zephyr/arch/xtensa/include/xtensa_rtos.h

203 lines
7.1 KiB
C

/*
* Copyright (c) 2016 Cadence Design Systems, Inc.
* SPDX-License-Identifier: Apache-2.0
*/
/*
* RTOS-SPECIFIC INFORMATION FOR XTENSA RTOS ASSEMBLER SOURCES
* (FreeRTOS Port)
*
* This header is the primary glue between generic Xtensa RTOS support
* sources and a specific RTOS port for Xtensa. It contains definitions
* and macros for use primarily by Xtensa assembly coded source files.
*
* Macros in this header map callouts from generic Xtensa files to specific
* RTOS functions. It may also be included in C source files.
*
* Xtensa RTOS ports support all RTOS-compatible configurations of the Xtensa
* architecture, using the Xtensa hardware abstraction layer (HAL) to deal
* with configuration specifics.
*
* Should be included by all Xtensa generic and RTOS port-specific sources.
*/
#ifndef XTENSA_RTOS_H
#define XTENSA_RTOS_H
#ifdef __ASSEMBLER__
#include <xtensa/coreasm.h>
#else
#include <xtensa/config/core.h>
#endif
#include <xtensa/corebits.h>
#include <xtensa/config/system.h>
#include <xtensa/simcall.h>
/*
* Convert FreeRTOSConfig definitions to XTENSA definitions.
* However these can still be overridden from the command line.
*/
#ifndef XT_SIMULATOR
#if CONFIG_SIMULATOR_XTENSA
#define XT_SIMULATOR 1 /* Simulator mode */
#endif
#endif
#ifndef XT_BOARD
#if CONFIG_BOARD_XTENSA
#define XT_BOARD 1 /* Board mode */
#endif
#endif
#ifndef XT_TIMER_INDEX
#if defined configXT_TIMER_INDEX
/* Index of hardware timer to be used */
#define XT_TIMER_INDEX configXT_TIMER_INDEX
#endif
#endif
#ifndef XT_INTEXC_HOOKS
#if configXT_INTEXC_HOOKS
#define XT_INTEXC_HOOKS 1 /* Enables exception hooks */
#endif
#endif
#if (!XT_SIMULATOR) && (!XT_BOARD)
#error Either XT_SIMULATOR or XT_BOARD must be defined.
#endif
/*
* Name of RTOS (for messages).
*/
#define XT_RTOS_NAME Zephyr
/*
* Define for enabling RTOS specific code. Enable only one of below lines.
*/
#define XT_RTOS_IS_ZEPHYR_OS 1
#undef XT_RTOS_IS_FREE_RTOS
/*
* Check some Xtensa configuration requirements and report error if not met.
* Error messages can be customize to the RTOS port.
*/
#if !XCHAL_HAVE_XEA2
#error "Zephyr/Xtensa requires XEA2 (exception architecture 2)."
#endif
/*
* RTOS CALLOUT MACROS MAPPED TO RTOS PORT-SPECIFIC FUNCTIONS.
*
* Define callout macros used in generic Xtensa code to interact with the RTOS.
* The macros are simply the function names for use in calls from assembler
* code.
* Some of these functions may call back to generic functions in
* xtensa_context.h .
*/
/*
* Inform RTOS of entry into an interrupt handler that will affect it.
* Allows RTOS to manage switch to any system stack and count nesting level.
* Called after minimal context has been saved, with interrupts disabled.
* RTOS port can call0 _xt_context_save to save the rest of the context.
* May only be called from assembly code by the 'call0' instruction.
*/
#define XT_RTOS_INT_ENTER _zxt_int_enter
/*
* Inform RTOS of completion of an interrupt handler, and give control to
* RTOS to perform thread/task scheduling, switch back from any system stack
* and restore the context, and return to the exit dispatcher saved in the
* stack frame at XT_STK_EXIT. RTOS port can call0 _xt_context_restore
* to save the context saved in XT_RTOS_INT_ENTER via _xt_context_save,
* leaving only a minimal part of the context to be restored by the exit
* dispatcher. This function does not return to the place it was called from.
* May only be called from assembly code by the 'call0' instruction.
*/
#define XT_RTOS_INT_EXIT _zxt_int_exit
/*
* Inform RTOS of the occurrence of a tick timer interrupt.
* If RTOS has no tick timer, leave XT_RTOS_TIMER_INT undefined.
* May be coded in or called from C or assembly, per ABI conventions.
* RTOS may optionally define XT_TICK_PER_SEC in its own way (eg. macro).
*/
#define XT_RTOS_TIMER_INT _zxt_timer_int
#define XT_TICK_PER_SEC CONFIG_SYS_CLOCK_TICKS_PER_SEC
/*
* Return in a15 the base address of the co-processor state save area for the
* thread that triggered a co-processor exception, or 0 if no thread was
* running. The state save area is structured as defined in xtensa_context.h
* and has size XT_CP_SIZE. Co-processor instructions should only be used in
* thread code, never in interrupt handlers or the RTOS kernel. May only be
* called from assembly code and by the 'call0' instruction. A result of 0
* indicates an unrecoverable error.
*
* The implementation may use only a2-4, a15 (all other regs must be
* preserved).
*/
#define XT_RTOS_CP_STATE _zxt_task_coproc_state
/*
* HOOKS TO DYNAMICALLY INSTALL INTERRUPT AND EXCEPTION HANDLERS PER LEVEL.
*
* This Xtensa RTOS port provides hooks for dynamically installing exception
* and interrupt handlers to facilitate automated testing where each test case
* can install its own handler for user exceptions and each interrupt priority
* (level). This consists of an array of function pointers indexed by interrupt
* priority, with index 0 being the user exception handler hook. Each entry in
* the array is initially 0, and may be replaced by a function pointer of type
* XT_INTEXC_HOOK. A handler may be uninstalled by installing 0.
*
* The handler for low and medium priority obeys ABI conventions so may be
* coded in C. For the exception handler, the cause is the contents of the
* EXCCAUSE reg, and the result is -1 if handled, else the cause (still needs
* handling). For interrupt handlers, the cause is a mask of pending enabled
* interrupts at that level, and the result is the same mask with the bits for
* the handled interrupts cleared (those not cleared still need handling). This
* allows a test case to either pre-handle or override the default handling for
* the exception or interrupt level (see xtensa_vectors.S).
*
* High priority handlers (including NMI) must be coded in assembly, are always
* called by 'call0' regardless of ABI, must preserve all registers except a0,
* and must not use or modify the interrupted stack. The hook argument 'cause'
* is not passed and the result is ignored, so as not to burden the caller
* with saving and restoring a2 (it assumes only one interrupt per level - see
* the discussion in high priority interrupts in xtensa_vectors.S). The handler
* therefore should be coded to prototype 'void h(void)' even though it plugs
* into an array of handlers of prototype 'unsigned h(unsigned)'.
*
* To enable interrupt/exception hooks, compile the RTOS with
* '-DXT_INTEXC_HOOKS'.
*/
#define XT_INTEXC_HOOK_NUM (1 + XCHAL_NUM_INTLEVELS + XCHAL_HAVE_NMI)
#ifndef __ASSEMBLER__
typedef unsigned int (*XT_INTEXC_HOOK)(unsigned int cause);
extern volatile XT_INTEXC_HOOK _xt_intexc_hooks[XT_INTEXC_HOOK_NUM];
#endif
/*
* CONVENIENCE INCLUSIONS.
*
* Ensures RTOS specific files need only include this one Xtensa-generic
* header. These headers are included last so they can use the RTOS
* definitions above.
*/
#include "xtensa_context.h"
#ifdef XT_RTOS_TIMER_INT
#include "xtensa_timer.h"
#endif
#endif /* XTENSA_RTOS_H */