[PATCH v1 1/3] ARM64 LPC: indirect ISA PORT IO introduced

[Rongrong Zou]

Indirect ISA port I/O accessing introduced, vendors can hook
their own in/out function to general inb/outb. Drivers can access
legacy ISA I/O port by inb/outb as it is done in x86 platform.

Signed-off-by: Rongrong Zou <zourongrong@xxxxxxxxx>
---
 arch/arm64/Kconfig.platforms |  5 ++-
 arch/arm64/include/asm/io.h  | 78 ++++++++++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/setup.c    |  5 +++
 3 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms
index 4043c35..98ae206 100644
--- a/arch/arm64/Kconfig.platforms
+++ b/arch/arm64/Kconfig.platforms
@@ -127,5 +127,8 @@ config ARCH_ZYNQMP
 	bool "Xilinx ZynqMP Family"
 	help
 	  This enables support for Xilinx ZynqMP Family
-
+config ARM64_INDIRECT_PIO
+	bool "ARM64 Indirect port I/O"
+	help
+	  This enables support for ARM64 indirect port I/O
 endmenu
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 44be1e0..0041f3b 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -193,6 +193,84 @@ extern void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size);
  */
 #define xlate_dev_kmem_ptr(p)	p
 
+#ifdef CONFIG_ARM64_INDIRECT_PIO
+#define DEF_PCI_HOOK_pio(x)   x
+#else
+#define DEF_PCI_HOOK_pio(x)   NULL
+#endif
+
+/*
+ * This value is equal to PCIBIOS_MIN_IO
+ */
+#define LEGACY_ISA_PORT_MAX 0x1000
+
+extern struct arm64_isa_io {
+	u8 (*inb)(unsigned long port);
+	u16 (*inw)(unsigned long port);
+	u32 (*inl)(unsigned long port);
+	void (*outb)(u8 value, unsigned long port);
+	void (*outw)(u16 value, unsigned long port);
+	void (*outl)(u32 value, unsigned long port);
+} arm64_isa_io;
+
+#define inb inb
+static inline u8 inb(unsigned long port)
+{
+	if (DEF_PCI_HOOK_pio(arm64_isa_io.inb) &&
+	    port < LEGACY_ISA_PORT_MAX)
+		return arm64_isa_io.inb(port);
+	return readb(PCI_IOBASE + port);
+}
+
+#define inw inw
+static inline u16 inw(unsigned long port)
+{
+	if (DEF_PCI_HOOK_pio(arm64_isa_io.inw) &&
+	    port < LEGACY_ISA_PORT_MAX)
+		return arm64_isa_io.inw(port);
+	return readw(PCI_IOBASE + port);
+}
+
+#define inl inl
+static inline u32 inl(unsigned long port)
+{
+	if (DEF_PCI_HOOK_pio(arm64_isa_io.inl) &&
+	    port < LEGACY_ISA_PORT_MAX)
+		return arm64_isa_io.inl(port);
+	return readl(PCI_IOBASE + port);
+}
+
+#define outb outb
+static inline void outb(u8 val, unsigned long port)
+{
+	if (DEF_PCI_HOOK_pio(arm64_isa_io.outb) &&
+	    port < LEGACY_ISA_PORT_MAX)
+		arm64_isa_io.outb(val, port);
+	else
+		writeb(val, PCI_IOBASE + port);
+}
+
+#define outw outw
+static inline void outw(u16 val, unsigned long port)
+{
+	if (DEF_PCI_HOOK_pio(arm64_isa_io.outw) &&
+	    port < LEGACY_ISA_PORT_MAX)
+		arm64_isa_io.outw(val, port);
+	else
+		writew(val, PCI_IOBASE + port);
+}
+
+#define outl outl
+static inline void outl(u32 val, unsigned long port)
+{
+	if (DEF_PCI_HOOK_pio(arm64_isa_io.outl) &&
+	    port < LEGACY_ISA_PORT_MAX)
+		arm64_isa_io.outl(val, port);
+	else
+		writel(val, PCI_IOBASE + port);
+}
+
+
 #include <asm-generic/io.h>
 
 /*
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 8119479..c689dd7 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -381,3 +381,8 @@ static int __init topology_init(void)
 	return 0;
 }
 subsys_initcall(topology_init);
+
+#if defined(CONFIG_ARM64_INDIRECT_PIO)
+struct arm64_isa_io arm64_isa_io;
+EXPORT_SYMBOL_GPL(arm64_isa_io);
+#endif
-- 
1.9.1

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