/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <string.h>
#include <errno.h>
#include <sys/ioctl.h>

#include "internal.h"
#include "hinawa_sigs_marshal.h"
#include "hinawa_enums.h"

/**
 * SECTION:fw_resp
 * @Title: HinawaFwResp
 * @Short_description: A transaction responder for a FireWire unit
 *
 * A HinawaFwResp responds requests from any units.
 *
 * This class is an application of Linux FireWire subsystem. All of operations
 * utilize ioctl(2) with subsystem specific request commands.
 */

/* For error handling. */
G_DEFINE_QUARK("HinawaFwResp", hinawa_fw_resp)
#define raise(exception, errno)						\
	g_set_error(exception, hinawa_fw_resp_quark(), errno,		\
		    "%d: %s", __LINE__, strerror(errno))

struct _HinawaFwRespPrivate {
	HinawaFwUnit *unit;

	guint width;
	guint64 addr_handle;

	guint8 *req_frame;
	unsigned int req_length;
	guint8 *resp_frame;
	unsigned int resp_length;
};
G_DEFINE_TYPE_WITH_PRIVATE(HinawaFwResp, hinawa_fw_resp, G_TYPE_OBJECT)

/* This object has one signal. */
enum fw_resp_sig_type {
	FW_RESP_SIG_TYPE_REQ = 0,
	FW_RESP_SIG_TYPE_COUNT,
};
static guint fw_resp_sigs[FW_RESP_SIG_TYPE_COUNT] = { 0 };

static void fw_resp_finalize(GObject *obj)
{
	HinawaFwResp *self = HINAWA_FW_RESP(obj);

	hinawa_fw_resp_unregister(self);

	G_OBJECT_CLASS(hinawa_fw_resp_parent_class)->finalize(obj);
}

static void hinawa_fw_resp_class_init(HinawaFwRespClass *klass)
{
	GObjectClass *gobject_class = G_OBJECT_CLASS(klass);

	gobject_class->get_property = NULL;
	gobject_class->set_property = NULL;
	gobject_class->finalize = fw_resp_finalize;

	/**
	 * HinawaFwResp::requested:
	 * @self: A #HinawaFwResp
	 * @tcode: One of #HinawaTcode enumerators
	 *
	 * When any units transfer requests to the range of address to which
	 * this object listening. The ::requested signal handler can get data
	 * frame by a call of ::get_req_frame and set data frame by a call of
	 * ::set_resp_frame, then returns rcode.
	 *
	 * Returns: One of #HinawaRcode enumerators corresponding to rcodes
	 * 	    defined in IEEE 1394 specification.
	 */
	fw_resp_sigs[FW_RESP_SIG_TYPE_REQ] =
		g_signal_new("requested",
			     G_OBJECT_CLASS_TYPE(klass),
			     G_SIGNAL_RUN_LAST,
			     G_STRUCT_OFFSET(HinawaFwRespClass, requested),
			     NULL, NULL,
			     hinawa_sigs_marshal_ENUM__ENUM,
			     HINAWA_TYPE_FW_RCODE, 1, HINAWA_TYPE_FW_TCODE);
}

static void hinawa_fw_resp_init(HinawaFwResp *self)
{
	return;
}

/**
 * hinawa_fw_resp_register:
 * @self: A #HinawaFwResp
 * @unit: A #HinawaFwUnit
 * @addr: A start address to listen to in host controller
 * @width: The byte width of address to listen to host controller
 * @exception: A #GError
 *
 * Start to listen to a range of address in host controller
 */
void hinawa_fw_resp_register(HinawaFwResp *self, HinawaFwUnit *unit,
			     guint64 addr, guint width, GError **exception)
{
	HinawaFwRespPrivate *priv;
	struct fw_cdev_allocate allocate = {0};
	int err;

	g_return_if_fail(HINAWA_IS_FW_RESP(self));
	priv = hinawa_fw_resp_get_instance_private(self);

	if (priv->unit != NULL) {
		raise(exception, EINVAL);
		return;
	}
	priv->unit = g_object_ref(unit);

	allocate.offset = addr;
	allocate.closure = (guint64)self;
	allocate.length = width;
	allocate.region_end = addr + width;

	hinawa_fw_unit_ioctl(priv->unit, FW_CDEV_IOC_ALLOCATE, &allocate, &err);
	if (err != 0) {
		raise(exception, err);
		g_object_unref(priv->unit);
		priv->unit = NULL;
		return;
	}

	priv->req_frame = g_malloc(allocate.length);
	if (!priv->req_frame) {
		raise(exception, ENOMEM);
		hinawa_fw_resp_unregister(self);
		return;
	}

	priv->resp_frame = g_malloc0(allocate.length);
	if (!priv->resp_frame) {
		raise(exception, ENOMEM);
		hinawa_fw_resp_unregister(self);
		return;
	}

	priv->width = allocate.length;
	priv->addr_handle = allocate.handle;
}

/**
 * hinawa_fw_resp_unregister:
 * @self: A HinawaFwResp
 *
 * stop to listen to a range of address in host controller
 */
void hinawa_fw_resp_unregister(HinawaFwResp *self)
{
	HinawaFwRespPrivate *priv;
	struct fw_cdev_deallocate deallocate = {0};
	int err;

	g_return_if_fail(HINAWA_IS_FW_RESP(self));
	priv = hinawa_fw_resp_get_instance_private(self);

	if (priv->unit == NULL)
		return;

	deallocate.handle = priv->addr_handle;
	hinawa_fw_unit_ioctl(priv->unit, FW_CDEV_IOC_DEALLOCATE, &deallocate,
			     &err);
	g_object_unref(priv->unit);
	priv->unit = NULL;

	if (priv->req_frame != NULL)
		g_free(priv->req_frame);
	priv->req_frame = NULL;

	if (priv->resp_frame)
		g_free(priv->resp_frame);
	priv->resp_frame = NULL;
	priv->resp_length = 0;
}

/**
 * hinawa_fw_resp_get_req_frame:
 * @self: A #HinawaFwResp
 * @frame: (element-type guint8)(array length=length)(out): a 8bit array for
 * 	   response frame.
 * @length: (out): The length of bytes for the frame.
 *
 * Retrieve byte frame to be requested.
 */
void hinawa_fw_resp_get_req_frame(HinawaFwResp *self, const guint8 **frame,
				  guint *length)
{
	HinawaFwRespPrivate *priv;

	g_return_if_fail(HINAWA_IS_FW_RESP(self));
	priv = hinawa_fw_resp_get_instance_private(self);

	if (frame && length && priv->req_length > 0) {
		*frame = (const guint8 *)priv->req_frame;
		*length = priv->req_length;
	}
}

/**
 * hinawa_fw_resp_set_resp_frame:
 * @self: A #HinawaFwResp
 * @frame: (element-type guint8)(array length=length): a 8bit array for response
 * 	   frame.
 * @length: The length of bytes for the frame.
 *
 * Register byte frame as response.
 */
void hinawa_fw_resp_set_resp_frame(HinawaFwResp *self, guint8 *frame,
				   guint length)
{
	HinawaFwRespPrivate *priv;

	g_return_if_fail(HINAWA_IS_FW_RESP(self));
	priv = hinawa_fw_resp_get_instance_private(self);

	if (frame && length <= priv->width) {
		memcpy(priv->resp_frame, frame, length);
		priv->resp_length = length;
	}
}

/* NOTE: For HinawaFwUnit, internal. */
void hinawa_fw_resp_handle_request(HinawaFwResp *self,
				   struct fw_cdev_event_request2 *event)
{
	HinawaFwRespPrivate *priv;
	struct fw_cdev_send_response resp = {0};
	HinawaFwTcode tcode;
	HinawaFwRcode rcode;
	int err;

	g_return_if_fail(HINAWA_IS_FW_RESP(self));
	priv = hinawa_fw_resp_get_instance_private(self);

	if (!priv->unit || event->length > priv->width) {
		resp.rcode = RCODE_CONFLICT_ERROR;
		goto respond;
	}

	/* Emit signal to handlers. */
	memcpy(priv->req_frame, event->data, event->length);
	priv->req_length = event->length;

	/* Emit signal to handlers. */
	tcode = (HinawaFwTcode)event->tcode;
	rcode = HINAWA_FW_RCODE_COMPLETE;
	g_signal_emit(self, fw_resp_sigs[FW_RESP_SIG_TYPE_REQ], 0, tcode,
		      &rcode);
	resp.rcode = (__u32)rcode;

	if (priv->resp_length > 0) {
		resp.length = priv->resp_length;
		resp.data = (guint64)priv->resp_frame;
	}
respond:
	resp.handle = event->handle;

	hinawa_fw_unit_ioctl(priv->unit, FW_CDEV_IOC_SEND_RESPONSE, &resp,
			     &err);

	memset(priv->resp_frame, 0, priv->width);
	priv->resp_length = 0;
}
