rt-thread/libcpu/risc-v/nuclei/cpuport.c

258 lines
7.9 KiB
C

/*
* Copyright (c) 2006-2021, RT-Thread Development Team
* Copyright (c) 2019-Present Nuclei Limited. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2020/03/26 Huaqi Nuclei RISC-V Core porting code.
*/
#include <rthw.h>
#include <rtthread.h>
#include <sys/types.h>
#include <unistd.h>
#include "cpuport.h"
#define SYSTICK_TICK_CONST (SOC_TIMER_FREQ / RT_TICK_PER_SECOND)
/* Interrupt level for kernel systimer interrupt and software timer interrupt */
#define RT_KERNEL_INTERRUPT_LEVEL 0
/* Initial CSR MSTATUS value when thread created */
#define RT_INITIAL_MSTATUS (MSTATUS_MPP | MSTATUS_MPIE | MSTATUS_FS_INITIAL)
/**
* @brief from thread used interrupt context switch
*
*/
volatile rt_ubase_t rt_interrupt_from_thread = 0;
/**
* @brief to thread used interrupt context switch
*
*/
volatile rt_ubase_t rt_interrupt_to_thread = 0;
/**
* @brief flag to indicate context switch in interrupt or not
*
*/
volatile rt_ubase_t rt_thread_switch_interrupt_flag = 0;
/**
* @brief thread stack frame of saved context
*
*/
struct rt_hw_stack_frame
{
rt_ubase_t epc; /*!< epc - epc - program counter */
rt_ubase_t ra; /*!< x1 - ra - return address for jumps */
rt_ubase_t t0; /*!< x5 - t0 - temporary register 0 */
rt_ubase_t t1; /*!< x6 - t1 - temporary register 1 */
rt_ubase_t t2; /*!< x7 - t2 - temporary register 2 */
rt_ubase_t s0_fp; /*!< x8 - s0/fp - saved register 0 or frame pointer */
rt_ubase_t s1; /*!< x9 - s1 - saved register 1 */
rt_ubase_t a0; /*!< x10 - a0 - return value or function argument 0 */
rt_ubase_t a1; /*!< x11 - a1 - return value or function argument 1 */
rt_ubase_t a2; /*!< x12 - a2 - function argument 2 */
rt_ubase_t a3; /*!< x13 - a3 - function argument 3 */
rt_ubase_t a4; /*!< x14 - a4 - function argument 4 */
rt_ubase_t a5; /*!< x15 - a5 - function argument 5 */
#ifndef __riscv_32e
rt_ubase_t a6; /*!< x16 - a6 - function argument 6 */
rt_ubase_t a7; /*!< x17 - s7 - function argument 7 */
rt_ubase_t s2; /*!< x18 - s2 - saved register 2 */
rt_ubase_t s3; /*!< x19 - s3 - saved register 3 */
rt_ubase_t s4; /*!< x20 - s4 - saved register 4 */
rt_ubase_t s5; /*!< x21 - s5 - saved register 5 */
rt_ubase_t s6; /*!< x22 - s6 - saved register 6 */
rt_ubase_t s7; /*!< x23 - s7 - saved register 7 */
rt_ubase_t s8; /*!< x24 - s8 - saved register 8 */
rt_ubase_t s9; /*!< x25 - s9 - saved register 9 */
rt_ubase_t s10; /*!< x26 - s10 - saved register 10 */
rt_ubase_t s11; /*!< x27 - s11 - saved register 11 */
rt_ubase_t t3; /*!< x28 - t3 - temporary register 3 */
rt_ubase_t t4; /*!< x29 - t4 - temporary register 4 */
rt_ubase_t t5; /*!< x30 - t5 - temporary register 5 */
rt_ubase_t t6; /*!< x31 - t6 - temporary register 6 */
#endif
rt_ubase_t mstatus; /*!< - machine status register */
};
/**
* This function will initialize thread stack
*
* @param tentry the entry of thread
* @param parameter the parameter of entry
* @param stack_addr the beginning stack address
* @param texit the function will be called when thread exit
*
* @return stack address
*/
rt_uint8_t *rt_hw_stack_init(void *tentry,
void *parameter,
rt_uint8_t *stack_addr,
void *texit)
{
struct rt_hw_stack_frame *frame;
rt_uint8_t *stk;
int i;
stk = stack_addr + sizeof(rt_ubase_t);
stk = (rt_uint8_t *)RT_ALIGN_DOWN((rt_ubase_t)stk, REGBYTES);
stk -= sizeof(struct rt_hw_stack_frame);
frame = (struct rt_hw_stack_frame *)stk;
for (i = 0; i < sizeof(struct rt_hw_stack_frame) / sizeof(rt_ubase_t); i++)
{
((rt_ubase_t *)frame)[i] = 0xdeadbeef;
}
frame->ra = (rt_ubase_t)texit;
frame->a0 = (rt_ubase_t)parameter;
frame->epc = (rt_ubase_t)tentry;
frame->mstatus = RT_INITIAL_MSTATUS;
return stk;
}
/**
* @brief Do rt-thread context switch in interrupt context
*
* @param from thread sp of from thread
* @param to thread sp of to thread
*/
void rt_hw_context_switch_interrupt(rt_ubase_t from, rt_ubase_t to)
{
if (rt_thread_switch_interrupt_flag == 0)
rt_interrupt_from_thread = from;
rt_interrupt_to_thread = to;
rt_thread_switch_interrupt_flag = 1;
RT_YIELD();
}
/**
* @brief Do rt-thread context switch in task context
*
* @param from thread sp of from thread
* @param to thread sp of to thread
*/
void rt_hw_context_switch(rt_ubase_t from, rt_ubase_t to)
{
rt_hw_context_switch_interrupt(from, to);
}
/**
* @brief shutdown CPU
*
*/
rt_weak void rt_hw_cpu_shutdown()
{
rt_base_t level;
rt_kprintf("shutdown...\n");
level = rt_hw_interrupt_disable();
while (level)
{
RT_ASSERT(0);
}
}
/**
* @brief Do extra task switch code
*
* @details
*
* - Clear software timer interrupt request flag
* - clear rt_thread_switch_interrupt_flag to 0
*/
void rt_hw_taskswitch(void)
{
/* Clear Software IRQ, A MUST */
SysTimer_ClearSWIRQ();
rt_thread_switch_interrupt_flag = 0;
}
/**
* @brief Setup systimer and software timer interrupt
*
* @details
*
* - Set Systimer interrupt as NON-VECTOR interrupt with lowest interrupt level
* - Set software timer interrupt as VECTOR interrupt with lowest interrupt level
* - Enable these two interrupts
*/
void rt_hw_ticksetup(void)
{
uint64_t ticks = SYSTICK_TICK_CONST;
/* Make SWI and SysTick the lowest priority interrupts. */
/* Stop and clear the SysTimer. SysTimer as Non-Vector Interrupt */
SysTick_Config(ticks);
ECLIC_DisableIRQ(SysTimer_IRQn);
ECLIC_SetLevelIRQ(SysTimer_IRQn, RT_KERNEL_INTERRUPT_LEVEL);
ECLIC_SetShvIRQ(SysTimer_IRQn, ECLIC_NON_VECTOR_INTERRUPT);
ECLIC_EnableIRQ(SysTimer_IRQn);
/* Set SWI interrupt level to lowest level/priority, SysTimerSW as Vector Interrupt */
ECLIC_SetShvIRQ(SysTimerSW_IRQn, ECLIC_VECTOR_INTERRUPT);
ECLIC_SetLevelIRQ(SysTimerSW_IRQn, RT_KERNEL_INTERRUPT_LEVEL);
ECLIC_EnableIRQ(SysTimerSW_IRQn);
}
/**
* systimer interrupt handler eclic_mtip_handler
* is hard coded in startup_<Device>.S
* We define SysTick_Handler as eclic_mtip_handler
* for easy understanding
*/
#define SysTick_Handler eclic_mtip_handler
/**
* @brief This is the timer interrupt service routine.
*
*/
void SysTick_Handler(void)
{
/* Reload systimer */
SysTick_Reload(SYSTICK_TICK_CONST);
/* enter interrupt */
rt_interrupt_enter();
/* tick increase */
rt_tick_increase();
/* leave interrupt */
rt_interrupt_leave();
}
/**
* @brief Disable cpu interrupt
*
* @details
*
* - Disable cpu interrupt by clear MIE bit in MSTATUS
* - Return the previous value in MSTATUS before clear MIE bit
*
* @return the previous value in MSTATUS before clear MIE bit
*/
rt_base_t rt_hw_interrupt_disable(void)
{
return __RV_CSR_READ_CLEAR(CSR_MSTATUS, MSTATUS_MIE);
}
/**
* @brief Restore previous saved interrupt status
*
* @param level previous saved MSTATUS value
*/
void rt_hw_interrupt_enable(rt_base_t level)
{
__RV_CSR_WRITE(CSR_MSTATUS, level);
}