Re: [PATCH v9 04/12] PCI: OF: Fix the conversion of IO ranges into IO resources.

Liviu Dudau
2014-08-22T13:09:27Z

On Thu, Aug 21, 2014 at 11:08:48PM -0500, Rob Herring wrote:
> On Tue, Aug 12, 2014 at 11:25 AM, Liviu Dudau <Liviu.Dudau@arm.com> wrote:
> > The ranges property for a host bridge controller in DT describes
> > the mapping between the PCI bus address and the CPU physical address.
> > The resources framework however expects that the IO resources start
> > at a pseudo "port" address 0 (zero) and have a maximum size of IO_SPACE_LIMIT.
> > The conversion from pci ranges to resources failed to take that into account.
> >
> > In the process move the function into drivers/of/address.c as it now
> > depends on pci_address_to_pio() code and make it return an error code.
> >
> > Cc: Grant Likely <grant.likely@linaro.org>
> > Cc: Rob Herring <robh+dt@kernel.org>
>
> Humm, this says I'm cc'ed, but I'm not which defeats the point of
> recording the Cc's in the commit.

Appologies, I've screwed up my git send-email arguments.

>
> I still have the same concerns that this will break existing users.
> Are you sure integrator is the only platform affected?

microblaze and powerpc have their similar handcoded routine for parsing ranges
where they pre-compute the io_base and adjust the values again when registering
resources. I'm not absolutely sure they are not broken as I lack the appropriate
platforms to test (I've been asking for an FPGA engineer to build me a microblaze
image with all the bits included but haven't received anything yet and it is
possible Xilinx has now shifted their interests towards ARM + PCI as the ML605
board that I have seems to have been discontinued).

mips is doing the same thing and I believe is not affected, pci-host-generic.c
was adjusting the returned values afterwards so that will not be needed and Lorenzo
has a patch for the driver to adapt it to this series anyway.

pcie-designware.c also recalculates the io.start and io.end values, so that's fine
for now. The only ones that I believe are still affected are pci-tegra.c and
pcie-rcar.c for which I will need to provide a patch similar to integrator unless
the code gets converted to the new range parsing.

Best regards,
Liviu

>
> Rob
>
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
> > ---
> > drivers/of/address.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> > include/linux/of_address.h | 13 ++-----------
> > 2 files changed, 48 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/of/address.c b/drivers/of/address.c
> > index 4dab700..3735ac7 100644
> > --- a/drivers/of/address.c
> > +++ b/drivers/of/address.c
> > @@ -906,3 +906,49 @@ bool of_dma_is_coherent(struct device_node *np)
> > return false;
> > }
> > EXPORT_SYMBOL_GPL(of_dma_is_coherent);
> > +
> > +/*
> > + * of_pci_range_to_resource - Create a resource from an of_pci_range
> > + * @range: the PCI range that describes the resource
> > + * @np: device node where the range belongs to
> > + * @res: pointer to a valid resource that will be updated to
> > + * reflect the values contained in the range.
> > + *
> > + * Returns EINVAL if the range cannot be converted to resource.
> > + *
> > + * Note that if the range is an IO range, the resource will be converted
> > + * using pci_address_to_pio() which can fail if it is called too early or
> > + * if the range cannot be matched to any host bridge IO space (our case here).
> > + * To guard against that we try to register the IO range first.
> > + * If that fails we know that pci_address_to_pio() will do too.
> > + */
> > +int of_pci_range_to_resource(struct of_pci_range *range,
> > + struct device_node *np, struct resource *res)
> > +{
> > + int err;
> > + res->flags = range->flags;
> > + res->parent = res->child = res->sibling = NULL;
> > + res->name = np->full_name;
> > +
> > + if (res->flags & IORESOURCE_IO) {
> > + unsigned long port = -1;
> > + err = pci_register_io_range(range->cpu_addr, range->size);
> > + if (err)
> > + goto invalid_range;
> > + port = pci_address_to_pio(range->cpu_addr);
> > + if (port == (unsigned long)-1) {
> > + err = -EINVAL;
> > + goto invalid_range;
> > + }
> > + res->start = port;
> > + } else {
> > + res->start = range->cpu_addr;
> > + }
> > + res->end = res->start + range->size - 1;
> > + return 0;
> > +
> > +invalid_range:
> > + res->start = (resource_size_t)OF_BAD_ADDR;
> > + res->end = (resource_size_t)OF_BAD_ADDR;
> > + return err;
> > +}
> > diff --git a/include/linux/of_address.h b/include/linux/of_address.h
> > index 28e6836..6015f21 100644
> > --- a/include/linux/of_address.h
> > +++ b/include/linux/of_address.h
> > @@ -23,17 +23,8 @@ struct of_pci_range {
> > #define for_each_of_pci_range(parser, range) \
> > for (; of_pci_range_parser_one(parser, range);)
> >
> > -static inline void of_pci_range_to_resource(struct of_pci_range *range,
> > - struct device_node *np,
> > - struct resource *res)
> > -{
> > - res->flags = range->flags;
> > - res->start = range->cpu_addr;
> > - res->end = range->cpu_addr + range->size - 1;
> > - res->parent = res->child = res->sibling = NULL;
> > - res->name = np->full_name;
> > -}
> > -
> > +extern int of_pci_range_to_resource(struct of_pci_range *range,
> > + struct device_node *np, struct resource *res);
> > /* Translate a DMA address from device space to CPU space */
> > extern u64 of_translate_dma_address(struct device_node *dev,
> > const __be32 *in_addr);
> > --
> > 2.0.4
> >
> >
> > _______________________________________________
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> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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