linux-kernel - Re: [PATCH v4 2/3] dwc: PCI: intel: PCIe RC controller driver

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Message-ID: <20191104104718.GK9723@e119886-lin.cambridge.arm.com>
Date:   Mon, 4 Nov 2019 10:47:19 +0000
From:   Andrew Murray <andrew.murray@....com>
To:     Dilip Kota <eswara.kota@...ux.intel.com>
Cc:     jingoohan1@...il.com, gustavo.pimentel@...opsys.com,
        lorenzo.pieralisi@....com, robh@...nel.org,
        martin.blumenstingl@...glemail.com, linux-pci@...r.kernel.org,
        hch@...radead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, andriy.shevchenko@...el.com,
        cheol.yong.kim@...el.com, chuanhua.lei@...ux.intel.com,
        qi-ming.wu@...el.com
Subject: Re: [PATCH v4 2/3] dwc: PCI: intel: PCIe RC controller driver

On Mon, Nov 04, 2019 at 05:34:54PM +0800, Dilip Kota wrote:
> 
> On 11/1/2019 6:59 PM, Andrew Murray wrote:
> > On Tue, Oct 29, 2019 at 04:59:17PM +0800, Dilip Kota wrote:
> > > On 10/25/2019 5:09 PM, Andrew Murray wrote:
> > > > On Tue, Oct 22, 2019 at 05:04:21PM +0800, Dilip Kota wrote:
> > > > > Hi Andrew Murray,
> > > > > 
> > > > > On 10/21/2019 9:03 PM, Andrew Murray wrote:
> > > > > > On Mon, Oct 21, 2019 at 02:39:19PM +0800, Dilip Kota wrote:
> > > > > > > +
> > > > > > > +void dw_pcie_link_set_n_fts(struct dw_pcie *pci, u32 n_fts)
> > > > > > > +{
> > > > > > > +	u32 val;
> > > > > > > +
> > > > > > > +	val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
> > > > > > > +	val &= ~PORT_LOGIC_N_FTS;
> > > > > > > +	val |= n_fts;
> > > > > > > +	dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
> > > > > > > +}
> > > > > > I notice that pcie-artpec6.c (artpec6_pcie_set_nfts) also writes the FTS
> > > > > > and defines a bunch of macros to support this. It doesn't make sense to
> > > > > > duplicate this there. Therefore I think we need to update pcie-artpec6.c
> > > > > > to use this new function.
> > > > > I think we can do in a separate patch after these changes get merged and
> > > > > keep this patch series for intel PCIe driver and required changes in PCIe
> > > > > DesignWare framework.
> > > > The pcie-artpec6.c is a DWC driver as well. So I think we can do all this
> > > > together. This helps reduce the technical debt that will otherwise build up
> > > > in duplicated code.
> > > I agree with you to remove duplicated code, but at this point not sure what
> > > all drivers has defined FTS configuration.
> > > Reviewing all other DWC drivers and removing them can be done in one single
> > > separate patch.
> > I'm not asking to set up an FTS configuration for all DWC drivers, but instead
> > to move this helper function you've created to somewhere like pcie-designware.c
> > and call it from this driver and pcie-artpec6.c.
> What i mean is, we need to check how many of the current DWC drivers are
> configuring the FTS
> and call the helper function.
> Today i have grep all the DWC based drivers and i see pcie-artpec6.c is the
> only driver doing FTS configuration.
> 
> I will add the helper function call in pcie-artpec6.c in the next patch
> version.

Thanks that's very much appreciated.

Thanks,

Andrew Murray

> 
> 
> Regards,
> Dilip
> 
> 
> > 
> > Thanks,
> > 
> > Andrew Murray
> > 
> > > Regards,
> > > Dilip