[RFC PATCH 2/2] asm-generic: Add new pci.h and use it

[Stafford Horne]

The asm/pci.h used for many newer architectures share similar
definitions.  Move the common parts to asm-generic/pci.h to allow for
sharing code.

Two things to note are:

 - isa_dma_bridge_buggy, traditionally this is defined in asm/dma.h but
   these architectures avoid creating that file and add the definition
   to asm/pci.h.
 - ARCH_GENERIC_PCI_MMAP_RESOURCE, csky does not define this so we
   undefine it after including asm-generic/pci.h.  Why doesn't csky
   define it?

Suggested-by: Arnd Bergmann <arnd at arndb.de>
Link: https://lore.kernel.org/lkml/CAK8P3a0JmPeczfmMBE__vn=Jbvf=nkbpVaZCycyv40pZNCJJXQ@mail.gmail.com/
Signed-off-by: Stafford Horne <shorne at gmail.com>
---
 arch/arm64/include/asm/pci.h | 18 ++--------------
 arch/csky/include/asm/pci.h  | 24 ++++------------------
 arch/riscv/include/asm/pci.h | 25 +++-------------------
 arch/um/include/asm/pci.h    | 24 ++--------------------
 include/asm-generic/pci.h    | 40 ++++++++++++++++++++++++++++++++++++
 5 files changed, 51 insertions(+), 80 deletions(-)
 create mode 100644 include/asm-generic/pci.h

diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h
index b33ca260e3c9..016eb6b46dc0 100644
--- a/arch/arm64/include/asm/pci.h
+++ b/arch/arm64/include/asm/pci.h
@@ -9,7 +9,6 @@
 #include <asm/io.h>
 
 #define PCIBIOS_MIN_IO		0x1000
-#define PCIBIOS_MIN_MEM		0
 
 /*
  * Set to 1 if the kernel should re-assign all PCI bus numbers
@@ -18,21 +17,8 @@
 	(pci_has_flag(PCI_REASSIGN_ALL_BUS))
 
 #define arch_can_pci_mmap_wc() 1
-#define ARCH_GENERIC_PCI_MMAP_RESOURCE	1
 
-extern int isa_dma_bridge_buggy;
-
-#ifdef CONFIG_PCI
-static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
-{
-	/* no legacy IRQ on arm64 */
-	return -ENODEV;
-}
-
-static inline int pci_proc_domain(struct pci_bus *bus)
-{
-	return 1;
-}
-#endif  /* CONFIG_PCI */
+/* Generic PCI */
+#include <asm-generic/pci.h>
 
 #endif  /* __ASM_PCI_H */
diff --git a/arch/csky/include/asm/pci.h b/arch/csky/include/asm/pci.h
index ebc765b1f78b..44866c1ad461 100644
--- a/arch/csky/include/asm/pci.h
+++ b/arch/csky/include/asm/pci.h
@@ -9,26 +9,10 @@
 
 #include <asm/io.h>
 
-#define PCIBIOS_MIN_IO		0
-#define PCIBIOS_MIN_MEM		0
+/* Generic PCI */
+#include <asm-generic/pci.h>
 
-/* C-SKY shim does not initialize PCI bus */
-#define pcibios_assign_all_busses() 1
-
-extern int isa_dma_bridge_buggy;
-
-#ifdef CONFIG_PCI
-static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
-{
-	/* no legacy IRQ on csky */
-	return -ENODEV;
-}
-
-static inline int pci_proc_domain(struct pci_bus *bus)
-{
-	/* always show the domain in /proc */
-	return 1;
-}
-#endif  /* CONFIG_PCI */
+/* csky doesn't use generic pci resource mapping */
+#undef ARCH_GENERIC_PCI_MMAP_RESOURCE
 
 #endif  /* __ASM_CSKY_PCI_H */
diff --git a/arch/riscv/include/asm/pci.h b/arch/riscv/include/asm/pci.h
index 7fd52a30e605..12ce8150cfb0 100644
--- a/arch/riscv/include/asm/pci.h
+++ b/arch/riscv/include/asm/pci.h
@@ -12,29 +12,7 @@
 
 #include <asm/io.h>
 
-#define PCIBIOS_MIN_IO		0
-#define PCIBIOS_MIN_MEM		0
-
-/* RISC-V shim does not initialize PCI bus */
-#define pcibios_assign_all_busses() 1
-
-#define ARCH_GENERIC_PCI_MMAP_RESOURCE 1
-
-extern int isa_dma_bridge_buggy;
-
 #ifdef CONFIG_PCI
-static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
-{
-	/* no legacy IRQ on risc-v */
-	return -ENODEV;
-}
-
-static inline int pci_proc_domain(struct pci_bus *bus)
-{
-	/* always show the domain in /proc */
-	return 1;
-}
-
 #ifdef	CONFIG_NUMA
 
 static inline int pcibus_to_node(struct pci_bus *bus)
@@ -50,4 +28,7 @@ static inline int pcibus_to_node(struct pci_bus *bus)
 
 #endif  /* CONFIG_PCI */
 
+/* Generic PCI */
+#include <asm-generic/pci.h>
+
 #endif  /* _ASM_RISCV_PCI_H */
diff --git a/arch/um/include/asm/pci.h b/arch/um/include/asm/pci.h
index da13fd5519ef..34fe4921b5fa 100644
--- a/arch/um/include/asm/pci.h
+++ b/arch/um/include/asm/pci.h
@@ -4,28 +4,8 @@
 #include <linux/types.h>
 #include <asm/io.h>
 
-#define PCIBIOS_MIN_IO		0
-#define PCIBIOS_MIN_MEM		0
-
-#define pcibios_assign_all_busses() 1
-
-extern int isa_dma_bridge_buggy;
-
-#ifdef CONFIG_PCI
-static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
-{
-	/* no legacy IRQs */
-	return -ENODEV;
-}
-#endif
-
-#ifdef CONFIG_PCI_DOMAINS
-static inline int pci_proc_domain(struct pci_bus *bus)
-{
-	/* always show the domain in /proc */
-	return 1;
-}
-#endif  /* CONFIG_PCI */
+/* Generic PCI */
+#include <asm-generic/pci.h>
 
 #ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
 /*
diff --git a/include/asm-generic/pci.h b/include/asm-generic/pci.h
new file mode 100644
index 000000000000..1aa4d7a08aca
--- /dev/null
+++ b/include/asm-generic/pci.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __ASM_GENERIC_PCI_H
+#define __ASM_GENERIC_PCI_H
+
+#include <linux/types.h>
+
+#ifndef PCIBIOS_MIN_IO
+#define PCIBIOS_MIN_IO		0
+#endif
+
+#define PCIBIOS_MIN_MEM		0
+
+#ifndef pcibios_assign_all_busses
+/* For bootloaders that do not initialize the PCI bus */
+#define pcibios_assign_all_busses() 1
+#endif
+
+extern int isa_dma_bridge_buggy;
+
+/* Enable generic resource mapping code in drivers/pci/ */
+#define ARCH_GENERIC_PCI_MMAP_RESOURCE
+
+#ifdef CONFIG_PCI
+
+static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
+{
+	/* no legacy ide irq support */
+	return -ENODEV;
+}
+
+static inline int pci_proc_domain(struct pci_bus *bus)
+{
+	/* always show the domain in /proc */
+	return 1;
+}
+
+#endif /* CONFIG_PCI */
+
+#endif /* __ASM_GENERIC_PCI_H */
-- 
2.36.1