Re: [PATCH 7/8] xen/arm: gic-v2: Detect automatically aliased GIC400

[Ian Campbell <ian.campbell@citrix.com>]

On Tue, 2015-09-22 at 18:47 +0100, Julien Grall wrote:

Subject: "automatically detect..."

> We are currently using a per-platform quirk to know if the 2 4KB region of
> the GIC CPU interface are each aligned to 64KB. Although, it may be
> possible to have different layout on a same platform (depending on the
> firmware version).
> 
> Rather than having a quirk it's possible to detect by reading the GIC
> memory. This patch is based from the Linux commit "irqchip/GIC: Add
> workaround
> for aliased GIC400" [1].
> 
> Take the opportunity to clean up the GICv2 of code which was only
> required because of the quirk.
> 
> Note that none of the platform using the gic-hip04 where actually using

s/where/were/

> @@ -688,7 +684,8 @@ static int __init hip04gic_init(void)
>      if ( !gicv2.map_hbase )
>          panic("GIC-HIP04: Failed to ioremap for GIC Virtual
> interface\n");
>  
> -    vgic_v2_setup_hw(dbase, cbase, vbase);
> +    /* XXX: Support aliased HIP04 GIC? */

I assume it doesn't need this, so lets drop the comment and assume that's
the lack of the quirk on this platform is correct.


> +    gicv2.map_cbase = ioremap_nocache(cbase, csize);
> +    if ( !gicv2.map_cbase )
>          panic("GICv2: Failed to ioremap for GIC CPU interface\n");

s/for/the/ or just s/for //.

>  
> +    if ( gicv2_is_aliased(cbase, csize) )
> +    {
> +        /*
> +         * Move the base up by 60kB, so that we have a 8kB contiguous
> +         * region, which allows us to use GICC_DIR at its
> +         * normal offset.
> +         * Note the variable cbase is not updated has we need the original

s/has/as/

>      printk("GICv3 compatible with GICv2 cbase %#"PRIpaddr" vbase %#"PRIpaddr"\n",
>             cbase, vbase);
>  
> -    vgic_v2_setup_hw(dbase, cbase, vbase);
> +    /* XXX: Support aliased GICv2 on GICv3? */

Nah.