Date:   Fri, 07 Jan 2022 18:53:50 +0000
Message-ID: <87wnjbtm0x.wl-maz@kernel.org>
From:   Marc Zyngier <maz@kernel.org>
To:     Pali =?UTF-8?B?Um9ow6Fy?= <pali@kernel.org>
Cc:     Marek =?UTF-8?B?QmVow7pu?= <kabel@kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Rob Herring <robh+dt@kernel.org>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Krzysztof =?UTF-8?B?V2lsY3p5xYRza2k=?= <kw@linux.com>,
        Russell King <rmk+kernel@armlinux.org.uk>,
        linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 10/11] PCI: mvebu: Implement support for legacy INTx interrupts
In-Reply-To: <20220107115053.k5d2uv7yrftrpcez@pali>
References: <20220105150239.9628-1-pali@kernel.org>
        <20220105150239.9628-11-pali@kernel.org>
        <87bl0ovq7f.wl-maz@kernel.org>
        <20220106154447.aie6taiuvav5wu6y@pali>
        <878rvsvoyo.wl-maz@kernel.org>
        <20220106162047.vqykmygs75eimfgy@pali>
        <877dbcvngf.wl-maz@kernel.org>
        <20220106182044.3ff0828c@thinkpad>
        <874k6gvkhz.wl-maz@kernel.org>
        <20220107115053.k5d2uv7yrftrpcez@pali>
User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue)
 FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1
 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO)
MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue")
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Fri, 07 Jan 2022 11:50:53 +0000,
Pali Roh=C3=A1r <pali@kernel.org> wrote:
>=20
> On Thursday 06 January 2022 17:31:36 Marc Zyngier wrote:
> > On Thu, 06 Jan 2022 17:20:44 +0000,
> > Marek Beh=C3=BAn <kabel@kernel.org> wrote:
> > >=20
> > > On Thu, 06 Jan 2022 16:27:44 +0000
> > > Marc Zyngier <maz@kernel.org> wrote:
> > > > You are completely missing my point. I'm talking about data
> > > > structures, you're talking about interrupts. You have this:
> > > >=20
> > > > struct mvebu_pcie_port {
> > > >        // Tons of stuff
> > > >        struct irq_chip intx_chip;
> > > > };
> > > >=20
> > > > What I want you to do is:
> > > >=20
> > > > struct mvebu_pcie_port {
> > > >        // Tons of stuff
> > > > };
> > > >=20
> > > > static struct irq_chip intx_chip =3D {
> > > > 	.name		=3D "INTx",
> > > > 	.irq_mask	=3D mvebu_pcie_intx_irq_mask,
> > > > 	.irq_unmask	=3D mvebu_pcie_intx_irq_unmask;
> > > > };
> > > >=20
> > > > That's it. No more, no less.
> > > >=20
> > > > 	M.
> > > >=20
> > >=20
> > > Hmm, but struct irq_chip contains a dynamic member,
> > >   struct device *parent_device;
> > > Isn't that used? Or are you planning to kill it?
> >=20
> > Indeed, and I am definitely planning to kill it. This is the wrong
> > place for this stuff, and I want it gone. There are thankfully very
> > few users of this misfeature.
>=20
> Ok, so what about this change?
>=20
> @@ -1458,7 +1617,17 @@ static int mvebu_pcie_remove(struct platform_devic=
e *pdev)
>  		mvebu_writel(port, cmd, PCIE_CMD_OFF);
> =20
>  		/* Mask all interrupt sources. */
> -		mvebu_writel(port, 0, PCIE_MASK_OFF);
> +		mvebu_writel(port, ~PCIE_INT_ALL_MASK, PCIE_INT_UNMASK_OFF);
> +
> +		/* Clear all interrupt causes. */
> +		mvebu_writel(port, ~PCIE_INT_ALL_MASK, PCIE_INT_CAUSE_OFF);
> +
> +		/* Remove IRQ domains. */
> +		if (port->intx_irq_domain)
> +			irq_domain_remove(port->intx_irq_domain);
> +
> +		if (irq > 0)
> +			irq_set_chained_handler_and_data(irq, NULL, NULL);

You really want this to be done *before* you remove the domain, as
there still could be interrupts in flight at this point.

	M.

--=20
Without deviation from the norm, progress is not possible.