RE: [PATCH v3] fpga: dfl: check feature type before parse irq info

[Zhang, Tianfei]

> -----Original Message-----
> From: Wu, Hao <hao.wu@xxxxxxxxx>
> Sent: Thursday, March 17, 2022 9:48 AM
> To: Zhang, Tianfei <tianfei.zhang@xxxxxxxxx>; trix@xxxxxxxxxx;
> mdf@xxxxxxxxxx; Xu, Yilun <yilun.xu@xxxxxxxxx>; linux-fpga@xxxxxxxxxxxxxxx;
> linux-doc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: corbet@xxxxxxx
> Subject: RE: [PATCH v3] fpga: dfl: check feature type before parse irq info
> 
> > -----Original Message-----
> > From: Zhang, Tianfei <tianfei.zhang@xxxxxxxxx>
> > Sent: Friday, March 11, 2022 10:11 AM
> > To: Wu, Hao <hao.wu@xxxxxxxxx>; trix@xxxxxxxxxx; mdf@xxxxxxxxxx; Xu,
> > Yilun <yilun.xu@xxxxxxxxx>; linux-fpga@xxxxxxxxxxxxxxx;
> > linux-doc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> > Cc: corbet@xxxxxxx; Zhang, Tianfei <tianfei.zhang@xxxxxxxxx>
> > Subject: [PATCH v3] fpga: dfl: check feature type before parse irq
> > info
> >
> > The feature ID of "Port User Interrupt" and the "PMCI Subsystem" are
> > identical, 0x12, but one is for FME, other is for Port. It should
> > check the feature type While parsing the irq info in
> > parse_feature_irqs().
> >
> 
> What about this
> "Previously the feature IDs defined are unique, no matter which feature type.
> But currently we want to extend its usage to have a per-type feature ID space,
> so this patch adds feature type checking as well just before look into feature ID
> for different features which have irq info."

This commit looks good for me.

> 
> > ---
> > v3: Remove "Fixes" in commit log with Hao's comment, this is a
> >     extension not a bug fix.
> >
> > v2: add DFL Feature ID Registry in documentation.
> >
> > Signed-off-by: Tianfei Zhang <tianfei.zhang@xxxxxxxxx>
> 
> Move up your signed off line before these changelogs.
> 
> > ---
> >  Documentation/fpga/dfl.rst | 11 +++++++++++
> >  drivers/fpga/dfl.c         | 38 ++++++++++++++++++++++----------------
> >  2 files changed, 33 insertions(+), 16 deletions(-)
> >
> > diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst
> > index ef9eec71f6f3..14f342bb85e4 100644
> > --- a/Documentation/fpga/dfl.rst
> > +++ b/Documentation/fpga/dfl.rst
> > @@ -502,6 +502,17 @@ Developer only needs to provide a sub feature
> > driver with matched feature id.
> >  FME Partial Reconfiguration Sub Feature driver (see
> > drivers/fpga/dfl-fme-pr.c)  could be a reference.
> >
> > +Individual DFL drivers are bound DFL devices based on Feature Type
> > +and
> > Feature ID.
> > +The definition of Feature Type and Feature ID can be found:
> > +
> > +https://github.com/OPAE/linux-dfl-feature-id/blob/master/dfl-feature-
> > +ids.rst
> > +
> > +If you want to add a new feature ID for FPGA DFL feature device, we
> > recommend that
> 
> "recommend" or "must"

I think it is "must" if you want to use linux dfl driver.

> 
> > +use a pull request to reserve a feature ID for DFL. Here is the DFL
> > +Feature ID
> > +Registry:
> > +
> > +https://github.com/OPAE/linux-dfl-feature-id
> > +
> 
> Actually we don't have to put all details in kernel doc, and feature ID is used
> inside the device, it could be used in linux or windows or other OS.
> What about putting a README file in your repo to describe the detailed process,
> not in kernel doc. And we can just put a link to that README here.
> Then split this one into another patch? How do you think?

I think the process is that submit a patch/pull request to " https://github.com/OPAE/linux-dfl-feature-id"; for review if you have a new FeatureID.

> 
> >  Location of DFLs on a PCI Device
> >  ================================
> >  The original method for finding a DFL on a PCI device assumed the
> > start of the diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> > index 599bb21d86af..6bff39ff21a0 100644
> > --- a/drivers/fpga/dfl.c
> > +++ b/drivers/fpga/dfl.c
> > @@ -940,9 +940,12 @@ static int parse_feature_irqs(struct
> > build_feature_devs_info *binfo,  {
> >  	void __iomem *base = binfo->ioaddr + ofst;
> >  	unsigned int i, ibase, inr = 0;
> > +	enum dfl_id_type type;
> >  	int virq;
> >  	u64 v;
> >
> > +	type = feature_dev_id_type(binfo->feature_dev);
> > +
> >  	/*
> >  	 * Ideally DFL framework should only read info from DFL header, but
> >  	 * current version DFL only provides mmio resources information for
> > @@ -957,22 +960,25 @@ static int parse_feature_irqs(struct
> > build_feature_devs_info *binfo,
> >  	 * code will be added. But in order to be compatible to old version
> >  	 * DFL, the driver may still fall back to these quirks.
> >  	 */
> > -	switch (fid) {
> > -	case PORT_FEATURE_ID_UINT:
> > -		v = readq(base + PORT_UINT_CAP);
> > -		ibase = FIELD_GET(PORT_UINT_CAP_FST_VECT, v);
> > -		inr = FIELD_GET(PORT_UINT_CAP_INT_NUM, v);
> > -		break;
> > -	case PORT_FEATURE_ID_ERROR:
> > -		v = readq(base + PORT_ERROR_CAP);
> > -		ibase = FIELD_GET(PORT_ERROR_CAP_INT_VECT, v);
> > -		inr = FIELD_GET(PORT_ERROR_CAP_SUPP_INT, v);
> > -		break;
> > -	case FME_FEATURE_ID_GLOBAL_ERR:
> > -		v = readq(base + FME_ERROR_CAP);
> > -		ibase = FIELD_GET(FME_ERROR_CAP_INT_VECT, v);
> > -		inr = FIELD_GET(FME_ERROR_CAP_SUPP_INT, v);
> > -		break;
> > +	if (type == PORT_ID) {
> > +		switch (fid) {
> > +		case PORT_FEATURE_ID_UINT:
> > +			v = readq(base + PORT_UINT_CAP);
> > +			ibase = FIELD_GET(PORT_UINT_CAP_FST_VECT, v);
> > +			inr = FIELD_GET(PORT_UINT_CAP_INT_NUM, v);
> > +			break;
> > +		case PORT_FEATURE_ID_ERROR:
> > +			v = readq(base + PORT_ERROR_CAP);
> > +			ibase = FIELD_GET(PORT_ERROR_CAP_INT_VECT, v);
> > +			inr = FIELD_GET(PORT_ERROR_CAP_SUPP_INT, v);
> > +			break;
> > +		}
> > +	} else if (type == FME_ID) {
> > +		if (fid == FME_FEATURE_ID_GLOBAL_ERR) {
> > +			v = readq(base + FME_ERROR_CAP);
> > +			ibase = FIELD_GET(FME_ERROR_CAP_INT_VECT, v);
> > +			inr = FIELD_GET(FME_ERROR_CAP_SUPP_INT, v);
> > +		}
> >  	}
> >
> >  	if (!inr) {
> > --
> > 2.26.2