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Message-ID: <20241007063408.2360874-5-chin-ting_kuo@aspeedtech.com>
Date: Mon, 7 Oct 2024 14:34:08 +0800
From: Chin-Ting Kuo <chin-ting_kuo@...eedtech.com>
To: <patrick@...cx.xyz>, <wim@...ux-watchdog.org>, <linux@...ck-us.net>,
<robh@...nel.org>, <krzk+dt@...nel.org>, <conor+dt@...nel.org>,
<joel@....id.au>, <andrew@...econstruct.com.au>,
<linux-watchdog@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>, <linux-aspeed@...ts.ozlabs.org>,
<linux-kernel@...r.kernel.org>
CC: <Peter.Yin@...ntatw.com>, <Patrick_NC_Lin@...ynn.com>,
<Bonnie_Lo@...ynn.com>, <DELPHINE_CHIU@...ynn.com>, <BMC-SW@...eedtech.com>
Subject: [PATCH 4/4] watchdog: aspeed: Add support for SW restart
WDT reset can be triggered when system hangs or a deliberate
SW restart scenario. Originally, system can only know it is
reset by WDT through a reset flag. However, since AST2600,
a SW reset mechanism is created, SW can trigger the reset
event consciously and directly without wait for WDT timeout.
This function can be achieved by adding "aspeed,restart-sw"
property in dts. After that, an independent reset event flag
will be set after system reset by SW.
Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@...eedtech.com>
---
drivers/watchdog/aspeed_wdt.c | 40 ++++++++++++++++++++++++++++++++++-
1 file changed, 39 insertions(+), 1 deletion(-)
diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index 68eaada8a564..eefca972dfa4 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -61,6 +61,7 @@ struct aspeed_wdt {
int idx;
u32 ctrl;
const struct aspeed_wdt_config *cfg;
+ u32 flags;
};
static const struct aspeed_wdt_config ast2400_config = {
@@ -130,6 +131,11 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
#define WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION BIT(0)
#define WDT_RESET_MASK1 0x1c
#define WDT_RESET_MASK2 0x20
+#define WDT_SW_RESET_CTRL 0x24
+#define WDT_SW_RESET_COUNT_CLEAR 0xDEADDEAD
+#define WDT_SW_RESET_ENABLE 0xAEEDF123
+#define WDT_SW_RESET_MASK1 0x28
+#define WDT_SW_RESET_MASK2 0x2c
/*
* WDT_RESET_WIDTH controls the characteristics of the external pulse (if
@@ -170,6 +176,9 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
#define WDT_DEFAULT_TIMEOUT 30
#define WDT_RATE_1MHZ 1000000
+/* WDT behavior control flag */
+#define WDT_RESTART_SYSTEM_SW 0x00000001
+
static struct aspeed_wdt *to_aspeed_wdt(struct watchdog_device *wdd)
{
return container_of(wdd, struct aspeed_wdt, wdd);
@@ -249,11 +258,31 @@ static int aspeed_wdt_set_pretimeout(struct watchdog_device *wdd,
return 0;
}
+static void aspeed_wdt_sw_reset(struct watchdog_device *wdd)
+{
+ struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
+ u32 ctrl = WDT_CTRL_RESET_MODE_SOC |
+ WDT_CTRL_RESET_SYSTEM;
+
+ writel(ctrl, wdt->base + WDT_CTRL);
+ writel(WDT_SW_RESET_COUNT_CLEAR,
+ wdt->base + WDT_SW_RESET_CTRL);
+ writel(WDT_SW_RESET_ENABLE, wdt->base + WDT_SW_RESET_CTRL);
+
+ /* system must be reset immediately */
+ mdelay(1000);
+}
+
static int aspeed_wdt_restart(struct watchdog_device *wdd,
unsigned long action, void *data)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
+ if (wdt->flags & WDT_RESTART_SYSTEM_SW) {
+ aspeed_wdt_sw_reset(wdd);
+ return 0;
+ }
+
wdt->ctrl &= ~WDT_CTRL_BOOT_SECONDARY;
aspeed_wdt_enable(wdt, 128 * WDT_RATE_1MHZ / 1000);
@@ -521,8 +550,11 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
ret = of_property_read_u32_array(np, "aspeed,reset-mask", reset_mask, nrstmask);
if (!ret) {
writel(reset_mask[0], wdt->base + WDT_RESET_MASK1);
- if (nrstmask > 1)
+ writel(reset_mask[0], wdt->base + WDT_SW_RESET_MASK1);
+ if (nrstmask > 1) {
writel(reset_mask[1], wdt->base + WDT_RESET_MASK2);
+ writel(reset_mask[1], wdt->base + WDT_SW_RESET_MASK2);
+ }
}
}
@@ -552,6 +584,12 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
writel(duration - 1, wdt->base + WDT_RESET_WIDTH);
}
+ wdt->flags = 0;
+ if (!of_device_is_compatible(np, "aspeed,ast2400-wdt") &&
+ !of_device_is_compatible(np, "aspeed,ast2500-wdt") &&
+ of_property_read_bool(np, "aspeed,restart-sw"))
+ wdt->flags |= WDT_RESTART_SYSTEM_SW;
+
ret = aspeed_wdt_get_bootstatus(dev, wdt);
if (ret)
return ret;
--
2.34.1
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