On 11/1/24 05:11, Chin-Ting Kuo wrote:
The boot status in the watchdog device struct is updated during
controller probe stage. Application layer can get the boot status
through the command, cat /sys/class/watchdog/watchdogX/bootstatus.
The boot status mapping rule follows 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
- WDIOF_EXTERN1 => system is reset by Software
- WDIOF_CARDRESET => system is reset by WDT SoC reset
- Others => other reset events, e.g., power on reset.
On ASPEED platform, the boot status is recorded in the SCU registers.
- AST2400: Only a bit represents for any WDT reset.
- AST2500: The reset triggered by different WDT controllers can be
distinguished by different SCU bits. But, WDIOF_EXTERN1 or
WDIOF_CARDRESET still cannot be identified due to
HW limitation.
- AST2600: Different from AST2500, additional HW bits are added for
distinguishing WDIOF_EXTERN1 and WDIOF_CARDRESET.
Besides, since alternating boot event is triggered by WDT SoC reset,
it is classified as WDIOF_CARDRESET.
Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@xxxxxxxxxxxxxx>
---
drivers/watchdog/aspeed_wdt.c | 83 ++++++++++++++++++++++++++++++++++-
1 file changed, 81 insertions(+), 2 deletions(-)
diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index b4773a6aaf8c..4ad6335ff25b 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -11,21 +11,31 @@
#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;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+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 {
@@ -39,18 +49,39 @@ 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 = 0x3c,
+ .wdt_reset_mask = 0x1,
+ .wdt_sw_reset_mask = 0,
+ .wdt_reset_mask_shift = 1,
+ },
};
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 = 0x3c,
+ .wdt_reset_mask = 0x1,
+ .wdt_sw_reset_mask = 0,
+ .wdt_reset_mask_shift = 2,
+ },
};
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 = 0x74,
+ .wdt_reset_mask = 0xf,
+ .wdt_sw_reset_mask = 0x8,
+ .wdt_reset_mask_shift = 16,
+ },
};
static const struct of_device_id aspeed_wdt_of_table[] = {
@@ -213,6 +244,52 @@ static int aspeed_wdt_restart(struct watchdog_device *wdd,
return 0;
}
+static int aspeed_wdt_update_bootstatus(struct platform_device *pdev,
+ struct aspeed_wdt *wdt)
+{
+ struct resource *res;
+ struct aspeed_wdt_scu scu = wdt->cfg->scu;
+ struct regmap *scu_base;
+ u32 reset_mask_width;
+ u32 reset_mask_shift;
+ u32 reg_size = 0;
Please no unnecesary initializations.
+ u32 idx = 0;
+ u32 status;
+ int ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ reg_size = res->end - res->start;
+
+ if (reg_size != 0)
+ idx = ((intptr_t)wdt->base & 0x00000fff) / reg_size;
+
+ /* On ast2400, only a bit is used to represent WDT reset */
+ if (of_device_is_compatible(pdev->dev.of_node, "aspeed,ast2400-wdt"))
+ idx = 0;
+
There is some redundancy in the above code, and platform_get_resource()
can return NULL. If idx==0 for aspeed,ast2400-wdt anyway, the code can be
rewritten as
if (!of_device_is_compatible(pdev->dev.of_node, "aspeed,ast2400-wdt")) {
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res) {
reg_size = res->end - res->start;
if (reg_size)
idx = ((intptr_t)wdt->base & 0x00000fff) / reg_size;
}
}
+ 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;
The above only affects bootstatus. Why fail to load the driver just because
bootstatus can not be read ?
+
+ reset_mask_width = hweight32(scu.wdt_reset_mask);
+ reset_mask_shift = scu.wdt_reset_mask_shift +
+ reset_mask_width * 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 = 0;
That is already 0.
+
+ return regmap_write(scu_base, scu.reset_status_reg,
+ scu.wdt_reset_mask << reset_mask_shift);
+}
+
/* 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)
@@ -458,10 +535,12 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
writel(duration - 1, wdt->base + WDT_RESET_WIDTH);
}
+ ret = aspeed_wdt_update_bootstatus(pdev, wdt);
+ if (ret)
+ return ret;
+
status = readl(wdt->base + WDT_TIMEOUT_STATUS);
if (status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY) {
- wdt->wdd.bootstatus = WDIOF_CARDRESET;
-
if (of_device_is_compatible(np, "aspeed,ast2400-wdt") ||
of_device_is_compatible(np, "aspeed,ast2500-wdt"))
wdt->wdd.groups = bswitch_groups;
