Re: [PATCH V2 22/23] pci, acpi: Match PCI config space accessors against platfrom specific quirks.

[Hanjun Guo]

On 12/22/2015 10:48 PM, Gabriele Paoloni wrote:
> Hi Tomasz
>
> > -----Original Message-----
> > From: linux-kernel-owner@xxxxxxxxxxxxxxx [mailto:linux-kernel-
> > owner@xxxxxxxxxxxxxxx] On Behalf Of Tomasz Nowicki
> > Sent: 22 December 2015 10:20
> > To: Gabriele Paoloni; bhelgaas@xxxxxxxxxx; arnd@xxxxxxxx;
> > will.deacon@xxxxxxx; catalin.marinas@xxxxxxx; rjw@xxxxxxxxxxxxx;
> > hanjun.guo@xxxxxxxxxx; Lorenzo.Pieralisi@xxxxxxx; okaya@xxxxxxxxxxxxxx;
> > jiang.liu@xxxxxxxxxxxxxxx; Stefano.Stabellini@xxxxxxxxxxxxx
> > Cc: robert.richter@xxxxxxxxxxxxxxxxxx; mw@xxxxxxxxxxxx;
> > Liviu.Dudau@xxxxxxx; ddaney@xxxxxxxxxxxxxxxxxx; tglx@xxxxxxxxxxxxx;
> > Wangyijing; Suravee.Suthikulpanit@xxxxxxx; msalter@xxxxxxxxxx; linux-
> > pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-
> > acpi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linaro-
> > acpi@xxxxxxxxxxxxxxxx; jchandra@xxxxxxxxxxxx; jcm@xxxxxxxxxx
> > Subject: Re: [PATCH V2 22/23] pci, acpi: Match PCI config space
> > accessors against platfrom specific quirks.
> >
> > On 21.12.2015 12:47, Gabriele Paoloni wrote:
> > > 2) In the quirk mechanism you proposed, I see that the callback
> > function
> > >      allows to do some preparation work for the host bridge. For
> > example in
> > >      Hisilicon hip05 case we would need to read some values from the
> > ACPI
> > >      table (see acpi_pci_root_hisi_add() function in
> > >      https://lkml.org/lkml/2015/12/3/426).
> > >      I am quite new to ACPI and I wonder if it is OK to add such
> > "Packages"
> > >      to the  PCI host bridge ACPI device...or maybe we need to declare
> > a new
> > >      one...?
> >
> > I may miss sth so please correct me in that case.
> >
> > https://lkml.org/lkml/2015/12/3/426 shows that you need special
> > handling for root->secondary.start bus number only, right? So how about
> > creating special MCFG region <rc-base:rc-base+rc-size> only for
> > <segment,bus>.
> > Like that:
> >
> > [0008]                       Base Address : <rc-base>
> > [0002]               Segment Group Number : <segment>
> > [0001]                   Start Bus Number : <root->secondary.start>
> > [0001]                     End Bus Number : <root->secondary.start>
> > [0004]                           Reserved : 00000000
> >
> >
> > static const struct dmi_system_id hisi_quirk[] = {
> > 	{
> > 		.ident = "HiSi...",
> > 		.matches = {
> > 			DMI_MATCH(<whatever you need to match your platform>),
> > 		},
> > 	},
> > 	{ }
> > };
> >
> > static struct pci_ops hisi_ecam_pci_ops = {
> > 	.map_bus = pci_mcfg_dev_base,
> > 	.read = hisi_pcie_cfg_read,
> > 	.write = hisi_pcie_cfg_write,
> > };
> >
> > DECLARE_ACPI_MCFG_FIXUP(hisi_quirk, &hisi_ecam_pci_ops,
> > 			<segment>, <bus>);
> >
> > With above code you can use your custom PCI config accessor only for
> > that region.
> >
> > Let me know if that is not enough for you.
>
> In principle I think it can work...
>
> Liudongdong, Guo Hanjun what is your opinion about?

Let me and Dongdong prepare a patch for Hip05 and then will
back to this discussion to see if we met some problems.

Thanks
Hanjun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/