> -----Original Message----- > From: Bjorn Helgaas [mailto:bhelgaas@xxxxxxxxxx] > Sent: Friday, September 18, 2015 11:55 PM > To: Gabriele Paoloni > Cc: jingoohan1@xxxxxxxxx; pratyush.anand@xxxxxxxxx; linux- > pci@xxxxxxxxxxxxxxx; Wangzhou (B); Yuanzhichang; Zhudacai; zhangjukuo; > qiuzhenfa; Liguozhu (Kenneth) > Subject: Re: [PATCH] PCI: Designware: make num-lanes an optional DT > property > > Hi Gabriele, > > On Fri, Sep 11, 2015 at 01:02:26AM +0800, Gabriele Paoloni wrote: > > From: gabriele paoloni <gabriele.paoloni@xxxxxxxxxx> > > > > Currently num-lanes is read in dw_pcie_host_init(). > > for A SoC that performs the link-up operation in UEFI num-lanes > > is not needed in the DTS but it has to be specified to any value; > > otherwise dw_pcie_host_init will fail. > > If the link is brought up in BIOS dw_pcie_setup_rc should not > > be called. > > This patch rework dw_pcie_host_init() so that, if num-lanes is > > not specified, it sets pp->lanes = 0. If later on dw_pcie_setup_rc > > is called and pp->num_lanes is not set to a valid value, > > dw_pcie_setup_rc will send an error message and return. > > Which systems don't call dw_pcie_setup_rc()? I don't have time for an > exhaustive search, but it looks like most or all designware drivers do > call > dw_pcie_setup_rc(), so if any left out num-lanes, they would report an > error. All of them currently call dw_pcie_setup_rc(), however the call is not needed if the link-up is done in BIOS. For instance if you look at exynos_pcie_establish_link(), you see that it will first check if the link is already up; if so the function will return as the BIOS has already brought up the link and dw_pcie_setup_rc is not called in this case. Therefore num-lanes is not mandatory for a platform with link-up setup in BIOS. > > > This patch is a follow-up of > > http://www.spinics.net/lists/linux-pci/msg44394.html > > > > Signed-off-by: Gabriele Paoloni <gabriele.paoloni@xxxxxxxxxx> > > --- > > Documentation/devicetree/bindings/pci/designware-pcie.txt | 3 ++- > > drivers/pci/host/pcie-designware.c | 10 > ++++++---- > > 2 files changed, 8 insertions(+), 5 deletions(-) > > > > diff --git a/Documentation/devicetree/bindings/pci/designware- > pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt > > index 9f4faa8..0036ab3 100644 > > --- a/Documentation/devicetree/bindings/pci/designware-pcie.txt > > +++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt > > @@ -14,7 +14,6 @@ Required properties: > > - interrupt-map-mask and interrupt-map: standard PCI properties > > to define the mapping of the PCIe interface to interrupt > > numbers. > > -- num-lanes: number of lanes to use > > - clocks: Must contain an entry for each entry in clock-names. > > See ../clocks/clock-bindings.txt for details. > > - clock-names: Must include the following entries: > > @@ -22,6 +21,8 @@ Required properties: > > - "pcie_bus" > > > > Optional properties: > > +- num-lanes: number of lanes to use (this property should be > specified unless > > + the link is brought already up in BIOS) > > - reset-gpio: gpio pin number of power good signal > > - bus-range: PCI bus numbers covered (it is recommended for new > devicetrees to > > specify this property, to keep backwards compatibility a range of > 0x00-0xff > > diff --git a/drivers/pci/host/pcie-designware.c > b/drivers/pci/host/pcie-designware.c > > index 52aa6e3..b0b40ed 100644 > > --- a/drivers/pci/host/pcie-designware.c > > +++ b/drivers/pci/host/pcie-designware.c > > @@ -482,10 +482,9 @@ int dw_pcie_host_init(struct pcie_port *pp) > > } > > } > > > > - if (of_property_read_u32(np, "num-lanes", &pp->lanes)) { > > - dev_err(pp->dev, "Failed to parse the number of lanes\n"); > > - return -EINVAL; > > - } > > + ret = of_property_read_u32(np, "num-lanes", &pp->lanes); > > + if (ret) > > + pp->lanes = 0; > > > > if (IS_ENABLED(CONFIG_PCI_MSI)) { > > if (!pp->ops->msi_host_init) { > > @@ -764,6 +763,9 @@ void dw_pcie_setup_rc(struct pcie_port *pp) > > case 8: > > val |= PORT_LINK_MODE_8_LANES; > > break; > > + default: > > + dev_err(pp->dev, "invalid pp->lanes value\n"); > > Maybe print the invalid value here, labelled "num-lanes"? Agreed, will fix in v2 > > Bjorn > > > + return; > > } > > dw_pcie_writel_rc(pp, val, PCIE_PORT_LINK_CONTROL); > > > > -- > > 1.9.1 > > > > -- > > 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 -- 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
