/* isr_wrapper.S - ARM CORTEX-M3 wrapper for ISRs with parameter  */

/*
 * Copyright (c) 2013-2014 Wind River Systems, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
DESCRIPTION

Wrapper installed in vector table for handling dynamic interrupts that accept
a parameter.
 */

#define _ASMLANGUAGE

#include <offsets.h>
#include <toolchain.h>
#include <sections.h>
#include <sw_isr_table.h>
#include <nano_private.h>
#include <arch/cpu.h>

_ASM_FILE_PROLOGUE

GDATA(_sw_isr_table)

GTEXT(_isr_wrapper)
GTEXT(_IntExit)

/**
 *
 * @brief Wrapper around ISRs when inserted in software ISR table
 *
 * When inserted in the vector table, _isr_wrapper() demuxes the ISR table using
 * the running interrupt number as the index, and invokes the registered ISR
 * with its correspoding argument. When returning from the ISR, it determines
 * if a context switch needs to happen (see documentation for __pendsv()) and
 * pends the PendSV exception if so: the latter will perform the context switch
 * itself.
 *
 * @return N/A
 */
SECTION_FUNC(TEXT, _isr_wrapper)

	_GDB_STUB_EXC_ENTRY

	push {lr}		/* lr is now the first item on the stack */

#ifdef CONFIG_KERNEL_EVENT_LOGGER_INTERRUPT
	push {lr}
	bl _sys_k_event_logger_interrupt
	pop {lr}
#endif

#ifdef CONFIG_ADVANCED_POWER_MANAGEMENT
	/*
	 * All interrupts are disabled when handling idle wakeup.  For tickless
	 * idle, this ensures that the calculation and programming of the device
	 * for the next timer deadline is not interrupted.  For non-tickless idle,
	 * this ensures that the clearing of the kernel idle state is not
	 * interrupted.  In each case, _sys_power_save_idle_exit is called with
	 * interrupts disabled.
	 */
	cpsid i  /* PRIMASK = 1 */

	/* is this a wakeup from idle ? */
	ldr r2, =_nanokernel
	ldr r0, [r2, #__tNANO_idle_OFFSET]  /* requested idle duration, in ticks */
	cmp r0, #0
	ittt ne
	movne	r1, #0
		strne	r1, [r2, #__tNANO_idle_OFFSET]  /* clear kernel idle state */
		blxne	_sys_power_save_idle_exit

	cpsie i		/* re-enable interrupts (PRIMASK = 0) */
#endif /* CONFIG_ADVANCED_POWER_MANAGEMENT */

	mrs r0, IPSR	/* get exception number */
	sub r0, r0, #16	/* get IRQ number */
	lsl r0, r0, #3	/* table is 8-byte wide */
	ldr r1, =_sw_isr_table
	add r1, r1, r0	/* table entry: ISRs must have their MSB set to stay
			 *			  in thumb mode */

	ldmia r1,{r0,r3}	/* arg in r0, ISR in r3 */
	blx r3		/* call ISR */

	pop {lr}

	/* exception return is done in _IntExit(), including _GDB_STUB_EXC_EXIT */
	b _IntExit