On Mon, Aug 26, 2019 at 09:49:35AM +0000, Xiaowei Bao wrote:
>
>
> > -----Original Message-----
> > From: Andrew Murray <andrew.murray@xxxxxxx>
> > Sent: 2019年8月23日 22:28
> > To: Xiaowei Bao <xiaowei.bao@xxxxxxx>
> > Cc: bhelgaas@xxxxxxxxxx; robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx;
> > shawnguo@xxxxxxxxxx; Leo Li <leoyang.li@xxxxxxx>; kishon@xxxxxx;
> > lorenzo.pieralisi@xxxxxx; arnd@xxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; M.h.
> > Lian <minghuan.lian@xxxxxxx>; Mingkai Hu <mingkai.hu@xxxxxxx>; Roy
> > Zang <roy.zang@xxxxxxx>; jingoohan1@xxxxxxxxx;
> > gustavo.pimentel@xxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx;
> > devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx
> > Subject: Re: [PATCH v2 08/10] PCI: layerscape: Add EP mode support for
> > ls1088a and ls2088a
> >
> > On Thu, Aug 22, 2019 at 07:22:40PM +0800, Xiaowei Bao wrote:
> > > Add PCIe EP mode support for ls1088a and ls2088a, there are some
> > > difference between LS1 and LS2 platform, so refactor the code of the
> > > EP driver.
> > >
> > > Signed-off-by: Xiaowei Bao <xiaowei.bao@xxxxxxx>
> > > ---
> > > v2:
> > > - New mechanism for layerscape EP driver.
> >
> > Was there a v1 of this patch?
> >
> > >
> > > drivers/pci/controller/dwc/pci-layerscape-ep.c | 76
> > > ++++++++++++++++++++------
> > > 1 file changed, 58 insertions(+), 18 deletions(-)
> > >
> > > diff --git a/drivers/pci/controller/dwc/pci-layerscape-ep.c
> > > b/drivers/pci/controller/dwc/pci-layerscape-ep.c
> > > index 7ca5fe8..2a66f07 100644
> > > --- a/drivers/pci/controller/dwc/pci-layerscape-ep.c
> > > +++ b/drivers/pci/controller/dwc/pci-layerscape-ep.c
> > > @@ -20,27 +20,29 @@
> > >
> > > #define PCIE_DBI2_OFFSET 0x1000 /* DBI2 base address*/
> > >
> > > -struct ls_pcie_ep {
> > > - struct dw_pcie *pci;
> > > - struct pci_epc_features *ls_epc;
> > > +#define to_ls_pcie_ep(x) dev_get_drvdata((x)->dev)
> > > +
> > > +struct ls_pcie_ep_drvdata {
> > > + u32 func_offset;
> > > + const struct dw_pcie_ep_ops *ops;
> > > + const struct dw_pcie_ops *dw_pcie_ops;
> > > };
> > >
> > > -#define to_ls_pcie_ep(x) dev_get_drvdata((x)->dev)
> > > +struct ls_pcie_ep {
> > > + struct dw_pcie *pci;
> > > + struct pci_epc_features *ls_epc;
> > > + const struct ls_pcie_ep_drvdata *drvdata; };
> > >
> > > static int ls_pcie_establish_link(struct dw_pcie *pci) {
> > > return 0;
> > > }
> > >
> > > -static const struct dw_pcie_ops ls_pcie_ep_ops = {
> > > +static const struct dw_pcie_ops dw_ls_pcie_ep_ops = {
> > > .start_link = ls_pcie_establish_link, };
> > >
> > > -static const struct of_device_id ls_pcie_ep_of_match[] = {
> > > - { .compatible = "fsl,ls-pcie-ep",},
> > > - { },
> > > -};
> > > -
> > > static const struct pci_epc_features* ls_pcie_ep_get_features(struct
> > > dw_pcie_ep *ep) { @@ -82,10 +84,44 @@ static int
> > > ls_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
> > > }
> > > }
> > >
> > > -static const struct dw_pcie_ep_ops pcie_ep_ops = {
> > > +static unsigned int ls_pcie_ep_func_conf_select(struct dw_pcie_ep *ep,
> > > + u8 func_no)
> > > +{
> > > + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > > + struct ls_pcie_ep *pcie = to_ls_pcie_ep(pci);
> > > + u8 header_type;
> > > +
> > > + header_type = ioread8(pci->dbi_base + PCI_HEADER_TYPE);
> > > +
> > > + if (header_type & (1 << 7))
> > > + return pcie->drvdata->func_offset * func_no;
> > > + else
> > > + return 0;
> >
> > It looks like there isn't a PCI define for multi function, the nearest I could find
> > was PCI_HEADER_TYPE_MULTIDEVICE in hotplug/ibmphp.h. A comment
> > above the test might be helpful to explain the test.
>
> OK, I will add a comment above this code.
>
> >
> > As the ls_pcie_ep_drvdata structures are static, the unset .func_offset will be
> > initialised to 0, so you could just drop the test above.
>
> Due to the different PCIe controller have different property, e.g. PCIe controller1 support
> multiple function feature, but PCIe controller2 don't support this feature, so I need to check
> which controller support it and return the correct offset value, but each board only have one
> ls_pcie_ep_drvdata, ^_^.
Yes but if they don't support the feature then func_offset will be 0.
>
> >
> > However something to the effect of the following may help spot
> > misconfiguration:
> >
> > WARN_ON(func_no && !pcie->drvdata->func_offset); return
> > pcie->drvdata->func_offset * func_no;
> >
> > The WARN is probably quite useful as if you are attempting to use non-zero
> > functions and func_offset isn't set - then things may appear to work normally
> > but actually will break horribly.
>
> As discussion before, I think the func_offset should not depends on the function
> number, even if other platforms of NXP may be use write registers way to access
> the different function config space.
I agree that func_offset is an optional parameter. But if you are attempting
to determine the offset of a function and you are given a non-zero function
number - then something has gone wrong if func_offset is 0.
Thanks,
Andrew Murray
>
> I have added the comments above the code, as follow, do you have any advice?
> +static unsigned int ls_pcie_ep_func_conf_select(struct dw_pcie_ep *ep,
> + u8 func_no)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> + struct ls_pcie_ep *pcie = to_ls_pcie_ep(pci);
> + u8 header_type;
> +
> + header_type = ioread8(pci->dbi_base + PCI_HEADER_TYPE);
> +
> + /*
> + * Read the Header Type register of config space to check
> + * whether this PCI device support the multiple function.
> + */
> + if (header_type & (1 << 7))
> + return pcie->drvdata->func_offset * func_no;
> +
> + return 0;
> +}
>
> Thanks a lot for your detail comments.
>
> >
> > Thanks,
> >
> > Andrew Murray
> >
> > > +}
> > > +
> > > +static const struct dw_pcie_ep_ops ls_pcie_ep_ops = {
> > > .ep_init = ls_pcie_ep_init,
> > > .raise_irq = ls_pcie_ep_raise_irq,
> > > .get_features = ls_pcie_ep_get_features,
> > > + .func_conf_select = ls_pcie_ep_func_conf_select, };
> > > +
> > > +static const struct ls_pcie_ep_drvdata ls1_ep_drvdata = {
> > > + .ops = &ls_pcie_ep_ops,
> > > + .dw_pcie_ops = &dw_ls_pcie_ep_ops,
> > > +};
> > > +
> > > +static const struct ls_pcie_ep_drvdata ls2_ep_drvdata = {
> > > + .func_offset = 0x20000,
> > > + .ops = &ls_pcie_ep_ops,
> > > + .dw_pcie_ops = &dw_ls_pcie_ep_ops,
> > > +};
> > > +
> > > +static const struct of_device_id ls_pcie_ep_of_match[] = {
> > > + { .compatible = "fsl,ls1046a-pcie-ep", .data = &ls1_ep_drvdata },
> > > + { .compatible = "fsl,ls1088a-pcie-ep", .data = &ls2_ep_drvdata },
> > > + { .compatible = "fsl,ls2088a-pcie-ep", .data = &ls2_ep_drvdata },
> > > + { },
> > > };
> > >
> > > static int __init ls_add_pcie_ep(struct ls_pcie_ep *pcie, @@ -98,7
> > > +134,7 @@ static int __init ls_add_pcie_ep(struct ls_pcie_ep *pcie,
> > > int ret;
> > >
> > > ep = &pci->ep;
> > > - ep->ops = &pcie_ep_ops;
> > > + ep->ops = pcie->drvdata->ops;
> > >
> > > res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > "addr_space");
> > > if (!res)
> > > @@ -137,14 +173,11 @@ static int __init ls_pcie_ep_probe(struct
> > platform_device *pdev)
> > > if (!ls_epc)
> > > return -ENOMEM;
> > >
> > > - dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > "regs");
> > > - pci->dbi_base = devm_pci_remap_cfg_resource(dev, dbi_base);
> > > - if (IS_ERR(pci->dbi_base))
> > > - return PTR_ERR(pci->dbi_base);
> > > + pcie->drvdata = of_device_get_match_data(dev);
> > >
> > > - pci->dbi_base2 = pci->dbi_base + PCIE_DBI2_OFFSET;
> > > pci->dev = dev;
> > > - pci->ops = &ls_pcie_ep_ops;
> > > + pci->ops = pcie->drvdata->dw_pcie_ops;
> > > +
> > > pcie->pci = pci;
> > >
> > > ls_epc->linkup_notifier = false,
> > > @@ -152,6 +185,13 @@ static int __init ls_pcie_ep_probe(struct
> > > platform_device *pdev)
> > >
> > > pcie->ls_epc = ls_epc;
> > >
> > > + dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > "regs");
> > > + pci->dbi_base = devm_pci_remap_cfg_resource(dev, dbi_base);
> > > + if (IS_ERR(pci->dbi_base))
> > > + return PTR_ERR(pci->dbi_base);
> > > +
> > > + pci->dbi_base2 = pci->dbi_base + PCIE_DBI2_OFFSET;
> > > +
> > > platform_set_drvdata(pdev, pcie);
> > >
> > > ret = ls_add_pcie_ep(pcie, pdev);
> > > --
> > > 2.9.5
> > >
