109 lines
4.0 KiB
C
109 lines
4.0 KiB
C
/* cmdPkt.c - library to manage statically allocated command packets */
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/*
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* Copyright (c) 2012, 2014 Wind River Systems, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1) Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2) Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3) Neither the name of Wind River Systems nor the names of its contributors
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* may be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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DESCRIPTION
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A command packet is an opaque data structure that maps to a k_args without
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exposing its innards. It allows a subsystem, like a driver, that needs its
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fibers or ISRs to communicate with tasks to define a set of such packets to
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be passed to the isr_xxx routines, such as isr_sem_give(), that, in turn,
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needs to obtain command packets to interact with the microkernel.
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Each command packet set is created in global memory using ...
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CMD_PKT_SET_INSTANCE(set variable name, # of command packets in the set);
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Once created, the command packet set is accessed using ...
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CMD_PKT_SET(set variable name).<member field name>
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A command packet set is a simple ring buffer. No error checking is performed
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when a command packet is retrieved from the set. Each obtained command packet
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is implicitly released once the command packet has been processed. Thus, it is
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important that each command packet be processed in a near-FIFO order to prevent
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corruption of command packets that are already in use. To this end, drivers
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that have an ISR component should use their own command packet set.
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*/
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#include <nanokernel.h>
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#include <arch/cpu.h>
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#include <microkernel/cmdPkt.h>
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#include <minik.h>
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#include <sections.h>
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/*
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* generate build error by defining a negative-size array if the hard-coded
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* command packet size differs from the actual size; otherwise, define
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* a zero-element array that gets thrown away by linker
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*/
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uint32_t _k_test_cmd_pkt_size
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[0 - ((CMD_PKT_SIZE_IN_WORDS * sizeof(uint32_t)) != sizeof(struct k_args))];
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/*******************************************************************************
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*
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* _cmd_pkt_get - get the next command packet
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*
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* This routine gets the next command packet from the specified set.
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*
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* RETURNS: pointer to the command packet
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*/
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cmdPkt_t *_cmd_pkt_get(
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struct cmd_pkt_set *pSet /* ptr to set of command packets */
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)
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{
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uint32_t index; /* index into command packet array */
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int key; /* interrupt lock level */
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key = irq_lock_inline();
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index = pSet->index;
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pSet->index++;
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if (pSet->index >= pSet->nPkts)
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pSet->index = 0;
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irq_unlock_inline(key);
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return &pSet->cmdPkt[index];
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}
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/*******************************************************************************
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*
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* _k_task_call - send command packet to be processed by K_swapper
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*
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* RETURNS: N/A
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*/
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void _k_task_call(struct k_args *cmd_packet)
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{
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cmd_packet->alloc = false;
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_k_current_task->Args = cmd_packet;
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nano_task_stack_push(&_k_command_stack, (uint32_t)cmd_packet);
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}
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