Re: [PATCH V5 2/3] ARM64 LPC: Add missing range exception for special ISA

liviu.dudau
2016-11-09T16:50:50Z

On Wed, Nov 09, 2016 at 04:16:17PM +0000, Gabriele Paoloni wrote:
> Hi Liviu
>
> Thanks for reviewing
>

[removed some irrelevant part of discussion, avoid crazy formatting]

> > > +/**
> > > + * addr_is_indirect_io - check whether the input taddr is for
> > indirectIO.
> > > + * @taddr: the io address to be checked.
> > > + *
> > > + * Returns 1 when taddr is in the range; otherwise return 0.
> > > + */
> > > +int addr_is_indirect_io(u64 taddr)
> > > +{
> > > + if (arm64_extio_ops->start > taddr || arm64_extio_ops->end <
> > taddr)
> >
> > start >= taddr ?
>
> Nope... if (taddr < arm64_extio_ops->start || taddr > arm64_extio_ops->end)
> then taddr is outside the range [start; end] and will return 0; otherwise
> it will return 1...

Oops, sorry, did not pay attention to the returned value. The check is
correct as it is, no need to change then.

>
> >
> > > + return 0;
> > > +
> > > + return 1;
> > > +}
> > >
> > > BUILD_EXTIO(b, u8)
> > >
> > > diff --git a/drivers/of/address.c b/drivers/of/address.c
> > > index 02b2903..cc2a05d 100644
> > > --- a/drivers/of/address.c
> > > +++ b/drivers/of/address.c
> > > @@ -479,6 +479,50 @@ static int of_empty_ranges_quirk(struct
> > device_node *np)
> > > return false;
> > > }
> > >
> > > +
> > > +/*
> > > + * of_isa_indirect_io - get the IO address from some isa reg
> > property value.
> > > + * For some isa/lpc devices, no ranges property in ancestor node.
> > > + * The device addresses are described directly in their regs
> > property.
> > > + * This fixup function will be called to get the IO address of
> > isa/lpc
> > > + * devices when the normal of_translation failed.
> > > + *
> > > + * @parent: points to the parent dts node;
> > > + * @bus: points to the of_bus which can be used to parse
> > address;
> > > + * @addr: the address from reg property;
> > > + * @na: the address cell counter of @addr;
> > > + * @presult: store the address paresed from @addr;
> > > + *
> > > + * return 1 when successfully get the I/O address;
> > > + * 0 will return for some failures.
> >
> > Bah, you are returning a signed int, why 0 for failure? Return a
> > negative value with
> > error codes. Otherwise change the return value into a bool.
>
> Yes we'll move to bool
>
> >
> > > + */
> > > +static int of_get_isa_indirect_io(struct device_node *parent,
> > > + struct of_bus *bus, __be32 *addr,
> > > + int na, u64 *presult)
> > > +{
> > > + unsigned int flags;
> > > + unsigned int rlen;
> > > +
> > > + /* whether support indirectIO */
> > > + if (!indirect_io_enabled())
> > > + return 0;
> > > +
> > > + if (!of_bus_isa_match(parent))
> > > + return 0;
> > > +
> > > + flags = bus->get_flags(addr);
> > > + if (!(flags & IORESOURCE_IO))
> > > + return 0;
> > > +
> > > + /* there is ranges property, apply the normal translation
> > directly. */
> >
> > s/there is ranges/if we have a 'ranges'/
>
> Thanks for spotting this
>
> >
> > > + if (of_get_property(parent, "ranges", &rlen))
> > > + return 0;
> > > +
> > > + *presult = of_read_number(addr + 1, na - 1);
> > > + /* this fixup is only valid for specific I/O range. */
> > > + return addr_is_indirect_io(*presult);
> > > +}
> > > +
> > > static int of_translate_one(struct device_node *parent, struct
> > of_bus *bus,
> > > struct of_bus *pbus, __be32 *addr,
> > > int na, int ns, int pna, const char *rprop)
> > > @@ -595,6 +639,15 @@ static u64 __of_translate_address(struct
> > device_node *dev,
> > > result = of_read_number(addr, na);
> > > break;
> > > }
> > > + /*
> > > + * For indirectIO device which has no ranges property, get
> > > + * the address from reg directly.
> > > + */
> > > + if (of_get_isa_indirect_io(dev, bus, addr, na, &result)) {
> > > + pr_debug("isa indirectIO matched(%s)..addr =
> > 0x%llx\n",
> > > + of_node_full_name(dev), result);
> > > + break;
> > > + }
> > >
> > > /* Get new parent bus and counts */
> > > pbus = of_match_bus(parent);
> > > @@ -688,8 +741,9 @@ static int __of_address_to_resource(struct
> > device_node *dev,
> > > if (taddr == OF_BAD_ADDR)
> > > return -EINVAL;
> > > memset(r, 0, sizeof(struct resource));
> > > - if (flags & IORESOURCE_IO) {
> > > + if (flags & IORESOURCE_IO && taddr >= PCIBIOS_MIN_IO) {
> > > unsigned long port;
> > > +
> > > port = pci_address_to_pio(taddr);
> > > if (port == (unsigned long)-1)
> > > return -EINVAL;
> > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > > index ba34907..1a08511 100644
> > > --- a/drivers/pci/pci.c
> > > +++ b/drivers/pci/pci.c
> > > @@ -3263,7 +3263,7 @@ int __weak pci_register_io_range(phys_addr_t
> > addr, resource_size_t size)
> > >
> > > #ifdef PCI_IOBASE
> > > struct io_range *range;
> > > - resource_size_t allocated_size = 0;
> > > + resource_size_t allocated_size = PCIBIOS_MIN_IO;
> > >
> > > /* check if the range hasn't been previously recorded */
> > > spin_lock(&io_range_lock);
> > > @@ -3312,7 +3312,7 @@ phys_addr_t pci_pio_to_address(unsigned long
> > pio)
> > >
> > > #ifdef PCI_IOBASE
> > > struct io_range *range;
> > > - resource_size_t allocated_size = 0;
> > > + resource_size_t allocated_size = PCIBIOS_MIN_IO;
> >
> > Have you checked that pci_pio_to_address still returns valid values
> > after this? I know that
> > you are trying to take into account PCIBIOS_MIN_IO limit when
> > allocating reserving the IO ranges,
> > but the values added in the io_range_list are still starting from zero,
> > no from PCIBIOS_MIN_IO,
>
> I think you're wrong here as in pci_address_to_pio we have:
> + resource_size_t offset = PCIBIOS_MIN_IO;
>
> This should be enough to guarantee that the PIOs start at
> PCIBIOS_MIN_IO...right?

I don't think you can guarantee that the pio value that gets passed into
pci_pio_to_address() always comes from a previously returned value by
pci_address_to_pio(). Maybe you can add a check in pci_pio_to_address()

if (pio < PCIBIOS_MIN_IO)
return address;

to avoid adding more checks in the list_for_each_entry() loop.

Best regards,
Liviu

>
>
> > so the calculation of the address in this function could return
> > negative values casted to pci_addr_t.
> >
> > Maybe you want to adjust the range->start value in
> > pci_register_io_range() as well to have it
> > offset by PCIBIOS_MIN_IO as well.
> >
> > Best regards,
> > Liviu
> >
> > >
> > > if (pio > IO_SPACE_LIMIT)
> > > return address;
> > > @@ -3335,7 +3335,7 @@ unsigned long __weak
> > pci_address_to_pio(phys_addr_t address)
> > > {
> > > #ifdef PCI_IOBASE
> > > struct io_range *res;
> > > - resource_size_t offset = 0;
> > > + resource_size_t offset = PCIBIOS_MIN_IO;
> > > unsigned long addr = -1;
> > >
> > > spin_lock(&io_range_lock);
> > > diff --git a/include/linux/of_address.h b/include/linux/of_address.h
> > > index 3786473..deec469 100644
> > > --- a/include/linux/of_address.h
> > > +++ b/include/linux/of_address.h
> > > @@ -24,6 +24,23 @@ struct of_pci_range {
> > > #define for_each_of_pci_range(parser, range) \
> > > for (; of_pci_range_parser_one(parser, range);)
> > >
> > > +
> > > +#ifndef indirect_io_enabled
> > > +#define indirect_io_enabled indirect_io_enabled
> > > +static inline bool indirect_io_enabled(void)
> > > +{
> > > + return false;
> > > +}
> > > +#endif
> > > +
> > > +#ifndef addr_is_indirect_io
> > > +#define addr_is_indirect_io addr_is_indirect_io
> > > +static inline int addr_is_indirect_io(u64 taddr)
> > > +{
> > > + return 0;
> > > +}
> > > +#endif
> > > +
> > > /* Translate a DMA address from device space to CPU space */
> > > extern u64 of_translate_dma_address(struct device_node *dev,
> > > const __be32 *in_addr);
> > > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > > index 0e49f70..7f6bbb6 100644
> > > --- a/include/linux/pci.h
> > > +++ b/include/linux/pci.h
> > > @@ -2130,4 +2130,12 @@ static inline bool pci_ari_enabled(struct
> > pci_bus *bus)
> > > /* provide the legacy pci_dma_* API */
> > > #include <linux/pci-dma-compat.h>
> > >
> > > +/*
> > > + * define this macro here to refrain from compilation error for some
> > > + * platforms. Please keep this macro at the end of this header file.
> > > + */
> > > +#ifndef PCIBIOS_MIN_IO
> > > +#define PCIBIOS_MIN_IO 0
> > > +#endif
> > > +
> > > #endif /* LINUX_PCI_H */
> > > --
> > > 1.9.1
> > >
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe linux-pci"
> > in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at http://vger.kernel.org/majordomo-info.html

--
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