Re: [PATCH v11 10/10] PCI: Introduce pci_remap_iospace() for remapping PCI I/O bus resources into CPU space

From: Rob Herring
Date: Fri Sep 19 2014 - 20:35:10 EST


On 09/17/2014 08:30 PM, Liviu Dudau wrote:
> Introduce a default implementation for remapping PCI bus I/O resources
> onto the CPU address space. Architectures with special needs may
> provide their own version, but most should be able to use this one.
>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Signed-off-by: Liviu Dudau <Liviu.Dudau@xxxxxxx>

One nit below, otherwise:

Reviewed-by: Rob Herring <robh@xxxxxxxxxx>

> ---
> drivers/pci/pci.c | 33 +++++++++++++++++++++++++++++++++
> include/asm-generic/pgtable.h | 4 ++++
> include/linux/pci.h | 3 +++
> 3 files changed, 40 insertions(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 2c9ac70..654b44c 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2704,6 +2704,39 @@ int pci_request_regions_exclusive(struct pci_dev *pdev, const char *res_name)
> }
> EXPORT_SYMBOL(pci_request_regions_exclusive);
>
> +/**
> + * pci_remap_iospace - Remap the memory mapped I/O space
> + * @res: Resource describing the I/O space
> + * @phys_addr: physical address where the range will be mapped.
> + *
> + * Remap the memory mapped I/O space described by the @res
> + * into the CPU physical address space. Only architectures
> + * that have memory mapped IO defined (and hence PCI_IOBASE)
> + * should call this function.
> + */
> +int __weak pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
> +{
> + int err = -ENODEV;
> +
> +#ifdef PCI_IOBASE
> + if (!(res->flags & IORESOURCE_IO))
> + return -EINVAL;
> +
> + if (res->end > IO_SPACE_LIMIT)
> + return -EINVAL;
> +
> + err = ioremap_page_range(res->start + (unsigned long)PCI_IOBASE,
> + res->end + 1 + (unsigned long)PCI_IOBASE,
> + phys_addr, pgprot_device(PAGE_KERNEL));
> +#else
> + /* this architecture does not have memory mapped I/O space,
> + so this function should never be called */
> + WARN_ON(1);

Printing what the comment says in the warning would be better than
making the user look-up why they got a warning.

Rob

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