Re: [PATCHv4 02/11] pci: use weak functions for MSI arch-specific functions

[Bjorn Helgaas <bhelgaas@google.com>]

On Mon, Jul 1, 2013 at 7:42 AM, Thomas Petazzoni
<thomas.petazzoni@free-electrons.com> wrote:
> Until now, the MSI architecture-specific functions could be overloaded
> using a fairly complex set of #define and compile-time
> conditionals. In order to prepare for the introduction of the msi_chip
> infrastructure, it is desirable to switch all those functions to use
> the 'weak' mechanism. This commit converts all the architectures that
> were overidding those MSI functions to use the new strategy.
>
> Note that we keep a separate, non-weak, function
> default_teardown_msi_irqs() for the default behavior of the
> arch_teardown_msi_irqs(), as the default behavior is needed by the Xen
> x86 PCI code.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> Cc: linux390@de.ibm.com
> Cc: linux-s390@vger.kernel.org
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: x86@kernel.org
> Cc: Russell King <linux@arm.linux.org.uk>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: linux-ia64@vger.kernel.org
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: linux-mips@linux-mips.org
> Cc: David S. Miller <davem@davemloft.net>
> Cc: sparclinux@vger.kernel.org
> Cc: Chris Metcalf <cmetcalf@tilera.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> ---
>  arch/mips/include/asm/pci.h    |  5 -----
>  arch/powerpc/include/asm/pci.h |  5 -----
>  arch/s390/include/asm/pci.h    |  4 ----
>  arch/x86/include/asm/pci.h     | 28 --------------------------
>  arch/x86/kernel/x86_init.c     | 21 ++++++++++++++++++++
>  drivers/pci/msi.c              | 45 +++++++++++++++++++-----------------------
>  include/linux/msi.h            |  7 ++++++-
>  7 files changed, 47 insertions(+), 68 deletions(-)
>
> diff --git a/arch/mips/include/asm/pci.h b/arch/mips/include/asm/pci.h
> index b8e24fd..031f4c1 100644
> --- a/arch/mips/include/asm/pci.h
> +++ b/arch/mips/include/asm/pci.h
> @@ -137,11 +137,6 @@ static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
>         return channel ? 15 : 14;
>  }
>
> -#ifdef CONFIG_CPU_CAVIUM_OCTEON
> -/* MSI arch hook for OCTEON */
> -#define arch_setup_msi_irqs arch_setup_msi_irqs
> -#endif
> -
>  extern char * (*pcibios_plat_setup)(char *str);
>
>  #ifdef CONFIG_OF
> diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h
> index 6653f27..95145a1 100644
> --- a/arch/powerpc/include/asm/pci.h
> +++ b/arch/powerpc/include/asm/pci.h
> @@ -113,11 +113,6 @@ extern int pci_domain_nr(struct pci_bus *bus);
>  /* Decide whether to display the domain number in /proc */
>  extern int pci_proc_domain(struct pci_bus *bus);
>
> -/* MSI arch hooks */
> -#define arch_setup_msi_irqs arch_setup_msi_irqs
> -#define arch_teardown_msi_irqs arch_teardown_msi_irqs
> -#define arch_msi_check_device arch_msi_check_device
> -
>  struct vm_area_struct;
>  /* Map a range of PCI memory or I/O space for a device into user space */
>  int pci_mmap_page_range(struct pci_dev *pdev, struct vm_area_struct *vma,
> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
> index 6c18012..8641e8d 100644
> --- a/arch/s390/include/asm/pci.h
> +++ b/arch/s390/include/asm/pci.h
> @@ -21,10 +21,6 @@ void pci_iounmap(struct pci_dev *, void __iomem *);
>  int pci_domain_nr(struct pci_bus *);
>  int pci_proc_domain(struct pci_bus *);
>
> -/* MSI arch hooks */
> -#define arch_setup_msi_irqs    arch_setup_msi_irqs
> -#define arch_teardown_msi_irqs arch_teardown_msi_irqs
> -
>  #define ZPCI_BUS_NR                    0       /* default bus number */
>  #define ZPCI_DEVFN                     0       /* default device number */
>
> diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
> index d9e9e6c..8c61de0 100644
> --- a/arch/x86/include/asm/pci.h
> +++ b/arch/x86/include/asm/pci.h
> @@ -100,29 +100,6 @@ static inline void early_quirks(void) { }
>  extern void pci_iommu_alloc(void);
>
>  #ifdef CONFIG_PCI_MSI
> -/* MSI arch specific hooks */
> -static inline int x86_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
> -{
> -       return x86_msi.setup_msi_irqs(dev, nvec, type);
> -}
> -
> -static inline void x86_teardown_msi_irqs(struct pci_dev *dev)
> -{
> -       x86_msi.teardown_msi_irqs(dev);
> -}
> -
> -static inline void x86_teardown_msi_irq(unsigned int irq)
> -{
> -       x86_msi.teardown_msi_irq(irq);
> -}
> -static inline void x86_restore_msi_irqs(struct pci_dev *dev, int irq)
> -{
> -       x86_msi.restore_msi_irqs(dev, irq);
> -}
> -#define arch_setup_msi_irqs x86_setup_msi_irqs
> -#define arch_teardown_msi_irqs x86_teardown_msi_irqs
> -#define arch_teardown_msi_irq x86_teardown_msi_irq
> -#define arch_restore_msi_irqs x86_restore_msi_irqs
>  /* implemented in arch/x86/kernel/apic/io_apic. */
>  struct msi_desc;
>  int native_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);
> @@ -130,11 +107,6 @@ void native_teardown_msi_irq(unsigned int irq);
>  void native_restore_msi_irqs(struct pci_dev *dev, int irq);
>  int setup_msi_irq(struct pci_dev *dev, struct msi_desc *msidesc,
>                   unsigned int irq_base, unsigned int irq_offset);
> -/* default to the implementation in drivers/lib/msi.c */
> -#define HAVE_DEFAULT_MSI_TEARDOWN_IRQS
> -#define HAVE_DEFAULT_MSI_RESTORE_IRQS
> -void default_teardown_msi_irqs(struct pci_dev *dev);
> -void default_restore_msi_irqs(struct pci_dev *dev, int irq);
>  #else
>  #define native_setup_msi_irqs          NULL
>  #define native_teardown_msi_irq                NULL
> diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
> index 45a14db..a2b189c 100644
> --- a/arch/x86/kernel/x86_init.c
> +++ b/arch/x86/kernel/x86_init.c
> @@ -116,6 +116,27 @@ struct x86_msi_ops x86_msi = {
>         .setup_hpet_msi         = default_setup_hpet_msi,
>  };
>
> +/* MSI arch specific hooks */
> +int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
> +{
> +       return x86_msi.setup_msi_irqs(dev, nvec, type);
> +}
> +
> +void arch_teardown_msi_irqs(struct pci_dev *dev)
> +{
> +       x86_msi.teardown_msi_irqs(dev);
> +}
> +
> +void arch_teardown_msi_irq(unsigned int irq)
> +{
> +       x86_msi.teardown_msi_irq(irq);
> +}
> +
> +void arch_restore_msi_irqs(struct pci_dev *dev, int irq)
> +{
> +       x86_msi.restore_msi_irqs(dev, irq);
> +}
> +
>  struct x86_io_apic_ops x86_io_apic_ops = {
>         .init                   = native_io_apic_init_mappings,
>         .read                   = native_io_apic_read,
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index 2c10752..289fbfd 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -30,20 +30,21 @@ static int pci_msi_enable = 1;
>
>  /* Arch hooks */
>
> -#ifndef arch_msi_check_device
> -int arch_msi_check_device(struct pci_dev *dev, int nvec, int type)
> +int __weak arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
>  {
> -       return 0;
> +       return -EINVAL;
>  }
> -#endif
>
> -#ifndef arch_setup_msi_irqs
> -# define arch_setup_msi_irqs default_setup_msi_irqs
> -# define HAVE_DEFAULT_MSI_SETUP_IRQS
> -#endif
> +void __weak arch_teardown_msi_irq(unsigned int irq)
> +{
> +}
>
> -#ifdef HAVE_DEFAULT_MSI_SETUP_IRQS
> -int default_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
> +int __weak arch_msi_check_device(struct pci_dev *dev, int nvec, int type)
> +{
> +       return 0;
> +}
> +
> +int __weak arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>  {
>         struct msi_desc *entry;
>         int ret;
> @@ -65,14 +66,11 @@ int default_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>
>         return 0;
>  }
> -#endif
>
> -#ifndef arch_teardown_msi_irqs
> -# define arch_teardown_msi_irqs default_teardown_msi_irqs
> -# define HAVE_DEFAULT_MSI_TEARDOWN_IRQS
> -#endif
> -
> -#ifdef HAVE_DEFAULT_MSI_TEARDOWN_IRQS
> +/*
> + * We have a default implementation available as a separate non-weak
> + * function, as it is used by the Xen x86 PCI code
> + */
>  void default_teardown_msi_irqs(struct pci_dev *dev)
>  {
>         struct msi_desc *entry;
> @@ -86,15 +84,13 @@ void default_teardown_msi_irqs(struct pci_dev *dev)
>                         arch_teardown_msi_irq(entry->irq + i);
>         }
>  }
> -#endif
>
> -#ifndef arch_restore_msi_irqs
> -# define arch_restore_msi_irqs default_restore_msi_irqs
> -# define HAVE_DEFAULT_MSI_RESTORE_IRQS
> -#endif
> +void __weak arch_teardown_msi_irqs(struct pci_dev *dev)
> +{
> +       return default_teardown_msi_irqs(dev);
> +}
>
> -#ifdef HAVE_DEFAULT_MSI_RESTORE_IRQS
> -void default_restore_msi_irqs(struct pci_dev *dev, int irq)
> +void __weak arch_restore_msi_irqs(struct pci_dev *dev, int irq)
>  {
>         struct msi_desc *entry;
>
> @@ -111,7 +107,6 @@ void default_restore_msi_irqs(struct pci_dev *dev, int irq)
>         if (entry)
>                 write_msi_msg(irq, &entry->msg);
>  }
> -#endif
>
>  static void msi_set_enable(struct pci_dev *dev, int enable)
>  {
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index 20c2d6d..c82ff8d 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -50,12 +50,17 @@ struct msi_desc {
>  };
>
>  /*
> - * The arch hook for setup up msi irqs
> + * The arch hooks to setup up msi irqs. Those functions are
> + * implemented as weak symbols so that they /can/ be overriden by
> + * architecture specific code if needed.
>   */
>  int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc);
>  void arch_teardown_msi_irq(unsigned int irq);
>  int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);
>  void arch_teardown_msi_irqs(struct pci_dev *dev);
>  int arch_msi_check_device(struct pci_dev* dev, int nvec, int type);
> +void arch_restore_msi_irqs(struct pci_dev *dev, int irq);
> +
> +void default_teardown_msi_irqs(struct pci_dev *dev);
>
>  #endif /* LINUX_MSI_H */
> --
> 1.8.1.2
>