[PATCH v4 1/3] watchdog: aspeed: Update bootstatus handling
Chin-Ting Kuo
chin-ting_kuo at aspeedtech.com
Thu Nov 7 16:35:07 AEDT 2024
Hi Guenter,
Thanks for the review.
> -----Original Message-----
> From: Guenter Roeck <groeck7 at gmail.com> On Behalf Of Guenter Roeck
> Sent: Saturday, November 2, 2024 6:17 AM
> Subject: Re: [PATCH v4 1/3] watchdog: aspeed: Update bootstatus handling
>
> 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-up
> date.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 at aspeedtech.com>
> > ---
> > 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.
>
Okay, it will be updated in the next patch version.
> > + 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;
> }
> }
>
Okay, it looks more concise. Thanks for the reminder.
> > + 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 ?
>
It will be updated in the next patch.
> > +
> > + 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.
>
Okay.
> > +
> > + 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;
Chin-Ting
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