From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH v6 2/9] PCI: mediatek: Fixup class ID for MT7622 as PCI_CLASS_BRIDGE_PCI Date: Mon, 8 Oct 2018 18:23:37 +0100 Message-ID: <20181008172337.GA13538@e107981-ln.cambridge.arm.com> References: <1538969088-7136-1-git-send-email-honghui.zhang@mediatek.com> <1538969088-7136-3-git-send-email-honghui.zhang@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1538969088-7136-3-git-send-email-honghui.zhang@mediatek.com> Sender: linux-kernel-owner@vger.kernel.org To: honghui.zhang@mediatek.com, bhelgaas@google.com Cc: linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, ryder.lee@mediatek.com, ulf.hansson@linaro.org, marc.zyngier@arm.com, matthias.bgg@gmail.com, devicetree@vger.kernel.org, yingjoe.chen@mediatek.com, eddie.huang@mediatek.com, youlin.pei@mediatek.com, yt.shen@mediatek.com, sean.wang@mediatek.com List-Id: devicetree@vger.kernel.org On Mon, Oct 08, 2018 at 11:24:41AM +0800, honghui.zhang@mediatek.com wrote: > From: Honghui Zhang > > The PCIe controller of MT7622 has TYPE 1 configuration space type, but > the HW default class type values is invalid. > > The commit 101c92dc80c8 ("PCI: mediatek: Set up vendor ID and class > type for MT7622") have set the class ID for MT7622 as > PCI_CLASS_BRIDGE_HOST, but it's not workable for MT7622: > > In __pci_bus_assign_resources, the framework only setup bridge's > resource window only if class type is PCI_CLASS_BRIDGE_PCI. Or it > will leave the subordinary PCIe device's MMIO window un-touched. > > Fixup the class type to PCI_CLASS_BRIDGE_PCI as most of the controller > driver do. I think that this patch is correct but the commit log fails to pin point the problem. The IP you are programming is a root port, that's why you have to have the proper class code, the patch looks fine but I would like to peek Bjorn's brain on this since it is a fundamental concept. If the kernel does not assign resources unless it detects a PCI_CLASS_BRIDGE_PCI this means that for components that are actually PCI_CLASS_BRIDGE_HOST their register set must come preprogrammed unless I am missing something. I would like to get to the bottom of this since it is a fundamental enumeration concept. Thanks, Lorenzo > > Signed-off-by: Honghui Zhang > Acked-by: Ryder Lee > --- > drivers/pci/controller/pcie-mediatek.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c > index 288b8e2..bcdac9b 100644 > --- a/drivers/pci/controller/pcie-mediatek.c > +++ b/drivers/pci/controller/pcie-mediatek.c > @@ -432,7 +432,7 @@ static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port) > val = PCI_VENDOR_ID_MEDIATEK; > writew(val, port->base + PCIE_CONF_VEND_ID); > > - val = PCI_CLASS_BRIDGE_HOST; > + val = PCI_CLASS_BRIDGE_PCI; > writew(val, port->base + PCIE_CONF_CLASS_ID); > } > > -- > 2.6.4 >