On Wed, Nov 23, 2022 at 06:08:50PM +0800, Rahul Tanwar wrote:
> Presently, init/boot time interrupt delivery mode is enumerated
> only for ACPI enabled systems by parsing MADT table or for older
> systems by parsing MP table. But for OF based x86 systems, it is
> assumed & hardcoded to legacy PIC mode. This causes boot time crash
> for platforms which do not use 8259 compliant legacy PIC.
>
> Add support for configuration of init time interrupt delivery mode
> for x86 OF based systems by introducing a new optional boolean
> property 'intel,virtual-wire-mode' for interrupt-controller node
> of local APIC. This property emulates IMCRP Bit 7 of MP feature
> info byte 2 of MP floating pointer structure.
>
> Defaults to legacy PIC mode if absent. Configures it to virtual
> wire compatibility mode if present.
>From code perspective looks good to me, but you need to have a blessing by DT
people for first two patches.
With whatever property name agreed on,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Signed-off-by: Rahul Tanwar <rtanwar@xxxxxxxxxxxxx>
> ---
> arch/x86/kernel/devicetree.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
> index fcc6f1b7818f..458e43490414 100644
> --- a/arch/x86/kernel/devicetree.c
> +++ b/arch/x86/kernel/devicetree.c
> @@ -167,7 +167,14 @@ static void __init dtb_lapic_setup(void)
> return;
> }
> smp_found_config = 1;
> - pic_mode = 1;
> + if (of_property_read_bool(dn, "intel,virtual-wire-mode")) {
> + pr_info("Virtual Wire compatibility mode.\n");
> + pic_mode = 0;
> + } else {
> + pr_info("IMCR and PIC compatibility mode.\n");
> + pic_mode = 1;
> + }
> +
> register_lapic_address(lapic_addr);
> }
>
> --
> 2.17.1
>
--
With Best Regards,
Andy Shevchenko
