From: "Biwen Li (OSS)" <biwen.li@oss.nxp.com>
To: Leo Li <leoyang.li@nxp.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
"Biwen Li (OSS)" <biwen.li@oss.nxp.com>,
"shawnguo@kernel.org" <shawnguo@kernel.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"mark.rutland@arm.com" <mark.rutland@arm.com>,
"Z.q. Hou" <zhiqiang.hou@nxp.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"jason@lakedaemon.net" <jason@lakedaemon.net>,
"maz@kernel.org" <maz@kernel.org>
Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Jiafei Pan <jiafei.pan@nxp.com>, Xiaobo Xie <xiaobo.xie@nxp.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: RE: [EXT] Re: [v2 01/11] irqchip: ls-extirq: Add LS1043A, LS1088A external interrupt
Date: Mon, 30 Nov 2020 01:38:17 +0000 [thread overview]
Message-ID: <DB6PR0401MB2438919F5B954B0FD6BA1B1E8FF50@DB6PR0401MB2438.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <CADRPPNTXnRrsRaAX-zBcU9vPo37u7BCKfAtzGG=2_Ut4syZwJA@mail.gmail.com>
> > > >>> Where did you get this information that the register on LS1043
> > > >>> and
> > > >>> LS1046 is bit reversed? I cannot find such information in the RM.
> > > >>> And does this mean all other SCFG registers are also bit reversed?
> > > >>> If this is some information that is not covered by the RM, we
> > > >>> probably should clarify it in the code and the commit message.
> > > >> Hi Leo,
> > > >>
> > > >> I directly use the same logic to write the bit(field IRQ0~11INTP)
> > > >> of the register SCFG_INTPCR in LS1043A and LS1046A.
> > > >> Such as,
> > > >> if I want to control the polarity of IRQ0(field IRQ0INTP, IRQ0 is
> > > >> active low) of LS1043A/LS1046A, then I just need write a value 1
> > > >> << (31 - 0)
> > > to it.
> > > >> The logic depends on register's definition in LS1043A/LS1046A's RM.
> > > >
> > > > Ok. The SCFG_SCFGREVCR seems to be a one-off fixup only existed
> > > > on
> > > LS1021. And it is mandatory to be bit_reversed according to the RM
> > > which is already taken care of in the RCW. So the bit reversed case
> > > should be the only case supported otherwise a lot of other places
> > > for SCFG access should be failed.
> > > >
> > > > I think we should remove the bit_reverse thing all together from
> > > > the driver
> > > for good. This will prevent future confusion. Rasmus, what do you think?
> > >
> > > Yes, all the ls1021a-derived boards I know of do have something like
> > >
> > > # Initialize bit reverse of SCFG registers
> > > 09570200 ffffffff
> > >
> > > in their pre-boot-loader config file. And yes, the RM does say
> > >
> > > This register must be written 0xFFFF_FFFF as a part of
> > > initialization sequence before writing to any other SCFG
> > > register.
> > >
> > > but nowhere does it say "or else...", nor a little honest addendum
> > > "because we accidentally released broken silicon with this
> > > misfeature _and_ wrong POR value".
> >
> > Yeah. I do think they messed up at the beginning when trying to integrate
> the big endian registers on little endian core. It is good that we are doing it
> correctly in later SoCs.
> >
> > >
> > > Can we have an official statement from NXP stating that SCFGREVCR is
> > > a hardware design bug? And can you send it through a time-machine so
> > > I had it three years ago avoiding the whole "fsl,bit-reverse
> > > device-tree-property, no, read the register if you're on a ls1021a and decide"
> hullabaloo.
> >
> > I'm not sure if it is possible to update the related documents right now for this.
> But definitely it was not your fault to have introduced this in the driver due to
> the confusion from document. My suggestion to remove it is just to prevent
> this from causing more confusions in the future as this driver is used on more
> SoCs.
>
> Hi Biwen,
>
> Would you send a new version of this patch? Thanks.
Hi Leo, sure, np.
>
> Regards,
> Leo
next prev parent reply other threads:[~2020-11-30 1:39 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 4:46 [v2 01/11] irqchip: ls-extirq: Add LS1043A, LS1088A external interrupt Biwen Li
2020-10-27 4:46 ` [v2 02/11] arm64: dts: ls1043a: add DT node for external interrupt lines Biwen Li
2020-10-27 4:46 ` [v2 03/11] arm64: dts: ls1046a: " Biwen Li
2020-10-27 4:46 ` [v2 04/11] arm64: dts: ls1046ardb: Add interrupt line for RTC node Biwen Li
2020-10-27 4:46 ` [v2 05/11] arm64: dts: ls1088a: add DT node for external interrupt lines Biwen Li
2020-10-27 4:46 ` [v2 06/11] arm64: dts: ls1088ardb: fix interrupt line for RTC node Biwen Li
2020-10-27 4:46 ` [v2 07/11] arm64: dts: ls208xa: add DT node for external interrupt lines Biwen Li
2020-10-27 4:46 ` [v2 08/11] arm64: dts: ls208xa-rdb: add interrupt line for RTC node Biwen Li
2020-10-27 4:46 ` [v2 09/11] arm64: dts: lx2160a: add DT node for external interrupt lines Biwen Li
2020-10-27 4:46 ` [v2 10/11] arm64: dts: lx2160ardb: fix interrupt line for RTC node Biwen Li
2020-10-27 4:46 ` [v2 11/11] dt-bindings: interrupt-controller: update bindings for supporting more SoCs Biwen Li
2020-10-27 7:40 ` [v2 01/11] irqchip: ls-extirq: Add LS1043A, LS1088A external interrupt Rasmus Villemoes
2020-10-27 7:48 ` [EXT] " Biwen Li
2020-10-27 21:30 ` Leo Li
2020-11-02 6:14 ` Biwen Li (OSS)
2020-11-02 21:22 ` Leo Li
2020-11-03 8:02 ` Rasmus Villemoes
2020-11-05 23:03 ` Leo Li
2020-11-24 1:33 ` Li Yang
2020-11-30 1:38 ` Biwen Li (OSS) [this message]
2020-10-27 9:33 ` Marc Zyngier
2020-10-27 10:35 ` Biwen Li (OSS)
2020-10-27 10:43 ` Marc Zyngier
2020-10-27 10:55 ` Biwen Li (OSS)
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