linux-kernel - Re: [PATCH 05/10] PCI: layerscape: Modify the way of getting capability with different PEX

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Message-ID: <20190816102545.GC14111@e119886-lin.cambridge.arm.com>
Date:   Fri, 16 Aug 2019 11:25:46 +0100
From:   Andrew Murray <andrew.murray@....com>
To:     Xiaowei Bao <xiaowei.bao@....com>
Cc:     "jingoohan1@...il.com" <jingoohan1@...il.com>,
        "gustavo.pimentel@...opsys.com" <gustavo.pimentel@...opsys.com>,
        "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        Leo Li <leoyang.li@....com>, "kishon@...com" <kishon@...com>,
        "lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
        "arnd@...db.de" <arnd@...db.de>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "M.h. Lian" <minghuan.lian@....com>,
        Mingkai Hu <mingkai.hu@....com>, Roy Zang <roy.zang@....com>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "Z.q. Hou" <zhiqiang.hou@....com>
Subject: Re: [PATCH 05/10] PCI: layerscape: Modify the way of getting
 capability with different PEX

On Fri, Aug 16, 2019 at 03:00:00AM +0000, Xiaowei Bao wrote:
> 
> 
> > -----Original Message-----
> > From: Andrew Murray <andrew.murray@....com>
> > Sent: 2019年8月15日 20:51
> > To: Xiaowei Bao <xiaowei.bao@....com>
> > Cc: jingoohan1@...il.com; gustavo.pimentel@...opsys.com;
> > bhelgaas@...gle.com; robh+dt@...nel.org; mark.rutland@....com;
> > shawnguo@...nel.org; Leo Li <leoyang.li@....com>; kishon@...com;
> > lorenzo.pieralisi@....com; arnd@...db.de; gregkh@...uxfoundation.org;
> > M.h. Lian <minghuan.lian@....com>; Mingkai Hu <mingkai.hu@....com>;
> > Roy Zang <roy.zang@....com>; linux-pci@...r.kernel.org;
> > devicetree@...r.kernel.org; linux-kernel@...r.kernel.org;
> > linux-arm-kernel@...ts.infradead.org; linuxppc-dev@...ts.ozlabs.org
> > Subject: Re: [PATCH 05/10] PCI: layerscape: Modify the way of getting
> > capability with different PEX
> > 
> > On Thu, Aug 15, 2019 at 04:37:11PM +0800, Xiaowei Bao wrote:
> > > The different PCIe controller in one board may be have different
> > > capability of MSI or MSIX, so change the way of getting the MSI
> > > capability, make it more flexible.
> > >
> > > Signed-off-by: Xiaowei Bao <xiaowei.bao@....com>
> > > ---
> > >  drivers/pci/controller/dwc/pci-layerscape-ep.c | 28
> > > +++++++++++++++++++-------
> > >  1 file changed, 21 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/drivers/pci/controller/dwc/pci-layerscape-ep.c
> > > b/drivers/pci/controller/dwc/pci-layerscape-ep.c
> > > index be61d96..9404ca0 100644
> > > --- a/drivers/pci/controller/dwc/pci-layerscape-ep.c
> > > +++ b/drivers/pci/controller/dwc/pci-layerscape-ep.c
> > > @@ -22,6 +22,7 @@
> > >
> > >  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)
> > > @@ -40,25 +41,26 @@ static const struct of_device_id
> > ls_pcie_ep_of_match[] = {
> > >  	{ },
> > >  };
> > >
> > > -static const struct pci_epc_features ls_pcie_epc_features = {
> > > -	.linkup_notifier = false,
> > > -	.msi_capable = true,
> > > -	.msix_capable = false,
> > > -};
> > > -
> > >  static const struct pci_epc_features*  ls_pcie_ep_get_features(struct
> > > dw_pcie_ep *ep)  {
> > > -	return &ls_pcie_epc_features;
> > > +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > > +	struct ls_pcie_ep *pcie = to_ls_pcie_ep(pci);
> > > +
> > > +	return pcie->ls_epc;
> > >  }
> > >
> > >  static void ls_pcie_ep_init(struct dw_pcie_ep *ep)  {
> > >  	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > > +	struct ls_pcie_ep *pcie = to_ls_pcie_ep(pci);
> > >  	enum pci_barno bar;
> > >
> > >  	for (bar = BAR_0; bar <= BAR_5; bar++)
> > >  		dw_pcie_ep_reset_bar(pci, bar);
> > > +
> > > +	pcie->ls_epc->msi_capable = ep->msi_cap ? true : false;
> > > +	pcie->ls_epc->msix_capable = ep->msix_cap ? true : false;
> > >  }
> > >
> > >  static int ls_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no, @@
> > > -118,6 +120,7 @@ static int __init ls_pcie_ep_probe(struct platform_device
> > *pdev)
> > >  	struct device *dev = &pdev->dev;
> > >  	struct dw_pcie *pci;
> > >  	struct ls_pcie_ep *pcie;
> > > +	struct pci_epc_features *ls_epc;
> > >  	struct resource *dbi_base;
> > >  	int ret;
> > >
> > > @@ -129,6 +132,10 @@ static int __init ls_pcie_ep_probe(struct
> > platform_device *pdev)
> > >  	if (!pci)
> > >  		return -ENOMEM;
> > >
> > > +	ls_epc = devm_kzalloc(dev, sizeof(*ls_epc), GFP_KERNEL);
> > > +	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))
> > > @@ -139,6 +146,13 @@ static int __init ls_pcie_ep_probe(struct
> > platform_device *pdev)
> > >  	pci->ops = &ls_pcie_ep_ops;
> > >  	pcie->pci = pci;
> > >
> > > +	ls_epc->linkup_notifier = false,
> > > +	ls_epc->msi_capable = true,
> > > +	ls_epc->msix_capable = true,
> > 
> > As [msi,msix]_capable is shortly set from ls_pcie_ep_init - is there any reason
> > to set them here (to potentially incorrect values)?
> This is a INIT value, maybe false is better for msi_capable and msix_capable, 
> of course, we don't need to set it.

ls_epc is kzalloc'd and so all zeros, so you get false for free. I think you
can remove these two lines (or all three if you don't care that linkup_notifier
isn't explicitly set).

Thanks,

Andrew Murray

> > 
> > Thanks,
> > 
> > Andrew Murray
> > 
> > > +	ls_epc->bar_fixed_64bit = (1 << BAR_2) | (1 << BAR_4),
> > > +
> > > +	pcie->ls_epc = ls_epc;
> > > +
> > >  	platform_set_drvdata(pdev, pcie);
> > >
> > >  	ret = ls_add_pcie_ep(pcie, pdev);
> > > --
> > > 2.9.5
> > >