incubator-nuttx/arch/sim/src/up_cpuidlestack.c

109 lines
4.5 KiB
C

/****************************************************************************
* arch/sim/src/up_cpuidlestack.c
*
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <nuttx/arch.h>
#include <nuttx/sched.h>
#include "up_internal.h"
#ifdef CONFIG_SMP
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_cpu_idlestack
*
* Description:
* Allocate a stack for the CPU[n] IDLE task (n > 0) if appropriate and
* setup up stack-related information in the IDLE task's TCB. This
* function is always called before up_cpu_start(). This function is
* only called for the CPU's initial IDLE task; up_create_task is used for
* all normal tasks, pthreads, and kernel threads for all CPUs.
*
* The initial IDLE task is a special case because the CPUs can be started
* in different wans in different environments:
*
* 1. The CPU may already have been started and waiting in a low power
* state for up_cpu_start(). In this case, the IDLE thread's stack
* has already been allocated and is already in use. Here
* up_cpu_idlestack() only has to provide information about the
* already allocated stack.
*
* 2. The CPU may be disabled but started when up_cpu_start() is called.
* In this case, a new stack will need to be created for the IDLE
* thread and this function is then equivalent to:
*
* return up_create_stack(tcb, stack_size, TCB_FLAG_TTYPE_KERNEL);
*
* The following TCB fields must be initialized by this function:
*
* - adj_stack_size: Stack size after adjustment for hardware, processor,
* etc. This value is retained only for debug purposes.
* - stack_alloc_ptr: Pointer to allocated stack
* - adj_stack_ptr: Adjusted stack_alloc_ptr for HW. The initial value of
* the stack pointer.
*
* Inputs:
* - cpu: CPU index that indicates which CPU the IDLE task is
* being created for.
* - tcb: The TCB of new CPU IDLE task
* - stack_size: The requested stack size for the IDLE task. At least
* this much must be allocated. This should be
* CONFIG_SMP_IDLETHREAD_STACKSIZE.
*
****************************************************************************/
int up_cpu_idlestack(int cpu, FAR struct tcb_s *tcb, size_t stack_size)
{
/* REVISIT: I don't think anything is needed here */
tcb->adj_stack_size = stack_size;
tcb->stack_alloc_ptr = NULL;
tcb->adj_stack_ptr = NULL;
return OK;
}
#endif /* CONFIG_SMP */