Commit f20ca595 authored by Li Hua Qian's avatar Li Hua Qian Committed by Wim Van Sebroeck
Browse files

watchdog:rit_wdt: Add support for WDIOF_CARDRESET 



This patch adds the WDIOF_CARDRESET support for the platform watchdog
whose hardware does not support this feature, to know if the board
reboot is due to a watchdog reset.

This is done via reserved memory(RAM), which indicates if specific
info saved, triggering the watchdog reset in last boot.

Signed-off-by: default avatarLi Hua Qian <huaqian.li@siemens.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230718021007.1338761-4-huaqian.li@siemens.com


[groeck: vaddr == NULL --> !vaddr]
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@linux-watchdog.org>
parent 11efe9e3

drivers/watchdog/rti_wdt.c

+48 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
#include <linux/mod_devicetable.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/platform_device.h>

#include <linux/pm_runtime.h>

#include <linux/types.h>
@@ -52,6 +54,11 @@ 


#define DWDST			BIT(1)



#define PON_REASON_SOF_NUM	0xBBBBCCCC

#define PON_REASON_MAGIC_NUM	0xDDDDDDDD

#define PON_REASON_EOF_NUM	0xCCCCBBBB

#define RESERVED_MEM_MIN_SIZE	12



static int heartbeat = DEFAULT_HEARTBEAT;



/*
@@ -198,6 +205,11 @@ static int rti_wdt_probe(struct platform_device *pdev) 
	struct rti_wdt_device *wdt;

	struct clk *clk;

	u32 last_ping = 0;

	struct device_node *node;

	u32 reserved_mem_size;

	struct resource res;

	u32 *vaddr;

	u64 paddr;



	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);

	if (!wdt)
@@ -284,6 +296,42 @@ static int rti_wdt_probe(struct platform_device *pdev) 
		}

	}



	node = of_parse_phandle(pdev->dev.of_node, "memory-region", 0);

	if (node) {

		ret = of_address_to_resource(node, 0, &res);

		if (ret) {

			dev_err(dev, "No memory address assigned to the region.\n");

			goto err_iomap;

		}



		/*

		 * If reserved memory is defined for watchdog reset cause.

		 * Readout the Power-on(PON) reason and pass to bootstatus.

		 */

		paddr = res.start;

		reserved_mem_size = resource_size(&res);

		if (reserved_mem_size < RESERVED_MEM_MIN_SIZE) {

			dev_err(dev, "The size of reserved memory is too small.\n");

			ret = -EINVAL;

			goto err_iomap;

		}



		vaddr = memremap(paddr, reserved_mem_size, MEMREMAP_WB);

		if (!vaddr) {

			dev_err(dev, "Failed to map memory-region.\n");

			ret = -ENOMEM;

			goto err_iomap;

		}



		if (vaddr[0] == PON_REASON_SOF_NUM &&

		    vaddr[1] == PON_REASON_MAGIC_NUM &&

		    vaddr[2] == PON_REASON_EOF_NUM) {

			wdd->bootstatus |= WDIOF_CARDRESET;

		}

		memset(vaddr, 0, reserved_mem_size);

		memunmap(vaddr);

	}



	watchdog_init_timeout(wdd, heartbeat, dev);



	ret = watchdog_register_device(wdd);