[PATCH] Store PCIe controllers address in struct of_pci_range

[Gabriele Paoloni]

Hi Rob

Many Thanks for your review

> -----Original Message-----
> From: Rob Herring [mailto:robherring2 at gmail.com]
> Sent: Friday, July 10, 2015 8:56 PM
> To: Gabriele Paoloni
> Cc: Arnd Bergmann; Lorenzo Pieralisi; Wangzhou (B); Bjorn Helgaas; Rob
> Herring; james.morse at arm.com; Liviu Dudau; linux-pci at vger.kernel.org;
> linux-arm-kernel at lists.infradead.org; devicetree at vger.kernel.org;
> Yuanzhichang; Zhudacai; zhangjukuo; qiuzhenfa; Liguozhu (Kenneth)
> Subject: Re: [PATCH] Store PCIe controllers address in struct
> of_pci_range
> 
> On Fri, Jul 10, 2015 at 3:48 AM, Gabriele Paoloni
> <gabriele.paoloni at huawei.com> wrote:
> > From: gabriele paoloni <gabriele.paoloni at huawei.com>
> >
> > This patch is needed port PCIe designware to new DT parsing API
> > As discussed in
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2015-
> January/317743.html
> > in designware we have a problem as the PCI addresses in the PCIe
> controller
> > address space are required in order to perform correct HW operation.
> >
> > In order to solve this problem commit
> > f4c55c5a3f7f68c06cc559ed7af8b2d017cbb0a7 "PCI: designware:
> 
> Please abbreviate hashs to 12 characters.

Sure, will do.

> 
> > Program ATU with untranslated address" added code to read the PCIe
> > controller start address directly from the DT ranges.
> >
> > In the new DT parsing API of_pci_get_host_bridge_resources() hides
> the
> > DT parser from the host controller drivers, so it is not possible
> > for drivers to parse values directly from the DT.
> >
> > In http://www.spinics.net/lists/linux-pci/msg42540.html we already
> tried
> > to use the new DT parsing API but there is a bug (obviously) in
> setting
> > the <*>_mod_base addresses
> > Applying this patch we can easily set "<*>_mod_base = win-
> >__res.start"
> >
> > This patch adds a new field in "struct of_pci_range" to store the
> > pci controller start address; it fills the field in
> of_pci_range_parser_one();
> > in of_pci_get_host_bridge_resources() it retrieve the resource entry
> > after it is created and added to the resource list and uses
> > entry->__res.start to store the pci controller address
> >
> > the patch is based on 4.2-rc1
> >
> > Signed-off-by: Gabriele Paoloni <gabriele.paoloni at huawei.com>
> > ---
> >  drivers/of/address.c               | 1 +
> >  drivers/of/of_pci.c                | 4 ++++
> >  drivers/pci/host/pcie-designware.c | 9 +++------
> >  include/linux/of_address.h         | 1 +
> >  4 files changed, 9 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/of/address.c b/drivers/of/address.c
> > index 8bfda6a..52f9321 100644
> > --- a/drivers/of/address.c
> > +++ b/drivers/of/address.c
> > @@ -265,6 +265,7 @@ struct of_pci_range
> *of_pci_range_parser_one(struct of_pci_range_parser *parser,
> >         range->pci_addr = of_read_number(parser->range + 1, ns);
> >         range->cpu_addr = of_translate_address(parser->node,
> >                                 parser->range + na);
> > +       range->pci_ctrl_addr = of_read_number(parser->range + na, ns) ;
> 
> This is wrong as the correct size to read is not "ns", but the parent
> bus #size-cells value.

Ok I will replace "ns" with "of_n_size_cells(parser->node)" 

> 
> I think "bus_addr" would be a better name. It is not the PCI
> controller's address (i.e. what is in reg prop). No "pci" because it
> has nothing to do with PCI bus addresses.

Ok I will change the name 

> 
> In general, this seems fragile as the dt address ranges/translation
> may not align with the h/w ranges. For example, what if you have 2
> levels of translations and you happen to need it translated with just
> 1 level of translation. That said, I don't really have a better
> suggestion and I guess we can deal with that case if needed later.

Ok so, we'll leave it like this for now

> 
> >         range->size = of_read_number(parser->range + parser->pna + na,
> ns);
> >
> >         parser->range += parser->np;
> > diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
> > index 5751dc5..2ccc749 100644
> > --- a/drivers/of/of_pci.c
> > +++ b/drivers/of/of_pci.c
> > @@ -198,6 +198,7 @@ int of_pci_get_host_bridge_resources(struct
> device_node *dev,
> >
> >         pr_debug("Parsing ranges property...\n");
> >         for_each_of_pci_range(&parser, &range) {
> > +               struct resource_entry *entry;
> >                 /* Read next ranges element */
> >                 if ((range.flags & IORESOURCE_TYPE_BITS) ==
> IORESOURCE_IO)
> >                         snprintf(range_type, 4, " IO");
> > @@ -240,6 +241,9 @@ int of_pci_get_host_bridge_resources(struct
> device_node *dev,
> >                 }
> >
> >                 pci_add_resource_offset(resources, res, res->start -
> range.pci_addr);
> > +               entry = list_last_entry(resources, struct
> resource_entry, node);
> > +               /*we are using __res for storing the PCI controller
> address*/
> > +               entry->__res.start = range.pci_ctrl_addr;
> 
> You will use this in a follow-up patch? I'd like to see this just
> split into core changes and DW changes. This looks like you are making
> intermediate DW changes which will be removed in subsequent patches.
> 
> Rob