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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file AVR/chcore.h
* @brief AVR architecture port macros and structures.
*
* @addtogroup AVR_CORE
* @{
*/
#ifndef _CHCORE_H_
#define _CHCORE_H_
#include <avr/io.h>
#include <avr/interrupt.h>
#if CH_DBG_ENABLE_STACK_CHECK
#error "option CH_DBG_ENABLE_STACK_CHECK not supported by this port"
#endif
/**
* @brief If enabled allows the idle thread to enter a low power mode.
*/
#ifndef ENABLE_WFI_IDLE
#define ENABLE_WFI_IDLE 0
#endif
/**
* @brief Macro defining the AVR architecture.
*/
#define CH_ARCHITECTURE_AVR
/**
* @brief Name of the implemented architecture.
*/
#define CH_ARCHITECTURE_NAME "AVR"
/**
* @brief Name of the architecture variant (optional).
*/
#define CH_CORE_VARIANT_NAME "MegaAVR"
/**
* @brief Name of the compiler supported by this port.
*/
#define CH_COMPILER_NAME "GCC "__VERSION__
/**
* @brief Port-specific information string.
*/
#define CH_PORT_INFO "None"
/**
* @brief 8 bits stack and memory alignment enforcement.
*/
typedef uint8_t stkalign_t;
/**
* @brief Interrupt saved context.
* @details This structure represents the stack frame saved during a
* preemption-capable interrupt handler.
* @note The field @p _next is not part of the context, it represents the
* offset of the structure relative to the stack pointer.
*/
struct extctx {
uint8_t _next;
uint8_t r31;
uint8_t r30;
uint8_t r27;
uint8_t r26;
uint8_t r25;
uint8_t r24;
uint8_t r23;
uint8_t r22;
uint8_t r21;
uint8_t r20;
uint8_t r19;
uint8_t r18;
uint8_t sr;
uint8_t r1;
uint8_t r0;
uint16_t pc;
};
/**
* @brief System saved context.
* @details This structure represents the inner stack frame during a context
* switching.
* @note The field @p _next is not part of the context, it represents the
* offset of the structure relative to the stack pointer.
*/
struct intctx {
uint8_t _next;
uint8_t r29;
uint8_t r28;
uint8_t r17;
uint8_t r16;
uint8_t r15;
uint8_t r14;
uint8_t r13;
uint8_t r12;
uint8_t r11;
uint8_t r10;
uint8_t r9;
uint8_t r8;
uint8_t r7;
uint8_t r6;
uint8_t r5;
uint8_t r4;
uint8_t r3;
uint8_t r2;
uint8_t pcl;
uint8_t pch;
};
/**
* @brief Platform dependent part of the @p Thread structure.
* @details In the AVR port this structure just holds a pointer to the
* @p intctx structure representing the stack pointer at the time
* of the context switch.
*/
struct context {
struct intctx *sp;
};
/**
* @brief Platform dependent part of the @p chThdCreateI() API.
* @details This code usually setup the context switching frame represented
* by an @p intctx structure.
*/
#define SETUP_CONTEXT(workspace, wsize, pf, arg) { \
tp->p_ctx.sp = (struct intctx*)((uint8_t *)workspace + wsize - \
sizeof(struct intctx)); \
tp->p_ctx.sp->r2 = (int)pf; \
tp->p_ctx.sp->r3 = (int)pf >> 8; \
tp->p_ctx.sp->r4 = (int)arg; \
tp->p_ctx.sp->r5 = (int)arg >> 8; \
tp->p_ctx.sp->pcl = (int)_port_thread_start >> 8; \
tp->p_ctx.sp->pch = (int)_port_thread_start; \
}
/**
* @brief Stack size for the system idle thread.
* @details This size depends on the idle thread implementation, usually
* the idle thread should take no more space than those reserved
* by @p PORT_INT_REQUIRED_STACK.
* @note In this port it is set to 8.
*/
#ifndef PORT_IDLE_THREAD_STACK_SIZE
#define PORT_IDLE_THREAD_STACK_SIZE 8
#endif
/**
* @brief Per-thread stack overhead for interrupts servicing.
* @details This constant is used in the calculation of the correct working
* area size.
* This value can be zero on those architecture where there is a
* separate interrupt stack and the stack space between @p intctx and
* @p extctx is known to be zero.
* @note In this port the default is 32 bytes per thread.
*/
#ifndef PORT_INT_REQUIRED_STACK
#define PORT_INT_REQUIRED_STACK 32
#endif
/**
* @brief Enforces a correct alignment for a stack area size value.
*/
#define STACK_ALIGN(n) ((((n) - 1) | (sizeof(stkalign_t) - 1)) + 1)
/**
* @brief Computes the thread working area global size.
*/
#define THD_WA_SIZE(n) STACK_ALIGN(sizeof(Thread) + \
(sizeof(struct intctx) - 1) + \
(sizeof(struct extctx) - 1) + \
(n) + (PORT_INT_REQUIRED_STACK))
/**
* @brief Static working area allocation.
* @details This macro is used to allocate a static thread working area
* aligned as both position and size.
*/
#define WORKING_AREA(s, n) stkalign_t s[THD_WA_SIZE(n) / sizeof(stkalign_t)]
/**
* @brief IRQ prologue code.
* @details This macro must be inserted at the start of all IRQ handlers
* enabled to invoke system APIs.
* @note This code tricks the compiler to save all the specified registers
* by "touching" them.
*/
#define PORT_IRQ_PROLOGUE() { \
asm ("" : : : "r18", "r19", "r20", "r21", "r22", "r23", "r24", \
"r25", "r26", "r27", "r30", "r31"); \
}
/**
* @brief IRQ epilogue code.
* @details This macro must be inserted at the end of all IRQ handlers
* enabled to invoke system APIs.
*/
#define PORT_IRQ_EPILOGUE() { \
dbg_check_lock(); \
if (chSchIsPreemptionRequired()) \
chSchDoReschedule(); \
dbg_check_unlock(); \
}
/**
* @brief IRQ handler function declaration.
* @note @p id can be a function name or a vector number depending on the
* port implementation.
*/
#define PORT_IRQ_HANDLER(id) ISR(id)
/**
* @brief Port-related initialization code.
* @note This function is empty in this port.
*/
#define port_init()
/**
* @brief Kernel-lock action.
* @details Usually this function just disables interrupts but may perform more
* actions.
* @note Implemented as global interrupt disable.
*/
#define port_lock() asm volatile ("cli" : : : "memory")
/**
* @brief Kernel-unlock action.
* @details Usually this function just enables interrupts but may perform more
* actions.
* @note Implemented as global interrupt enable.
*/
#define port_unlock() asm volatile ("sei" : : : "memory")
/**
* @brief Kernel-lock action from an interrupt handler.
* @details This function is invoked before invoking I-class APIs from
* interrupt handlers. The implementation is architecture dependent,
* in its simplest form it is void.
* @note This function is empty in this port.
*/
#define port_lock_from_isr()
/**
* @brief Kernel-unlock action from an interrupt handler.
* @details This function is invoked after invoking I-class APIs from interrupt
* handlers. The implementation is architecture dependent, in its
* simplest form it is void.
* @note This function is empty in this port.
*/
#define port_unlock_from_isr()
/**
* @brief Disables all the interrupt sources.
* @note Of course non maskable interrupt sources are not included.
* @note Implemented as global interrupt disable.
*/
#define port_disable() asm volatile ("cli" : : : "memory")
/**
* @brief Disables the interrupt sources below kernel-level priority.
* @note Interrupt sources above kernel level remains enabled.
* @note Same as @p port_disable() in this port, there is no difference
* between the two states.
*/
#define port_suspend() asm volatile ("cli" : : : "memory")
/**
* @brief Enables all the interrupt sources.
* @note Implemented as global interrupt enable.
*/
#define port_enable() asm volatile ("sei" : : : "memory")
/**
* @brief Enters an architecture-dependent IRQ-waiting mode.
* @details The function is meant to return when an interrupt becomes pending.
* The simplest implementation is an empty function or macro but this
* would not take advantage of architecture-specific power saving
* modes.
* @note This port function is implemented as inlined code for performance
* reasons.
*/
#if ENABLE_WFI_IDLE != 0
#define port_wait_for_interrupt() { \
asm volatile ("sleep" : : : "memory"); \
}
#else
#define port_wait_for_interrupt()
#endif
#ifdef __cplusplus
extern "C" {
#endif
void port_switch(Thread *ntp, Thread *otp);
void port_halt(void);
void _port_thread_start(void);
#ifdef __cplusplus
}
#endif
#endif /* _CHCORE_H_ */
/** @} */
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