[PATCH 3/4] watchdog: aspeed: Update bootstatus handling

From: Chin-Ting Kuo
Date: Mon Oct 07 2024 - 02:34:59 EST

Update the bootstatus according to the latest design guide
from the OpenBMC shown as below.
https://github.com/openbmc/docs/blob/master/designs/bmc-reboot-cause-update.md#proposed-design

In short,
- WDIOF_EXTERN1 => system is reset by Software
- WDIOF_CARDRESET => system is reset by WDT
- Others => other reset events, e.g., power on reset.

On AST2400 platform, only a bit, SCU3C[1], represents that the
system is reset by WDT1 or WDT2.

On AST2500 platform, SCU3C[4:2] are WDT reset flags.
SCU3C[4]: system is reset by WDT3.
SCU3C[3]: system is reset by WDT2.
SCU3C[2]: system is reset by WDT1.

On AST2600 platform, SCU074[31:16] are WDT reset flags.
SCU074[31:28]: system is reset by WDT4
SCU074[31]: system is reset by WDT4 software reset.
SCU074[27:24]: system is reset by WDT3
SCU074[27]: system is reset by WDT3 software reset.
SCU074[23:20]: system is reset by WDT2
SCU074[23]: system is reset by WDT2 software reset.
SCU074[19:16]: system is reset by WDT1
SCU074[19]: system is reset by WDT1 software reset.

Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@xxxxxxxxxxxxxx>
---
drivers/watchdog/aspeed_wdt.c | 109 +++++++++++++++++++++++++++++++---
1 file changed, 101 insertions(+), 8 deletions(-)

diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index b4773a6aaf8c..68eaada8a564 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -11,10 +11,12 @@
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/kstrtox.h>
+#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
+#include <linux/regmap.h>
#include <linux/watchdog.h>

static bool nowayout = WATCHDOG_NOWAYOUT;
@@ -22,15 +24,41 @@ module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

+
+/* AST SCU Register for System Reset Event Log Register Set
+ * ast2600 is scu074 ast2400/2500 is scu03c
+ */
+#define AST2400_SCU_SYS_RESET_STATUS 0x3c
+#define AST2400_SCU_SYS_RESET_WDT_MASK 0x1
+#define AST2400_SCU_SYS_RESET_WDT_MASK_SHIFT 1
+
+#define AST2500_SCU_SYS_RESET_WDT_MASK 0x1
+#define AST2500_SCU_SYS_RESET_WDT_MASK_SHIFT 2
+
+#define AST2600_SCU_SYS_RESET_STATUS 0x74
+#define AST2600_SCU_SYS_RESET_WDT_MASK 0xf
+#define AST2600_SCU_SYS_RESET_WDT_SW_MASK 0x8
+#define AST2600_SCU_SYS_RESET_WDT_MASK_SHIFT 16
+
+struct aspeed_wdt_scu {
+ const char *compatible;
+ u32 reset_status_reg;
+ u32 wdt_reset_mask;
+ u32 wdt_sw_reset_mask;
+ u32 wdt_reset_mask_shift;
+};
+
struct aspeed_wdt_config {
u32 ext_pulse_width_mask;
u32 irq_shift;
u32 irq_mask;
+ struct aspeed_wdt_scu scu;
};

struct aspeed_wdt {
struct watchdog_device wdd;
void __iomem *base;
+ int idx;
u32 ctrl;
const struct aspeed_wdt_config *cfg;
};
@@ -39,18 +67,39 @@ static const struct aspeed_wdt_config ast2400_config = {
.ext_pulse_width_mask = 0xff,
.irq_shift = 0,
.irq_mask = 0,
+ .scu = {
+ .compatible = "aspeed,ast2400-scu",
+ .reset_status_reg = AST2400_SCU_SYS_RESET_STATUS,
+ .wdt_reset_mask = AST2400_SCU_SYS_RESET_WDT_MASK,
+ .wdt_sw_reset_mask = 0,
+ .wdt_reset_mask_shift = AST2400_SCU_SYS_RESET_WDT_MASK_SHIFT,
+ },
};

static const struct aspeed_wdt_config ast2500_config = {
.ext_pulse_width_mask = 0xfffff,
.irq_shift = 12,
.irq_mask = GENMASK(31, 12),
+ .scu = {
+ .compatible = "aspeed,ast2500-scu",
+ .reset_status_reg = AST2400_SCU_SYS_RESET_STATUS,
+ .wdt_reset_mask = AST2500_SCU_SYS_RESET_WDT_MASK,
+ .wdt_sw_reset_mask = 0,
+ .wdt_reset_mask_shift = AST2500_SCU_SYS_RESET_WDT_MASK_SHIFT,
+ },
};

static const struct aspeed_wdt_config ast2600_config = {
.ext_pulse_width_mask = 0xfffff,
.irq_shift = 0,
.irq_mask = GENMASK(31, 10),
+ .scu = {
+ .compatible = "aspeed,ast2600-scu",
+ .reset_status_reg = AST2600_SCU_SYS_RESET_STATUS,
+ .wdt_reset_mask = AST2600_SCU_SYS_RESET_WDT_MASK,
+ .wdt_sw_reset_mask = AST2600_SCU_SYS_RESET_WDT_SW_MASK,
+ .wdt_reset_mask_shift = AST2600_SCU_SYS_RESET_WDT_MASK_SHIFT,
+ },
};

static const struct of_device_id aspeed_wdt_of_table[] = {
@@ -213,6 +262,52 @@ static int aspeed_wdt_restart(struct watchdog_device *wdd,
return 0;
}

+static int aspeed_wdt_get_bootstatus(struct device *dev,
+ struct aspeed_wdt *wdt)
+{
+ struct device_node *np = dev->of_node;
+ struct aspeed_wdt_scu scu = wdt->cfg->scu;
+ struct regmap *scu_base;
+ u32 reset_mask_width;
+ u32 reset_mask_shift;
+ u32 status;
+ int ret;
+
+ wdt->idx = of_alias_get_id(np, "watchdog");
+ if (wdt->idx < 0)
+ wdt->idx = 0;
+
+ scu_base = syscon_regmap_lookup_by_compatible(scu.compatible);
+ if (IS_ERR(scu_base))
+ return PTR_ERR(scu_base);
+
+ ret = regmap_read(scu_base, scu.reset_status_reg, &status);
+ if (ret)
+ return ret;
+
+ /* On AST2400, only a bit used to represent WDT reset */
+ if (of_device_is_compatible(np, "aspeed,ast2400-wdt"))
+ wdt->idx = 0;
+
+ reset_mask_width = hweight32(scu.wdt_reset_mask);
+ reset_mask_shift = scu.wdt_reset_mask_shift +
+ reset_mask_width * wdt->idx;
+
+ if (status & (scu.wdt_sw_reset_mask << reset_mask_shift))
+ wdt->wdd.bootstatus = WDIOF_EXTERN1;
+ else if (status & (scu.wdt_reset_mask << reset_mask_shift))
+ wdt->wdd.bootstatus = WDIOF_CARDRESET;
+ else
+ wdt->wdd.bootstatus = WDIOF_UNKNOWN;
+
+ ret = regmap_write(scu_base, scu.reset_status_reg,
+ scu.wdt_reset_mask << reset_mask_shift);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
/* access_cs0 shows if cs0 is accessible, hence the reverted bit */
static ssize_t access_cs0_show(struct device *dev,
struct device_attribute *attr, char *buf)
@@ -312,7 +407,6 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
struct device_node *np;
const char *reset_type;
u32 duration;
- u32 status;
int ret;

wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
@@ -458,14 +552,13 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
writel(duration - 1, wdt->base + WDT_RESET_WIDTH);
}

- status = readl(wdt->base + WDT_TIMEOUT_STATUS);
- if (status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY) {
- wdt->wdd.bootstatus = WDIOF_CARDRESET;
+ ret = aspeed_wdt_get_bootstatus(dev, wdt);
+ if (ret)
+ return ret;

- if (of_device_is_compatible(np, "aspeed,ast2400-wdt") ||
- of_device_is_compatible(np, "aspeed,ast2500-wdt"))
- wdt->wdd.groups = bswitch_groups;
- }
+ if (of_device_is_compatible(np, "aspeed,ast2400-wdt") ||
+ of_device_is_compatible(np, "aspeed,ast2500-wdt"))
+ wdt->wdd.groups = bswitch_groups;

dev_set_drvdata(dev, wdt);

--
2.34.1