armv7m_pendsv.c

/*
 * Copyright (c) 2015 Thomas Roell.  All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal with the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 *  1. Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimers.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimers in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of Thomas Roell, nor the names of its contributors
 *     may be used to endorse or promote products derived from this Software
 *     without specific prior written permission.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
 * CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * WITH THE SOFTWARE.
 */

#include "kitty.h"

typedef struct _armv7m_pendsv_device_t {
    volatile uint32_t                 mask;
    volatile armv7m_pendsv_callback_t callbacks[PENDSV_SLOT_COUNT];
} armv7m_pendsv_device_t;

armv7m_pendsv_device_t armv7m_pendsv_device;

void PendSV_Handler(void)
{
    unsigned int slot;
    uint32_t mask;
    armv7m_pendsv_callback_t callback;

    while ((mask = armv7m_pendsv_device.mask))
    {
	slot = 31 - armv7m_clz(mask);

	armv7m_bitband_sram_write(&armv7m_pendsv_device.mask, slot, 0);

	callback = armv7m_pendsv_device.callbacks[slot];

	if (callback)
	{
	    (*callback)();
	}
    }
}

void armv7m_pendsv_pending(unsigned int slot)
{
    armv7m_bitband_sram_write(&armv7m_pendsv_device.mask, slot, 1);

    SCB->ICSR = SCB_ICSR_PENDSVSET_Msk;
    
}

void armv7m_pendsv_callback(unsigned int slot, armv7m_pendsv_callback_t callback)
{
    armv7m_pendsv_device.callbacks[slot] = callback;
}

void armv7m_pendsv_initialize(void)
{
    NVIC_SetPriority(PendSV_IRQn, 7);
}