stk_arch_risc-v.h

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/*
 * SuperTinyKernel(TM) RTOS: Lightweight High-Performance Deterministic C++ RTOS for Embedded Systems.
 *
 * Source: https://github.com/SuperTinyKernel-RTOS
 *
 * Copyright (c) 2022-2026 Neutron Code Limited <stk@neutroncode.com>. All Rights Reserved.
 * License: MIT License, see LICENSE for a full text.
 */
 
#ifndef STK_ARCH_RISC_V_H_
#define STK_ARCH_RISC_V_H_
 
#include "stk_common.h"

 
namespace stk {

class PlatformRiscV : public IPlatform
{
public:
    STK_VIRT_DTOR ~PlatformRiscV() = default;

    class ISpecificEventHandler
    {
    public:
        virtual bool OnException(Word cause) = 0;
    };
 
    void Initialize(IEventHandler *event_handler, IKernelService *service, uint32_t resolution_us, Stack *exit_trap) override;
    void Start() override;
    void Stop() override;
    void InitStack(EStackType stack_type, Stack *stack, IStackMemory *stack_memory, ITask *user_task) override;
    uint32_t GetTickResolution() const override;
    Cycles GetSysTimerCount() const override;
    uint32_t GetSysTimerFrequency() const override;
    void SwitchToNext() override;
    void ForceContextSwitch(TId id) override;
    void Sleep(Timeout ticks) override;
    bool SleepUntil(Ticks timestamp) override;
    EWaitResult Wait(ISyncObject *sync_obj, IMutex *mutex, Timeout timeout) override;
    void ProcessTick() override;
    void ProcessHardFault() override;
    void SetEventOverrider(IEventOverrider *overrider, bool non_secure) override;
    Word GetCallerSP() const override;
    TId GetTid() const override;
    Timeout Suspend() override;
    void Resume(Timeout elapsed_ticks) override;
    void SetCpuFrequency(uint8_t core_id, uint32_t frequency) override;
 
    void SetSpecificEventHandler(ISpecificEventHandler *handler);
};

typedef PlatformRiscV PlatformDefault;
 
// Inline TLS via x4/tp. Active when both STK_TLS and STK_TLS_PREFER_REGISTER are enabled.
#if STK_TLS && STK_TLS_PREFER_REGISTER

static __stk_forceinline Word GetTls()
{
    Word tp;
    __asm volatile("mv %0, tp" : "=r"(tp) : /* input: none */ : /* clobbers: none */);
    return tp;
}

static __stk_forceinline void SetTls(Word tp)
{
    __asm volatile("mv tp, %0" : /* output: none */ : "r"(tp) : /* clobbers: none */);
}
 
// Notify stk_arch.h that we defined inline versions of GetTls/SetTls.
#define STK_INLINE_TLS (1)
 
#endif // STK_TLS && STK_TLS_PREFER_REGISTER
 
} // namespace stk

static __stk_forceinline void __stk_dmb() { __asm volatile("fence rw, rw" ::: "memory"); }

#ifndef STK_SUBMICORSECOND_PRECISION_TIMER
    #define STK_SUBMICORSECOND_PRECISION_TIMER 0
#endif

#ifndef STK_SYSTEM_CORE_CLOCK_FREQUENCY
    #define STK_SYSTEM_CORE_CLOCK_FREQUENCY 150000000U
#endif

extern "C" volatile uint32_t STK_SYSTEM_CORE_CLOCK_VAR;
 
#endif /* STK_ARCH_RISC_V_H_ */