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

[Gabriele Paoloni]

Hi Liviu

> -----Original Message-----
> From: liviu.dudau@xxxxxxx [mailto:liviu.dudau@xxxxxxx]
> Sent: 09 November 2016 16:51
> To: Gabriele Paoloni
> Cc: Yuanzhichang; catalin.marinas@xxxxxxx; will.deacon@xxxxxxx;
> robh+dt@xxxxxxxxxx; bhelgaas@xxxxxxxxxx; mark.rutland@xxxxxxx;
> olof@xxxxxxxxx; arnd@xxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> lorenzo.pieralisi@xxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Linuxarm;
> devicetree@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux-
> serial@xxxxxxxxxxxxxxx; minyard@xxxxxxx; benh@xxxxxxxxxxxxxxxxxxx;
> zourongrong@xxxxxxxxx; John Garry; zhichang.yuan02@xxxxxxxxx;
> kantyzc@xxxxxxx; xuwei (O)
> Subject: Re: [PATCH V5 2/3] ARM64 LPC: Add missing range exception for
> special ISA
> 
> 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()

Maybe I am missing something...could you make an exampleof a case
where an IO toke doesnât come from pci_address_to_pio() ?

Thanks

Gab


> 
> 	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
> > > >
> > > > --
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> info.html
> 
> --
> ====================
> | I would like to |
> | fix the world,  |
> | but they're not |
> | giving me the   |
>  \ source code!  /
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