[kvm-unit-tests PATCH 3/7] riscv: Add ACPI support for timer frequency discovery

[Andrew Jones]

Another ACPI naming comment

On Thu, Sep 24, 2026 at 11:39:41AM +0800, Xiang W wrote:
> When a DT is not provided, read the system time base frequency from
> the RHCT instead of aborting in timer_get_frequency().
> 
> RHCT Time Base Frequency is the ACPI equivalent of the DT
> /cpus timebase-frequency property and is the same for all harts.
> Keep DT as the preferred path when one is available.
> 
> Signed-off-by: Xiang W <wangxiang at iscas.ac.cn>
> ---
>  lib/acpi.h        |  9 +++++++++
>  lib/riscv/timer.c | 37 +++++++++++++++++++++++++------------
>  2 files changed, 34 insertions(+), 12 deletions(-)
> 
> diff --git a/lib/acpi.h b/lib/acpi.h
> index a905807d..2597e8ce 100644
> --- a/lib/acpi.h
> +++ b/lib/acpi.h
> @@ -20,6 +20,7 @@
>  #define MADT_SIGNATURE ACPI_SIGNATURE('A','P','I','C')
>  #define SPCR_SIGNATURE ACPI_SIGNATURE('S','P','C','R')
>  #define GTDT_SIGNATURE ACPI_SIGNATURE('G','T','D','T')
> +#define RHCT_SIGNATURE ACPI_SIGNATURE('R','H','C','T')
>  
>  #define ACPI_SIGNATURE_8BYTE(c1, c2, c3, c4, c5, c6, c7, c8) \
>  	(((uint64_t)(ACPI_SIGNATURE(c1, c2, c3, c4))) |	     \
> @@ -328,6 +329,14 @@ struct acpi_table_gtdt {
>  	u32 virtual_el2_timer_flags;
>  };
>  
> +struct acpi_table_rhct {
> +	ACPI_TABLE_HEADER_DEF
> +	u32 flags;
> +	u64 timebase_frequency;

Linux calls this time_base_freq

Thanks,
drew