/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2013 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */


/*
 * C Bootstrap code for the coreboot
 */

#include <bootstate.h>
#include <console/console.h>
#include <version.h>
#include <device/device.h>
#include <device/pci.h>
#include <delay.h>
#include <stdlib.h>
#include <reset.h>
#include <boot/tables.h>
#include <boot/elf.h>
#include <cbfs.h>
#include <lib.h>
#if CONFIG_HAVE_ACPI_RESUME
#include <arch/acpi.h>
#endif
#include <timer.h>
#include <timestamp.h>

#if BOOT_STATE_DEBUG
#define BS_DEBUG_LVL BIOS_DEBUG
#else
#define BS_DEBUG_LVL BIOS_NEVER
#endif

static boot_state_t bs_pre_device(void *arg);
static boot_state_t bs_dev_init_chips(void *arg);
static boot_state_t bs_dev_enumerate(void *arg);
static boot_state_t bs_dev_resources(void *arg);
static boot_state_t bs_dev_eanble(void *arg);
static boot_state_t bs_dev_init(void *arg);
static boot_state_t bs_post_device(void *arg);
static boot_state_t bs_os_resume_check(void *arg);
static boot_state_t bs_os_resume(void *arg);
static boot_state_t bs_write_tables(void *arg);
static boot_state_t bs_payload_load(void *arg);
static boot_state_t bs_payload_boot(void *arg);

/*
 * Typically a state will take 4 time samples:
 *   1. Before state entry callbacks
 *   2. After state entry callbacks / Before state function.
 *   3. After state function / Before state exit callbacks.
 *   4. After state exit callbacks.
 */
#define MAX_TIME_SAMPLES 4
struct boot_state_times {
	int num_samples;
	struct mono_time samples[MAX_TIME_SAMPLES];
};

struct boot_state {
	const char *name;
	boot_state_t id;
	struct boot_state_callback *seq_callbacks[2];
	boot_state_t (*run_state)(void *arg);
	void *arg;
	int complete : 1;
	int timers_drain : 1;
#if CONFIG_HAVE_MONOTONIC_TIMER
	struct boot_state_times times;
#endif
};

#define BS_INIT(state_, run_func_, drain_timers_)		\
	{							\
		.name = #state_,				\
		.id = state_,					\
		.seq_callbacks = { NULL, NULL },		\
		.run_state = run_func_,				\
		.arg = NULL,					\
		.complete = 0,					\
		.timers_drain = drain_timers_,			\
	}
#define BS_INIT_ENTRY(state_, run_func_)	\
	[state_] = BS_INIT(state_, run_func_, 0)
#define BS_INIT_ENTRY_DRAIN_TIMERS(state_, run_func_)	\
	[state_] = BS_INIT(state_, run_func_, 1)

static struct boot_state boot_states[] = {
	BS_INIT_ENTRY(BS_PRE_DEVICE, bs_pre_device),
	BS_INIT_ENTRY(BS_DEV_INIT_CHIPS, bs_dev_init_chips),
	BS_INIT_ENTRY(BS_DEV_ENUMERATE, bs_dev_enumerate),
	BS_INIT_ENTRY(BS_DEV_RESOURCES, bs_dev_resources),
	BS_INIT_ENTRY(BS_DEV_ENABLE, bs_dev_eanble),
	BS_INIT_ENTRY(BS_DEV_INIT, bs_dev_init),
	BS_INIT_ENTRY(BS_POST_DEVICE, bs_post_device),
	BS_INIT_ENTRY(BS_OS_RESUME_CHECK, bs_os_resume_check),
	BS_INIT_ENTRY_DRAIN_TIMERS(BS_OS_RESUME, bs_os_resume),
	BS_INIT_ENTRY_DRAIN_TIMERS(BS_WRITE_TABLES, bs_write_tables),
	BS_INIT_ENTRY_DRAIN_TIMERS(BS_PAYLOAD_LOAD, bs_payload_load),
	BS_INIT_ENTRY_DRAIN_TIMERS(BS_PAYLOAD_BOOT, bs_payload_boot),
};

static boot_state_t bs_pre_device(void *arg)
{
	return BS_DEV_INIT_CHIPS;
}

static boot_state_t bs_dev_init_chips(void *arg)
{
	timestamp_stash(TS_DEVICE_ENUMERATE);

	/* Initialize chips early, they might disable unused devices. */
	dev_initialize_chips();

	return BS_DEV_ENUMERATE;
}

static boot_state_t bs_dev_enumerate(void *arg)
{
	/* Find the devices we don't have hard coded knowledge about. */
	dev_enumerate();
	post_code(POST_DEVICE_ENUMERATION_COMPLETE);

	return BS_DEV_RESOURCES;
}

static boot_state_t bs_dev_resources(void *arg)
{
	timestamp_stash(TS_DEVICE_CONFIGURE);
	/* Now compute and assign the bus resources. */
	dev_configure();
	post_code(POST_DEVICE_CONFIGURATION_COMPLETE);

	return BS_DEV_ENABLE;
}

static boot_state_t bs_dev_eanble(void *arg)
{
	timestamp_stash(TS_DEVICE_ENABLE);
	/* Now actually enable devices on the bus */
	dev_enable();
	post_code(POST_DEVICES_ENABLED);

	return BS_DEV_INIT;
}

static boot_state_t bs_dev_init(void *arg)
{
	timestamp_stash(TS_DEVICE_INITIALIZE);
	/* And of course initialize devices on the bus */
	dev_initialize();
	post_code(POST_DEVICES_INITIALIZED);

	return BS_POST_DEVICE;
}

static boot_state_t bs_post_device(void *arg)
{
	timestamp_stash(TS_DEVICE_DONE);

	timestamp_sync();

	return BS_OS_RESUME_CHECK;
}

static boot_state_t bs_os_resume_check(void *arg)
{
#if CONFIG_HAVE_ACPI_RESUME
	void *wake_vector;

	wake_vector = acpi_find_wakeup_vector();

	if (wake_vector != NULL) {
		boot_states[BS_OS_RESUME].arg = wake_vector;
		return BS_OS_RESUME;
	}
	post_code(0x8a);
#endif
	timestamp_add_now(TS_CBMEM_POST);

	return BS_WRITE_TABLES;
}

static boot_state_t bs_os_resume(void *wake_vector)
{
#if CONFIG_HAVE_ACPI_RESUME
	acpi_resume(wake_vector);
#endif
	return BS_WRITE_TABLES;
}

static boot_state_t bs_write_tables(void *arg)
{
	timestamp_add_now(TS_WRITE_TABLES);

	/* Now that we have collected all of our information
	 * write our configuration tables.
	 */
	write_tables();

	return BS_PAYLOAD_LOAD;
}

static boot_state_t bs_payload_load(void *arg)
{
	void *payload;
	void *entry;

	timestamp_add_now(TS_LOAD_PAYLOAD);

	payload = cbfs_load_payload(CBFS_DEFAULT_MEDIA,
				    CONFIG_CBFS_PREFIX "/payload");
	if (! payload)
		die("Could not find a payload\n");

	entry = selfload(get_lb_mem(), payload);

	if (! entry)
		die("Could not load payload\n");

	/* Pass the payload to the next state. */
	boot_states[BS_PAYLOAD_BOOT].arg = entry;

	return BS_PAYLOAD_BOOT;
}

static boot_state_t bs_payload_boot(void *entry)
{
	selfboot(entry);

	printk(BIOS_EMERG, "Boot failed");
	/* Returning from this state will fail because the following signals
	 * return to a completed state. */
	return BS_PAYLOAD_BOOT;
}

#if CONFIG_HAVE_MONOTONIC_TIMER
static void bs_sample_time(struct boot_state *state)
{
	struct mono_time *mt;

	mt = &state->times.samples[state->times.num_samples];
	timer_monotonic_get(mt);
	state->times.num_samples++;
}

static void bs_report_time(struct boot_state *state)
{
	struct rela_time entry_time;
	struct rela_time run_time;
	struct rela_time exit_time;
	struct boot_state_times *times;

	times = &state->times;
	entry_time = mono_time_diff(&times->samples[0], &times->samples[1]);
	run_time = mono_time_diff(&times->samples[1], &times->samples[2]);
	exit_time = mono_time_diff(&times->samples[2], &times->samples[3]);

	printk(BIOS_DEBUG, "BS: %s times (us): entry %ld run %ld exit %ld\n",
	       state->name,
	       rela_time_in_microseconds(&entry_time),
	       rela_time_in_microseconds(&run_time),
	       rela_time_in_microseconds(&exit_time));
}
#else
static inline void bs_sample_time(struct boot_state *state) {}
static inline void bs_report_time(struct boot_state *state) {}
#endif

#if CONFIG_TIMER_QUEUE
static void bs_run_timers(int drain)
{
	/* Drain all timer callbacks until none are left, if directed.
	 * Otherwise run the timers only once. */
	do {
		if (!timers_run())
			break;
	} while (drain);
}
#else
static void bs_run_timers(int drain) {}
#endif

static void bs_call_callbacks(struct boot_state *state,
                              boot_state_sequence_t seq)
{
	while (state->seq_callbacks[seq] != NULL) {
		struct boot_state_callback *bscb;

		/* Remove the first callback. */
		bscb = state->seq_callbacks[seq];
		state->seq_callbacks[seq] = bscb->next;
		bscb->next = NULL;

#if BOOT_STATE_DEBUG
		printk(BS_DEBUG_LVL, "BS: callback (%p) @ %s.\n",
		       bscb, bscb->location);
#endif
		bscb->callback(bscb->arg);
	}
}

static void bs_walk_state_machine(boot_state_t current_state_id)
{

	while (1) {
		struct boot_state *state;

		state = &boot_states[current_state_id];

		if (state->complete) {
			printk(BIOS_EMERG, "BS: %s state already executed.\n",
			       state->name);
			break;
		}

		printk(BS_DEBUG_LVL, "BS: Entering %s state.\n", state->name);

		bs_run_timers(state->timers_drain);

		bs_sample_time(state);

		bs_call_callbacks(state, BS_ON_ENTRY);

		bs_sample_time(state);

		current_state_id = state->run_state(state->arg);

		printk(BS_DEBUG_LVL, "BS: Exiting %s state.\n", state->name);

		bs_sample_time(state);

		bs_call_callbacks(state, BS_ON_EXIT);

		bs_sample_time(state);

		bs_report_time(state);

		state->complete = 1;
	}
}

static int boot_state_sched_callback(struct boot_state *state,
                                     struct boot_state_callback *bscb,
                                     boot_state_sequence_t seq)
{
	if (state->complete) {
		printk(BIOS_WARNING,
		       "Tried to schedule callback on completed state %s.\n",
		       state->name);

		return -1;
	}

	bscb->next = state->seq_callbacks[seq];
	state->seq_callbacks[seq] = bscb;

	return 0;
}

int boot_state_sched_on_entry(struct boot_state_callback *bscb,
                              boot_state_t state_id)
{
	struct boot_state *state = &boot_states[state_id];

	return boot_state_sched_callback(state, bscb, BS_ON_ENTRY);
}

int boot_state_sched_on_exit(struct boot_state_callback *bscb,
                             boot_state_t state_id)
{
	struct boot_state *state = &boot_states[state_id];

	return boot_state_sched_callback(state, bscb, BS_ON_EXIT);
}

static void boot_state_schedule_static_entries(void)
{
	extern struct boot_state_init_entry _bs_init_begin;
	extern struct boot_state_init_entry _bs_init_end;
	struct boot_state_init_entry *cur;

	cur = &_bs_init_begin;

	while (cur != &_bs_init_end) {
		if (cur->when == BS_ON_ENTRY)
			boot_state_sched_on_entry(&cur->bscb, cur->state);
		else
			boot_state_sched_on_exit(&cur->bscb, cur->state);
		cur++;
	}
}

void hardwaremain(int boot_complete)
{
	timestamp_stash(TS_START_RAMSTAGE);
	post_code(POST_ENTRY_RAMSTAGE);

	/* console_init() MUST PRECEDE ALL printk()! */
	console_init();

	post_code(POST_CONSOLE_READY);

	printk(BIOS_NOTICE, "coreboot-%s%s %s %s...\n",
		      coreboot_version, coreboot_extra_version, coreboot_build,
		      (boot_complete)?"rebooting":"booting");

	post_code(POST_CONSOLE_BOOT_MSG);

	/* If we have already booted attempt a hard reboot */
	if (boot_complete) {
		hard_reset();
	}

	/* Schedule the static boot state entries. */
	boot_state_schedule_static_entries();

	/* FIXME: Is there a better way to handle this? */
	init_timer();

	bs_walk_state_machine(BS_PRE_DEVICE);
	die("Boot state machine failure.\n");
}