Re: [PATCH v8 4/9] pci: OF: Fix the conversion of IO ranges into IO resources.

[Rob Herring]

On Tue, Jul 1, 2014 at 1:43 PM, Liviu Dudau <Liviu.Dudau@xxxxxxx> 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.

I don't think this change is right. There are 2 resources: the PCI bus
addresses and cpu addresses. This function deals with the cpu
addresses. Returning pci addresses for i/o and cpu addresses for
memory is going to be error prone. We probably need both cpu and pci
resources exposed to host controllers.

Making the new function only deal with i/o bus resources and naming it
of_pci_range_to_io_resource would be better.

Rob

> 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 message.
>
> Signed-off-by: Liviu Dudau <Liviu.Dudau@xxxxxxx>
> Tested-by: Tanmay Inamdar <tinamdar@xxxxxxx>
> ---
>  drivers/of/address.c       | 47 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/of_address.h | 13 ++-----------
>  2 files changed, 49 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 1345733..cbbaed2 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -872,3 +872,50 @@ 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 ac4aac4..33c0420 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);
> --
> 2.0.0
>
>
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