/*
 * Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <assert.h>
#include <errno.h>
#include <string.h>

#include <arch_helpers.h>
#include <bl31/bl31.h>
#include <bl31/ehf.h>
#include <bl31/interrupt_mgmt.h>
#include <common/debug.h>
#include <common/runtime_svc.h>
#include <lib/el3_runtime/context_mgmt.h>
#include <lib/smccc.h>
#include <lib/spinlock.h>
#include <lib/utils.h>
#include <lib/xlat_tables/xlat_tables_v2.h>
#include <plat/common/platform.h>
#include <services/spm_svc.h>
#include <services/sprt_svc.h>
#include <smccc_helpers.h>

#include "spm_private.h"

/*******************************************************************************
 * Secure Partition context information.
 ******************************************************************************/
sp_context_t sp_ctx_array[PLAT_SPM_MAX_PARTITIONS];

/* Last Secure Partition last used by the CPU */
sp_context_t *cpu_sp_ctx[PLATFORM_CORE_COUNT];

void spm_cpu_set_sp_ctx(unsigned int linear_id, sp_context_t *sp_ctx)
{
	assert(linear_id < PLATFORM_CORE_COUNT);

	cpu_sp_ctx[linear_id] = sp_ctx;
}

sp_context_t *spm_cpu_get_sp_ctx(unsigned int linear_id)
{
	assert(linear_id < PLATFORM_CORE_COUNT);

	return cpu_sp_ctx[linear_id];
}

/*******************************************************************************
 * Functions to keep track of how many requests a Secure Partition has received
 * and hasn't finished.
 ******************************************************************************/
void spm_sp_request_increase(sp_context_t *sp_ctx)
{
	spin_lock(&(sp_ctx->request_count_lock));
	sp_ctx->request_count++;
	spin_unlock(&(sp_ctx->request_count_lock));
}

void spm_sp_request_decrease(sp_context_t *sp_ctx)
{
	spin_lock(&(sp_ctx->request_count_lock));
	sp_ctx->request_count--;
	spin_unlock(&(sp_ctx->request_count_lock));
}

/* Returns 0 if it was originally 0, -1 otherwise. */
int spm_sp_request_increase_if_zero(sp_context_t *sp_ctx)
{
	int ret = -1;

	spin_lock(&(sp_ctx->request_count_lock));
	if (sp_ctx->request_count == 0U) {
		sp_ctx->request_count++;
		ret = 0U;
	}
	spin_unlock(&(sp_ctx->request_count_lock));

	return ret;
}

/*******************************************************************************
 * This function returns a pointer to the context of the Secure Partition that
 * handles the service specified by an UUID. It returns NULL if the UUID wasn't
 * found.
 ******************************************************************************/
sp_context_t *spm_sp_get_by_uuid(const uint32_t (*svc_uuid)[4])
{
	unsigned int i;

	for (i = 0U; i < PLAT_SPM_MAX_PARTITIONS; i++) {

		sp_context_t *sp_ctx = &sp_ctx_array[i];

		if (sp_ctx->is_present == 0) {
			continue;
		}

		struct sp_rd_sect_service *rdsvc;

		for (rdsvc = sp_ctx->rd.service; rdsvc != NULL;
		     rdsvc = rdsvc->next) {
			uint32_t *rd_uuid = (uint32_t *)(rdsvc->uuid);

			if (memcmp(rd_uuid, svc_uuid, sizeof(rd_uuid)) == 0) {
				return sp_ctx;
			}
		}
	}

	return NULL;
}

/*******************************************************************************
 * Set state of a Secure Partition context.
 ******************************************************************************/
void sp_state_set(sp_context_t *sp_ptr, sp_state_t state)
{
	spin_lock(&(sp_ptr->state_lock));
	sp_ptr->state = state;
	spin_unlock(&(sp_ptr->state_lock));
}

/*******************************************************************************
 * Wait until the state of a Secure Partition is the specified one and change it
 * to the desired state.
 ******************************************************************************/
void sp_state_wait_switch(sp_context_t *sp_ptr, sp_state_t from, sp_state_t to)
{
	int success = 0;

	while (success == 0) {
		spin_lock(&(sp_ptr->state_lock));

		if (sp_ptr->state == from) {
			sp_ptr->state = to;

			success = 1;
		}

		spin_unlock(&(sp_ptr->state_lock));
	}
}

/*******************************************************************************
 * Check if the state of a Secure Partition is the specified one and, if so,
 * change it to the desired state. Returns 0 on success, -1 on error.
 ******************************************************************************/
int sp_state_try_switch(sp_context_t *sp_ptr, sp_state_t from, sp_state_t to)
{
	int ret = -1;

	spin_lock(&(sp_ptr->state_lock));

	if (sp_ptr->state == from) {
		sp_ptr->state = to;

		ret = 0;
	}

	spin_unlock(&(sp_ptr->state_lock));

	return ret;
}

/*******************************************************************************
 * This function takes an SP context pointer and performs a synchronous entry
 * into it.
 ******************************************************************************/
uint64_t spm_sp_synchronous_entry(sp_context_t *sp_ctx, int can_preempt)
{
	uint64_t rc;
	unsigned int linear_id = plat_my_core_pos();

	assert(sp_ctx != NULL);

	/* Assign the context of the SP to this CPU */
	spm_cpu_set_sp_ctx(linear_id, sp_ctx);
	cm_set_context(&(sp_ctx->cpu_ctx), SECURE);

	/* Restore the context assigned above */
	cm_el1_sysregs_context_restore(SECURE);
	cm_set_next_eret_context(SECURE);

	/* Invalidate TLBs at EL1. */
	tlbivmalle1();
	dsbish();

	if (can_preempt == 1) {
		enable_intr_rm_local(INTR_TYPE_NS, SECURE);
	} else {
		disable_intr_rm_local(INTR_TYPE_NS, SECURE);
	}

	/* Enter Secure Partition */
	rc = spm_secure_partition_enter(&sp_ctx->c_rt_ctx);

	/* Save secure state */
	cm_el1_sysregs_context_save(SECURE);

	return rc;
}

/*******************************************************************************
 * This function returns to the place where spm_sp_synchronous_entry() was
 * called originally.
 ******************************************************************************/
__dead2 void spm_sp_synchronous_exit(uint64_t rc)
{
	/* Get context of the SP in use by this CPU. */
	unsigned int linear_id = plat_my_core_pos();
	sp_context_t *ctx = spm_cpu_get_sp_ctx(linear_id);

	/*
	 * The SPM must have initiated the original request through a
	 * synchronous entry into the secure partition. Jump back to the
	 * original C runtime context with the value of rc in x0;
	 */
	spm_secure_partition_exit(ctx->c_rt_ctx, rc);

	panic();
}

/*******************************************************************************
 * This function is the handler registered for Non secure interrupts by the SPM.
 * It validates the interrupt and upon success arranges entry into the normal
 * world for handling the interrupt.
 ******************************************************************************/
static uint64_t spm_ns_interrupt_handler(uint32_t id, uint32_t flags,
					  void *handle, void *cookie)
{
	/* Check the security state when the exception was generated */
	assert(get_interrupt_src_ss(flags) == SECURE);

	spm_sp_synchronous_exit(SPM_SECURE_PARTITION_PREEMPTED);
}

/*******************************************************************************
 * Jump to each Secure Partition for the first time.
 ******************************************************************************/
static int32_t spm_init(void)
{
	uint64_t rc = 0;
	sp_context_t *ctx;

	for (unsigned int i = 0U; i < PLAT_SPM_MAX_PARTITIONS; i++) {

		ctx = &sp_ctx_array[i];

		if (ctx->is_present == 0) {
			continue;
		}

		INFO("Secure Partition %u init...\n", i);

		ctx->state = SP_STATE_RESET;

		rc = spm_sp_synchronous_entry(ctx, 0);
		if (rc != SPRT_YIELD_AARCH64) {
			ERROR("Unexpected return value 0x%llx\n", rc);
			panic();
		}

		ctx->state = SP_STATE_IDLE;

		INFO("Secure Partition %u initialized.\n", i);
	}

	return rc;
}

/*******************************************************************************
 * Initialize contexts of all Secure Partitions.
 ******************************************************************************/
int32_t spm_setup(void)
{
	int rc;
	sp_context_t *ctx;
	void *sp_base, *rd_base;
	size_t sp_size, rd_size;
	uint64_t flags = 0U;

	/* Disable MMU at EL1 (initialized by BL2) */
	disable_mmu_icache_el1();

	/*
	 * Non-blocking services can be interrupted by Non-secure interrupts.
	 * Register an interrupt handler for NS interrupts when generated while
	 * the CPU is in secure state. They are routed to EL3.
	 */
	set_interrupt_rm_flag(flags, SECURE);

	uint64_t rc_int = register_interrupt_type_handler(INTR_TYPE_NS,
				spm_ns_interrupt_handler, flags);
	if (rc_int) {
		ERROR("SPM: Failed to register NS interrupt handler with rc = %llx\n",
		      rc_int);
		panic();
	}

	/* Setup shim layer */
	spm_exceptions_xlat_init_context();

	/*
	 * Setup all Secure Partitions.
	 */
	unsigned int i = 0U;

	while (1) {
		rc = plat_spm_sp_get_next_address(&sp_base, &sp_size,
						&rd_base, &rd_size);
		if (rc < 0) {
			/* Reached the end of the package. */
			break;
		}

		if (i >= PLAT_SPM_MAX_PARTITIONS) {
			ERROR("Too many partitions in the package.\n");
			panic();
		}

		ctx = &sp_ctx_array[i];

		assert(ctx->is_present == 0);

		/* Initialize context of the SP */
		INFO("Secure Partition %u context setup start...\n", i);

		/* Save location of the image in physical memory */
		ctx->image_base = (uintptr_t)sp_base;
		ctx->image_size = sp_size;

		rc = plat_spm_sp_rd_load(&ctx->rd, rd_base, rd_size);
		if (rc < 0) {
			ERROR("Error while loading RD blob.\n");
			panic();
		}

		spm_sp_setup(ctx);

		ctx->is_present = 1;

		INFO("Secure Partition %u setup done.\n", i);

		i++;
	}

	if (i == 0U) {
		ERROR("No present partitions in the package.\n");
		panic();
	}

	/* Register init function for deferred init.  */
	bl31_register_bl32_init(&spm_init);

	return 0;
}
