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/*
* Copyright (c) 2006-2025, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2018-10-28 Bernard The unify RISC-V porting code.
* 2025-04-20 GuEe-GUI Port ffsN and clz, spinlock
*/
#include <rthw.h>
#include <rtthread.h>
#include <asm-generic.h>
#ifdef RT_USING_CPU_FFS
int __rt_ffs(int value)
{
#ifdef __GNUC__
return __builtin_ffs(value);
#else
#error Unsupport ffs
#endif
}
unsigned long __rt_ffsl(unsigned long value)
{
#ifdef __GNUC__
return __builtin_ffsl(value);
#else
#error Unsupport ffsl
#endif
}
unsigned long __rt_clz(unsigned long value)
{
#ifdef __GNUC__
return __builtin_clzl(value);
#else
#error Unsupport clz
#endif
}
#endif /* RT_USING_CPU_FFS */
#ifdef RT_USING_SMART
#if defined(RT_USING_SMP) && RT_CPUS_NR > 1
extern void percpu_write(rt_ubase_t offset, const void *data, rt_size_t size);
void rt_hw_set_process_id(int pid)
{
percpu_write(0, &pid, sizeof(pid));
}
#else
static int process_id;
void rt_hw_set_process_id(int pid)
{
process_id = pid;
}
#endif /* RT_USING_SMP && RT_CPUS_NR > 1 */
#endif /* RT_USING_SMART */
#ifdef RT_USING_SMP
void rt_hw_spin_lock_init(rt_hw_spinlock_t *lock)
{
lock->slock = 0;
}
void rt_hw_spin_lock(rt_hw_spinlock_t *lock)
{
unsigned long tmp;
unsigned short ticket;
/*
* The two 16-bit counters occupy the low word, also on RV64.
* Use an AMO so ticket allocation cannot livelock with an unlock
* retrying LR/SC on the same reservation. Word width wraps next at 16 bits.
*/
__asm__ volatile (
"amoadd.w.aqrl %0, %2, (%1)"
: "=&r" (tmp)
: "r" (&lock->slock), "r" (1UL << 16)
: "memory");
ticket = (tmp >> 16) & 0xffff;
while (HWREG16(&lock->tickets.owner) != ticket)
{
__asm__ volatile (OPC_PAUSE_I);
}
/* Order critical-section accesses after observing the owner's release. */
rt_hw_barrier();
}
void rt_hw_spin_unlock(rt_hw_spinlock_t *lock)
{
/*
* Only the holder writes owner. Publish critical-section accesses before
* advancing it; a halfword store preserves concurrently allocated tickets.
*/
rt_hw_barrier();
HWREG16(&lock->tickets.owner) =
(unsigned short)(HWREG16(&lock->tickets.owner) + 1);
rt_hw_barrier();
}
#endif /* RT_USING_SMP */
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