Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Makarand Pawagi <makarand.pawagi@nxp.com>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC:     "netdev@vger.kernel.org" <netdev@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>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "linux@armlinux.org.uk" <linux@armlinux.org.uk>,
        "jon@solid-run.com" <jon@solid-run.com>,
        Cristi Sovaiala <cristian.sovaiala@nxp.com>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        Ioana Ciornei <ioana.ciornei@nxp.com>,
        Varun Sethi <V.Sethi@nxp.com>,
        Calvin Johnson <calvin.johnson@nxp.com>,
        Pankaj Bansal <pankaj.bansal@nxp.com>,
        "guohanjun@huawei.com" <guohanjun@huawei.com>,
        "sudeep.holla@arm.com" <sudeep.holla@arm.com>,
        "rjw@rjwysocki.net" <rjw@rjwysocki.net>,
        "lenb@kernel.org" <lenb@kernel.org>,
        "stuyoder@gmail.com" <stuyoder@gmail.com>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "jason@lakedaemon.net" <jason@lakedaemon.net>,
        "maz@kernel.org" <maz@kernel.org>,
        "shameerali.kolothum.thodi@huawei.com" 
        <shameerali.kolothum.thodi@huawei.com>,
        "will@kernel.org" <will@kernel.org>,
        "robin.murphy@arm.com" <robin.murphy@arm.com>,
        "nleeder@codeaurora.org" <nleeder@codeaurora.org>,
        Andy Wang <Andy.Wang@arm.com>, Paul Yang <Paul.Yang@arm.com>
Subject: RE: [EXT] Re: [PATCH] bus: fsl-mc: Add ACPI support for fsl-mc
Thread-Topic: [EXT] Re: [PATCH] bus: fsl-mc: Add ACPI support for fsl-mc
Thread-Index: AQHV1bJXocSJjYU2TkeOIM2eKr9F06f/610AgARn+SA=
Date:   Fri, 31 Jan 2020 10:35:48 +0000
Message-ID: <DB8PR04MB7164DDF48480956F05886DABEB070@DB8PR04MB7164.eurprd04.prod.outlook.com>
References: <1580198925-50411-1-git-send-email-makarand.pawagi@nxp.com>
 <20200128110916.GA491@e121166-lin.cambridge.arm.com>
In-Reply-To: <20200128110916.GA491@e121166-lin.cambridge.arm.com>
Accept-Language: en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: nxp.com does not designate
 permitted sender hosts)
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: 08561246-569a-4957-5daf-08d7a6395650
X-MS-Exchange-CrossTenant-originalarrivaltime: 31 Jan 2020 10:35:48.6483
 (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: XbDxYcCLtRcqlRKSofOnVNLRPaEqaU8K96MAWP04WbLNxpAHhhl/52b7D+soYVhFjMl1bCyNjFrYk/SiCtuDqQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB8PR04MB7081
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

> -----Original Message-----
> From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Sent: Tuesday, January 28, 2020 4:39 PM
> To: Makarand Pawagi <makarand.pawagi@nxp.com>
> Cc: netdev@vger.kernel.org; linux-kernel@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-acpi@vger.kernel.org; linux@armlinux.or=
g.uk;
> jon@solid-run.com; Cristi Sovaiala <cristian.sovaiala@nxp.com>; Laurentiu
> Tudor <laurentiu.tudor@nxp.com>; Ioana Ciornei <ioana.ciornei@nxp.com>;
> Varun Sethi <V.Sethi@nxp.com>; Calvin Johnson <calvin.johnson@nxp.com>;
> Pankaj Bansal <pankaj.bansal@nxp.com>; guohanjun@huawei.com;
> sudeep.holla@arm.com; rjw@rjwysocki.net; lenb@kernel.org;
> stuyoder@gmail.com; tglx@linutronix.de; jason@lakedaemon.net;
> maz@kernel.org; shameerali.kolothum.thodi@huawei.com; will@kernel.org;
> robin.murphy@arm.com; nleeder@codeaurora.org
> Subject: [EXT] Re: [PATCH] bus: fsl-mc: Add ACPI support for fsl-mc
>=20
> Caution: EXT Email
>=20
> On Tue, Jan 28, 2020 at 01:38:45PM +0530, Makarand Pawagi wrote:
> > ACPI support is added in the fsl-mc driver. Driver will parse MC DSDT
> > table to extract memory and other resorces.
> >
> > Interrupt (GIC ITS) information will be extracted from MADT table by
> > drivers/irqchip/irq-gic-v3-its-fsl-mc-msi.c.
> >
> > IORT table will be parsed to configure DMA.
> >
> > Signed-off-by: Makarand Pawagi <makarand.pawagi@nxp.com>
> > ---
> >  drivers/acpi/arm64/iort.c                   | 53 +++++++++++++++++++++
> >  drivers/bus/fsl-mc/dprc-driver.c            |  3 +-
> >  drivers/bus/fsl-mc/fsl-mc-bus.c             | 48 +++++++++++++------
> >  drivers/bus/fsl-mc/fsl-mc-msi.c             | 10 +++-
> >  drivers/bus/fsl-mc/fsl-mc-private.h         |  4 +-
> >  drivers/irqchip/irq-gic-v3-its-fsl-mc-msi.c | 71
> ++++++++++++++++++++++++++++-
> >  include/linux/acpi_iort.h                   |  5 ++
> >  7 files changed, 174 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> > index 33f7198..beb9cd5 100644
> > --- a/drivers/acpi/arm64/iort.c
> > +++ b/drivers/acpi/arm64/iort.c
> > @@ -15,6 +15,7 @@
> >  #include <linux/kernel.h>
> >  #include <linux/list.h>
> >  #include <linux/pci.h>
> > +#include <linux/fsl/mc.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/slab.h>
> >
> > @@ -622,6 +623,29 @@ static int iort_dev_find_its_id(struct device
> > *dev, u32 req_id,  }
> >
> >  /**
> > + * iort_get_fsl_mc_device_domain() - Find MSI domain related to a
> > +device
> > + * @dev: The device.
> > + * @mc_icid: ICID for the fsl_mc device.
> > + *
> > + * Returns: the MSI domain for this device, NULL otherwise  */ struct
> > +irq_domain *iort_get_fsl_mc_device_domain(struct device *dev,
> > +                                                     u32 mc_icid) {
> > +     struct fwnode_handle *handle;
> > +     int its_id;
> > +
> > +     if (iort_dev_find_its_id(dev, mc_icid, 0, &its_id))
> > +             return NULL;
> > +
> > +     handle =3D iort_find_domain_token(its_id);
> > +     if (!handle)
> > +             return NULL;
> > +
> > +     return irq_find_matching_fwnode(handle, DOMAIN_BUS_FSL_MC_MSI);
> > +}
>=20
> NAK
>=20
> I am not willing to take platform specific code in the generic IORT layer=
.
>=20
> ACPI on ARM64 works on platforms that comply with SBSA/SBBR guidelines:
>=20
>=20
> https://developer.arm.com/architectures/platform-design/server-systems
>
> Deviating from those requires butchering ACPI specifications (ie IORT) an=
d
> related kernel code which goes totally against what ACPI is meant for on =
ARM64
> systems, so there is no upstream pathway for this code I am afraid.
>=20
Reason of adding this platform specific function in the generic IORT layer =
is=20
That iort_get_device_domain() only deals with PCI bus (DOMAIN_BUS_PCI_MSI).

fsl-mc objects when probed, need to find irq_domain which is associated wit=
h
the fsl-mc bus (DOMAIN_BUS_FSL_MC_MSI). It will not be possible to do that
if we do not add this function because there are no other suitable APIs exp=
orted
by IORT layer to do the job.