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nios2: implement asm_inline_gcc functions for sys_io.h

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Nios II has no special instructions for testing bits, ffs, etc.
However, when poking memory-mapped peripherals, special *io variants
of ld and st instructions must be used to avoid issues with the
caches.

find_msb_set / find_lsb_set are implemented using universal GCC
compiler built-ins. It's not clear why this approach was not taken
on other arches.

The sys_in/sys_out/sys_io functions are completely removed as there
is no concept of these on Nios II.

sys_read/sys_write functions implemented using special GCC builtins
for the Nios II so that we don't have to use inline assembly.

Rest of the operations implemented in C, there is no requirement that
they be atomic.

Change-Id: Ic251fc7d7f342543dace4ccb3e429937b303215e
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2016-05-06 14:30:55 -07:00 • committed by Benjamin Walsh
commit c5a62dcc9c
1 changed files with 45 additions and 163 deletions
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208
include/arch/nios2/asm_inline_gcc.h
View file

@ -44,9 +44,9 @@ extern "C" {
static ALWAYS_INLINE unsigned int find_msb_set(uint32_t op)
{
ARG_UNUSED(op);
/* STUB */
return 0;
if (!op)
return 0;
return 32 - __builtin_clz(op);
}
/**
@ -63,257 +63,139 @@ static ALWAYS_INLINE unsigned int find_msb_set(uint32_t op)
static ALWAYS_INLINE unsigned int find_lsb_set(uint32_t op)
{
ARG_UNUSED(op);
/* STUB */
return 0;
return __builtin_ffs(op);
}
/* Implementation of sys_io.h's documented functions */
static inline __attribute__((always_inline))
void sys_out8(uint8_t data, io_port_t port)
{
ARG_UNUSED(data);
ARG_UNUSED(port);
/* STUB */
}
static inline __attribute__((always_inline))
uint8_t sys_in8(io_port_t port)
{
ARG_UNUSED(port);
/* STUB */
return 0;
}
static inline __attribute__((always_inline))
void sys_out16(uint16_t data, io_port_t port)
{
ARG_UNUSED(data);
ARG_UNUSED(port);
/* STUB */
}
static inline __attribute__((always_inline))
uint16_t sys_in16(io_port_t port)
{
ARG_UNUSED(port);
/* STUB */
return 0;
}
static inline __attribute__((always_inline))
void sys_out32(uint32_t data, io_port_t port)
{
ARG_UNUSED(data);
ARG_UNUSED(port);
/* STUB */
}
static inline __attribute__((always_inline))
uint32_t sys_in32(io_port_t port)
{
ARG_UNUSED(port);
/* STUB */
return 0;
}
static inline __attribute__((always_inline))
void sys_io_set_bit(io_port_t port, unsigned int bit)
{
ARG_UNUSED(port);
ARG_UNUSED(bit);
/* STUB */
}
static inline __attribute__((always_inline))
void sys_io_clear_bit(io_port_t port, unsigned int bit)
{
ARG_UNUSED(port);
ARG_UNUSED(bit);
/* STUB */
}
static inline __attribute__((always_inline))
int sys_io_test_bit(io_port_t port, unsigned int bit)
{
ARG_UNUSED(port);
ARG_UNUSED(bit);
/* STUB */
return 0;
}
static inline __attribute__((always_inline))
int sys_io_test_and_set_bit(io_port_t port, unsigned int bit)
{
ARG_UNUSED(port);
ARG_UNUSED(bit);
/* STUB */
return 0;
}
static inline __attribute__((always_inline))
int sys_io_test_and_clear_bit(io_port_t port, unsigned int bit)
{
ARG_UNUSED(port);
ARG_UNUSED(bit);
/* STUB */
return 0;
}
/* Using the *io variants of these instructions to prevent issues on
* devices that have an instruction/data cache
*/
static inline __attribute__((always_inline))
void sys_write8(uint8_t data, mm_reg_t addr)
{
ARG_UNUSED(addr);
ARG_UNUSED(data);
/* STUB */
__builtin_stbio((void *)addr, data);
}
static inline __attribute__((always_inline))
uint8_t sys_read8(mm_reg_t addr)
{
ARG_UNUSED(addr);
/* STUB */
return 0;
return __builtin_ldbuio((void *)addr);
}
static inline __attribute__((always_inline))
void sys_write16(uint16_t data, mm_reg_t addr)
{
ARG_UNUSED(addr);
ARG_UNUSED(data);
/* STUB */
__builtin_sthio((void *)addr, data);
}
static inline __attribute__((always_inline))
uint16_t sys_read16(mm_reg_t addr)
{
ARG_UNUSED(addr);
/* STUB */
return 0;
return __builtin_ldhuio((void *)addr);
}
static inline __attribute__((always_inline))
void sys_write32(uint32_t data, mm_reg_t addr)
{
ARG_UNUSED(addr);
ARG_UNUSED(data);
/* STUB */
__builtin_stwio((void *)addr, data);
}
static inline __attribute__((always_inline))
uint32_t sys_read32(mm_reg_t addr)
{
ARG_UNUSED(addr);
/* STUB */
return 0;
return __builtin_ldwio((void *)addr);
}
/* NIOS II does not have any special instructions for manipulating bits,
* so just read, modify, write in C
*/
static inline __attribute__((always_inline))
void sys_set_bit(mem_addr_t addr, unsigned int bit)
{
ARG_UNUSED(addr);
ARG_UNUSED(bit);
/* STUB */
sys_write32(sys_read32(addr) | (1 << bit), addr);
}
static inline __attribute__((always_inline))
void sys_clear_bit(mem_addr_t addr, unsigned int bit)
{
ARG_UNUSED(addr);
ARG_UNUSED(bit);
/* STUB */
sys_write32(sys_read32(addr) & ~(1 << bit), addr);
}
static inline __attribute__((always_inline))
int sys_test_bit(mem_addr_t addr, unsigned int bit)
{
ARG_UNUSED(addr);
ARG_UNUSED(bit);
/* STUB */
return 0;
return sys_read32(addr) & (1 << bit);
}
/* These are not required to be atomic, just do it in C */
static inline __attribute__((always_inline))
int sys_test_and_set_bit(mem_addr_t addr, unsigned int bit)
{
ARG_UNUSED(addr);
ARG_UNUSED(bit);
int ret;
/* STUB */
ret = sys_test_bit(addr, bit);
sys_set_bit(addr, bit);
return 0;
return ret;
}
static inline __attribute__((always_inline))
int sys_test_and_clear_bit(mem_addr_t addr, unsigned int bit)
{
ARG_UNUSED(addr);
ARG_UNUSED(bit);
int ret;
/* STUB */
ret = sys_test_bit(addr, bit);
sys_clear_bit(addr, bit);
return 0;
return ret;
}
static inline __attribute__((always_inline))
void sys_bitfield_set_bit(mem_addr_t addr, unsigned int bit)
{
ARG_UNUSED(addr);
ARG_UNUSED(bit);
/* STUB */
/* Doing memory offsets in terms of 32-bit values to prevent
* alignment issues
*/
sys_set_bit(addr + ((bit >> 5) << 2), bit & 0x1F);
}
static inline __attribute__((always_inline))
void sys_bitfield_clear_bit(mem_addr_t addr, unsigned int bit)
{
ARG_UNUSED(addr);
ARG_UNUSED(bit);
/* STUB */
sys_clear_bit(addr + ((bit >> 5) << 2), bit & 0x1F);
}
static inline __attribute__((always_inline))
int sys_bitfield_test_bit(mem_addr_t addr, unsigned int bit)
{
ARG_UNUSED(addr);
ARG_UNUSED(bit);
/* STUB */
return 0;
return sys_test_bit(addr + ((bit >> 5) << 2), bit & 0x1F);
}
static inline __attribute__((always_inline))
int sys_bitfield_test_and_set_bit(mem_addr_t addr, unsigned int bit)
{
ARG_UNUSED(addr);
ARG_UNUSED(bit);
int ret;
/* STUB */
ret = sys_bitfield_test_bit(addr, bit);
sys_bitfield_set_bit(addr, bit);
return 0;
return ret;
}
static inline __attribute__((always_inline))
int sys_bitfield_test_and_clear_bit(mem_addr_t addr, unsigned int bit)
{
ARG_UNUSED(addr);
ARG_UNUSED(bit);
int ret;
/* STUB */
ret = sys_bitfield_test_bit(addr, bit);
sys_bitfield_clear_bit(addr, bit);
return 0;
return ret;
}
#endif /* _ASMLANGUAGE */
#ifdef __cplusplus