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SubjectRe: [PATCH 9/16 v6] PCI: add boot option to align MMIO resources
Date
On Wednesday 22 October 2008 02:43:24 am Yu Zhao wrote:
> This patch adds boot option to align MMIO resource for a device.
> The alignment is a bigger value between the PAGE_SIZE and the
> resource size.

It looks like this forces alignment on PAGE_SIZE, not "a bigger
value between the PAGE_SIZE and the resource size." Can you
clarify the changelog to specify exactly what alignment this
option forces?

> The boot option can be used as:
> pci=align-mmio=0000:01:02.3
> '[0000:]01:02.3' is the domain, bus, device and function number
> of the device.

I think you also support using multiple "align-mmio=DDDD:BB:dd.f"
options separated by ";", but I had to read the code to figure that
out. Can you give an example of this in the changelog and the
kernel-parameters.txt patch?

Bjorn

> Cc: Alex Chiang <achiang@hp.com>
> Cc: Grant Grundler <grundler@parisc-linux.org>
> Cc: Greg KH <greg@kroah.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
> Cc: Matthew Wilcox <matthew@wil.cx>
> Cc: Randy Dunlap <randy.dunlap@oracle.com>
> Cc: Roland Dreier <rdreier@cisco.com>
> Signed-off-by: Yu Zhao <yu.zhao@intel.com>
>
> ---
> arch/x86/pci/common.c | 37 +++++++++++++++++++++++++++++++++++++
> drivers/pci/pci.c | 20 ++++++++++++++++++--
> include/linux/pci.h | 1 +
> 3 files changed, 56 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
> index 06e1ce0..3c5d230 100644
> --- a/arch/x86/pci/common.c
> +++ b/arch/x86/pci/common.c
> @@ -139,6 +139,7 @@ static void __devinit pcibios_fixup_device_resources(struct pci_dev *dev)
>
> static char *pci_assign_pio;
> static char *pci_assign_mmio;
> +static char *pci_align_mmio;
>
> static int pcibios_bus_resource_needs_fixup(struct pci_bus *bus)
> {
> @@ -192,6 +193,36 @@ static void __devinit pcibios_fixup_bus_resources(struct pci_bus *bus)
> }
> }
>
> +int pcibios_resource_alignment(struct pci_dev *dev, int resno)
> +{
> + int domain, busnr, slot, func;
> + char *str = pci_align_mmio;
> +
> + if (dev->resource[resno].flags & IORESOURCE_IO)
> + return 0;
> +
> + while (str && *str) {
> + if (sscanf(str, "%04x:%02x:%02x.%d",
> + &domain, &busnr, &slot, &func) != 4) {
> + if (sscanf(str, "%02x:%02x.%d",
> + &busnr, &slot, &func) != 3)
> + break;
> + domain = 0;
> + }
> +
> + if (pci_domain_nr(dev->bus) == domain &&
> + dev->bus->number == busnr &&
> + dev->devfn == PCI_DEVFN(slot, func))
> + return PAGE_SIZE;
> +
> + str = strchr(str, ';');
> + if (str)
> + str++;
> + }
> +
> + return 0;
> +}
> +
> int pcibios_resource_needs_fixup(struct pci_dev *dev, int resno)
> {
> struct pci_bus *bus;
> @@ -200,6 +231,9 @@ int pcibios_resource_needs_fixup(struct pci_dev *dev, int resno)
> if (pcibios_bus_resource_needs_fixup(bus))
> return 1;
>
> + if (pcibios_resource_alignment(dev, resno))
> + return 1;
> +
> return 0;
> }
>
> @@ -592,6 +626,9 @@ char * __devinit pcibios_setup(char *str)
> } else if (!strncmp(str, "assign-mmio=", 12)) {
> pci_assign_mmio = str + 12;
> return NULL;
> + } else if (!strncmp(str, "align-mmio=", 11)) {
> + pci_align_mmio = str + 11;
> + return NULL;
> }
> return str;
> }
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index b02167a..11ecd6f 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -1015,6 +1015,20 @@ int __attribute__ ((weak)) pcibios_set_pcie_reset_state(struct pci_dev *dev,
> }
>
> /**
> + * pcibios_resource_alignment - get resource alignment requirement
> + * @dev: the PCI device
> + * @resno: resource number
> + *
> + * Queries the resource alignment from PCI low level code. Returns positive
> + * if there is alignment requirement of the resource, or 0 otherwise.
> + */
> +int __attribute__ ((weak)) pcibios_resource_alignment(struct pci_dev *dev,
> + int resno)
> +{
> + return 0;
> +}
> +
> +/**
> * pci_set_pcie_reset_state - set reset state for device dev
> * @dev: the PCI-E device reset
> * @state: Reset state to enter into
> @@ -1913,12 +1927,14 @@ int pci_select_bars(struct pci_dev *dev, unsigned long flags)
> */
> int pci_resource_alignment(struct pci_dev *dev, int resno)
> {
> - resource_size_t align;
> + resource_size_t align, bios_align;
> struct resource *res = dev->resource + resno;
>
> + bios_align = pcibios_resource_alignment(dev, resno);
> +
> align = resource_alignment(res);
> if (align)
> - return align;
> + return align > bios_align ? align : bios_align;
>
> dev_err(&dev->dev, "alignment: invalid resource #%d\n", resno);
> return 0;
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 2ada2b6..6ac69af 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1121,6 +1121,7 @@ int pcibios_add_platform_entries(struct pci_dev *dev);
> void pcibios_disable_device(struct pci_dev *dev);
> int pcibios_set_pcie_reset_state(struct pci_dev *dev,
> enum pcie_reset_state state);
> +int pcibios_resource_alignment(struct pci_dev *dev, int resno);
>
> #ifdef CONFIG_PCI_MMCONFIG
> extern void __init pci_mmcfg_early_init(void);




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