/****************************************************************************
* arch/z16/common/up_usestack.c
*
* Copyright (C) 2008-2009, 2013 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 <stdint.h>
#include <sched.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/arch.h>
#include "up_internal.h"
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Global Functions
****************************************************************************/
/****************************************************************************
* Name: up_use_stack
*
* Description:
* Setup up stack-related information in the TCB using pre-allocated stack
* memory. This function is called only from task_init() when a task or
* kernel thread is started (never for pthreads).
*
* The following TCB fields must be initialized:
*
* - 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:
* - tcb: The TCB of new task
* - stack_size: The allocated stack size.
*
* NOTE: Unlike up_stack_create() and up_stack_release, this function
* does not require the task type (ttype) parameter. The TCB flags will
* always be set to provide the task type to up_use_stack() if it needs
* that information.
*
****************************************************************************/
int up_use_stack(struct tcb_s *tcb, void *stack, size_t stack_size)
{
size_t top_of_stack;
size_t size_of_stack;
/* Is there already a stack allocated? */
if (tcb->stack_alloc_ptr)
{
/* Yes.. Release the old stack allocation */
up_release_stack(tcb, tcb->flags & TCB_FLAG_TTYPE_MASK);
}
/* Save the new stack allocation */
tcb->stack_alloc_ptr = stack;
/* The ZNEO uses a push-down stack: the stack grows toward lower
* addresses in memory. The stack pointer register, points to the
* lowest, valid work address (the "top" of the stack). Items on
* the stack are referenced as positive word offsets from sp.
*/
top_of_stack = (uint32_t)tcb->stack_alloc_ptr + stack_size - 4;
/* Align the stack to word (4 byte) boundaries. This is probably
* a greater alignement than is required.
*/
top_of_stack &= ~3;
size_of_stack = top_of_stack - (uint32_t)tcb->stack_alloc_ptr + 4;
/* Save the adjusted stack values in the struct tcb_s */
tcb->adj_stack_size = top_of_stack;
tcb->adj_stack_size = size_of_stack;
return OK;
}
