Russell,
As the arch/arm/kernel/ maintainer, what is your position regarding the
below patch?
Thanks for your review,
Thomas
On Mon, 28 Jan 2013 19:56:14 +0100, Thomas Petazzoni wrote:
> The PCI specifications says that an I/O region must be aligned on a 4
> KB boundary, and a memory region aligned on a 1 MB boundary.
>
> However, the Marvell PCIe interfaces rely on address decoding windows
> (which allow to associate a range of physical addresses with a given
> device). For PCIe memory windows, those windows are defined with a 1
> MB granularity (which matches the PCI specs), but PCIe I/O windows can
> only be defined with a 64 KB granularity, so they have to be 64 KB
> aligned. We therefore need to tell the PCI core about this special
> alignement requirement.
>
> The PCI core already calls pcibios_align_resource() in the ARM PCI
> core, specifically for such purposes. So this patch extends the ARM
> PCI core so that it calls a ->align_resource() hook registered by the
> PCI driver, exactly like the existing ->map_irq() and ->swizzle()
> hooks.
>
> A particular PCI driver can register a align_resource() hook, and do
> its own specific alignement, depending on the specific constraints of
> the underlying hardware.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
> ---
> arch/arm/include/asm/mach/pci.h | 11 +++++++++++
> arch/arm/kernel/bios32.c | 6 ++++++
> 2 files changed, 17 insertions(+)
>
> diff --git a/arch/arm/include/asm/mach/pci.h b/arch/arm/include/asm/mach/pci.h
> index 5cf2e97..7d2c3c8 100644
> --- a/arch/arm/include/asm/mach/pci.h
> +++ b/arch/arm/include/asm/mach/pci.h
> @@ -30,6 +30,11 @@ struct hw_pci {
> void (*postinit)(void);
> u8 (*swizzle)(struct pci_dev *dev, u8 *pin);
> int (*map_irq)(const struct pci_dev *dev, u8 slot, u8 pin);
> + resource_size_t (*align_resource)(struct pci_dev *dev,
> + const struct resource *res,
> + resource_size_t start,
> + resource_size_t size,
> + resource_size_t align);
> };
>
> /*
> @@ -51,6 +56,12 @@ struct pci_sys_data {
> u8 (*swizzle)(struct pci_dev *, u8 *);
> /* IRQ mapping */
> int (*map_irq)(const struct pci_dev *, u8, u8);
> + /* Resource alignement requirements */
> + resource_size_t (*align_resource)(struct pci_dev *dev,
> + const struct resource *res,
> + resource_size_t start,
> + resource_size_t size,
> + resource_size_t align);
> void *private_data; /* platform controller private data */
> };
>
> diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
> index 5401645..be2e6c9 100644
> --- a/arch/arm/kernel/bios32.c
> +++ b/arch/arm/kernel/bios32.c
> @@ -462,6 +462,7 @@ static void __init pcibios_init_hw(struct hw_pci *hw, struct list_head *head)
> sys->busnr = busnr;
> sys->swizzle = hw->swizzle;
> sys->map_irq = hw->map_irq;
> + sys->align_resource = hw->align_resource;
> INIT_LIST_HEAD(&sys->resources);
>
> if (hw->private_data)
> @@ -574,6 +575,8 @@ char * __init pcibios_setup(char *str)
> resource_size_t pcibios_align_resource(void *data, const struct resource *res,
> resource_size_t size, resource_size_t align)
> {
> + struct pci_dev *dev = data;
> + struct pci_sys_data *sys = dev->sysdata;
> resource_size_t start = res->start;
>
> if (res->flags & IORESOURCE_IO && start & 0x300)
> @@ -581,6 +584,9 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
>
> start = (start + align - 1) & ~(align - 1);
>
> + if (sys->align_resource)
> + return sys->align_resource(dev, res, start, size, align);
> +
> return start;
> }
>
--
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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