tsp_interrupt.c

/*
 * Copyright (c) 2014-2015, ARM Limited and Contributors. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 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.
 *
 * Neither the name of ARM 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 HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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 */

#include <arch_helpers.h>
#include <assert.h>
#include <debug.h>
#include <gic_v2.h>
#include <platform.h>
#include <platform_def.h>
#include <tsp.h>
#include "tsp_private.h"

/*******************************************************************************
 * This function updates the TSP statistics for FIQs handled synchronously i.e
 * the ones that have been handed over by the TSPD. It also keeps count of the
 * number of times control was passed back to the TSPD after handling an FIQ.
 * In the future it will be possible that the TSPD hands over an FIQ to the TSP
 * but does not expect it to return execution. This statistic will be useful to
 * distinguish between these two models of synchronous FIQ handling.
 * The 'elr_el3' parameter contains the address of the instruction in normal
 * world where this FIQ was generated.
 ******************************************************************************/
void tsp_update_sync_fiq_stats(uint32_t type, uint64_t elr_el3)
{
	uint32_t linear_id = plat_my_core_pos();

	tsp_stats[linear_id].sync_fiq_count++;
	if (type == TSP_HANDLE_FIQ_AND_RETURN)
		tsp_stats[linear_id].sync_fiq_ret_count++;

#if LOG_LEVEL >= LOG_LEVEL_VERBOSE
	spin_lock(&console_lock);
	VERBOSE("TSP: cpu 0x%lx sync fiq request from 0x%lx\n",
		read_mpidr(), elr_el3);
	VERBOSE("TSP: cpu 0x%lx: %d sync fiq requests, %d sync fiq returns\n",
		read_mpidr(),
		tsp_stats[linear_id].sync_fiq_count,
		tsp_stats[linear_id].sync_fiq_ret_count);
	spin_unlock(&console_lock);
#endif
}

/******************************************************************************
 * This function is invoked when a non S-EL1 interrupt is received and causes
 * the preemption of TSP. This function returns TSP_PREEMPTED and results
 * in the control being handed over to EL3 for handling the interrupt.
 *****************************************************************************/
int32_t tsp_handle_preemption(void)
{
	uint32_t linear_id = plat_my_core_pos();

	tsp_stats[linear_id].preempt_intr_count++;
#if LOG_LEVEL >= LOG_LEVEL_VERBOSE
	spin_lock(&console_lock);
	VERBOSE("TSP: cpu 0x%lx: %d preempt interrupt requests\n",
		read_mpidr(), tsp_stats[linear_id].preempt_intr_count);
	spin_unlock(&console_lock);
#endif
	return TSP_PREEMPTED;
}

/*******************************************************************************
 * TSP FIQ handler called as a part of both synchronous and asynchronous
 * handling of FIQ interrupts. It returns 0 upon successfully handling a S-EL1
 * FIQ and treats all other FIQs as EL3 interrupts. It assumes that the GIC
 * architecture version in v2.0 and the secure physical timer interrupt is the
 * only S-EL1 interrupt that it needs to handle.
 ******************************************************************************/
int32_t tsp_fiq_handler(void)
{
	uint32_t linear_id = plat_my_core_pos(), id;

	/*
	 * Get the highest priority pending interrupt id and see if it is the
	 * secure physical generic timer interrupt in which case, handle it.
	 * Otherwise throw this interrupt at the EL3 firmware.
	 *
	 * There is a small time window between reading the highest priority
	 * pending interrupt and acknowledging it during which another
	 * interrupt of higher priority could become the highest pending
	 * interrupt. This is not expected to happen currently for TSP.
	 */
	id = plat_ic_get_pending_interrupt_id();

	/* TSP can only handle the secure physical timer interrupt */
	if (id != TSP_IRQ_SEC_PHY_TIMER)
		return tsp_handle_preemption();

	/*
	 * Acknowledge and handle the secure timer interrupt. Also sanity check
	 * if it has been preempted by another interrupt through an assertion.
	 */
	id = plat_ic_acknowledge_interrupt();
	assert(id == TSP_IRQ_SEC_PHY_TIMER);
	tsp_generic_timer_handler();
	plat_ic_end_of_interrupt(id);

	/* Update the statistics and print some messages */
	tsp_stats[linear_id].fiq_count++;
#if LOG_LEVEL >= LOG_LEVEL_VERBOSE
	spin_lock(&console_lock);
	VERBOSE("TSP: cpu 0x%lx handled fiq %d\n",
	       read_mpidr(), id);
	VERBOSE("TSP: cpu 0x%lx: %d fiq requests\n",
	     read_mpidr(), tsp_stats[linear_id].fiq_count);
	spin_unlock(&console_lock);
#endif
	return 0;
}