From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vidya Sagar Subject: Re: [PATCH V7 02/15] PCI: Disable MSI for Tegra194 root port Date: Wed, 22 May 2019 01:04:58 +0530 Message-ID: <220fcb99-c3b5-58dc-a37a-57cbe9efa072@nvidia.com> References: <20190517123846.3708-1-vidyas@nvidia.com> <20190517123846.3708-3-vidyas@nvidia.com> <20190521102729.GB29166@ulmo> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Thierry Reding Cc: lorenzo.pieralisi@arm.com, bhelgaas@google.com, robh+dt@kernel.org, mark.rutland@arm.com, jonathanh@nvidia.com, kishon@ti.com, catalin.marinas@arm.com, will.deacon@arm.com, jingoohan1@gmail.com, gustavo.pimentel@synopsys.com, mperttunen@nvidia.com, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kthota@nvidia.com, mmaddireddy@nvidia.com, sagar.tv@gmail.com List-Id: devicetree@vger.kernel.org On 5/21/2019 10:17 PM, Vidya Sagar wrote: > On 5/21/2019 3:57 PM, Thierry Reding wrote: >> On Fri, May 17, 2019 at 06:08:33PM +0530, Vidya Sagar wrote: >>> Tegra194 rootports don't generate MSI interrupts for PME events and hen= ce >>> MSI needs to be disabled for them to avoid root ports service drivers >>> registering their respective ISRs with MSI interrupt. >>> >>> Signed-off-by: Vidya Sagar >>> --- >>> Changes since [v6]: >>> * This is a new patch >>> >>> =A0 drivers/pci/quirks.c | 14 ++++++++++++++ >>> =A0 1 file changed, 14 insertions(+) >>> >>> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c >>> index 0f16acc323c6..28f9a0380df5 100644 >>> --- a/drivers/pci/quirks.c >>> +++ b/drivers/pci/quirks.c >>> @@ -2592,6 +2592,20 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, >>> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 PCI_DEVICE_ID_NVIDIA_NVENET_15, >>> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 nvenet_msi_disable); >>> +/* >>> + * Tegra194's PCIe root ports don't generate MSI interrupts for PME ev= ents >>> + * instead legacy interrupts are generated. Hence, to avoid service dr= ivers >>> + * registering their respective ISRs for MSIs, need to disable MSI int= errupts >>> + * for root ports. >>> + */ >>> +static void disable_tegra194_rp_msi(struct pci_dev *dev) >>> +{ >>> +=A0=A0=A0 dev->no_msi =3D 1; >>> +} >>> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x1ad0, disable_tegra194= _rp_msi); >>> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x1ad1, disable_tegra194= _rp_msi); >>> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x1ad2, disable_tegra194= _rp_msi); >>> + >> >> Later functions in this file seem to use a more consistent naming >> pattern, according to which the name for this would become: >> >> =A0=A0=A0=A0pci_quirk_nvidia_tegra194_disable_rp_msi >> >> Might be worth considering making this consistent. >> >> This could also be moved to the DWC driver to restrict this to where it >> is needed. In either case, this seems like a good solution, so: >> >> Reviewed-by: Thierry Reding >> > Ok. I'll move it to DWC driver along with name change for the quirk API. >=20 I see that if quirk macros and API are present in pcie-tegra194.c file and = driver is built as a module, quirk API is not getting invoked by the system, whereas it get= s invoked if driver is built into kernel. Is this behavior expected? I think it is because of q= uirk API symbol not available as part of global quirk symbol table when driver is built as = a module? for now, I'm going to keep quirk macros and API in pci/quirks.c file itself= .