[RFC PATCH 1/2] asm-generic: Remove pci.h copying code out to architectures

[RFC PATCH 1/2] asm-generic: Remove pci.h copying code out to architectures

[Stafford Horne]

The generic pci.h header provides a definition of pci_get_legacy_ide_irq
which is used by architectures that use PC-style interrupt numbers.

This patch removes the old pci.h in order to make room for a new
pci.h to be used by arm64, riscv, openrisc, etc.

The existing code in pci.h is moved out to architectures.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/lkml/CAK8P3a0JmPeczfmMBE__vn=Jbvf=nkbpVaZCycyv40pZNCJJXQ@mail.gmail.com/
Signed-off-by: Stafford Horne <shorne@gmail.com>
---
 arch/alpha/include/asm/pci.h   |  1 -
 arch/ia64/include/asm/pci.h    |  1 -
 arch/m68k/include/asm/pci.h    |  7 +++++--
 arch/powerpc/include/asm/pci.h |  1 -
 arch/s390/include/asm/pci.h    |  6 +++++-
 arch/sparc/include/asm/pci.h   |  5 ++++-
 arch/x86/include/asm/pci.h     |  6 ++++--
 arch/xtensa/include/asm/pci.h  |  6 ++++--
 include/asm-generic/pci.h      | 17 -----------------
 9 files changed, 22 insertions(+), 28 deletions(-)
 delete mode 100644 include/asm-generic/pci.h

diff --git a/arch/alpha/include/asm/pci.h b/arch/alpha/include/asm/pci.h
index cf6bc1e64d66..8ac5af0fc4da 100644
--- a/arch/alpha/include/asm/pci.h
+++ b/arch/alpha/include/asm/pci.h
@@ -56,7 +56,6 @@ struct pci_controller {
 
 /* IOMMU controls.  */
 
-/* TODO: integrate with include/asm-generic/pci.h ? */
 static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
 {
 	return channel ? 15 : 14;
diff --git a/arch/ia64/include/asm/pci.h b/arch/ia64/include/asm/pci.h
index 8c163d1d0189..218412d963c2 100644
--- a/arch/ia64/include/asm/pci.h
+++ b/arch/ia64/include/asm/pci.h
@@ -63,7 +63,6 @@ static inline int pci_proc_domain(struct pci_bus *bus)
 	return (pci_domain_nr(bus) != 0);
 }
 
-#define HAVE_ARCH_PCI_GET_LEGACY_IDE_IRQ
 static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
 {
 	return channel ? isa_irq_to_vector(15) : isa_irq_to_vector(14);
diff --git a/arch/m68k/include/asm/pci.h b/arch/m68k/include/asm/pci.h
index 5a4bc223743b..0c272ff515cc 100644
--- a/arch/m68k/include/asm/pci.h
+++ b/arch/m68k/include/asm/pci.h
@@ -2,11 +2,14 @@
 #ifndef _ASM_M68K_PCI_H
 #define _ASM_M68K_PCI_H
 
-#include <asm-generic/pci.h>
-
 #define	pcibios_assign_all_busses()	1
 
 #define	PCIBIOS_MIN_IO		0x00000100
 #define	PCIBIOS_MIN_MEM		0x02000000
 
+static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
+{
+	return channel ? 15 : 14;
+}
+
 #endif /* _ASM_M68K_PCI_H */
diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h
index 915d6ee4b40a..f9da506751bb 100644
--- a/arch/powerpc/include/asm/pci.h
+++ b/arch/powerpc/include/asm/pci.h
@@ -39,7 +39,6 @@
 #define pcibios_assign_all_busses() \
 	(pci_has_flag(PCI_REASSIGN_ALL_BUS))
 
-#define HAVE_ARCH_PCI_GET_LEGACY_IDE_IRQ
 static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
 {
 	if (ppc_md.pci_get_legacy_ide_irq)
diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index fdb9745ee998..93cd0167f8aa 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -6,7 +6,6 @@
 #include <linux/mutex.h>
 #include <linux/iommu.h>
 #include <linux/pci_hotplug.h>
-#include <asm-generic/pci.h>
 #include <asm/pci_clp.h>
 #include <asm/pci_debug.h>
 #include <asm/sclp.h>
@@ -233,6 +232,11 @@ int zpci_init_iommu(struct zpci_dev *zdev);
 void zpci_destroy_iommu(struct zpci_dev *zdev);
 
 #ifdef CONFIG_PCI
+static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
+{
+	return channel ? 15 : 14;
+}
+
 static inline bool zpci_use_mio(struct zpci_dev *zdev)
 {
 	return static_branch_likely(&have_mio) && zdev->mio_capable;
diff --git a/arch/sparc/include/asm/pci.h b/arch/sparc/include/asm/pci.h
index 4deddf430e5d..6d283fc7b55b 100644
--- a/arch/sparc/include/asm/pci.h
+++ b/arch/sparc/include/asm/pci.h
@@ -46,7 +46,10 @@ static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
 	return PCI_IRQ_NONE;
 }
 #else
-#include <asm-generic/pci.h>
+static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
+{
+	return channel ? 15 : 14;
+}
 #endif
 
 #endif /* ___ASM_SPARC_PCI_H */
diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
index f3fd5928bcbb..7da27f665cfe 100644
--- a/arch/x86/include/asm/pci.h
+++ b/arch/x86/include/asm/pci.h
@@ -105,8 +105,10 @@ static inline void early_quirks(void) { }
 
 extern void pci_iommu_alloc(void);
 
-/* generic pci stuff */
-#include <asm-generic/pci.h>
+static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
+{
+	return channel ? 15 : 14;
+}
 
 #ifdef CONFIG_NUMA
 /* Returns the node based on pci bus */
diff --git a/arch/xtensa/include/asm/pci.h b/arch/xtensa/include/asm/pci.h
index 8e2b48a268db..f57ede61f5db 100644
--- a/arch/xtensa/include/asm/pci.h
+++ b/arch/xtensa/include/asm/pci.h
@@ -43,7 +43,9 @@
 #define ARCH_GENERIC_PCI_MMAP_RESOURCE	1
 #define arch_can_pci_mmap_io()		1
 
-/* Generic PCI */
-#include <asm-generic/pci.h>
+static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
+{
+	return channel ? 15 : 14;
+}
 
 #endif	/* _XTENSA_PCI_H */
diff --git a/include/asm-generic/pci.h b/include/asm-generic/pci.h
deleted file mode 100644
index 6bb3cd3d695a..000000000000
--- a/include/asm-generic/pci.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * linux/include/asm-generic/pci.h
- *
- *  Copyright (C) 2003 Russell King
- */
-#ifndef _ASM_GENERIC_PCI_H
-#define _ASM_GENERIC_PCI_H
-
-#ifndef HAVE_ARCH_PCI_GET_LEGACY_IDE_IRQ
-static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
-{
-	return channel ? 15 : 14;
-}
-#endif /* HAVE_ARCH_PCI_GET_LEGACY_IDE_IRQ */
-
-#endif /* _ASM_GENERIC_PCI_H */
-- 
2.36.1

Re: [RFC PATCH 1/2] asm-generic: Remove pci.h copying code out to architectures

[Max Filippov]

On Thu, Jul 14, 2022 at 2:47 PM Stafford Horne <shorne@gmail.com> wrote:
>
> The generic pci.h header provides a definition of pci_get_legacy_ide_irq
> which is used by architectures that use PC-style interrupt numbers.
>
> This patch removes the old pci.h in order to make room for a new
> pci.h to be used by arm64, riscv, openrisc, etc.
>
> The existing code in pci.h is moved out to architectures.
>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Link: https://lore.kernel.org/lkml/CAK8P3a0JmPeczfmMBE__vn=Jbvf=nkbpVaZCycyv40pZNCJJXQ@mail.gmail.com/
> Signed-off-by: Stafford Horne <shorne@gmail.com>
> ---
>  arch/alpha/include/asm/pci.h   |  1 -
>  arch/ia64/include/asm/pci.h    |  1 -
>  arch/m68k/include/asm/pci.h    |  7 +++++--
>  arch/powerpc/include/asm/pci.h |  1 -
>  arch/s390/include/asm/pci.h    |  6 +++++-
>  arch/sparc/include/asm/pci.h   |  5 ++++-
>  arch/x86/include/asm/pci.h     |  6 ++++--
>  arch/xtensa/include/asm/pci.h  |  6 ++++--
>  include/asm-generic/pci.h      | 17 -----------------
>  9 files changed, 22 insertions(+), 28 deletions(-)
>  delete mode 100644 include/asm-generic/pci.h

[...]

> diff --git a/arch/xtensa/include/asm/pci.h b/arch/xtensa/include/asm/pci.h
> index 8e2b48a268db..f57ede61f5db 100644
> --- a/arch/xtensa/include/asm/pci.h
> +++ b/arch/xtensa/include/asm/pci.h
> @@ -43,7 +43,9 @@
>  #define ARCH_GENERIC_PCI_MMAP_RESOURCE 1
>  #define arch_can_pci_mmap_io()         1
>
> -/* Generic PCI */
> -#include <asm-generic/pci.h>

Ok.

> +static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
> +{
> +       return channel ? 15 : 14;
> +}

This addition does not make sense for the xtensa as it isn't even possible
to enable PNP support (the only user of this function) on xtensa.

-- 
Thanks.
-- Max

Re: [RFC PATCH 1/2] asm-generic: Remove pci.h copying code out to architectures

[Stafford Horne]

On Thu, Jul 14, 2022 at 06:45:27PM -0700, Max Filippov wrote:
> On Thu, Jul 14, 2022 at 2:47 PM Stafford Horne <shorne@gmail.com> wrote:
> >
> > The generic pci.h header provides a definition of pci_get_legacy_ide_irq
> > which is used by architectures that use PC-style interrupt numbers.
> >
> > This patch removes the old pci.h in order to make room for a new
> > pci.h to be used by arm64, riscv, openrisc, etc.
> >
> > The existing code in pci.h is moved out to architectures.
> >
> > Suggested-by: Arnd Bergmann <arnd@arndb.de>
> > Link: https://lore.kernel.org/lkml/CAK8P3a0JmPeczfmMBE__vn=Jbvf=nkbpVaZCycyv40pZNCJJXQ@mail.gmail.com/
> > Signed-off-by: Stafford Horne <shorne@gmail.com>
> > ---
> >  arch/alpha/include/asm/pci.h   |  1 -
> >  arch/ia64/include/asm/pci.h    |  1 -
> >  arch/m68k/include/asm/pci.h    |  7 +++++--
> >  arch/powerpc/include/asm/pci.h |  1 -
> >  arch/s390/include/asm/pci.h    |  6 +++++-
> >  arch/sparc/include/asm/pci.h   |  5 ++++-
> >  arch/x86/include/asm/pci.h     |  6 ++++--
> >  arch/xtensa/include/asm/pci.h  |  6 ++++--
> >  include/asm-generic/pci.h      | 17 -----------------
> >  9 files changed, 22 insertions(+), 28 deletions(-)
> >  delete mode 100644 include/asm-generic/pci.h
> 
> [...]
> 
> > diff --git a/arch/xtensa/include/asm/pci.h b/arch/xtensa/include/asm/pci.h
> > index 8e2b48a268db..f57ede61f5db 100644
> > --- a/arch/xtensa/include/asm/pci.h
> > +++ b/arch/xtensa/include/asm/pci.h
> > @@ -43,7 +43,9 @@
> >  #define ARCH_GENERIC_PCI_MMAP_RESOURCE 1
> >  #define arch_can_pci_mmap_io()         1
> >
> > -/* Generic PCI */
> > -#include <asm-generic/pci.h>
> 
> Ok.
> 
> > +static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
> > +{
> > +       return channel ? 15 : 14;
> > +}
> 
> This addition does not make sense for the xtensa as it isn't even possible
> to enable PNP support (the only user of this function) on xtensa.

Thanks for your feedback, this is the kind of feedback I was hoping to fish out
with this patch.  I will look into completely removing this then.

-Stafford

Re: [RFC PATCH 1/2] asm-generic: Remove pci.h copying code out to architectures

[Arnd Bergmann]

On Fri, Jul 15, 2022 at 3:45 AM Max Filippov <jcmvbkbc@gmail.com> wrote:
> On Thu, Jul 14, 2022 at 2:47 PM Stafford Horne <shorne@gmail.com> wrote:
>
> > +static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
> > +{
> > +       return channel ? 15 : 14;
> > +}
>
> This addition does not make sense for the xtensa as it isn't even possible
> to enable PNP support (the only user of this function) on xtensa.

Nice catch! I had looked at this function earlier and only tried to infer
which architectures might have this based on who has those interrupt
numbers reserved for ISA devices, but looking at CONFIG_PNP is clearly
better here.

PNP depends on "ISA || ACPI", and this already rules out most
architectures. The remaining ones are:

* x86, ia64, alpha: These clearly use PNP based on-board devices on
   common machines, and use PC-style interrupts

* arm64, loongarch: These select PNP when ACPI is enabled. I don't
   think they actually use PNP, but for the moment the function needs to
  be defined, probably returning 0. Loongarch still lacks PCI support
  though, so asm/pci.h is not yet there.

* arm, mips, powerpc: Only a few older machines in each of these
  support ISA devices, and the function is probably machine specific.
  These all have a custom pci.h already and don't use the asm-generic
  version.

* m68k: there are two that enable CONFIG_ISA and one that enables
  CONFIG_PCI, but nothing that has both, so we don't need this
  function.

In summary, I think only x86 actually uses this function, and it is
correct there, everything else either has its own implementation
or does not need it, so the existing asm-generic/pci.h file can
just be folded into the x86 asm/pci.h. That is a great cleanup.

        Arnd