Regarding the AST2600 specification, the WDTn Timeout Status Register
(WDT10) has bit 1 reserved. Bit 1 of the status register indicates
on ast2500 if the boot was from the second boot source.
It does not indicate that the most recent reset was triggered by
the watchdog. The code should just be changed to set WDIOF_CARDRESET
if bit 0 of the status register is set. However, this bit can be clear when
watchdog register 0x0c bit1(Reset System after timeout) is enabled.
Thereforce include SCU register to veriy WDIOF_EXTERN1 and WDIOF_CARDRESET
in ast2600 SCU74 or ast2400/ast2500 SCU3C.
Fixes: 49d4d277ca54 ("aspeed: watchdog: Set bootstatus during probe")
Signed-off-by: Peter Yin <[email protected]>
---
drivers/watchdog/aspeed_wdt.c | 90 +++++++++++++++++++++++++++++++----
1 file changed, 82 insertions(+), 8 deletions(-)
diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index b4773a6aaf8c..556493763793 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;
@@ -22,10 +24,38 @@ 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 AST_SCU_SYS_RESET_POWERON_MASK BIT(0)
+#define AST_SCU_SYS_RESET_EXTERN_FLAG BIT(1)
+
+#define AST2400_SYSTEM_RESET_STATUS 0x3C
+#define AST2400_WATCHDOG_RESET_MASK BIT(1)
+#define AST2400_RESET_FLAG_CLEAR GENMASK(2, 0)
+
+#define AST2500_WATCHDOG_RESET_MASK GENMASK(4, 2)
+#define AST2500_RESET_FLAG_CLEAR (AST2500_WATCHDOG_RESET_MASK | \
+ AST_SCU_SYS_RESET_POWERON_MASK | \
+ AST_SCU_SYS_RESET_EXTERN_FLAG)
+
+#define AST2600_SYSTEM_RESET_STATUS 0x74
+#define AST2600_WATCHDOG_RESET_MASK GENMASK(31, 16)
+#define AST2600_RESET_FLAG_CLEAR (AST2600_WATCHDOG_RESET_MASK | \
+ AST_SCU_SYS_RESET_POWERON_MASK | \
+ AST_SCU_SYS_RESET_EXTERN_FLAG)
+
struct aspeed_wdt_config {
u32 ext_pulse_width_mask;
u32 irq_shift;
u32 irq_mask;
+ struct {
+ const char *compatible;
+ u32 reset_status_reg;
+ u32 watchdog_reset_mask;
+ u32 extern_reset_mask;
+ u32 reset_flag_clear;
+ } scu;
};
struct aspeed_wdt {
@@ -39,18 +69,39 @@ 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_SYSTEM_RESET_STATUS,
+ .watchdog_reset_mask = AST2400_WATCHDOG_RESET_MASK,
+ .extern_reset_mask = 0,
+ .reset_flag_clear = AST2400_RESET_FLAG_CLEAR,
+ }
};
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_SYSTEM_RESET_STATUS,
+ .watchdog_reset_mask = AST2500_WATCHDOG_RESET_MASK,
+ .extern_reset_mask = AST_SCU_SYS_RESET_EXTERN_FLAG,
+ .reset_flag_clear = AST2500_RESET_FLAG_CLEAR,
+ }
};
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_SYSTEM_RESET_STATUS,
+ .watchdog_reset_mask = AST2600_WATCHDOG_RESET_MASK,
+ .extern_reset_mask = AST_SCU_SYS_RESET_EXTERN_FLAG,
+ .reset_flag_clear = AST2600_RESET_FLAG_CLEAR,
+ }
};
static const struct of_device_id aspeed_wdt_of_table[] = {
@@ -310,6 +361,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
const struct of_device_id *ofdid;
struct aspeed_wdt *wdt;
struct device_node *np;
+ struct regmap *scu;
const char *reset_type;
u32 duration;
u32 status;
@@ -458,14 +510,36 @@ 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;
-
- if (of_device_is_compatible(np, "aspeed,ast2400-wdt") ||
- of_device_is_compatible(np, "aspeed,ast2500-wdt"))
- wdt->wdd.groups = bswitch_groups;
- }
+ /*
+ * Power on reset is set when triggered by AC or SRSRST.
+ * Thereforce, we clear flag to ensure
+ * next boot cause is a real watchdog case.
+ * We use the external reset flag to determine
+ * if it is an external reset or card reset.
+ * However, The ast2400 watchdog flag is cleared by an external reset,
+ * so it only supports WDIOF_CARDRESET.
+ */
+ scu = syscon_regmap_lookup_by_compatible(wdt->cfg->scu.compatible);
+ if (IS_ERR(scu))
+ return PTR_ERR(scu);
+
+ ret = regmap_read(scu, wdt->cfg->scu.reset_status_reg, &status);
+ if (ret)
+ return ret;
+
+ if (!(status & AST_SCU_SYS_RESET_POWERON_MASK) &&
+ status & wdt->cfg->scu.watchdog_reset_mask)
+ wdt->wdd.bootstatus = (status & wdt->cfg->scu.extern_reset_mask)
+ ? WDIOF_EXTERN1 : WDIOF_CARDRESET;
+
+ status = wdt->cfg->scu.reset_flag_clear;
+ ret = regmap_write(scu, wdt->cfg->scu.reset_status_reg, status);
+ 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;
dev_set_drvdata(dev, wdt);
--
2.25.1
Hi Peter,
Overall this seems okay, however I have some follow-ups to my naming
nitpicks on v8. Broadly, my preferences are that:
* It's clear from the macro name what SoC, controller and register
each macro applies to
* We have a consistent structure in the macro naming -
<soc>_<controller>_<register>_<description> - i.e. the values for
<soc> (AST, AST2400, AST2500, AST2600), <controller> (SCU), and
<register> (SYS_RESET) are consistent across the macro names
* I prefer consistent use of 'mask' instead of 'flag' for things that
are used as masks, as to me flag implies a constraint of a single
bit, where mask doesn't feel like it has such a constraint. However,
it's fine if a mask consists of a single bit, it's still a mask.
On Tue, 2024-04-30 at 22:31 +0800, Peter Yin wrote:
> Regarding the AST2600 specification, the WDTn Timeout Status Register
> (WDT10) has bit 1 reserved. Bit 1 of the status register indicates
> on ast2500 if the boot was from the second boot source.
> It does not indicate that the most recent reset was triggered by
> the watchdog. The code should just be changed to set WDIOF_CARDRESET
> if bit 0 of the status register is set. However, this bit can be clear when
> watchdog register 0x0c bit1(Reset System after timeout) is enabled.
> Thereforce include SCU register to veriy WDIOF_EXTERN1 and WDIOF_CARDRESET
> in ast2600 SCU74 or ast2400/ast2500 SCU3C.
>
> Fixes: 49d4d277ca54 ("aspeed: watchdog: Set bootstatus during probe")
> Signed-off-by: Peter Yin <[email protected]>
> ---
> drivers/watchdog/aspeed_wdt.c | 90 +++++++++++++++++++++++++++++++----
> 1 file changed, 82 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
> index b4773a6aaf8c..556493763793 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;
> @@ -22,10 +24,38 @@ 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 AST_SCU_SYS_RESET_POWERON_MASK BIT(0)
> +#define AST_SCU_SYS_RESET_EXTERN_FLAG BIT(1)
s/_FLAG/_MASK/ here too?
> +
> +#define AST2400_SYSTEM_RESET_STATUS 0x3C
You chose to use my suggestion of `..._SCU_SYS_RESET_...` for the
POWERON and EXTERN macros above, but here you've dropped `SCU` and also
used `SYSTEM_RESET` instead `SYS_RESET`. I'd prefer we pick a
consistent register name, so
```
#define AST2400_SCU_SYS_RESET_STATUS 0x3c
```
> +#define AST2400_WATCHDOG_RESET_MASK BIT(1)
Again, I'd prefer all these field macros at least have `SCU` in the
name, and preferably the register name too, so:
```
#define AST2400_SCU_SYS_RESET_WDT_MASK BIT(1)
```
> +#define AST2400_RESET_FLAG_CLEAR GENMASK(2, 0)
s/FLAG/FLAGS/ given it's defined over multiple bits? Also, to include
the register name in the macro name:
```
#define AST2400_SCU_SYS_RESET_FLAGS_CLEAR GENMASK(2, 0)
```
> +
> +#define AST2500_WATCHDOG_RESET_MASK GENMASK(4, 2)
> +#define AST2500_RESET_FLAG_CLEAR (AST2500_WATCHDOG_RESET_MASK | \
> + AST_SCU_SYS_RESET_POWERON_MASK | \
> + AST_SCU_SYS_RESET_EXTERN_FLAG)
The same comments above apply to the AST2500 macros.
> +
> +#define AST2600_SYSTEM_RESET_STATUS 0x74
> +#define AST2600_WATCHDOG_RESET_MASK GENMASK(31, 16)
> +#define AST2600_RESET_FLAG_CLEAR (AST2600_WATCHDOG_RESET_MASK | \
> + AST_SCU_SYS_RESET_POWERON_MASK | \
> + AST_SCU_SYS_RESET_EXTERN_FLAG)
.. and the AST2600 macros.
> +
> struct aspeed_wdt_config {
> u32 ext_pulse_width_mask;
> u32 irq_shift;
> u32 irq_mask;
> + struct {
> + const char *compatible;
> + u32 reset_status_reg;
> + u32 watchdog_reset_mask;
> + u32 extern_reset_mask;
> + u32 reset_flag_clear;
> + } scu;
> };
> struct aspeed_wdt {
> @@ -39,18 +69,39 @@ 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_SYSTEM_RESET_STATUS,
> + .watchdog_reset_mask = AST2400_WATCHDOG_RESET_MASK,
> + .extern_reset_mask = 0,
> + .reset_flag_clear = AST2400_RESET_FLAG_CLEAR,
> + }
> };
> 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_SYSTEM_RESET_STATUS,
> + .watchdog_reset_mask = AST2500_WATCHDOG_RESET_MASK,
> + .extern_reset_mask = AST_SCU_SYS_RESET_EXTERN_FLAG,
> + .reset_flag_clear = AST2500_RESET_FLAG_CLEAR,
> + }
> };
> 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_SYSTEM_RESET_STATUS,
> + .watchdog_reset_mask = AST2600_WATCHDOG_RESET_MASK,
> + .extern_reset_mask = AST_SCU_SYS_RESET_EXTERN_FLAG,
> + .reset_flag_clear = AST2600_RESET_FLAG_CLEAR,
> + }
> };
> static const struct of_device_id aspeed_wdt_of_table[] = {
> @@ -310,6 +361,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
> const struct of_device_id *ofdid;
> struct aspeed_wdt *wdt;
> struct device_node *np;
> + struct regmap *scu;
> const char *reset_type;
> u32 duration;
> u32 status;
> @@ -458,14 +510,36 @@ 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;
> -
> - if (of_device_is_compatible(np, "aspeed,ast2400-wdt") ||
> - of_device_is_compatible(np, "aspeed,ast2500-wdt"))
> - wdt->wdd.groups = bswitch_groups;
> - }
> + /*
> + * Power on reset is set when triggered by AC or SRSRST.
s/SRSRST/SRST/
> + * Thereforce, we clear flag to ensure
s/Thereforce/Therefore/
Also the line-wrapping for the comment seems a bit aggressive?
> + * next boot cause is a real watchdog case.
> + * We use the external reset flag to determine
> + * if it is an external reset or card reset.
> + * However, The ast2400 watchdog flag is cleared by an external reset,
> + * so it only supports WDIOF_CARDRESET.
> + */
> + scu = syscon_regmap_lookup_by_compatible(wdt->cfg->scu.compatible);
> + if (IS_ERR(scu))
> + return PTR_ERR(scu);
> +
> + ret = regmap_read(scu, wdt->cfg->scu.reset_status_reg, &status);
> + if (ret)
> + return ret;
> +
> + if (!(status & AST_SCU_SYS_RESET_POWERON_MASK) &&
> + status & wdt->cfg->scu.watchdog_reset_mask)
> + wdt->wdd.bootstatus = (status & wdt->cfg->scu.extern_reset_mask)
> + ? WDIOF_EXTERN1 : WDIOF_CARDRESET;
> +
> + status = wdt->cfg->scu.reset_flag_clear;
Seems unnecessary to assign the mask to clear the reset state into
status?
Andrew
> + ret = regmap_write(scu, wdt->cfg->scu.reset_status_reg, status);
> + 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;
> dev_set_drvdata(dev, wdt);