From:   Vladimir Oltean <vladimir.oltean@nxp.com>
To:     "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>
CC:     Marc Zyngier <maz@kernel.org>, Rob Herring <robh+dt@kernel.org>,
        Shawn Guo <shawnguo@kernel.org>, Leo Li <leoyang.li@nxp.com>,
        Biwen Li <biwen.li@nxp.com>, "Z.Q. Hou" <zhiqiang.hou@nxp.com>,
        Kurt Kanzenbach <kurt@linutronix.de>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: Re: [PATCH v2 devicetree] Revert "arm64: dts: freescale: Fix
 'interrupt-map' parent address cells"
Thread-Topic: [PATCH v2 devicetree] Revert "arm64: dts: freescale: Fix
 'interrupt-map' parent address cells"
Thread-Index: AQHX8PLFuZGYqGm80USNgHy7kOyTS6xNAmwA
Date:   Fri, 31 Dec 2021 18:13:51 +0000
Message-ID: <20211231181350.qwfnrwvdfnfssdjt@skbuf>
References: <20211214135852.2934670-1-vladimir.oltean@nxp.com>
In-Reply-To: <20211214135852.2934670-1-vladimir.oltean@nxp.com>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?FXGCIMrY0pGyzP9H5czrT5Yn7wDTGBnmq9CIYmeZnRoTkspkbQWI1IfphgFB?=
 =?us-ascii?Q?EEUOZYteHt5KFdjuLwnt1k/asA/lnGd89UOjsoxVfcUlRftQFtP+ok1kq4XI?=
 =?us-ascii?Q?MbAR6ubUfCecmoiVZI7+wUh08GHB3EpGWKmro7vD8AwtxRhV74P/hIrfsPqu?=
 =?us-ascii?Q?2AcvbWW1JsRH8op4QllJreXH2cQDQRP0HXdC38aLgXUi82NWIrnoKQa1kcPf?=
 =?us-ascii?Q?hPw+ghORiQmhUwk/ULeYwz1qZp/qaCjtgU7QR0UBQZ/xhqGE1y6rcoz2VB3b?=
 =?us-ascii?Q?Jkv6Gh7CtkqB/SBHUIuIuSAg4s0Guh1qbkN38CYgp9izvkQZghfPF0qpdnM7?=
 =?us-ascii?Q?/MuH8ESw17y8znJxXiSx33yV57sSQ0+ojfnIqYSChHP3X9XBVdPsVTrbeiai?=
 =?us-ascii?Q?+lg99/OCD0EFIRRRptLRbcrSdpTLr++3ixnZtgm3rVZn7YkSwy+LHPE9D/3A?=
 =?us-ascii?Q?+98Xj8OUbdKxThxVlxqw8ylLqJL3wq73qy3S14sFSbgKSMtPryuyXc8veiUM?=
 =?us-ascii?Q?CpzsHOGb0AKBUNUHUt92+3ynEID5ntwnWnP8lm6jl+eUQDy+8e9pSn3Mw6E4?=
 =?us-ascii?Q?o8gmf3Fe3l2QgDrd2b7jwgoN25plUei+7ayR+X1cmWmgBunaY8TKoCLfVces?=
 =?us-ascii?Q?UlyqbezMsmvhFAOA9N3Evfjm3kkmc9n3ZJ2zgMkJ+rnGMECl3Y3YmgNBGdfp?=
 =?us-ascii?Q?BgoIKetR2Jtj1rLtfpaXQ4ONL4C09Zf2JqIjmg53k3r1FE4o/d388IzysbCE?=
 =?us-ascii?Q?Czs9/UvZt88NOs4mYzktAg/Aj3dZ693rM2vp44/OvLl/IQrqKOGpKIDV8Sxw?=
 =?us-ascii?Q?Byg5jMGMdGQAvskiXhQG45iclIomrLo+XevL3LGt79gQTVmu1llJutwc9+SV?=
 =?us-ascii?Q?K+rBX8myE54EvDP24RElncTxyj31yGIndo/SqUgQdoqt0U2Aa0pFQVGM6sjO?=
 =?us-ascii?Q?HNY7H0YGlC3sVyBXvVXyufMEFRc9DyyaRpwC1NpQCoU2ynRtjePFtR6uqSPl?=
 =?us-ascii?Q?PEXg5qWB38ymycB3st9WkT/lgA7Bzul44RoUpE0RmgHNHMD8SzXgYOTxfAwo?=
 =?us-ascii?Q?kjplELAFBKl7YXR8f5NViaGQZYf3Mi4Pgfg06FQfG1hCliyw0Gn6x1akgaOO?=
 =?us-ascii?Q?ud4/7NzCAm9QTnPKdkskTJtSBQNFB30o+9r7J0d9jFYOqPoOsl3arlBEF+HT?=
 =?us-ascii?Q?mDT/lkumcmKIpikZqDx3Gd1W+wIDKCiLS5+iJPlqqYW2gOqJojMSEJ3zjLFa?=
 =?us-ascii?Q?9LToBWmI7zZZvIsO/wAGixjogdtXKWVFWCWDeUuklO7XL4OuybjupJZvwvX3?=
 =?us-ascii?Q?VAEJ8dkWurPv997a+vWyyfzRKVU1PAbrjcfDh6IK+tyy/Zc7MOfkwTDAIZri?=
 =?us-ascii?Q?P1FWuUHbRcvWhKAV5xMvHX/rxWom/9Uj/9qhESch1I9KDYe4z4AybWX6lc0k?=
 =?us-ascii?Q?UnSJxko3lEPtNdFqJAQkwtzItAooY5UhzZ07s9gC3gDUeN58sSL5AUtoIf0c?=
 =?us-ascii?Q?IN0pBw26AT1rV0bhluFt9a1S29MbwCCqUCO/CpbSEVmhovEb7SB7juAetDSW?=
 =?us-ascii?Q?0pWvrRhNR5j9/yBkST30YACsnYBTn707IAaXeCRA5XcHuDv62cgO/z2Pr1Vh?=
 =?us-ascii?Q?M+7IeCntS8gqcVpl3SL4AK0=3D?=
Content-Type: text/plain; charset="us-ascii"
Content-ID: <7BF76291621DAC40B6164099865EA96B@eurprd04.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: nxp.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: VI1PR04MB5136.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 23becfe3-8245-4e5b-9452-08d9cc894c7e
X-MS-Exchange-CrossTenant-originalarrivaltime: 31 Dec 2021 18:13:51.4179
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: hzKCjzIb/ozM8lln6Jy9qabkiNquG4CVsu1TEJRcWBxn+Kq5ue0pLcCZ4CdqZaEZ+EPwh1JCRsGeAw/ckkqbgQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR0402MB2862
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hello,

On Tue, Dec 14, 2021 at 03:58:52PM +0200, Vladimir Oltean wrote:
> 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.
>=20
> 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/
>=20
> 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:
>=20
> (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/
>=20
> (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/
>=20
> 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.
>=20
> 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.
>=20
> 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.
>=20
> Fixes: 869f0ec048dc ("arm64: dts: freescale: Fix 'interrupt-map' parent a=
ddress cells")
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> ---
> v1->v2: remove the other 9 patches that rename "interrupt-map" to
>         "fsl,extirq-map", at Marc's suggestion.

Could this patch be considered for merging in v5.16? The problem is
going to be quite a bit more severe and tricky to fix otherwise. Thanks.=