[+cc Thomas for MSI driver file placement question + PCI MSI driver structure] Hi Minghuan, Your reply was base64-encoded and thus rejected by the vger mailing lists. I mentioned this before (http://lkml.kernel.org/r/20151011191027.GA29221@localhost). You might want to fix your mail strategy, because it's really hard to carry on a conversation if nobody can hear your side :) But I'll include your response here again by hand. Minghuan wrote: > On Wed, Oct 21, 2015 at 04:34:16PM -0500, Bjorn Helgaas wrote: > > Hi Minghuan, > > > > On Fri, Oct 16, 2015 at 03:19:20PM +0800, Minghuan Lian wrote: > > > Layerscape PCIe has its own MSI implementation. The patch registers > > > ls_pcie_msi_host_init() to avoid using Designware's MSI. > > > > > > Signed-off-by: Minghuan Lian <Minghuan.Lian@xxxxxxxxxxxxx> > > > --- > > > Change log > > > v4: split from [PATCH v3] PCI: layerscape: Add PCIe support for LS1043a and LS2080a > > > > > > drivers/pci/host/pci-layerscape.c | 17 +++++++++++++++++ > > > 1 file changed, 17 insertions(+) > > > > > > diff --git a/drivers/pci/host/pci-layerscape.c b/drivers/pci/host/pci-layerscape.c > > > index c53692a..8fac6c8 100644 > > > --- a/drivers/pci/host/pci-layerscape.c > > > +++ b/drivers/pci/host/pci-layerscape.c > > > @@ -150,14 +150,31 @@ static void ls_pcie_host_init(struct pcie_port *pp) > > > iowrite32(0, pcie->dbi + PCIE_DBI_RO_WR_EN); > > > } > > > > > > +static int ls_pcie_msi_host_init(struct pcie_port *pp, > > > + struct msi_controller *chip) > > > +{ > > > + struct device_node *msi_node; > > > + struct device_node *np = pp->dev->of_node; > > > + > > > + msi_node = of_parse_phandle(np, "msi-parent", 0); > > > + if (!msi_node) { > > > + dev_err(pp->dev, "failed to find msi-parent\n"); > > > + return -EINVAL; > > > + } > > > + > > > + return 0; > > > > I don't see how this can be right. I think it's OK if you want to enforce > > the presence of "msi-parent", but the other implementations of > > .msi_host_init (ks_dw_pcie_msi_host_init() and the default implementation > > in dw_pcie_host_init()) both set pp->irq_domain and call > > irq_create_mapping(). > > > > You don't do either of those, so I don't see how MSIs can work, because I > > assume the generic DesignWare code will depend on pp->irq_domain. If > > you're planning to add more Layerscape-specific MSI support later, I think > > you should wait and include this patch with that work. > Regarding MSI, both LS1021a and LS1043a use SCFG to implement it. I have submitted patch: > https://patchwork.kernel.org/patch/7411131/ > https://patchwork.kernel.org/patch/7411141/ > While ls2085a use ITS for it, we just re-use the ITS driver. > I notice some platform MSI driver files were placed in pci/host > folder not irqchip. If it is ok, I would like to change driver > folder and re-submitted the MSI patch. I suppose you're referring to drivers/pci/host/pci-xgene-msi.c. That file doesn't really have much PCI stuff in it. It does call pci_msi_create_irq_domain(), but that's really the only PCI interface or data structure it uses. So I don't know if drivers/pci/host or drivers/irqchip is the best place for it and for your irq-ls-scfg-msi.c. The connection between pci-xgene-msi.c and pci-xgene.c is not very clear to me, and that's sort of what I'm complaining about here. You're overriding a default MSI initialization method. Usually that means you do the same thing as the default method, but in a different way. You aren't doing the same thing at all, which makes the code hard to review. Maybe a comment about how the MSI controller gets connected to devices below this host bridge would be enough. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
