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Re: [PATCH 7/7] hw/watchdog/wdt_aspeed: Reduce timer precision to micro-
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [PATCH 7/7] hw/watchdog/wdt_aspeed: Reduce timer precision to micro-second |
Date: |
Wed, 17 Jun 2020 05:41:37 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 |
Hi Andrew,
On 6/17/20 3:18 AM, Andrew Jeffery wrote:
> On Tue, 16 Jun 2020, at 17:21, Philippe Mathieu-Daudé wrote:
>> The current implementation uses nano-second precision, while
>> the watchdog can not be more precise than a micro-second.
>
> What's the basis for this assertion? It's true for the AST2500 and AST2600,
> but
> the AST2400 can run the watchdog from either a 1MHz clock source or the APB
> clock (which must be at least 16.5MHz on palmetto). The reset state on the
> AST2400 configures the watchdog for the APB clock rate.
>
> The Linux driver will eventually configure the watchdog for 1MHz mode
> regardless so perhaps the AST2400 reset state is a bit of a corner case, but
> I feel the assertion should be watered down a bit?
What about this description?
"The current implementation uses nano-second precision, but
is not more precise than micro-second precision.
Simplify by using a micro-second based timer.
Rename the timer 'timer_us' to have the unit explicit."
>
> Andrew
>
- Re: [PATCH 1/7] qemu-common: Briefly document qemu_timedate_diff() unit, (continued)
- [PATCH 2/7] block/qcow2: Document cache_clean_interval field holds seconds, Philippe Mathieu-Daudé, 2020/06/16
- [PATCH 3/7] block/curl: Reduce timer precision to milli-second, Philippe Mathieu-Daudé, 2020/06/16
- [PATCH 4/7] hw/virtio/virtio-balloon: Rename timer field including 'ms' unit, Philippe Mathieu-Daudé, 2020/06/16
- [PATCH 5/7] hw/rtc/m48t59: Reduce timer precision to milli-second, Philippe Mathieu-Daudé, 2020/06/16
- [PATCH 6/7] hw/ipmi/ipmi_bmc_extern: Reduce timer precision to milli-second, Philippe Mathieu-Daudé, 2020/06/16
- [PATCH 7/7] hw/watchdog/wdt_aspeed: Reduce timer precision to micro-second, Philippe Mathieu-Daudé, 2020/06/16
Re: [PATCH 0/7] misc: Reduce QEMUTimer pressure by using lower precision when possible, Paolo Bonzini, 2020/06/18