]> git.itanic.dy.fi Git - linux-stable/commit
Revert "arm64: dts: freescale: Fix 'interrupt-map' parent address cells"
authorVladimir Oltean <vladimir.oltean@nxp.com>
Tue, 14 Dec 2021 13:58:52 +0000 (15:58 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 23 Mar 2022 08:18:50 +0000 (09:18 +0100)
commit439b7bb6705aeaf7a5678c02fdfc4e469bca3e8d
treee3274c1398bfbd74dd1cb36b7b7c5d4bc02d16b0
parent2a55a52bd8f86cf3fd9c3f32ea78bbc8fb82f458
Revert "arm64: dts: freescale: Fix 'interrupt-map' parent address cells"

commit 1447c635802fd0f5e213ad5277753108d56a4db3 upstream.

This reverts commit 869f0ec048dc8fd88c0b2003373bd985795179fb. That
updated the expected device tree binding format for the ls-extirq
driver, without also updating the parsing code (ls_extirq_parse_map)
to the new format.

The context is that the ls-extirq driver uses the standard
"interrupt-map" OF property in a non-standard way, as suggested by
Rob Herring during review:
https://lore.kernel.org/lkml/20190927161118.GA19333@bogus/

This has turned out to be problematic, as Marc Zyngier discovered
through commit 041284181226 ("of/irq: Allow matching of an interrupt-map
local to an interrupt controller"), later fixed through commit
de4adddcbcc2 ("of/irq: Add a quirk for controllers with their own
definition of interrupt-map"). Marc's position, expressed on multiple
opportunities, is that:

(a) [ making private use of the reserved "interrupt-map" name in a
    driver ] "is wrong, by the very letter of what an interrupt-map
    means. If the interrupt map points to an interrupt controller,
    that's the target for the interrupt."
https://lore.kernel.org/lkml/87k0g8jlmg.wl-maz@kernel.org/

(b) [ updating the driver's bindings to accept a non-reserved name for
    this property, as an alternative, is ] "is totally pointless. These
    machines have been in the wild for years, and existing DTs will be
    there *forever*."
https://lore.kernel.org/lkml/87ilvrk1r0.wl-maz@kernel.org/

Considering the above, the Linux kernel has quirks in place to deal with
the ls-extirq's non-standard use of the "interrupt-map". These quirks
may be needed in other operating systems that consume this device tree,
yet this is seen as the only viable solution.

Therefore, the premise of the patch being reverted here is invalid.
It doesn't matter whether the driver, in its non-standard use of the
property, complies to the standard format or not, since this property
isn't expected to be used for interrupt translation by the core.

This change restores LS1088A, LS2088A/LS2085A and LX2160A to their
previous bindings, which allows these systems to continue to use
external interrupt lines with the correct polarity.

Fixes: 869f0ec048dc ("arm64: dts: freescale: Fix 'interrupt-map' parent address cells")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi
arch/arm64/boot/dts/freescale/fsl-ls208xa.dtsi
arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi