/*
 * This file is part of the coreboot project.
 *
 * Copyright 2014 Google Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc.
 */

#include <stdint.h>
#include <stdlib.h>
#include <arch/cache.h>
#include <arch/cpu.h>
#include <arch/lib_helpers.h>
#include <cpu/cpu.h>
#include <console/console.h>
#include <gic.h>
#include <timer.h>
#include "cpu-internal.h"

void __attribute__((weak)) arm64_arch_timer_init(void)
{
	/* Default weak implementation does nothing. */
}

static inline void cpu_disable_dev(device_t dev)
{
	dev->enabled = 0;
}

static struct cpu_driver *locate_cpu_driver(uint32_t midr)
{
	struct cpu_driver *cur;

	for (cur = cpu_drivers; cur != ecpu_drivers; cur++) {
		const struct cpu_device_id *id_table = cur->id_table;

		for (; id_table->midr != CPU_ID_END; id_table++) {
			if (id_table->midr == midr)
				return cur;
		}
	}
	return NULL;
}

static int cpu_set_device_operations(device_t dev)
{
	uint32_t midr;
	struct cpu_driver *driver;

	midr = raw_read_midr_el1();
	driver = locate_cpu_driver(midr);

	if (driver == NULL) {
		printk(BIOS_WARNING, "No CPU driver for MIDR %08x\n", midr);
		return -1;
	}
	dev->ops = driver->ops;
	return 0;
}

/* Set up default SCR values. */
static void el3_init(void)
{
	uint32_t scr;

	if (get_current_el() != EL3)
		return;

	scr = raw_read_scr_el3();
	/* Default to non-secure EL1 and EL0. */
	scr &= ~(SCR_NS_MASK);
	scr |= SCR_NS_ENABLE;
	/* Disable IRQ, FIQ, and external abort interrupt routing. */
	scr &= ~(SCR_IRQ_MASK | SCR_FIQ_MASK | SCR_EA_MASK);
	scr |= SCR_IRQ_DISABLE | SCR_FIQ_DISABLE | SCR_EA_DISABLE;
	/* Enable HVC */
	scr &= ~(SCR_HVC_MASK);
	scr |= SCR_HVC_ENABLE;
	/* Disable SMC */
	scr &= ~(SCR_SMC_MASK);
	scr |= SCR_SMC_DISABLE;
	/* Disable secure instruction fetches. */
	scr &= ~(SCR_SIF_MASK);
	scr |= SCR_SIF_DISABLE;
	/* All lower exception levels 64-bit by default. */
	scr &= ~(SCR_RW_MASK);
	scr |= SCR_LOWER_AARCH64;
	/* Disable secure EL1 access to secure timer. */
	scr &= ~(SCR_ST_MASK);
	scr |= SCR_ST_DISABLE;
	/* Don't trap on WFE or WFI instructions. */
	scr &= ~(SCR_TWI_MASK | SCR_TWE_MASK);
	scr |= SCR_TWI_DISABLE | SCR_TWE_DISABLE;
	raw_write_scr_el3(scr);
	isb();
}

static void init_this_cpu(void *arg)
{
	struct cpu_info *ci = arg;
	device_t dev = ci->cpu;

	cpu_set_device_operations(dev);

	printk(BIOS_DEBUG, "CPU%x: MPIDR: %llx\n", ci->id, ci->mpidr);

	/* Initialize the GIC. */
	gic_init();

	/*
	 * Disable coprocessor traps to EL3:
	 * TCPAC [20] = 0, disable traps for EL2 accesses to CPTR_EL2 or HCPTR
	 * and EL2/EL1 access to CPACR_EL1.
	 * TTA [20] = 0, disable traps for trace register access from any EL.
	 * TFP [10] = 0, disable traps for floating-point instructions from any
	 * EL.
	 */
	raw_write_cptr_el3(CPTR_EL3_TCPAC_DISABLE | CPTR_EL3_TTA_DISABLE |
			   CPTR_EL3_TFP_DISABLE);

	/*
	 * Allow FPU accesses:
	 * FPEN [21:20] = 3, disable traps for floating-point instructions from
	 * EL0/EL1.
	 * TTA [28] = 0, disable traps for trace register access from EL0/EL1.
	 */
	raw_write_cpacr_el1(CPACR_TRAP_FP_DISABLE | CPACR_TTA_DISABLE);

	/* Arch Timer init: setup cntfrq per CPU */
	arm64_arch_timer_init();

	if (dev->ops != NULL && dev->ops->init != NULL) {
		dev->initialized = 1;
		printk(BIOS_DEBUG, "%s init\n", dev_path(dev));
		dev->ops->init(dev);
	}
}

/* Fill in cpu_info structures according to device tree. */
static void init_cpu_info(struct bus *bus)
{
	device_t cur;

	for (cur = bus->children; cur != NULL; cur = cur->sibling) {
		struct cpu_info *ci;
		unsigned int id = cur->path.cpu.id;

		if (cur->path.type != DEVICE_PATH_CPU)
			continue;

		/* IDs are currently mapped 1:1 with logical CPU numbers. */
		if (id >= CONFIG_MAX_CPUS) {
			printk(BIOS_WARNING,
				"CPU id %x too large. Disabling.\n", id);
			cpu_disable_dev(cur);
			continue;
		}

		ci = cpu_info_for_cpu(id);
		if (ci->cpu != NULL) {
			printk(BIOS_WARNING,
				"Duplicate ID %x in device tree.\n", id);
			cpu_disable_dev(cur);
		}

		ci->cpu = cur;
		ci->id = cur->path.cpu.id;
	}
}

void arch_initialize_cpus(device_t cluster, struct cpu_control_ops *cntrl_ops)
{
	size_t max_cpus;
	size_t i;
	struct cpu_info *ci;
	void (*entry)(void);
	struct bus *bus;

	if (cluster->path.type != DEVICE_PATH_CPU_CLUSTER) {
		printk(BIOS_ERR,
			"CPU init failed. Device is not a CPU_CLUSTER: %s\n",
			dev_path(cluster));
		return;
	}

	bus = cluster->link_list;

	/* Check if no children under this device. */
	if (bus == NULL)
		return;

	/*
	 * el3_init must be performed prior to prepare_secondary_cpu_startup.
	 * This is important since el3_init initializes SCR values on BSP CPU
	 * and then prepare_secondary_cpu_startup reads the initialized SCR
	 * value and saves it for use by non-BSP CPUs.
	 */
	el3_init();
	/* Mark current cpu online. */
	cpu_mark_online(cpu_info());
	entry = prepare_secondary_cpu_startup();

	/* Initialize the cpu_info structures. */
	init_cpu_info(bus);
	max_cpus = cntrl_ops->total_cpus();

	if (max_cpus > CONFIG_MAX_CPUS) {
		printk(BIOS_WARNING,
			"max_cpus (%zu) exceeds CONFIG_MAX_CPUS (%zu).\n",
			max_cpus, (size_t)CONFIG_MAX_CPUS);
		max_cpus = CONFIG_MAX_CPUS;
	}

	for (i = 0; i < max_cpus; i++) {
		device_t dev;
		struct cpu_action action;
		struct stopwatch sw;

		ci = cpu_info_for_cpu(i);
		dev = ci->cpu;

		/* Disregard CPUs not in device tree. */
		if (dev == NULL)
			continue;

		/* Skip disabled CPUs. */
		if (!dev->enabled)
			continue;

		if (!cpu_online(ci)) {
			/* Start the CPU. */
			printk(BIOS_DEBUG, "Starting CPU%x\n", ci->id);

			if (cntrl_ops->start_cpu(ci->id, entry)) {
				printk(BIOS_ERR,
					"Failed to start CPU%x\n", ci->id);
				continue;
			}
			stopwatch_init_msecs_expire(&sw, 1000);
			/* Wait for CPU to come online. */
			while (!stopwatch_expired(&sw)) {
				if (!cpu_online(ci))
					continue;
				printk(BIOS_DEBUG,
					"CPU%x online in %ld usecs.\n",
					ci->id, stopwatch_duration_usecs(&sw));
				break;
			}
		}

		if (!cpu_online(ci)) {
			printk(BIOS_DEBUG,
				"CPU%x failed to come online in %ld usecs.\n",
				ci->id, stopwatch_duration_usecs(&sw));
			continue;
		}

		/* Send it the init action. */
		action.run = init_this_cpu;
		action.arg = ci;
		arch_run_on_cpu(ci->id, &action);
	}
}

void arch_secondary_cpu_init(void)
{
	/* Mark this CPU online. */
	cpu_mark_online(cpu_info());

	arch_cpu_wait_for_action();
}