Hi Mark > -----Original Message----- > From: Mark Rutland [mailto:mark.rutland@xxxxxxx] > Sent: 10 March 2017 17:41 > To: liudongdong (C); Bjorn Helgaas > Cc: Gabriele Paoloni; Wangzhou (B); devicetree@xxxxxxxxxxxxxxx; linux- > pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Subject: Bad DT binding (hisi-pcie-almost-ecam) > > I've just spotted commit: > > a2ec1996098c7da0 ("PCI: hisi: Add DT almost-ECAM support for > Hip06/Hip07 host controllers") > > ... which went in for v4.11-rc1. > > I hadn't seen this until now, and as far as I can tell this never went > to the devicetree list. Sorry about this, we'll be more careful next time > > The commit adds the "hisilicon,pcie-almost-ecam", which goes against > the > usual DT conventions, and is non-sensical in that it describes the IP > based on what it isn't. > > This binding shouldn't have gone in as-is, and we should fix it before > v4.11. > > The binding states that this IP is found in Hip06 and Hip07. For these > cases we'd usually take the name of the first implementation, e.g. > something like "hisilicon,hip06-pcie", which can be used as a fallback > in the compatible list if reused in subsequent SoC generations. > > I also see that "hisilicon,hip06-pcie" already exists, so I'm even more > suspicious. For Hip06 the IP is the same but in we have a different BIOS configuration that allows the controller be ECAM compliant for all the devices of the hierarchy except the RC. > > What exactly is the "hisilicon,pcie-almost-ecam" binding trying to > describe? Is it a different IP also found on Hip06, or is it a new > binding for the same IP? The reason why we need this new BIOS is to support the recent PCIe quirks for the ACPI Root Port driver (commit 5b69b85ba1ddd36be01f5c57830b37a3c8256009 "PCI/ACPI: Check for platform-specific MCFG quirks"). So using one BIOS we support both DT and ACPI. This is the reason why you see Hip-06 being already there... About the name to use here from what you suggest we should use "hisilicon,hip06-pcie-almost-ecam" and re-use it for hip07 SoC. To be honest I would prefer it either as it is now or to modify the driver as: diff --git a/drivers/pci/dwc/pcie-hisi.c b/drivers/pci/dwc/pcie-hisi.c index 52f1e3f..7527b4c 100644 --- a/drivers/pci/dwc/pcie-hisi.c +++ b/drivers/pci/dwc/pcie-hisi.c @@ -381,7 +381,11 @@ struct pci_ecam_ops hisi_pcie_platform_ops = { static const struct of_device_id hisi_pcie_almost_ecam_of_match[] = { { - .compatible = "hisilicon,pcie-almost-ecam", + .compatible = "hisilicon,pcie-almost-ecam-hip06", + .data = (void *) &hisi_pcie_platform_ops, + }, + { + .compatible = "hisilicon,pcie-almost-ecam-hip07", .data = (void *) &hisi_pcie_platform_ops, }, {}, What do you think? Many Thanks Gab > > Thanks, > Mark.
