[PATCHv8 01/10] PCI: use weak functions for MSI arch-specific functions

[PATCHv8 01/10] PCI: use weak functions for MSI arch-specific functions

[Thomas Petazzoni]

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 two separate, non-weak, functions
default_teardown_msi_irqs() and default_restore_msi_irqs() for the
default behavior of the arch_teardown_msi_irqs() and
arch_restore_msi_irqs(), as the default behavior is needed by x86 PCI
code.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Daniel Price <daniel.price@gmail.com>
Tested-by: Thierry Reding <thierry.reding@gmail.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>
---
 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              | 48 +++++++++++++++++++++---------------------
 include/linux/msi.h            |  8 ++++++-
 7 files changed, 52 insertions(+), 67 deletions(-)

diff --git a/arch/mips/include/asm/pci.h b/arch/mips/include/asm/pci.h
index fa8e0aa..f194c08 100644
--- a/arch/mips/include/asm/pci.h
+++ b/arch/mips/include/asm/pci.h
@@ -136,11 +136,6 @@ 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 6e577ba..262b91b 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 5f24c71..4c374a9 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 aca7578..823c386 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;
@@ -89,14 +87,12 @@ 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)
 {
 	struct msi_desc *entry;
@@ -114,7 +110,11 @@ void default_restore_msi_irqs(struct pci_dev *dev, int irq)
 	if (entry)
 		write_msi_msg(irq, &entry->msg);
 }
-#endif
+
+void __weak arch_restore_msi_irqs(struct pci_dev *dev, int irq)
+{
+	return default_restore_msi_irqs(dev, irq);
+}
 
 static void msi_set_enable(struct pci_dev *dev, int enable)
 {
diff --git a/include/linux/msi.h b/include/linux/msi.h
index ee66f3a..271dfd1 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -51,12 +51,18 @@ 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);
+void default_restore_msi_irqs(struct pci_dev *dev, int irq);
 
 #endif /* LINUX_MSI_H */
-- 
1.8.1.2

Re: [PATCHv8 01/10] PCI: use weak functions for MSI arch-specific functions

[Benjamin Herrenschmidt]

On Fri, 2013-08-09 at 00:17 +0200, Thomas Petazzoni 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 two separate, non-weak, functions
> default_teardown_msi_irqs() and default_restore_msi_irqs() for the
> default behavior of the arch_teardown_msi_irqs() and
> arch_restore_msi_irqs(), as the default behavior is needed by x86 PCI
> code.

Looks good, I'll give it a quick spin to make sure there is no
accidental breakage on ppc today.

> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> Tested-by: Daniel Price <daniel.price@gmail.com>
> Tested-by: Thierry Reding <thierry.reding@gmail.com>

Acked-by: 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>
> ---
>  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              | 48 +++++++++++++++++++++---------------------
>  include/linux/msi.h            |  8 ++++++-
>  7 files changed, 52 insertions(+), 67 deletions(-)
> 
> diff --git a/arch/mips/include/asm/pci.h b/arch/mips/include/asm/pci.h
> index fa8e0aa..f194c08 100644
> --- a/arch/mips/include/asm/pci.h
> +++ b/arch/mips/include/asm/pci.h
> @@ -136,11 +136,6 @@ 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 6e577ba..262b91b 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 5f24c71..4c374a9 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 aca7578..823c386 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;
> @@ -89,14 +87,12 @@ 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)
>  {
>  	struct msi_desc *entry;
> @@ -114,7 +110,11 @@ void default_restore_msi_irqs(struct pci_dev *dev, int irq)
>  	if (entry)
>  		write_msi_msg(irq, &entry->msg);
>  }
> -#endif
> +
> +void __weak arch_restore_msi_irqs(struct pci_dev *dev, int irq)
> +{
> +	return default_restore_msi_irqs(dev, irq);
> +}
>  
>  static void msi_set_enable(struct pci_dev *dev, int enable)
>  {
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index ee66f3a..271dfd1 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -51,12 +51,18 @@ 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);
> +void default_restore_msi_irqs(struct pci_dev *dev, int irq);
>  
>  #endif /* LINUX_MSI_H */

[PATCHv8 02/10] PCI: remove ARCH_SUPPORTS_MSI kconfig option

[Thomas Petazzoni]

Now that we have weak versions for each of the PCI MSI architecture
functions, we can actually build the MSI support for all platforms,
regardless of whether they provide or not architecture-specific
versions of those functions. For this reason, the ARCH_SUPPORTS_MSI
hidden kconfig boolean becomes useless, and this patch gets rid of it.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Daniel Price <daniel.price@gmail.com>
Tested-by: Thierry Reding <thierry.reding@gmail.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>
---
 arch/arm/Kconfig     | 1 -
 arch/ia64/Kconfig    | 1 -
 arch/mips/Kconfig    | 2 --
 arch/powerpc/Kconfig | 1 -
 arch/s390/Kconfig    | 1 -
 arch/sparc/Kconfig   | 1 -
 arch/tile/Kconfig    | 1 -
 arch/x86/Kconfig     | 1 -
 drivers/pci/Kconfig  | 4 ----
 9 files changed, 13 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 37c0f4e..41b6c96 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -441,7 +441,6 @@ config ARCH_NETX
 config ARCH_IOP13XX
 	bool "IOP13xx-based"
 	depends on MMU
-	select ARCH_SUPPORTS_MSI
 	select CPU_XSC3
 	select NEED_MACH_MEMORY_H
 	select NEED_RET_TO_USER
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 5a768ad..098602b 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -9,7 +9,6 @@ config IA64
 	select PCI if (!IA64_HP_SIM)
 	select ACPI if (!IA64_HP_SIM)
 	select PM if (!IA64_HP_SIM)
-	select ARCH_SUPPORTS_MSI
 	select HAVE_UNSTABLE_SCHED_CLOCK
 	select HAVE_IDE
 	select HAVE_OPROFILE
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index c3abed3..01b5f5a 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -726,7 +726,6 @@ config CAVIUM_OCTEON_SOC
 	select SYS_HAS_CPU_CAVIUM_OCTEON
 	select SWAP_IO_SPACE
 	select HW_HAS_PCI
-	select ARCH_SUPPORTS_MSI
 	select ZONE_DMA32
 	select USB_ARCH_HAS_OHCI
 	select USB_ARCH_HAS_EHCI
@@ -762,7 +761,6 @@ config NLM_XLR_BOARD
 	select CEVT_R4K
 	select CSRC_R4K
 	select IRQ_CPU
-	select ARCH_SUPPORTS_MSI
 	select ZONE_DMA32 if 64BIT
 	select SYNC_R4K
 	select SYS_HAS_EARLY_PRINTK
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 3bf72cd..183a165 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -727,7 +727,6 @@ config PCI
 	default y if !40x && !CPM2 && !8xx && !PPC_83xx \
 		&& !PPC_85xx && !PPC_86xx && !GAMECUBE_COMMON
 	default PCI_QSPAN if !4xx && !CPM2 && 8xx
-	select ARCH_SUPPORTS_MSI
 	select GENERIC_PCI_IOMAP
 	help
 	  Find out whether your system includes a PCI bus. PCI is the name of
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 22f75b5..e9982a3 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -428,7 +428,6 @@ menuconfig PCI
 	bool "PCI support"
 	default n
 	depends on 64BIT
-	select ARCH_SUPPORTS_MSI
 	select PCI_MSI
 	help
 	  Enable PCI support.
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index a00cbd3..1570ad2 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -52,7 +52,6 @@ config SPARC32
 
 config SPARC64
 	def_bool 64BIT
-	select ARCH_SUPPORTS_MSI
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_GRAPH_FP_TEST
diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index 24565a7..74dff90 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -380,7 +380,6 @@ config PCI
 	select PCI_DOMAINS
 	select GENERIC_PCI_IOMAP
 	select TILE_GXIO_TRIO if TILEGX
-	select ARCH_SUPPORTS_MSI if TILEGX
 	select PCI_MSI if TILEGX
 	---help---
 	  Enable PCI root complex support, so PCIe endpoint devices can
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b32ebf9..5db62ef 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2014,7 +2014,6 @@ menu "Bus options (PCI etc.)"
 config PCI
 	bool "PCI support"
 	default y
-	select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
 	---help---
 	  Find out whether you have a PCI motherboard. PCI is the name of a
 	  bus system, i.e. the way the CPU talks to the other stuff inside
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 81944fb..b6a99f7 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -1,13 +1,9 @@
 #
 # PCI configuration
 #
-config ARCH_SUPPORTS_MSI
-	bool
-
 config PCI_MSI
 	bool "Message Signaled Interrupts (MSI and MSI-X)"
 	depends on PCI
-	depends on ARCH_SUPPORTS_MSI
 	help
 	   This allows device drivers to enable MSI (Message Signaled
 	   Interrupts).  Message Signaled Interrupts enable a device to
-- 
1.8.1.2

Re: [PATCHv8 02/10] PCI: remove ARCH_SUPPORTS_MSI kconfig option

[Benjamin Herrenschmidt]

On Fri, 2013-08-09 at 00:17 +0200, Thomas Petazzoni wrote:
> Now that we have weak versions for each of the PCI MSI architecture
> functions, we can actually build the MSI support for all platforms,
> regardless of whether they provide or not architecture-specific
> versions of those functions. For this reason, the ARCH_SUPPORTS_MSI
> hidden kconfig boolean becomes useless, and this patch gets rid of it.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> Tested-by: Daniel Price <daniel.price@gmail.com>
> Tested-by: Thierry Reding <thierry.reding@gmail.com>

Acked-by: 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>
> ---
>  arch/arm/Kconfig     | 1 -
>  arch/ia64/Kconfig    | 1 -
>  arch/mips/Kconfig    | 2 --
>  arch/powerpc/Kconfig | 1 -
>  arch/s390/Kconfig    | 1 -
>  arch/sparc/Kconfig   | 1 -
>  arch/tile/Kconfig    | 1 -
>  arch/x86/Kconfig     | 1 -
>  drivers/pci/Kconfig  | 4 ----
>  9 files changed, 13 deletions(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 37c0f4e..41b6c96 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -441,7 +441,6 @@ config ARCH_NETX
>  config ARCH_IOP13XX
>  	bool "IOP13xx-based"
>  	depends on MMU
> -	select ARCH_SUPPORTS_MSI
>  	select CPU_XSC3
>  	select NEED_MACH_MEMORY_H
>  	select NEED_RET_TO_USER
> diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
> index 5a768ad..098602b 100644
> --- a/arch/ia64/Kconfig
> +++ b/arch/ia64/Kconfig
> @@ -9,7 +9,6 @@ config IA64
>  	select PCI if (!IA64_HP_SIM)
>  	select ACPI if (!IA64_HP_SIM)
>  	select PM if (!IA64_HP_SIM)
> -	select ARCH_SUPPORTS_MSI
>  	select HAVE_UNSTABLE_SCHED_CLOCK
>  	select HAVE_IDE
>  	select HAVE_OPROFILE
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index c3abed3..01b5f5a 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -726,7 +726,6 @@ config CAVIUM_OCTEON_SOC
>  	select SYS_HAS_CPU_CAVIUM_OCTEON
>  	select SWAP_IO_SPACE
>  	select HW_HAS_PCI
> -	select ARCH_SUPPORTS_MSI
>  	select ZONE_DMA32
>  	select USB_ARCH_HAS_OHCI
>  	select USB_ARCH_HAS_EHCI
> @@ -762,7 +761,6 @@ config NLM_XLR_BOARD
>  	select CEVT_R4K
>  	select CSRC_R4K
>  	select IRQ_CPU
> -	select ARCH_SUPPORTS_MSI
>  	select ZONE_DMA32 if 64BIT
>  	select SYNC_R4K
>  	select SYS_HAS_EARLY_PRINTK
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 3bf72cd..183a165 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -727,7 +727,6 @@ config PCI
>  	default y if !40x && !CPM2 && !8xx && !PPC_83xx \
>  		&& !PPC_85xx && !PPC_86xx && !GAMECUBE_COMMON
>  	default PCI_QSPAN if !4xx && !CPM2 && 8xx
> -	select ARCH_SUPPORTS_MSI
>  	select GENERIC_PCI_IOMAP
>  	help
>  	  Find out whether your system includes a PCI bus. PCI is the name of
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index 22f75b5..e9982a3 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -428,7 +428,6 @@ menuconfig PCI
>  	bool "PCI support"
>  	default n
>  	depends on 64BIT
> -	select ARCH_SUPPORTS_MSI
>  	select PCI_MSI
>  	help
>  	  Enable PCI support.
> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
> index a00cbd3..1570ad2 100644
> --- a/arch/sparc/Kconfig
> +++ b/arch/sparc/Kconfig
> @@ -52,7 +52,6 @@ config SPARC32
>  
>  config SPARC64
>  	def_bool 64BIT
> -	select ARCH_SUPPORTS_MSI
>  	select HAVE_FUNCTION_TRACER
>  	select HAVE_FUNCTION_GRAPH_TRACER
>  	select HAVE_FUNCTION_GRAPH_FP_TEST
> diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
> index 24565a7..74dff90 100644
> --- a/arch/tile/Kconfig
> +++ b/arch/tile/Kconfig
> @@ -380,7 +380,6 @@ config PCI
>  	select PCI_DOMAINS
>  	select GENERIC_PCI_IOMAP
>  	select TILE_GXIO_TRIO if TILEGX
> -	select ARCH_SUPPORTS_MSI if TILEGX
>  	select PCI_MSI if TILEGX
>  	---help---
>  	  Enable PCI root complex support, so PCIe endpoint devices can
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index b32ebf9..5db62ef 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2014,7 +2014,6 @@ menu "Bus options (PCI etc.)"
>  config PCI
>  	bool "PCI support"
>  	default y
> -	select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
>  	---help---
>  	  Find out whether you have a PCI motherboard. PCI is the name of a
>  	  bus system, i.e. the way the CPU talks to the other stuff inside
> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> index 81944fb..b6a99f7 100644
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -1,13 +1,9 @@
>  #
>  # PCI configuration
>  #
> -config ARCH_SUPPORTS_MSI
> -	bool
> -
>  config PCI_MSI
>  	bool "Message Signaled Interrupts (MSI and MSI-X)"
>  	depends on PCI
> -	depends on ARCH_SUPPORTS_MSI
>  	help
>  	   This allows device drivers to enable MSI (Message Signaled
>  	   Interrupts).  Message Signaled Interrupts enable a device to