivers/watchdog/watchdog_dev.c +32 -0

index 6aaefba..b519257 100644
@@ -218,6 +218,38 @@ out_timeout:
  }
 
  /*
+ *     watchdog_set_pretimeout: set the watchdog timer pretimeout
+ *     @wddev: the watchdog device to set the timeout for
+ *     @pretimeout: pretimeout to set in seconds
+ */
+
+static int watchdog_set_pretimeout(struct watchdog_device *wddev,
+                                  unsigned int pretimeout)
+{
+       int err;
+
+       if (!wddev->ops->set_pretimeout ||
+           !(wddev->info->options & WDIOF_PRETIMEOUT))
+               return -EOPNOTSUPP;
+
+       if (watchdog_pretimeout_invalid(wddev, pretimeout))
+               return -EINVAL;
+
+       mutex_lock(&wddev->lock);
+
+       if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+               err = -ENODEV;
+               goto out_pretimeout;
+       }
+
+       err = wddev->ops->set_pretimeout(wddev, pretimeout);
+
+out_pretimeout:
+       mutex_unlock(&wddev->lock);
+       return err;
+}
+
+/*
   *    watchdog_get_timeleft: wrapper to get the time left before a

reboot
* @wddev: the watchdog device to get the remaining time from
* @timeleft: the time that's left

drivers/watchdog/watchdog_dev.c +3 -0

@@ -388,6 +420,22 @@ static long watchdog_ioctl(struct file *file,
 unsigned int cmd,
                if (wdd->timeout == 0)
                        return -EOPNOTSUPP;
                return put_user(wdd->timeout, p);
+       case WDIOC_SETPRETIMEOUT:
+               if (get_user(val, p))
+                       return -EFAULT;

drivers/watchdog/watchdog_dev.c static long watchdog_ioctl(struct file *file, unsigned int cmd, · line 430

Quoted 5 lines

drivers/watchdog/watchdog_dev.c +5 -0

+               err = watchdog_set_pretimeout(wdd, val);
+               if (err < 0)
+                       return err;
+               /* If the watchdog is active then we send a keepalive ping
+                * to make sure that the watchdog keep's running (and if

s/keep's/keeps/

drivers/watchdog/watchdog_dev.c static long watchdog_ioctl(struct file *file, unsigned int cmd, · line 431

Quoted 2 lines

drivers/watchdog/watchdog_dev.c +1 -0

+                * possible that it takes the new timeout) */

Please use the common multi-line comment style (that it isn't used above is not
an argument).

Quoted 83 lines

drivers/watchdog/watchdog_dev.c +7 -0

+               watchdog_ping(wdd);
+               /* Fall */
+       case WDIOC_GETPRETIMEOUT:
+               /* timeout == 0 means that we don't use the pretimeout */
+               if (wdd->pretimeout == 0)
+                       return -EOPNOTSUPP;
+               return put_user(wdd->pretimeout, p);
        case WDIOC_GETTIMELEFT:
                err = watchdog_get_timeleft(wdd, &val);

if (err)

include/linux/watchdog.h +0 -0

index a746bf5..f0a3c5b 100644
@@ -25,6 +25,7 @@ struct watchdog_device;
   * @ping:     The routine that sends a keepalive ping to the watchdog

device.
* @status: The routine that shows the status of the watchdog device.
* @set_timeout:The routine for setting the watchdog devices timeout
value.
+ * @set_pretimeout:The routine for setting the watchdog devices pretimeout value
* @get_timeleft:The routine that get's the time that's left before a
reset.
* @ref: The ref operation for dyn. allocated watchdog_device
structs
* @unref: The unref operation for dyn. allocated watchdog_device
structs

include/linux/watchdog.h +7 -0

@@ -44,6 +45,7 @@ struct watchdog_ops {
        int (*ping)(struct watchdog_device *);
        unsigned int (*status)(struct watchdog_device *);
        int (*set_timeout)(struct watchdog_device *, unsigned int);
+       int (*set_pretimeout)(struct watchdog_device *, unsigned int);
        unsigned int (*get_timeleft)(struct watchdog_device *);
        void (*ref)(struct watchdog_device *);
        void (*unref)(struct watchdog_device *);

@@ -62,6 +64,9 @@ struct watchdog_ops {
   * @timeout:  The watchdog devices timeout value.
   * @min_timeout:The watchdog devices minimum timeout value.
   * @max_timeout:The watchdog devices maximum timeout value.
+ * @pretimeout:        The watchdog devices pretimeout value.
+ * @min_pretimeout:The watchdog devices minimum pretimeout value.
+ * @max_pretimeout:The watchdog devices maximum pretimeout value.
   * @driver-data:Pointer to the drivers private data.
   * @lock:     Lock for watchdog core internal use only.
   * @status:   Field that contains the devices internal status bits.

@@ -86,6 +91,9 @@ struct watchdog_device {
        unsigned int timeout;
        unsigned int min_timeout;
        unsigned int max_timeout;
+       unsigned int pretimeout;
+       unsigned int min_pretimeout;
+       unsigned int max_pretimeout;
        void *driver_data;
        struct mutex lock;
        unsigned long status;

@@ -120,6 +128,14 @@ static inline bool watchdog_timeout_invalid(struct

watchdog_device *wdd, unsigne

                (t < wdd->min_timeout || t > wdd->max_timeout));

}

+/* Use the following function to check if a pretimeout value is invalid */
+static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd,

include/linux/watchdog.h +6 -0

+                                              unsigned int t)
+{
+       return ((wdd->max_pretimeout != 0) &&
+               (t < wdd->min_pretimeout || t > wdd->max_pretimeout));
+}
+
  /* Use the following functions to manipulate watchdog driver specific

data */
static inline void watchdog_set_drvdata(struct watchdog_device *wdd,
void *data)
{

include/linux/watchdog.h +0 -0

@@ -134,6 +150,9 @@ static inline void *watchdog_get_drvdata(struct
 watchdog_device *wdd)
  /* drivers/watchdog/watchdog_core.c */
  extern int watchdog_init_timeout(struct watchdog_device *wdd,
                                  unsigned int timeout_parm, struct device

include/linux/watchdog.h static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) · line 155

Quoted 4 lines

include/linux/watchdog.h +3 -0

 *dev);
+extern int watchdog_init_pretimeout(struct watchdog_device *wdd,
+                                   unsigned int pretimeout_parm,
+                                   struct device *dev);

Please drop the 'extern'. Guess it may be time to clean up the watchdog core code ;-).

Thanks,
Guenter

Quoted 2 lines

Quoted 2 lines

The new API function also needs to be documented in Documentation/watchdog/watchdog-kernel-api.txt.

good point, thanks will do

Quoted 3 lines · Fu Wei

Quoted 2 lines

Quoted 2 lines

The new API function also needs to be documented in Documentation/watchdog/watchdog-kernel-api.txt.

good point, thanks will do

Yes, please, since my driver does not use or need any pre-timeout support, so I don't understand why this patch exists. What is pre-timeout anyway?

Hi Guenter,

Great thanks for your review,
feedback inline below :-)

On 15 May 2015 at 21:33, Guenter Roeck <[email protected]> wrote:

Quoted 8 lines

drivers/watchdog/watchdog_core.c static void watchdog_check_min_max_timeout(struct watchdog_device *wdd) · line 64

Quoted 6 lines

+ if (wdd->max_pretimeout && wdd->max_timeout < wdd->max_pretimeout)
{
+ pr_info("Invalid max timeout, resetting to max
pretimeout!\n");

drivers/watchdog/watchdog_core.c +2 -0

+               wdd->max_timeout = wdd->max_pretimeout;
+       }

Quoted 5 lines

I am a bit concerned about the context dependency introduced here. If someone calls
_init_pretimeout after calling init_timeout, this may result in still invalid timeout
values.

yes, that logic is not very clean, so my thought is :
maybe we can integrate watchdog_init_timeout and watchdog_init_pretimeout, if maintainer agree to add pretimeout into framework.

Quoted 6 lines · Fu Wei

Hi Guenter,

Great thanks for your review,
feedback inline below :-)

On 15 May 2015 at 21:33, Guenter Roeck <[email protected]> wrote:

[ ... ]

Quoted 14 lines

Quoted 8 lines

drivers/watchdog/watchdog_core.c static void watchdog_check_min_max_timeout(struct watchdog_device *wdd) · line 64

Quoted 6 lines

+ if (wdd->max_pretimeout && wdd->max_timeout < wdd->max_pretimeout)
{
+ pr_info("Invalid max timeout, resetting to max
pretimeout!\n");

drivers/watchdog/watchdog_core.c +2 -0

+               wdd->max_timeout = wdd->max_pretimeout;
+       }

Quoted 5 lines

I am a bit concerned about the context dependency introduced here. If someone calls
_init_pretimeout after calling init_timeout, this may result in still invalid timeout
values.

Quoted 4 lines

yes, that logic is not very clean, so my thought is :
maybe we can integrate watchdog_init_timeout and watchdog_init_pretimeout, if maintainer agree to add pretimeout into framework.

I think we should just assume that Wim will accept it, and try to find the best possible solution (or at least a good one).

Guenter

drivers/watchdog/watchdog_core.c +33 -0

+/**
+ * watchdog_init_pretimeout() - initialize the pretimeout field
+ * @pretimeout_parm: pretimeout module parameter
+ * @dev: Device that stores the timeout-sec property
+ *
+ * Initialize the pretimeout field of the watchdog_device struct with either
+ * the pretimeout module parameter (if it is valid value) or the timeout-sec
+ * property (only if it is a valid value and the timeout_parm is out of bounds).
+ * If none of them are valid then we keep the old value (which should normally
+ * be the default pretimeout value.
+ *
+ * A zero is returned on success and -EINVAL for failure.
+ */
+int watchdog_init_pretimeout(struct watchdog_device *wdd,
+                            unsigned int pretimeout_parm, struct device *dev)
+{
+       int ret = 0;
+       u32 timeouts[2];
+
+       watchdog_check_min_max_pretimeout(wdd);
+
+       /* try to get the timeout module parameter first */
+       if (!watchdog_pretimeout_invalid(wdd, pretimeout_parm) &&
+           pretimeout_parm) {
+               wdd->pretimeout = pretimeout_parm;
+               return ret;
+       }
+       if (pretimeout_parm)
+               ret = -EINVAL;
+
+       /* try to get the timeout_sec property */
+       if (!dev || !dev->of_node)
+               return ret;

drivers/watchdog/watchdog_core.c int watchdog_init_timeout(struct watchdog_device *wdd, · line 120

Quoted 12 lines · On Friday 15 May 2015 19:24:48 [email protected]…

drivers/watchdog/watchdog_core.c +12 -0

+static void watchdog_check_min_max_pretimeout(struct watchdog_device *wdd)
+{
+       /*
+        * Check that we have valid min and max pretimeout values, if
+        * not reset them both to 0 (=not used or unknown)
+        */
+       if (wdd->min_pretimeout > wdd->max_pretimeout) {
+               pr_info("Invalid min and max pretimeout, resetting to 0!\n");
+               wdd->min_pretimeout = 0;
+               wdd->max_pretimeout = 0;
+       }
+}

I would probably just fold this function into the existing watchdog_check_min_max_timeout() and check both normal and pre-timeout there.

Quoted 34 lines

drivers/watchdog/watchdog_core.c +33 -0

+/**
+ * watchdog_init_pretimeout() - initialize the pretimeout field
+ * @pretimeout_parm: pretimeout module parameter
+ * @dev: Device that stores the timeout-sec property
+ *
+ * Initialize the pretimeout field of the watchdog_device struct with either
+ * the pretimeout module parameter (if it is valid value) or the timeout-sec
+ * property (only if it is a valid value and the timeout_parm is out of bounds).
+ * If none of them are valid then we keep the old value (which should normally
+ * be the default pretimeout value.
+ *
+ * A zero is returned on success and -EINVAL for failure.
+ */
+int watchdog_init_pretimeout(struct watchdog_device *wdd,
+                            unsigned int pretimeout_parm, struct device *dev)
+{
+       int ret = 0;
+       u32 timeouts[2];
+
+       watchdog_check_min_max_pretimeout(wdd);
+
+       /* try to get the timeout module parameter first */
+       if (!watchdog_pretimeout_invalid(wdd, pretimeout_parm) &&
+           pretimeout_parm) {
+               wdd->pretimeout = pretimeout_parm;
+               return ret;
+       }
+       if (pretimeout_parm)
+               ret = -EINVAL;
+
+       /* try to get the timeout_sec property */
+       if (!dev || !dev->of_node)
+               return ret;

drivers/watchdog/watchdog_core.c int watchdog_init_timeout(struct watchdog_device *wdd, · line 164

Quoted 10 lines

drivers/watchdog/watchdog_core.c +10 -0

+       ret = of_property_read_u32_array(dev->of_node,
+                                        "timeout-sec", timeouts, 2);
+       if (!watchdog_pretimeout_invalid(wdd, timeouts[1]) && timeouts[1])
+               wdd->pretimeout = timeouts[1];
+       else
+               ret = -EINVAL;
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(watchdog_init_pretimeout);

Same here: the function is very similar to the watchdog_init_timeout function, and it reads the same property, so just do both here.

The easiest way for that is probably to use of_find_property() and of_prop_next_u32() to read the two numbers.

Arnd

Hi Arnd,

Great thanks for your suggestion :-)

feedback inline below

Quoted 17 lines · Arnd Bergmann

drivers/watchdog/watchdog_core.c int watchdog_init_timeout(struct watchdog_device *wdd, · line 120

Quoted 12 lines · On Friday 15 May 2015 19:24:48 [email protected] wrote:

drivers/watchdog/watchdog_core.c +12 -0

+static void watchdog_check_min_max_pretimeout(struct watchdog_device *wdd)
+{
+       /*
+        * Check that we have valid min and max pretimeout values, if
+        * not reset them both to 0 (=not used or unknown)
+        */
+       if (wdd->min_pretimeout > wdd->max_pretimeout) {
+               pr_info("Invalid min and max pretimeout, resetting to 0!\n");
+               wdd->min_pretimeout = 0;
+               wdd->max_pretimeout = 0;
+       }
+}

I would probably just fold this function into the existing watchdog_check_min_max_timeout() and check both normal and pre-timeout there.

yes, I can do that , and that is good idea

Quoted 48 lines

Quoted 34 lines

drivers/watchdog/watchdog_core.c +33 -0

+/**
+ * watchdog_init_pretimeout() - initialize the pretimeout field
+ * @pretimeout_parm: pretimeout module parameter
+ * @dev: Device that stores the timeout-sec property
+ *
+ * Initialize the pretimeout field of the watchdog_device struct with either
+ * the pretimeout module parameter (if it is valid value) or the timeout-sec
+ * property (only if it is a valid value and the timeout_parm is out of bounds).
+ * If none of them are valid then we keep the old value (which should normally
+ * be the default pretimeout value.
+ *
+ * A zero is returned on success and -EINVAL for failure.
+ */
+int watchdog_init_pretimeout(struct watchdog_device *wdd,
+                            unsigned int pretimeout_parm, struct device *dev)
+{
+       int ret = 0;
+       u32 timeouts[2];
+
+       watchdog_check_min_max_pretimeout(wdd);
+
+       /* try to get the timeout module parameter first */
+       if (!watchdog_pretimeout_invalid(wdd, pretimeout_parm) &&
+           pretimeout_parm) {
+               wdd->pretimeout = pretimeout_parm;
+               return ret;
+       }
+       if (pretimeout_parm)
+               ret = -EINVAL;
+
+       /* try to get the timeout_sec property */
+       if (!dev || !dev->of_node)
+               return ret;

drivers/watchdog/watchdog_core.c int watchdog_init_timeout(struct watchdog_device *wdd, · line 164

Quoted 10 lines

drivers/watchdog/watchdog_core.c +10 -0

+       ret = of_property_read_u32_array(dev->of_node,
+                                        "timeout-sec", timeouts, 2);
+       if (!watchdog_pretimeout_invalid(wdd, timeouts[1]) && timeouts[1])
+               wdd->pretimeout = timeouts[1];
+       else
+               ret = -EINVAL;
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(watchdog_init_pretimeout);

Same here: the function is very similar to the watchdog_init_timeout function, and it reads the same property, so just do both here.

Quoted 2 lines

The easiest way for that is probably to use of_find_property() and of_prop_next_u32() to read the two numbers.

integrate watchdog_init_pretimeout and watchdog_init_timeout will be a little hard,
we may need to change this API to :

watchdog_init_timeouts(struct watchdog_device *wdd, unsigned int timeout_parm,
unsigned int pretimeout_parm, struct device *dev)

then we need to update all the watchdog drivers which use this API, maybe we can do this in a individual patchset, after this pretimeout patch is merged.

Is that OK ? :-) any thought?

Quoted 82 lines · Fu Wei

Hi Arnd,

Great thanks for your suggestion :-)

feedback inline below

Quoted 17 lines · Arnd Bergmann

drivers/watchdog/watchdog_core.c int watchdog_init_timeout(struct watchdog_device *wdd, · line 120

Quoted 12 lines · On Friday 15 May 2015 19:24:48 [email protected] wrote:

drivers/watchdog/watchdog_core.c +12 -0

+static void watchdog_check_min_max_pretimeout(struct watchdog_device *wdd)
+{
+       /*
+        * Check that we have valid min and max pretimeout values, if
+        * not reset them both to 0 (=not used or unknown)
+        */
+       if (wdd->min_pretimeout > wdd->max_pretimeout) {
+               pr_info("Invalid min and max pretimeout, resetting to 0!\n");
+               wdd->min_pretimeout = 0;
+               wdd->max_pretimeout = 0;
+       }
+}

I would probably just fold this function into the existing watchdog_check_min_max_timeout() and check both normal and pre-timeout there.

yes, I can do that , and that is good idea

Quoted 48 lines

Quoted 34 lines

drivers/watchdog/watchdog_core.c +33 -0

+/**
+ * watchdog_init_pretimeout() - initialize the pretimeout field
+ * @pretimeout_parm: pretimeout module parameter
+ * @dev: Device that stores the timeout-sec property
+ *
+ * Initialize the pretimeout field of the watchdog_device struct with either
+ * the pretimeout module parameter (if it is valid value) or the timeout-sec
+ * property (only if it is a valid value and the timeout_parm is out of bounds).
+ * If none of them are valid then we keep the old value (which should normally
+ * be the default pretimeout value.
+ *
+ * A zero is returned on success and -EINVAL for failure.
+ */
+int watchdog_init_pretimeout(struct watchdog_device *wdd,
+                            unsigned int pretimeout_parm, struct device *dev)
+{
+       int ret = 0;
+       u32 timeouts[2];
+
+       watchdog_check_min_max_pretimeout(wdd);
+
+       /* try to get the timeout module parameter first */
+       if (!watchdog_pretimeout_invalid(wdd, pretimeout_parm) &&
+           pretimeout_parm) {
+               wdd->pretimeout = pretimeout_parm;
+               return ret;
+       }
+       if (pretimeout_parm)
+               ret = -EINVAL;
+
+       /* try to get the timeout_sec property */
+       if (!dev || !dev->of_node)
+               return ret;

drivers/watchdog/watchdog_core.c int watchdog_init_timeout(struct watchdog_device *wdd, · line 164

Quoted 10 lines

drivers/watchdog/watchdog_core.c +10 -0

+       ret = of_property_read_u32_array(dev->of_node,
+                                        "timeout-sec", timeouts, 2);
+       if (!watchdog_pretimeout_invalid(wdd, timeouts[1]) && timeouts[1])
+               wdd->pretimeout = timeouts[1];
+       else
+               ret = -EINVAL;
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(watchdog_init_pretimeout);

Same here: the function is very similar to the watchdog_init_timeout function, and it reads the same property, so just do both here.

Quoted 2 lines

The easiest way for that is probably to use of_find_property() and of_prop_next_u32() to read the two numbers.

integrate watchdog_init_pretimeout and watchdog_init_timeout will be a little hard,
we may need to change this API to :

Quoted 9 lines

watchdog_init_timeouts(struct watchdog_device *wdd, unsigned int timeout_parm,
unsigned int pretimeout_parm, struct device *dev)

then we need to update all the watchdog drivers which use this API, maybe we can do this in a individual patchset, after this pretimeout patch is merged.

Is that OK ? :-) any thought?

That is what I would recommend.

Guenter