spm/cactus/cactus_interrupt.c

/*
 * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <debug.h>

#include "cactus_message_loop.h"
#include "cactus_test_cmds.h"
#include <drivers/arm/sp805.h>
#include <ffa_helpers.h>
#include <sp_helpers.h>
#include "spm_common.h"
#include <spm_helpers.h>

#include <platform_def.h>

#define NOTIFICATION_PENDING_INTERRUPT_INTID 5

extern void notification_pending_interrupt_handler(void);

extern ffa_id_t g_ffa_id;
extern ffa_id_t g_dir_req_source_id;
static uint32_t managed_exit_interrupt_id;

/* Secure virtual interrupt that was last handled by Cactus SP. */
uint32_t last_serviced_interrupt[PLATFORM_CORE_COUNT];

extern spinlock_t sp_handler_lock[NUM_VINT_ID];

/*
 * Managed exit ID discoverable by querying the SPMC through
 * FFA_FEATURES API.
 */
void discover_managed_exit_interrupt_id(void)
{
	struct ffa_value ffa_ret;

	/* Interrupt ID value is returned through register W2. */
	ffa_ret = ffa_features(FFA_FEATURE_MEI);
	managed_exit_interrupt_id = ffa_feature_intid(ffa_ret);

	VERBOSE("Discovered managed exit interrupt ID: %d\n",
	     managed_exit_interrupt_id);
}

static void post_interrupt_handler(uint32_t intid)
{
	unsigned int core_pos = get_current_core_id();

	last_serviced_interrupt[core_pos] = intid;

	/* Invoke the tail end handler registered by the SP. */
	spin_lock(&sp_handler_lock[intid]);
	if (sp_interrupt_tail_end_handler[intid]) {
		sp_interrupt_tail_end_handler[intid]();
	}
	spin_unlock(&sp_handler_lock[intid]);
}

/*
 * Cactus SP does not implement application threads. Hence, once the Cactus SP
 * sends the managed exit response to the direct request originator, execution
 * is still frozen in interrupt handler context.
 * Though it moves to WAITING state, it is not able to accept new direct request
 * message from any endpoint. It can only receive a direct request message with
 * the command CACTUS_RESUME_AFTER_MANAGED_EXIT from the originator of the
 * suspended direct request message in order to return from the interrupt
 * handler context and resume the processing of suspended request.
 */
void send_managed_exit_response(void)
{
	struct ffa_value ffa_ret;
	bool waiting_resume_after_managed_exit;

	/* Send managed exit response. */
	ffa_ret = cactus_response(g_ffa_id, g_dir_req_source_id,
			MANAGED_EXIT_INTERRUPT_ID);
	waiting_resume_after_managed_exit = true;

	while (waiting_resume_after_managed_exit) {

		waiting_resume_after_managed_exit =
			(ffa_func_id(ffa_ret) != FFA_MSG_SEND_DIRECT_REQ_SMC32 &&
			 ffa_func_id(ffa_ret) != FFA_MSG_SEND_DIRECT_REQ_SMC64) ||
			 ffa_dir_msg_source(ffa_ret) != g_dir_req_source_id ||
			 cactus_get_cmd(ffa_ret) != CACTUS_RESUME_AFTER_MANAGED_EXIT;

		if (waiting_resume_after_managed_exit) {
			VERBOSE("Expected a direct message request from endpoint"
			      " %x with command CACTUS_RESUME_AFTER_MANAGED_EXIT\n",
			       g_dir_req_source_id);
			ffa_ret = cactus_error_resp(g_ffa_id,
						    ffa_dir_msg_source(ffa_ret),
						    CACTUS_ERROR_TEST);
		}
	}
	VERBOSE("Resuming the suspended command\n");
}

void cactus_interrupt_handler_irq(void)
{
	uint32_t intid = spm_interrupt_get();

	if (intid == managed_exit_interrupt_id) {
		/*
		 * A secure partition performs its housekeeping and
		 * sends a direct response to signal interrupt
		 * completion. This is a pure virtual interrupt, no
		 * need for deactivation.
		 */
		VERBOSE("vIRQ: Sending ME response to %x\n",
			g_dir_req_source_id);
		send_managed_exit_response();
	} else {
		switch (intid) {
		case IRQ_TWDOG_INTID:
			/*
			 * Interrupt triggered due to Trusted watchdog timer expiry.
			 * Clear the interrupt and stop the timer.
			 */
			VERBOSE("Trusted WatchDog timer stopped\n");
			sp805_twdog_stop();

			/* Perform secure interrupt de-activation. */
			spm_interrupt_deactivate(intid);

			break;
		case NOTIFICATION_PENDING_INTERRUPT_INTID:
			notification_pending_interrupt_handler();
			break;
		default:
			ERROR("%s: Interrupt ID %x not handled!\n", __func__,
				 intid);
			panic();
			break;
		}
	}
	post_interrupt_handler(intid);
}

void cactus_interrupt_handler_fiq(void)
{
	uint32_t intid = spm_interrupt_get();

	switch (intid) {
	case MANAGED_EXIT_INTERRUPT_ID:
		/*
		 * A secure partition performs its housekeeping and sends a
		 * direct response to signal interrupt completion.
		 * This is a pure virtual interrupt, no need for deactivation.
		 */
		VERBOSE("vFIQ: Sending ME response to %x\n",
			g_dir_req_source_id);
		send_managed_exit_response();
		break;
	default:
		/*
		 * Currently only managed exit interrupt is supported by vFIQ.
		 */
		panic();
		break;
	}
	post_interrupt_handler(intid);
}