On Sun, Oct 11, 2015 at 12:10 PM, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > [+cc Thomas, Jason, Tanmay] > > Hi Minghuan, > > You responded to this message, but your response was rejected by the > mailing list, I think because it was not plain text. See > http://vger.kernel.org/majordomo-info.html > > I went ahead and reconstructed what your response would have looked > like so I could continue the conversation. But please fix your email > setup before responding again :) > > Minghuan wrote: >> On Wed, Oct 07, 2015 at 12:57:25PM -0500, Bjorn Helgaas wrote: >> > Hi Minghuan, >> > >> > On Thu, Sep 17, 2015 at 05:13:39PM +0800, Minghuan Lian wrote: >> > > The patch adds PCIe support for LS1043a and LS2080a. >> > > >> > > Signed-off-by: Minghuan Lian <Minghuan.Lian@xxxxxxxxxxxxx> >> > > --- >> > > This patch is based on v4.3-rc1 and [PATCH v9 0/6] >> > > PCI: hisi: Add PCIe host support for HiSilicon SoC Hip05 >> > > patchset from Zhou Wang. >> > > >> > > change log >> > > v2: >> > > 1. rename ls2085a to ls2080a >> > > 2. Add ls_pcie_msi_host_init() >> > > >> > > drivers/pci/host/Kconfig | 2 +- >> > > drivers/pci/host/pci-layerscape.c | 227 ++++++++++++++++++++++++++------------ >> > > 2 files changed, 157 insertions(+), 72 deletions(-) >> > > >> > > diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig >> > > index ae873be..38fe8a8 100644 >> > > --- a/drivers/pci/host/Kconfig >> > > +++ b/drivers/pci/host/Kconfig >> > > @@ -105,7 +105,7 @@ config PCI_XGENE_MSI >> > > >> > > config PCI_LAYERSCAPE >> > > bool "Freescale Layerscape PCIe controller" >> > > - depends on OF && ARM >> > > + depends on OF && (ARM || ARM64) >> > >> > It seems like there are a couple things going on here, and I wonder if >> > you can split them out into separate patches. >> > >> > 1) Making this work on ARM64 as well as on ARM. This may be of >> > interest for other DesignWare-based drivers, so if you split this out, >> > maybe it would be a useful template for converting the other drivers, >> > too. >> > >> > 2) Adding LS1043a and LS2080a. Obviously, this is only of interest to >> > this driver, but maybe it could be separated out into a separate >> > patch? > >> The patch is based on v4.3-rc1 and [PATCH v9 0/6] PCI: hisi: Add PCIe host >> support for HiSilicon SoC Hip05 patchset from Zhou Wang which adds arm and >> arm64 support. >> >> The original code with the Zhou Wang's patches can support arm64 as well. >> Because both LS1043a and LS2085 are armv8 (arm64) architecture, the patch >> updates Kconfig to add 'arm64'. >> >> If splitting two patches, the first patch for arm64 support only includes one >> line changes of Kconfig. So, I think it is unnecessary. > > It's OK if the first patch is very small. The point is that the patch > does two orthogonal things, and those two things should be in separate > commits. This makes bisection work better, and it reduces the amount > of functionality removed if we have to revert something. > >> > > +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; >> > > + } >> > >> > This doesn't actually *do* anything except complain if "msi-parent" is >> > missing. I'm not sure that's worth doing: if we need "msi-parent" >> > somewhere, we should complain there if we don't find it. If we don't >> > need it, why complain if it's missing? > >> driver/of/irq.c void of_msi_configure(struct device *dev, struct >> device_node *np) will bind "msi-parent" to each device if there is >> "msi-parent" handler. The PCIe driver do not need to do anything. If >> we do not check "msi-parent" here, we will have no chance to check it. >> The common code of 'of' and 'pci' bus driver will not complain, >> because the msi controller may be found by other way. > > Hmm. In mvebu_pcie_msi_enable() and xgene_pcie_msi_enable(), we > also look for "msi-parent". If that fails, mvebu continues silently > and xgene complains (but only if CONFIG_PCI_MSI=y). > > This seems like three unnecessarily different ways of doing the same > thing. For X-Gene MSI, this is the old code where at the time the code was prepared, msi_controller needs to be assigned to a host bridge so that the bridge can support MSI. Until now, with recent changes on MSI irqdomain from Marc and others, we can drop this msi_controller assignment completely as my recent patch that you merged to pci/host-xgene branch: https://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/commit/?h=pci/host-xgene > > I cc'd the maintainers of those drivers; maybe we can agree on a single > strategy. > >> > > static int __init ls_pcie_probe(struct platform_device *pdev) >> > > { >> > > ... >> > > - ret = ls_add_pcie_port(pcie); >> > > - if (ret < 0) >> > > + ret = dw_pcie_host_init(pp); >> > >> > We have several DesignWare-based drivers (dra7xx, exynos, imx6, ks, >> > ls, spear13xx), and I'd like to keep their structure as similar as >> > possible. For example, they all have basically this structure: >> > >> > X_pcie_probe >> > X_add_pcie_port >> > dw_pcie_host_init # pp->ops->host_init callback >> > X_pcie_host_init >> > X_pcie_establish_link >> > >> > This patch removes ls_add_pcie_port() and ls_pcie_establish_link(), so >> > we're diverging a bit. That makes it harder to see the similarities >> > across these drivers, which I think is a loss. > >> I will add X_add_pcie_port. But we do not need X_pcie_establish_link >> because we do not need change/reset phy to establish link, besides, >> the PCIe controller slot may be not inserted any PCIe device at all. >> If each controller waits some time for link, the start time will >> increase a lot. In some scenes, long start-up time is not acceptable. > > If we wait for a timeout trying to establish a link when the slot is > empty, it sounds like something's wrong. Can't we tell from presence > detect whether a card is present, even without trying to bring up the > link? > > If we truly do not need a piece like X_pcie_establish_link(), I'm OK > with entirely omitting it. What I really object to is when we have > the same functionality two places with different names or structured > two different ways. > > 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 Regards, Duc Dang. -- 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
