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#ifndef _GPXE_X86_IO_H
#define _GPXE_X86_IO_H
/** @file
*
* gPXE I/O API for x86
*
* i386 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,
* 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
*
*/
/*
* 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 phys_to_virt ( bus_addr );
}
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 32 bits
*
*/
#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 );
#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 );
/*
* 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 /* _GPXE_X86_IO_H */
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