Messages in this thread | | | Date | Tue, 27 Feb 2024 20:36:56 +0530 | Subject | Re: [PATCH v2] watchdog: qcom: fine tune the max timeout value calculation | From | Kathiravan Thirumoorthy <> |
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On 2/3/2024 12:07 PM, Kathiravan Thirumoorthy wrote: > > > On 1/16/2024 8:32 PM, Guenter Roeck wrote: >> On 1/16/24 00:22, Kathiravan Thirumoorthy wrote: >>> To determine the max_timeout value, the below calculation is used. >>> >>> max_timeout = 0x10000000 / clk_rate >>> >>> cat >>> /sys/devices/platform/soc@0/b017000.watchdog/watchdog/watchdog0/max_timeout >>> 8388 >>> >>> However, this is not valid for all the platforms. IPQ SoCs starting from >>> IPQ40xx and recent Snapdragron SoCs also has the bark and bite time >>> field >>> length of 20bits, which can hold max up to 32 seconds if the clk_rate is >>> 32KHz. >>> >>> If the user tries to configure the timeout more than 32s, then the value >>> will be truncated and the actual value will not be reflected in the HW. >>> >>> To avoid this, lets add a variable called max_tick_count in the >>> device data, >>> which defines max counter value of the WDT controller. Using this, >>> max-timeout >>> will be calculated in runtime for various WDT contorllers. >>> >>> With this change, we get the proper max_timeout as below and restricts >>> the user from configuring the timeout higher than this. >>> >>> cat >>> /sys/devices/platform/soc@0/b017000.watchdog/watchdog/watchdog0/max_timeout >>> 32 >>> >>> Signed-off-by: Kathiravan Thirumoorthy <quic_kathirav@quicinc.com> >> >> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > > > Guenter / Will, Can this be picked for v6.9? I don't see this in linux- > next yet, so please consider this as a gentle reminder!
Guenter / Will, Gentle Reminder... is this change queued for v6.9?
> >> >>> --- >>> Changes in v2: >>> - drop the minimum timeout change from 30s to 32s >>> - Link to v1: >>> https://lore.kernel.org/r/20240111-wdt-v1-1-28c648b3b1f3@quicinc.com >>> --- >>> drivers/watchdog/qcom-wdt.c | 7 +++++-- >>> 1 file changed, 5 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c >>> index 9e790f0c2096..006f9c61aa64 100644 >>> --- a/drivers/watchdog/qcom-wdt.c >>> +++ b/drivers/watchdog/qcom-wdt.c >>> @@ -41,6 +41,7 @@ static const u32 reg_offset_data_kpss[] = { >>> struct qcom_wdt_match_data { >>> const u32 *offset; >>> bool pretimeout; >>> + u32 max_tick_count; >>> }; >>> struct qcom_wdt { >>> @@ -177,11 +178,13 @@ static const struct watchdog_info >>> qcom_wdt_pt_info = { >>> static const struct qcom_wdt_match_data match_data_apcs_tmr = { >>> .offset = reg_offset_data_apcs_tmr, >>> .pretimeout = false, >>> + .max_tick_count = 0x10000000U, >>> }; >>> static const struct qcom_wdt_match_data match_data_kpss = { >>> .offset = reg_offset_data_kpss, >>> .pretimeout = true, >>> + .max_tick_count = 0xFFFFFU, >>> }; >>> static int qcom_wdt_probe(struct platform_device *pdev) >>> @@ -236,7 +239,7 @@ static int qcom_wdt_probe(struct platform_device >>> *pdev) >>> */ >>> wdt->rate = clk_get_rate(clk); >>> if (wdt->rate == 0 || >>> - wdt->rate > 0x10000000U) { >>> + wdt->rate > data->max_tick_count) { >>> dev_err(dev, "invalid clock rate\n"); >>> return -EINVAL; >>> } >>> @@ -260,7 +263,7 @@ static int qcom_wdt_probe(struct platform_device >>> *pdev) >>> wdt->wdd.ops = &qcom_wdt_ops; >>> wdt->wdd.min_timeout = 1; >>> - wdt->wdd.max_timeout = 0x10000000U / wdt->rate; >>> + wdt->wdd.max_timeout = data->max_tick_count / wdt->rate; >>> wdt->wdd.parent = dev; >>> wdt->layout = data->offset; >>> >>> --- >>> base-commit: 9e21984d62c56a0f6d1fc6f76b646212cfd7fe88 >>> change-id: 20240111-wdt-5bd079ecf14d >>> >>> Best regards, >> >
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