Re: [PATCH 2/2] watchdog: aspeed: Add support for aspeed,reset-mask DT property

From: Zev Weiss
Date: Wed Oct 11 2023 - 15:20:51 EST


On Wed, Oct 11, 2023 at 02:26:32AM PDT, Joel Stanley wrote:
>On Fri, 22 Sept 2023 at 20:12, Zev Weiss <zev@xxxxxxxxxxxxxxxxx> wrote:
>>
>> This property allows the device-tree to specify how the Aspeed
>> watchdog timer's reset mask register(s) should be set, so that
>> peripherals can be individually exempted from (or opted in to) being
>> reset when the watchdog timer expires.
>>
>> Signed-off-by: Zev Weiss <zev@xxxxxxxxxxxxxxxxx>
>
>Reviewed-by: Joel Stanley <joel@xxxxxxxxx>
>
>A note below.
>
>> ---
>> drivers/watchdog/aspeed_wdt.c | 11 +++++++++++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
>> index b72a858bbac7..b4773a6aaf8c 100644
>> --- a/drivers/watchdog/aspeed_wdt.c
>> +++ b/drivers/watchdog/aspeed_wdt.c
>> @@ -79,6 +79,8 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
>> #define WDT_TIMEOUT_STATUS_BOOT_SECONDARY BIT(1)
>> #define WDT_CLEAR_TIMEOUT_STATUS 0x14
>> #define WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION BIT(0)
>> +#define WDT_RESET_MASK1 0x1c
>> +#define WDT_RESET_MASK2 0x20
>>
>> /*
>> * WDT_RESET_WIDTH controls the characteristics of the external pulse (if
>> @@ -402,6 +404,8 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>>
>> if ((of_device_is_compatible(np, "aspeed,ast2500-wdt")) ||
>> (of_device_is_compatible(np, "aspeed,ast2600-wdt"))) {
>> + u32 reset_mask[2];
>> + size_t nrstmask = of_device_is_compatible(np, "aspeed,ast2600-wdt") ? 2 : 1;
>> u32 reg = readl(wdt->base + WDT_RESET_WIDTH);
>>
>> reg &= wdt->cfg->ext_pulse_width_mask;
>> @@ -419,6 +423,13 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>> reg |= WDT_OPEN_DRAIN_MAGIC;
>>
>> writel(reg, wdt->base + WDT_RESET_WIDTH);
>> +
>> + ret = of_property_read_u32_array(np, "aspeed,reset-mask", reset_mask, nrstmask);
>> + if (!ret) {
>> + writel(reset_mask[0], wdt->base + WDT_RESET_MASK1);
>> + if (nrstmask > 1)
>> + writel(reset_mask[1], wdt->base + WDT_RESET_MASK2);
>> + }
>
>This will do funky things if someone is careless enough to put the
>property in an ast2400 device tree.
>
>The ast2700 has four reset mask registers. Not really your problem at
>this point, but we might need to move to a per-soc callback in the
>platform data or similar.
>

This chunk is within an 'if' block that only runs on ast2500 & ast2600,
so it should be safely ignored on anything else.

>> }
>>
>> if (!of_property_read_u32(np, "aspeed,ext-pulse-duration", &duration)) {
>> --
>> 2.40.0.5.gf6e3b97ba6d2.dirty
>>