[PATCH v2] arm64: dts: renesas: r8a78000: Fix GIC-720AE View 1 Redistributor description

[Geert Uytterhoeven]

On Thu, 14 May 2026 at 14:53, Marek Vasut
<marek.vasut+renesas at mailbox.org> wrote:
> The Renesas R-Car X5H (R8A78000) SoC contains Arm CoreLink GIC-720AE
> Generic Interrupt Controller with Multi View capability. Firmware has
> access to configuration View 0, Linux kernel has access to View 1.
>
> The Arm CoreLink GIC-720AE Generic Interrupt Controller Technical
> Reference Manual, currently latest r2p1 [1], chapter "5. Programmers
> model for GIC-720AE", subchapter "5.4 Redistributor registers
> for control and physical LPIs summary", part "5.4.3 GICR_TYPER,
> Redistributor Type Register", "Table 5-50: GICR_TYPER bit descriptions"
> on page 200, clarifies register "GICR_TYPER" bit 4 "Last" behavior
> in Multi View setup as follows:
>
> "
> Last
> Last Redistributor:
>
> 0 ... This Redistributor is not the last Redistributor on the chip.
> 1 ... This Redistributor is the last Redistributor on the chip.
>       When GICD_CFGID.VIEW == 1, for views 1, 2, or 3 this bit
>       always returns 1.
> "
>
> On this SoC, GICD_CFGID.VIEW is 1 and the Linux kernel has access to
> View 1, therefore Linux kernel GICv3 driver will interpret register
> "GICR_TYPER" bit 4 "Last" = 1 in the first Redistributor in continuous
> Redistributor page as that first Redistributor being the one and only
> Redistributor and will stop processing the continuous Redistributor
> page further. This will prevent the other Redistributors from being
> recognized by the system and used for other PEs.
>
> Because the hardware indicates that the continuous Redistributor page
> is not continuous for View 1, 2, or 3, describe every Redistributor
> separately in the DT. This makes all Redistributors for all cores
> accessible in Linux.
>
> [1] https://documentation-service.arm.com/static/69ef3c1cd35efd294e335c43
>     Arm® CoreLink™ GIC-720AE Generic Interrupt Controller
>     Revision: r2p1 / Issue 12 / 102666_0201_12_en
>
> Fixes: 63500d12cf76 ("arm64: dts: renesas: Add R8A78000 SoC support")
> Acked-by: Marc Zyngier <maz at kernel.org>
> Signed-off-by: Marek Vasut <marek.vasut+renesas at mailbox.org>

> V2: - Update GIC-700AE documentation link to generated PDF
>     - Update commit message to match the PDF
>     - Add AB from Marc

LGTM, so
Reviewed-by: Geert Uytterhoeven <geert+renesas at glider.be>
i.e. will queue in renesas-devel for v7.2.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds