Re: [Xen-devel] [PATCH v3 24/27] IA64/MSI: Use MSI chip framework to configure MSI/MSI-X irq

[Bjorn Helgaas <bhelgaas@xxxxxxxxxx>]

On Wed, Oct 15, 2014 at 11:07:12AM +0800, Yijing Wang wrote:
> Use MSI chip framework instead of arch MSI functions to configure
> MSI/MSI-X irq. So we can manage MSI/MSI-X irq in a unified framework.

This needs slightly more detail.  You're using the MSI chip framework
"instead of arch MSI functions".  Well, there are still arch-specific
functions, i.e., arch_ia64_setup_msi_irq() and
arch_ia64_teardown_msi_irq().

We used to have arch_setup_msi_irq() which had a weak default
implementation, and a strong arch-specific implementation here, and you're
replacing that model with the new "msi-ops" model.  I don't know how you
want to write that, but it's not that you're getting rid of the
arch-specific code; you're keeping arch-specific code but structuring it
differently.

> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
> ---
>  arch/ia64/include/asm/pci.h |   10 ++++++++++
>  arch/ia64/kernel/msi_ia64.c |   14 ++++++++++----
>  arch/ia64/pci/pci.c         |    1 +
>  3 files changed, 21 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/ia64/include/asm/pci.h b/arch/ia64/include/asm/pci.h
> index 52af5ed..907dcba 100644
> --- a/arch/ia64/include/asm/pci.h
> +++ b/arch/ia64/include/asm/pci.h
> @@ -94,6 +94,7 @@ struct pci_controller {
>       int segment;
>       int node;               /* nearest node with memory or NUMA_NO_NODE for 
> global allocation */
>  
> +     struct msi_chip *msi_chip;
>       void *platform_data;
>  };
>  
> @@ -101,6 +102,15 @@ struct pci_controller {
>  #define PCI_CONTROLLER(busdev) ((struct pci_controller *) busdev->sysdata)
>  #define pci_domain_nr(busdev)    (PCI_CONTROLLER(busdev)->segment)
>  
> +extern struct msi_chip chip;

Please make this name more descriptive.  "chip" is way too generic for a
global name.

> +static inline struct msi_chip *pci_msi_chip(struct pci_bus *bus)
> +{
> +     struct pci_controller *ctrl = bus->sysdata;
> +
> +     return ctrl->msi_chip;
> +}
> +
>  extern struct pci_ops pci_root_ops;
>  
>  static inline int pci_proc_domain(struct pci_bus *bus)
> diff --git a/arch/ia64/kernel/msi_ia64.c b/arch/ia64/kernel/msi_ia64.c
> index 8c3730c..401fc98 100644
> --- a/arch/ia64/kernel/msi_ia64.c
> +++ b/arch/ia64/kernel/msi_ia64.c
> @@ -112,15 +112,16 @@ static struct irq_chip ia64_msi_chip = {
>  };
>  
>  
> -int arch_setup_msi_irq(struct pci_dev *pdev, struct msi_desc *desc)
> +static int arch_ia64_setup_msi_irq(struct msi_chip *chip,
> +             struct pci_dev *dev, struct msi_desc *desc)
>  {
>       if (platform_setup_msi_irq)
> -             return platform_setup_msi_irq(pdev, desc);
> +             return platform_setup_msi_irq(dev, desc);
>  
> -     return ia64_setup_msi_irq(pdev, desc);
> +     return ia64_setup_msi_irq(dev, desc);

Please don't make gratuitous changes ("pdev" -> "dev") at the same time,
especially since the rest of the file still uses "pdev".

>  }
>  
> -void arch_teardown_msi_irq(unsigned int irq)
> +static void arch_ia64_teardown_msi_irq(struct msi_chip *chip, unsigned int 
> irq)
>  {
>       if (platform_teardown_msi_irq)
>               return platform_teardown_msi_irq(irq);
> @@ -128,6 +129,11 @@ void arch_teardown_msi_irq(unsigned int irq)
>       return ia64_teardown_msi_irq(irq);
>  }
>  
> +struct msi_chip chip = {
> +     .setup_irq = arch_ia64_setup_msi_irq,
> +     .teardown_irq = arch_ia64_teardown_msi_irq,
> +};
> +
>  #ifdef CONFIG_INTEL_IOMMU
>  #ifdef CONFIG_SMP
>  static int dmar_msi_set_affinity(struct irq_data *data,
> diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
> index 291a582..299b67d 100644
> --- a/arch/ia64/pci/pci.c
> +++ b/arch/ia64/pci/pci.c
> @@ -437,6 +437,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root 
> *root)
>  
>       controller->companion = device;
>       controller->node = acpi_get_node(device->handle);
> +     controller->msi_chip = &chip;
>  
>       info = kzalloc(sizeof(*info), GFP_KERNEL);
>       if (!info) {
> -- 
> 1.7.1
> 
> --
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