2023-07-17 04:10:46

by Li, Hua Qian

Subject: [PATCH v4 3/3] watchdog:rit_wdt: Add support for WDIOF_CARDRESET

From: Li Hua Qian <[email protected]>

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.

Reviewed-by: Guenter Roeck <[email protected]>
Signed-off-by: Li Hua Qian <[email protected]>
---
drivers/watchdog/rti_wdt.c | 48 ++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
index ce8f18e93aa9..901109d979f0 100644
--- a/drivers/watchdog/rti_wdt.c
+++ b/drivers/watchdog/rti_wdt.c
@@ -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 == NULL) {
+ 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);
--
2.34.1

2023-07-17 06:24:06

by Krzysztof Kozlowski

Subject: Re: [PATCH v4 3/3] watchdog:rit_wdt: Add support for WDIOF_CARDRESET

On 17/07/2023 06:07, [email protected] wrote:
> From: Li Hua Qian <[email protected]>
>
> 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.
>
> Reviewed-by: Guenter Roeck <[email protected]>

Really? Where?

Best regards,
Krzysztof