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Re: [PATCH for-6.2 21/25] hw/timer/armv7m_systick: Use clock inputs inst
From: |
Peter Maydell |
Subject: |
Re: [PATCH for-6.2 21/25] hw/timer/armv7m_systick: Use clock inputs instead of system_clock_scale |
Date: |
Tue, 17 Aug 2021 16:59:07 +0100 |
On Tue, 17 Aug 2021 at 16:55, Damien Hedde <damien.hedde@greensocs.com> wrote:
>
>
>
> On 8/12/21 11:33 AM, Peter Maydell wrote:
> According to
> https://developer.arm.com/documentation/ddi0403/d/System-Level-Architecture/System-Address-Map/The-system-timer--SysTick/SysTick-Calibration-value-Register--SYST-CALIB
> , the field is 24bits wide.
>
> Should we prevent an overflow into the reserved bits and other fields ?
> by doing something like this:
> val &= SYSCALIB_TENMS;
> with the following #define with the other ones, above.
> #define SYSCALIB_TENMS ((1U << 24) - 1)
>
> Note, the overflow would happen around ~1.68GHz refclk frequency, it is
> probably a config that will never happen. I'm not sure if we should care
> or do something if this happens because it is probably an error
> somewhere else.
I guess we should do something, yes, though pretty much anything
we do will not really provide the guest with sensible data...
I suppose masking out the higher bits is no worse than anything else.
-- PMM
[PATCH for-6.2 20/25] hw/arm/msf2-soc: Wire up refclk, Peter Maydell, 2021/08/12
[PATCH for-6.2 22/25] hw/arm/stellaris: Fix code style issues in GPTM code, Peter Maydell, 2021/08/12
[PATCH for-6.2 24/25] hw/timer/stellaris-gptm: Use Clock input instead of system_clock_scale, Peter Maydell, 2021/08/12
[PATCH for-6.2 18/25] hw/arm/msf2_soc: Don't allocate separate MemoryRegions, Peter Maydell, 2021/08/12
[PATCH for-6.2 23/25] hw/arm/stellaris: Split stellaris-gptm into its own file, Peter Maydell, 2021/08/12