| Message ID | 20190812042435.25102-3-Zhiqiang.Hou@nxp.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | Layerscape: Remove num-lanes property from PCIe nodes | expand |
On Mon, Aug 12, 2019 at 04:22:22AM +0000, Z.q. Hou wrote: > From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com> > > The num-lanes is optional, so probably it isn't added > on some platforms. The subsequent programming is base > on the num-lanes, hence return when it is not found. > > Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com> > --- > drivers/pci/controller/dwc/pcie-designware.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c > index 7d25102c304c..0a89bfd1636e 100644 > --- a/drivers/pci/controller/dwc/pcie-designware.c > +++ b/drivers/pci/controller/dwc/pcie-designware.c > @@ -423,8 +423,10 @@ void dw_pcie_setup(struct dw_pcie *pci) > > > ret = of_property_read_u32(np, "num-lanes", &lanes); > - if (ret) > - lanes = 0; > + if (ret) { > + dev_dbg(pci->dev, "property num-lanes isn't found\n"); > + return; > + } The existing code would assign a value of 0 to lanes when num-lanes isn't specified, however this value isn't supported by the following switch statement - thus we'd also print an error and return. Therefore the only and subtle effect effect of this patch is to change a dev_err to a dev_dbg when num-lanes isn't specified and avoid a read of PCIE_PORT_LINK_CONTROL. Given that num-lanes is described as optional this makes perfect sense. Though the commit message/hunk does give the apperance that this provides a more functional change. Anyway: Reviewed-by: Andrew Murray <andrew.murray@arm.com> > > /* Set the number of lanes */ > val = dw_pcie_readl_dbi(pci, PCIE_PORT_LINK_CONTROL); > -- > 2.17.1 >
Hi Andrew, Thanks a lot for your review! B.R, Zhiqiang > -----Original Message----- > From: Andrew Murray <andrew.murray@arm.com> > Sent: 2019年8月12日 16:34 > To: Z.q. Hou <zhiqiang.hou@nxp.com> > Cc: linux-pci@vger.kernel.org; devicetree@vger.kernel.org; > linux-kernel@vger.kernel.org; gustavo.pimentel@synopsys.com; > jingoohan1@gmail.com; bhelgaas@google.com; robh+dt@kernel.org; > mark.rutland@arm.com; shawnguo@kernel.org; Leo Li > <leoyang.li@nxp.com>; lorenzo.pieralisi@arm.com; M.h. Lian > <minghuan.lian@nxp.com> > Subject: Re: [PATCH 2/4] PCI: dwc: Return directly when num-lanes is not > found > > On Mon, Aug 12, 2019 at 04:22:22AM +0000, Z.q. Hou wrote: > > From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com> > > > > The num-lanes is optional, so probably it isn't added on some > > platforms. The subsequent programming is base on the num-lanes, hence > > return when it is not found. > > > > Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com> > > --- > > drivers/pci/controller/dwc/pcie-designware.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c > > b/drivers/pci/controller/dwc/pcie-designware.c > > index 7d25102c304c..0a89bfd1636e 100644 > > --- a/drivers/pci/controller/dwc/pcie-designware.c > > +++ b/drivers/pci/controller/dwc/pcie-designware.c > > @@ -423,8 +423,10 @@ void dw_pcie_setup(struct dw_pcie *pci) > > > > > > ret = of_property_read_u32(np, "num-lanes", &lanes); > > - if (ret) > > - lanes = 0; > > + if (ret) { > > + dev_dbg(pci->dev, "property num-lanes isn't found\n"); > > + return; > > + } > > The existing code would assign a value of 0 to lanes when num-lanes isn't > specified, however this value isn't supported by the following switch > statement - thus we'd also print an error and return. > > Therefore the only and subtle effect effect of this patch is to change a > dev_err to a dev_dbg when num-lanes isn't specified and avoid a read of > PCIE_PORT_LINK_CONTROL. > > Given that num-lanes is described as optional this makes perfect sense. > Though the commit message/hunk does give the apperance that this > provides a more functional change. > > Anyway: > > Reviewed-by: Andrew Murray <andrew.murray@arm.com> > > > > > > /* Set the number of lanes */ > > val = dw_pcie_readl_dbi(pci, PCIE_PORT_LINK_CONTROL); > > -- > > 2.17.1 > >
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c index 7d25102c304c..0a89bfd1636e 100644 --- a/drivers/pci/controller/dwc/pcie-designware.c +++ b/drivers/pci/controller/dwc/pcie-designware.c @@ -423,8 +423,10 @@ void dw_pcie_setup(struct dw_pcie *pci) ret = of_property_read_u32(np, "num-lanes", &lanes); - if (ret) - lanes = 0; + if (ret) { + dev_dbg(pci->dev, "property num-lanes isn't found\n"); + return; + } /* Set the number of lanes */ val = dw_pcie_readl_dbi(pci, PCIE_PORT_LINK_CONTROL);