--- /dev/null
+#ifndef _IPXE_X86_IO_H
+#define _IPXE_X86_IO_H
+
+/** @file
+ *
+ * iPXE I/O API for x86
+ *
+ * x86 uses direct pointer dereferences for accesses to memory-mapped
+ * I/O space, and the inX/outX instructions for accesses to
+ * port-mapped I/O space.
+ *
+ * 64-bit atomic accesses (readq() and writeq()) use MMX instructions
+ * under i386, and will crash original Pentium and earlier CPUs.
+ * Fortunately, no hardware that requires atomic 64-bit accesses will
+ * physically fit into a machine with such an old CPU anyway.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#ifdef IOAPI_X86
+#define IOAPI_PREFIX_x86
+#else
+#define IOAPI_PREFIX_x86 __x86_
+#endif
+
+/*
+ * Memory space mappings
+ *
+ */
+
+/** Page shift */
+#define PAGE_SHIFT 12
+
+/*
+ * Physical<->Bus and Bus<->I/O address mappings
+ *
+ */
+
+static inline __always_inline unsigned long
+IOAPI_INLINE ( x86, phys_to_bus ) ( unsigned long phys_addr ) {
+ return phys_addr;
+}
+
+static inline __always_inline unsigned long
+IOAPI_INLINE ( x86, bus_to_phys ) ( unsigned long bus_addr ) {
+ return bus_addr;
+}
+
+static inline __always_inline void *
+IOAPI_INLINE ( x86, ioremap ) ( unsigned long bus_addr, size_t len __unused ) {
+ return ( bus_addr ? phys_to_virt ( bus_addr ) : NULL );
+}
+
+static inline __always_inline void
+IOAPI_INLINE ( x86, iounmap ) ( volatile const void *io_addr __unused ) {
+ /* Nothing to do */
+}
+
+static inline __always_inline unsigned long
+IOAPI_INLINE ( x86, io_to_bus ) ( volatile const void *io_addr ) {
+ return virt_to_phys ( io_addr );
+}
+
+/*
+ * MMIO reads and writes up to native word size
+ *
+ */
+
+#define X86_READX( _api_func, _type ) \
+static inline __always_inline _type \
+IOAPI_INLINE ( x86, _api_func ) ( volatile _type *io_addr ) { \
+ return *io_addr; \
+}
+X86_READX ( readb, uint8_t );
+X86_READX ( readw, uint16_t );
+X86_READX ( readl, uint32_t );
+#ifdef __x86_64__
+X86_READX ( readq, uint64_t );
+#endif
+
+#define X86_WRITEX( _api_func, _type ) \
+static inline __always_inline void \
+IOAPI_INLINE ( x86, _api_func ) ( _type data, \
+ volatile _type *io_addr ) { \
+ *io_addr = data; \
+}
+X86_WRITEX ( writeb, uint8_t );
+X86_WRITEX ( writew, uint16_t );
+X86_WRITEX ( writel, uint32_t );
+#ifdef __x86_64__
+X86_WRITEX ( writeq, uint64_t );
+#endif
+
+/*
+ * PIO reads and writes up to 32 bits
+ *
+ */
+
+#define X86_INX( _insn_suffix, _type, _reg_prefix ) \
+static inline __always_inline _type \
+IOAPI_INLINE ( x86, in ## _insn_suffix ) ( volatile _type *io_addr ) { \
+ _type data; \
+ __asm__ __volatile__ ( "in" #_insn_suffix " %w1, %" _reg_prefix "0" \
+ : "=a" ( data ) : "Nd" ( io_addr ) ); \
+ return data; \
+} \
+static inline __always_inline void \
+IOAPI_INLINE ( x86, ins ## _insn_suffix ) ( volatile _type *io_addr, \
+ _type *data, \
+ unsigned int count ) { \
+ unsigned int discard_D; \
+ __asm__ __volatile__ ( "rep ins" #_insn_suffix \
+ : "=D" ( discard_D ) \
+ : "d" ( io_addr ), "c" ( count ), \
+ "0" ( data ) ); \
+}
+X86_INX ( b, uint8_t, "b" );
+X86_INX ( w, uint16_t, "w" );
+X86_INX ( l, uint32_t, "k" );
+
+#define X86_OUTX( _insn_suffix, _type, _reg_prefix ) \
+static inline __always_inline void \
+IOAPI_INLINE ( x86, out ## _insn_suffix ) ( _type data, \
+ volatile _type *io_addr ) { \
+ __asm__ __volatile__ ( "out" #_insn_suffix " %" _reg_prefix "0, %w1" \
+ : : "a" ( data ), "Nd" ( io_addr ) ); \
+} \
+static inline __always_inline void \
+IOAPI_INLINE ( x86, outs ## _insn_suffix ) ( volatile _type *io_addr, \
+ const _type *data, \
+ unsigned int count ) { \
+ unsigned int discard_S; \
+ __asm__ __volatile__ ( "rep outs" #_insn_suffix \
+ : "=S" ( discard_S ) \
+ : "d" ( io_addr ), "c" ( count ), \
+ "0" ( data ) ); \
+}
+X86_OUTX ( b, uint8_t, "b" );
+X86_OUTX ( w, uint16_t, "w" );
+X86_OUTX ( l, uint32_t, "k" );
+
+/*
+ * Slow down I/O
+ *
+ */
+
+static inline __always_inline void
+IOAPI_INLINE ( x86, iodelay ) ( void ) {
+ __asm__ __volatile__ ( "outb %al, $0x80" );
+}
+
+/*
+ * Memory barrier
+ *
+ */
+
+static inline __always_inline void
+IOAPI_INLINE ( x86, mb ) ( void ) {
+ __asm__ __volatile__ ( "lock; addl $0, 0(%%esp)" : : : "memory" );
+}
+
+#endif /* _IPXE_X86_IO_H */
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