/*
 * Copyright (C) 2021, TUXEDO Computers GmbH
 *
 * SPDX-License-Identifier: LGPL-2.1+
 */

#include "config.h"

#include <fwupdplugin.h>

#include <string.h>

#include "fu-superio-common.h"
#include "fu-superio-it55-device.h"

/* ROM of IT5570 consists of 64KB blocks. Blocks can be further subdivided in
 * 256-byte chunks, which is especially visible when erasing the ROM. This is
 * because in case of erasure offset within a block is specified in chunks (even
 * though erasure is done one kilobyte at a time).
 *
 * Accessing ROM requires entering a special mode, which should be always left
 * to restore normal operation of EC (handling of buttons, keyboard, etc.). */

#define SIO_CMD_EC_WRITE_BLOCK	   0x02
#define SIO_CMD_EC_READ_BLOCK	   0x03
#define SIO_CMD_EC_ERASE_KBYTE	   0x05
#define SIO_CMD_EC_WRITE_1ST_KBYTE 0x06
#define EC_ROM_ACCESS_ON_1	   0xDE
#define EC_ROM_ACCESS_ON_2	   0xDC
#define EC_ROM_ACCESS_OFF	   0xFE

#define BLOCK_SIZE	0x10000
#define CHUNK_SIZE	0x100
#define CHUNKS_IN_KBYTE 0x4
#define CHUNKS_IN_BLOCK 0x100

#define MAX_FLASHING_ATTEMPTS 5

typedef enum {
	AUTOLOAD_NO_ACTION,
	AUTOLOAD_DISABLE,
	AUTOLOAD_SET_ON,
	AUTOLOAD_SET_OFF,
} AutoloadAction;

struct _FuEcIt55Device {
	FuSuperioDevice parent_instance;
	gchar *prj_name;
	AutoloadAction autoload_action;
};

G_DEFINE_TYPE(FuEcIt55Device, fu_superio_it55_device, FU_TYPE_SUPERIO_DEVICE)

static void
fu_superio_it55_device_to_string(FuDevice *device, guint idt, GString *str)
{
	FuEcIt55Device *self = FU_SUPERIO_IT55_DEVICE(device);

	/* FuSuperioDevice->to_string */
	FU_DEVICE_CLASS(fu_superio_it55_device_parent_class)->to_string(device, idt, str);

	fu_common_string_append_kx(str, idt, "AutoloadAction", self->autoload_action);
}

static gboolean
fu_superio_it55_device_ec_project(FuSuperioDevice *device, GError **error)
{
	FuEcIt55Device *self = FU_SUPERIO_IT55_DEVICE(device);
	gchar project[16] = {0x0};

	if (!fu_superio_device_ec_write_cmd(device, SIO_CMD_EC_GET_NAME_STR, error))
		return FALSE;

	for (guint i = 0; i < sizeof(project) - 1; ++i) {
		guint8 tmp = 0;
		if (!fu_superio_device_ec_read_data(device, &tmp, error)) {
			g_prefix_error(error, "failed to read firmware project: ");
			return FALSE;
		}
		if (tmp == '$')
			break;
		project[i] = tmp;
	}

	self->prj_name = g_strdup(project);

	/* success */
	return TRUE;
}

static gboolean
fu_superio_it55_device_ec_version(FuSuperioDevice *self, GError **error)
{
	gchar version[16] = {'1', '.', '\0'};

	if (!fu_superio_device_ec_write_cmd(self, SIO_CMD_EC_GET_VERSION_STR, error))
		return FALSE;

	for (guint i = 2; i < sizeof(version) - 1; i++) {
		guint8 tmp = 0;
		if (!fu_superio_device_ec_read_data(self, &tmp, error)) {
			g_prefix_error(error, "failed to read firmware version: ");
			return FALSE;
		}
		if (tmp == '$')
			break;

		version[i] = tmp;
	}

	fu_device_set_version(FU_DEVICE(self), version);

	/* success */
	return TRUE;
}

static gboolean
fu_superio_it55_device_ec_size(FuSuperioDevice *self, GError **error)
{
	guint8 tmp = 0;

	if (!fu_superio_device_reg_read(self, 0xf9, &tmp, error))
		return FALSE;
	switch (tmp & 0xf0) {
	case 0xf0:
		fu_device_set_firmware_size(FU_DEVICE(self), BLOCK_SIZE * 4);
		break;
	case 0x40:
		fu_device_set_firmware_size(FU_DEVICE(self), BLOCK_SIZE * 3);
		break;
	default:
		fu_device_set_firmware_size(FU_DEVICE(self), BLOCK_SIZE * 2);
		break;
	}

	return TRUE;
}

static gboolean
fu_superio_it55_device_setup(FuDevice *device, GError **error)
{
	FuSuperioDevice *self = FU_SUPERIO_DEVICE(device);

	/* FuSuperioDevice->setup */
	if (!FU_DEVICE_CLASS(fu_superio_it55_device_parent_class)->setup(device, error))
		return FALSE;

	/* basic initialization */
	if (!fu_superio_device_reg_write(self, 0xf9, 0x20, error) ||
	    !fu_superio_device_reg_write(self, 0xfa, 0x02, error) ||
	    !fu_superio_device_reg_write(self, 0xfb, 0x00, error) ||
	    !fu_superio_device_reg_write(self, 0xf8, 0xb1, error)) {
		g_prefix_error(error, "initialization: ");
		return FALSE;
	}

	/* Order of interactions with EC below matters. Additionally, reading EC
	 * project seems to be mandatory for successful firmware operations.
	 * Test after making changes here! */

	/* get size from the EC */
	if (!fu_superio_it55_device_ec_size(self, error))
		return FALSE;

	/* get installed firmware project from the EC */
	if (!fu_superio_it55_device_ec_project(self, error))
		return FALSE;

	/* get installed firmware version from the EC */
	if (!fu_superio_it55_device_ec_version(self, error))
		return FALSE;

	/* success */
	return TRUE;
}

static void
fu_superio_it55_device_progress_cb(goffset current, goffset total, gpointer user_data)
{
	FuDevice *device = FU_DEVICE(user_data);
	fu_device_set_progress_full(device, (gsize)current, (gsize)total);
}

static GBytes *
fu_plugin_superio_patch_autoload(FuDevice *device, GBytes *fw, GError **error)
{
	FuEcIt55Device *self = FU_SUPERIO_IT55_DEVICE(device);
	guint offset;
	gsize sz = 0;
	const guint8 *unpatched = g_bytes_get_data(fw, &sz);
	gboolean small_flash = (sz <= BLOCK_SIZE * 2);
	g_autofree guint8 *patched = NULL;

	if (self->autoload_action == AUTOLOAD_NO_ACTION)
		return g_bytes_ref(fw);

	for (offset = 0; offset < sz - 6; ++offset) {
		if (unpatched[offset] == 0xa5 &&
		    (unpatched[offset + 1] == 0xa5 || unpatched[offset + 1] == 0xa4) &&
		    unpatched[offset + 5] == 0x5a)
			break;
	}

	if (offset >= sz - 6)
		return g_bytes_ref(fw);

	/* not big enough */
	if (offset + 8 >= sz) {
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_NOT_SUPPORTED,
				    "image is too small to patch");
		return NULL;
	}

	patched = fu_memdup_safe(unpatched, sz, error);
	if (patched == NULL)
		return NULL;

	if (self->autoload_action == AUTOLOAD_DISABLE) {
		patched[offset + 2] = (small_flash ? 0x94 : 0x85);
		patched[offset + 8] = 0x00;
	} else if (self->autoload_action == AUTOLOAD_SET_ON) {
		patched[offset + 2] = (small_flash ? 0x94 : 0x85);
		patched[offset + 8] = (small_flash ? 0x7f : 0xbe);
	} else if (self->autoload_action == AUTOLOAD_SET_OFF) {
		patched[offset + 2] = (small_flash ? 0xa5 : 0xb5);
		patched[offset + 8] = 0xaa;
	}

	return g_bytes_new_take(g_steal_pointer(&patched), sz);
}

/* progress callback is optional to not affect device progress during writing
 * firmware */
static GBytes *
fu_superio_it55_device_get_firmware(FuDevice *device,
				    GFileProgressCallback progress_cb,
				    GError **error)
{
	FuSuperioDevice *self = FU_SUPERIO_DEVICE(device);
	guint64 fwsize = fu_device_get_firmware_size_min(device);
	guint64 block_count = (fwsize + BLOCK_SIZE - 1) / BLOCK_SIZE;
	goffset offset = 0;
	g_autofree guint8 *buf = NULL;

	buf = g_malloc0(fwsize);
	for (guint i = 0; i < block_count; ++i) {
		if (!fu_superio_device_ec_write_cmd(self, SIO_CMD_EC_READ_BLOCK, error) ||
		    !fu_superio_device_ec_write_cmd(self, i, error))
			return NULL;

		for (guint j = 0; j < BLOCK_SIZE; ++j, ++offset) {
			if (!fu_superio_device_ec_read_data(self, &buf[offset], error))
				return NULL;

			if (progress_cb != NULL)
				progress_cb(offset, (goffset)fwsize, self);
		}
	}

	return g_bytes_new_take(g_steal_pointer(&buf), fwsize);
}

static GBytes *
fu_superio_it55_device_dump_firmware(FuDevice *device, GError **error)
{
	g_autoptr(FuDeviceLocker) locker = NULL;

	/* require detach -> attach */
	locker = fu_device_locker_new_full(device,
					   (FuDeviceLockerFunc)fu_device_detach,
					   (FuDeviceLockerFunc)fu_device_attach,
					   error);
	if (locker == NULL)
		return NULL;

	fu_device_set_status(device, FWUPD_STATUS_DEVICE_READ);
	return fu_superio_it55_device_get_firmware(device,
						   fu_superio_it55_device_progress_cb,
						   error);
}

static gboolean
fu_superio_it55_device_attach(FuDevice *device, GError **error)
{
	FuSuperioDevice *self = FU_SUPERIO_DEVICE(device);

	if (!fu_device_has_flag(device, FWUPD_DEVICE_FLAG_IS_BOOTLOADER))
		return TRUE;

	/* leave ROM access mode */
	if (!fu_superio_device_ec_write_cmd(self, EC_ROM_ACCESS_OFF, error))
		return FALSE;

	/* success */
	fu_device_remove_flag(device, FWUPD_DEVICE_FLAG_IS_BOOTLOADER);
	return TRUE;
}

static gboolean
fu_superio_it55_device_detach(FuDevice *device, GError **error)
{
	FuSuperioDevice *self = FU_SUPERIO_DEVICE(device);

	if (fu_device_has_flag(device, FWUPD_DEVICE_FLAG_IS_BOOTLOADER))
		return TRUE;

	/* enter ROM access mode */
	if (!fu_superio_device_ec_write_cmd(self, EC_ROM_ACCESS_ON_1, error) ||
	    !fu_superio_device_ec_write_cmd(self, EC_ROM_ACCESS_ON_2, error))
		return FALSE;

	/* success */
	fu_device_add_flag(device, FWUPD_DEVICE_FLAG_IS_BOOTLOADER);
	return TRUE;
}

static gboolean
fu_superio_it55_device_erase(FuDevice *device, GError **error)
{
	FuSuperioDevice *self = FU_SUPERIO_DEVICE(device);
	guint64 fwsize = fu_device_get_firmware_size_min(device);
	guint64 chunk_count = (fwsize + CHUNK_SIZE - 1) / CHUNK_SIZE;

	for (guint i = 0; i < chunk_count; i += CHUNKS_IN_KBYTE) {
		if (!fu_superio_device_ec_write_cmd(self, SIO_CMD_EC_ERASE_KBYTE, error) ||
		    !fu_superio_device_ec_write_cmd(self, i / CHUNKS_IN_BLOCK, error) ||
		    !fu_superio_device_ec_write_cmd(self, i % CHUNKS_IN_BLOCK, error) ||
		    !fu_superio_device_ec_write_cmd(self, 0x00, error))
			return FALSE;

		g_usleep(1000);
	}

	g_usleep(100000);
	return TRUE;
}

static gboolean
fu_superio_it55_device_write_attempt(FuDevice *device, GBytes *firmware, GError **error)
{
	FuSuperioDevice *self = FU_SUPERIO_DEVICE(device);
	gsize fwsize = g_bytes_get_size(firmware);
	guint64 total = (fwsize + CHUNK_SIZE - 1) / CHUNK_SIZE;
	const guint8 *fw_data = NULL;
	g_autoptr(GBytes) erased_fw = NULL;
	g_autoptr(GBytes) written_fw = NULL;
	g_autoptr(GPtrArray) blocks = NULL;

	if (!fu_superio_it55_device_erase(device, error))
		return FALSE;

	erased_fw = fu_superio_it55_device_get_firmware(device, NULL, error);
	if (erased_fw == NULL) {
		g_prefix_error(error, "failed to read erased firmware");
		return FALSE;
	}
	if (!fu_common_bytes_is_empty(erased_fw)) {
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_READ,
				    "firmware was not erased");
		return FALSE;
	}

	/* write everything but the first kilobyte */
	blocks = fu_chunk_array_new_from_bytes(firmware, 0x00, 0x00, BLOCK_SIZE);
	for (guint i = 0; i < blocks->len; ++i) {
		FuChunk *block = g_ptr_array_index(blocks, i);
		gboolean first = (i == 0);
		guint32 offset = 0;
		guint32 bytes_left = fu_chunk_get_data_sz(block);
		const guint8 *data = fu_chunk_get_data(block);

		if (!fu_superio_device_ec_write_cmd(self, SIO_CMD_EC_WRITE_BLOCK, error) ||
		    !fu_superio_device_ec_write_cmd(self, 0x00, error) ||
		    !fu_superio_device_ec_write_cmd(self, i, error) ||
		    !fu_superio_device_ec_write_cmd(self, first ? 0x04 : 0x00, error) ||
		    !fu_superio_device_ec_write_cmd(self, 0x00, error))
			return FALSE;

		for (guint j = 0; j < CHUNKS_IN_BLOCK; ++j) {
			gsize progress = i * CHUNKS_IN_BLOCK + j;

			if (first && j < CHUNKS_IN_KBYTE) {
				offset += CHUNK_SIZE;
				bytes_left -= CHUNK_SIZE;
				fu_device_set_progress_full(device, progress, (gsize)total);
				continue;
			}

			for (guint k = 0; k < CHUNK_SIZE; ++k) {
				if (bytes_left == 0) {
					if (!fu_superio_device_ec_write_data(self, 0xff, error))
						return FALSE;
					continue;
				}

				if (!fu_superio_device_ec_write_data(self, data[offset], error))
					return FALSE;

				++offset;
				--bytes_left;
			}

			fu_device_set_progress_full(device, progress, (gsize)total);
		}
	}

	/* now write the first kilobyte */
	if (!fu_superio_device_ec_write_cmd(self, SIO_CMD_EC_WRITE_1ST_KBYTE, error))
		return FALSE;
	fw_data = g_bytes_get_data(firmware, NULL);
	for (guint i = 0; i < CHUNK_SIZE * CHUNKS_IN_KBYTE; ++i)
		if (!fu_superio_device_ec_write_data(self, fw_data[i], error))
			return FALSE;

	g_usleep(1000);

	written_fw = fu_superio_it55_device_get_firmware(device, NULL, error);
	if (written_fw == NULL) {
		g_prefix_error(error, "failed to read erased firmware");
		return FALSE;
	}
	if (!fu_common_bytes_compare(written_fw, firmware, error)) {
		g_prefix_error(error, "firmware verification");
		return FALSE;
	}

	/* success */
	fu_device_set_progress(device, 100);
	return TRUE;
}

static gboolean
fu_superio_it55_device_write_firmware(FuDevice *device,
				      FuFirmware *firmware,
				      FwupdInstallFlags flags,
				      GError **error)
{
	gsize fwsize;
	g_autoptr(GBytes) fw = NULL;
	g_autoptr(GBytes) fw_patched = NULL;
	g_autoptr(FuDeviceLocker) locker = NULL;

	/* require detach -> attach */
	locker = fu_device_locker_new_full(device,
					   (FuDeviceLockerFunc)fu_device_detach,
					   (FuDeviceLockerFunc)fu_device_attach,
					   error);
	if (locker == NULL)
		return FALSE;

	/* get default image */
	fw = fu_firmware_get_bytes(firmware, error);
	if (fw == NULL)
		return FALSE;

	fwsize = g_bytes_get_size(fw);
	if (fwsize < 1024) {
		g_prefix_error(error, "firmware is too small: %u", (guint)fwsize);
		return FALSE;
	}

	fw_patched = fu_plugin_superio_patch_autoload(device, fw, error);
	if (fw_patched == NULL)
		return FALSE;

	fu_device_set_status(device, FWUPD_STATUS_DEVICE_WRITE);

	/* try this many times; the failure-to-flash case leaves you without a
	 * keyboard and future boot may completely fail */
	for (guint i = 1;; ++i) {
		g_autoptr(GError) error_chk = NULL;
		if (fu_superio_it55_device_write_attempt(device, fw_patched, &error_chk))
			break;

		if (i == MAX_FLASHING_ATTEMPTS) {
			g_propagate_error(error, g_steal_pointer(&error_chk));
			return FALSE;
		}

		g_warning("failure %u: %s", i, error_chk->message);
	}

	/* success */
	return TRUE;
}

static gchar *
fu_ec_extract_field(GBytes *fw, const gchar *name, GError **error)
{
	guint offset;
	gsize prefix_len;
	gsize fwsz = 0;
	const gchar *value;
	const guint8 *buf = g_bytes_get_data(fw, &fwsz);
	g_autofree gchar *field = g_strdup_printf("%s:", name);

	prefix_len = strlen(field);

	for (offset = 0; offset < fwsz - prefix_len; ++offset) {
		if (memcmp(&buf[offset], field, prefix_len) == 0)
			break;
	}

	if (offset >= fwsz - prefix_len) {
		g_set_error(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_INVALID_FILE,
			    "did not find %s field in the firmware image",
			    name);
		return NULL;
	}

	offset += prefix_len;
	value = (const gchar *)&buf[offset];

	for (; offset < fwsz; ++offset) {
		if (buf[offset] == '$')
			return g_strndup(value, (const gchar *)&buf[offset] - value);
	}

	g_set_error(error,
		    FWUPD_ERROR,
		    FWUPD_ERROR_INVALID_FILE,
		    "couldn't extract %s field value from the firmware image",
		    name);
	return NULL;
}

static FuFirmware *
fu_superio_it55_device_prepare_firmware(FuDevice *device,
					GBytes *fw,
					FwupdInstallFlags flags,
					GError **error)
{
	FuEcIt55Device *self = FU_SUPERIO_IT55_DEVICE(device);
	g_autofree gchar *date = NULL;
	g_autofree gchar *prj_name = NULL;
	g_autofree gchar *version = NULL;

	prj_name = fu_ec_extract_field(fw, "PRJ", error);
	if (prj_name == NULL)
		return NULL;

	version = fu_ec_extract_field(fw, "VER", error);
	if (version == NULL)
		version = g_strdup("(unknown version)");

	date = fu_ec_extract_field(fw, "DATE", error);
	if (date == NULL)
		date = g_strdup("(unknown build date)");

	g_debug("New firmware: %s %s built on %s", prj_name, version, date);
	if (g_strcmp0(prj_name, self->prj_name) != 0) {
		g_set_error(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_NOT_SUPPORTED,
			    "firmware targets %s instead of %s",
			    prj_name,
			    self->prj_name);
		return NULL;
	}

	return fu_firmware_new_from_bytes(fw);
}

static gboolean
fu_superio_it55_device_set_quirk_kv(FuDevice *device,
				    const gchar *key,
				    const gchar *value,
				    GError **error)
{
	FuEcIt55Device *self = FU_SUPERIO_IT55_DEVICE(device);

	/* FuSuperioDevice->set_quirk_kv */
	if (!FU_DEVICE_CLASS(fu_superio_it55_device_parent_class)
		 ->set_quirk_kv(device, key, value, error))
		return FALSE;

	if (g_strcmp0(key, "SuperioAutoloadAction") == 0) {
		if (g_strcmp0(value, "none") == 0) {
			self->autoload_action = AUTOLOAD_NO_ACTION;
		} else if (g_strcmp0(value, "disable") == 0) {
			self->autoload_action = AUTOLOAD_DISABLE;
		} else if (g_strcmp0(value, "on") == 0) {
			self->autoload_action = AUTOLOAD_SET_ON;
		} else if (g_strcmp0(value, "off") == 0) {
			self->autoload_action = AUTOLOAD_SET_OFF;
		} else {
			g_set_error_literal(error,
					    G_IO_ERROR,
					    G_IO_ERROR_INVALID_DATA,
					    "invalid value");
			return FALSE;
		}
	}

	/* success */
	return TRUE;
}

static void
fu_superio_it55_device_init(FuEcIt55Device *self)
{
	fu_device_add_flag(FU_DEVICE(self), FWUPD_DEVICE_FLAG_UPDATABLE);
	fu_device_add_flag(FU_DEVICE(self), FWUPD_DEVICE_FLAG_ONLY_OFFLINE);
	fu_device_add_flag(FU_DEVICE(self), FWUPD_DEVICE_FLAG_REQUIRE_AC);
	fu_device_add_flag(FU_DEVICE(self), FWUPD_DEVICE_FLAG_NEEDS_REBOOT);
	fu_device_add_flag(FU_DEVICE(self), FWUPD_DEVICE_FLAG_REQUIRE_AC);
	/* version string example: 1.07.02TR1 */
	fu_device_set_version_format(FU_DEVICE(self), FWUPD_VERSION_FORMAT_PLAIN);
}

static void
fu_superio_it55_device_finalize(GObject *obj)
{
	FuEcIt55Device *self = FU_SUPERIO_IT55_DEVICE(obj);
	g_free(self->prj_name);
}

static void
fu_superio_it55_device_class_init(FuEcIt55DeviceClass *klass)
{
	FuDeviceClass *klass_device = FU_DEVICE_CLASS(klass);
	G_OBJECT_CLASS(klass)->finalize = fu_superio_it55_device_finalize;
	klass_device->to_string = fu_superio_it55_device_to_string;
	klass_device->attach = fu_superio_it55_device_attach;
	klass_device->detach = fu_superio_it55_device_detach;
	klass_device->dump_firmware = fu_superio_it55_device_dump_firmware;
	klass_device->write_firmware = fu_superio_it55_device_write_firmware;
	klass_device->setup = fu_superio_it55_device_setup;
	klass_device->prepare_firmware = fu_superio_it55_device_prepare_firmware;
	klass_device->set_quirk_kv = fu_superio_it55_device_set_quirk_kv;
}