/*-
 * Copyright (c) 2025, Samsung Electronics Co., Ltd.
 * Written by Jaeyoon Choi
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <sys/param.h>

#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/cam_debug.h>
#include <cam/cam_sim.h>
#include <cam/cam_xpt_sim.h>
#include <cam/scsi/scsi_all.h>

#include "ufshci_private.h"

#define sim2ctrlr(sim) ((struct ufshci_controller *)cam_sim_softc(sim))

static void
ufshci_sim_scsiio_done(void *ccb_arg, const struct ufshci_completion *cpl,
    bool error)
{
	const uint8_t *sense_data;
	uint16_t sense_data_max_size;
	uint16_t sense_data_len;

	union ccb *ccb = (union ccb *)ccb_arg;

	/*
	 * Let the periph know the completion, and let it sort out what
	 * it means. Report an error or success based on OCS and UPIU
	 * response code. And We need to copy the sense data to be handled
	 * by the CAM.
	 */
	sense_data = cpl->response_upiu.cmd_response_upiu.sense_data;
	sense_data_max_size = sizeof(
	    cpl->response_upiu.cmd_response_upiu.sense_data);
	sense_data_len = be16toh(
	    cpl->response_upiu.cmd_response_upiu.sense_data_len);
	memcpy(&ccb->csio.sense_data, sense_data,
	    min(sense_data_len, sense_data_max_size));

	ccb->ccb_h.status &= ~CAM_SIM_QUEUED;
	if (error) {
		ccb->ccb_h.status = CAM_REQ_CMP_ERR;
		xpt_done(ccb);
	} else {
		ccb->ccb_h.status = CAM_REQ_CMP;
		xpt_done_direct(ccb);
	}
}

/*
 * Complete the command as an illegal command with invalid field
 */
static void
ufshci_sim_illegal_request(union ccb *ccb)
{
	scsi_set_sense_data(&ccb->csio.sense_data,
	    /*sense_format*/ SSD_TYPE_NONE,
	    /*current_error*/ 1,
	    /*sense_key*/ SSD_KEY_ILLEGAL_REQUEST,
	    /*asc*/ 0x24, /* 24h/00h INVALID FIELD IN CDB */
	    /*ascq*/ 0x00,
	    /*extra args*/ SSD_ELEM_NONE);
	ccb->csio.scsi_status = SCSI_STATUS_CHECK_COND;
	ccb->ccb_h.status = CAM_SCSI_STATUS_ERROR | CAM_AUTOSNS_VALID |
	    CAM_DEV_QFRZN;
	xpt_freeze_devq(ccb->ccb_h.path, 1);
	xpt_done(ccb);
}

static void
ufshchi_sim_scsiio(struct cam_sim *sim, union ccb *ccb)
{
	struct ccb_scsiio *csio = &ccb->csio;
	struct ufshci_request *req;
	void *payload;
	struct ufshci_cmd_command_upiu *upiu;
	uint8_t *cdb;
	uint32_t payload_len;
	bool is_write;
	struct ufshci_controller *ctrlr;
	uint8_t data_direction;
	int error;

	/* UFS device cannot process these commands */
	if (csio->cdb_io.cdb_bytes[0] == MODE_SENSE_6 ||
	    csio->cdb_io.cdb_bytes[0] == MODE_SELECT_6 ||
	    csio->cdb_io.cdb_bytes[0] == READ_12 ||
	    csio->cdb_io.cdb_bytes[0] == WRITE_12) {
		ufshci_sim_illegal_request(ccb);
		return;
	}

	ctrlr = sim2ctrlr(sim);
	payload = csio->data_ptr;

	payload_len = csio->dxfer_len;
	is_write = csio->ccb_h.flags & CAM_DIR_OUT;

	/* TODO: Check other data type */
	if ((csio->ccb_h.flags & CAM_DATA_MASK) == CAM_DATA_BIO)
		req = ufshci_allocate_request_bio((struct bio *)payload,
		    M_NOWAIT, ufshci_sim_scsiio_done, ccb);
	else
		req = ufshci_allocate_request_vaddr(payload, payload_len,
		    M_NOWAIT, ufshci_sim_scsiio_done, ccb);

	req->request_size = sizeof(struct ufshci_cmd_command_upiu);
	req->response_size = sizeof(struct ufshci_cmd_response_upiu);

	switch (ccb->ccb_h.flags & CAM_DIR_MASK) {
	case CAM_DIR_IN:
		data_direction = UFSHCI_DATA_DIRECTION_FROM_TGT_TO_SYS;
		break;
	case CAM_DIR_OUT:
		data_direction = UFSHCI_DATA_DIRECTION_FROM_SYS_TO_TGT;
		break;
	default:
		data_direction = UFSHCI_DATA_DIRECTION_NO_DATA_TRANSFER;
	}
	req->data_direction = data_direction;

	upiu = (struct ufshci_cmd_command_upiu *)&req->request_upiu;
	memset(upiu, 0, req->request_size);
	upiu->header.trans_type = UFSHCI_UPIU_TRANSACTION_CODE_COMMAND;
	upiu->header.operational_flags = is_write ? UFSHCI_OPERATIONAL_FLAG_W :
						    UFSHCI_OPERATIONAL_FLAG_R;
	upiu->header.lun = csio->ccb_h.target_lun;
	upiu->header.cmd_set_type = UFSHCI_COMMAND_SET_TYPE_SCSI;

	upiu->expected_data_transfer_length = htobe32(payload_len);

	ccb->ccb_h.status |= CAM_SIM_QUEUED;

	if (csio->ccb_h.flags & CAM_CDB_POINTER)
		cdb = csio->cdb_io.cdb_ptr;
	else
		cdb = csio->cdb_io.cdb_bytes;

	if (cdb == NULL || csio->cdb_len > sizeof(upiu->cdb)) {
		ccb->ccb_h.status = CAM_REQ_INVALID;
		xpt_done(ccb);
		return;
	}
	memcpy(upiu->cdb, cdb, csio->cdb_len);

	error = ufshci_ctrlr_submit_io_request(ctrlr, req);
	if (error == EBUSY) {
		ccb->ccb_h.status = CAM_SCSI_BUSY;
		xpt_done(ccb);
		return;
	} else if (error) {
		ccb->ccb_h.status = CAM_REQ_INVALID;
		xpt_done(ccb);
		return;
	}
}

static uint32_t
ufshci_link_kBps(struct ufshci_controller *ctrlr)
{
	uint32_t gear = ctrlr->hs_gear;
	uint32_t lanes = ctrlr->rx_lanes;

	/*
	 * per-lane effective bandwidth (KB/s, SI 1 KB = 1000 B)
	 * All HS-Gears use 8b/10b line coding, i.e. 80 % efficiency.
	 * - KB/s per lane = raw-rate(Gbps) × 0.8(8b/10b) / 8(bit)
	 */
	static const uint32_t kbps_per_lane[] = {
		0,	 /* unused */
		145920,	 /* HS-Gear1 : 1459.2 Mbps */
		291840,	 /* HS-Gear2 : 2918.4 Mbps */
		583680,	 /* HS-Gear3 : 5836.8 Mbps */
		1167360, /* HS-Gear4 : 11673.6 Mbps */
		2334720	 /* HS-Gear5 : 23347.2 Mbps */
	};

	/* Sanity checks */
	if (gear >= nitems(kbps_per_lane))
		gear = 0; /* out-of-range -> treat as invalid */

	if (lanes == 0 || lanes > 2)
		lanes = 1; /* UFS spec allows 1–2 data lanes */

	return kbps_per_lane[gear] * lanes;
}

static void
ufshci_cam_action(struct cam_sim *sim, union ccb *ccb)
{
	struct ufshci_controller *ctrlr = sim2ctrlr(sim);

	if (ctrlr == NULL) {
		ccb->ccb_h.status = CAM_SEL_TIMEOUT;
		xpt_done(ccb);
		return;
	}

	/* Perform the requested action */
	switch (ccb->ccb_h.func_code) {
	case XPT_SCSI_IO:
		ufshchi_sim_scsiio(sim, ccb);
		return;
	case XPT_PATH_INQ: {
		struct ccb_pathinq *cpi = &ccb->cpi;

		cpi->version_num = 1;
		cpi->hba_inquiry = PI_SDTR_ABLE | PI_TAG_ABLE;
		cpi->target_sprt = 0;
		cpi->hba_misc = PIM_UNMAPPED | PIM_NO_6_BYTE;
		cpi->hba_eng_cnt = 0;
		cpi->max_target = 0;
		cpi->max_lun = ctrlr->max_lun_count;
		cpi->async_flags = 0;
		cpi->maxio = ctrlr->max_xfer_size;
		cpi->initiator_id = 1;
		strlcpy(cpi->sim_vid, "FreeBSD", SIM_IDLEN);
		strlcpy(cpi->hba_vid, "UFSHCI", HBA_IDLEN);
		strlcpy(cpi->dev_name, cam_sim_name(sim), DEV_IDLEN);
		cpi->unit_number = cam_sim_unit(sim);
		cpi->base_transfer_speed = ufshci_link_kBps(ctrlr);
		cpi->transport = XPORT_UFSHCI;
		cpi->transport_version = 1;
		cpi->protocol = PROTO_SCSI;
		cpi->protocol_version = SCSI_REV_SPC5;
		ccb->ccb_h.status = CAM_REQ_CMP;
		break;
	}
	case XPT_RESET_BUS:
		ccb->ccb_h.status = CAM_REQ_CMP;
		break;
	case XPT_RESET_DEV:
		if (ufshci_dev_reset(ctrlr))
			ccb->ccb_h.status = CAM_REQ_CMP_ERR;
		else
			ccb->ccb_h.status = CAM_REQ_CMP;
		break;
	case XPT_ABORT:
		/* TODO: Implement Task Management CMD*/
		ccb->ccb_h.status = CAM_FUNC_NOTAVAIL;
		break;
	case XPT_SET_TRAN_SETTINGS:
		ccb->ccb_h.status = CAM_FUNC_NOTAVAIL;
		break;
	case XPT_GET_TRAN_SETTINGS: {
		struct ccb_trans_settings *cts;
		struct ccb_trans_settings_ufshci *ufshcix;

		cts = &ccb->cts;
		ufshcix = &cts->xport_specific.ufshci;

		ufshcix->hs_gear = ctrlr->hs_gear;
		ufshcix->tx_lanes = ctrlr->tx_lanes;
		ufshcix->rx_lanes = ctrlr->rx_lanes;
		ufshcix->max_hs_gear = ctrlr->max_rx_hs_gear;
		ufshcix->max_tx_lanes = ctrlr->max_tx_lanes;
		ufshcix->max_rx_lanes = ctrlr->max_rx_lanes;
		ufshcix->valid = CTS_UFSHCI_VALID_LINK;

		cts->transport = XPORT_UFSHCI;
		cts->transport_version = 1;
		cts->protocol = PROTO_SCSI;
		cts->protocol_version = SCSI_REV_SPC5;
		ccb->ccb_h.status = CAM_REQ_CMP;
		break;
	}
	case XPT_CALC_GEOMETRY:
		cam_calc_geometry(&ccb->ccg, 1);
		break;
	case XPT_NOOP:
		ccb->ccb_h.status = CAM_REQ_CMP;
		break;
	default:
		printf("invalid ccb=%p func=%#x\n", ccb, ccb->ccb_h.func_code);
		break;
	}
	xpt_done(ccb);

	return;
}

static void
ufshci_cam_poll(struct cam_sim *sim)
{
	struct ufshci_controller *ctrlr = sim2ctrlr(sim);

	ufshci_ctrlr_poll(ctrlr);
}

int
ufshci_sim_attach(struct ufshci_controller *ctrlr)
{
	device_t dev;
	struct cam_devq *devq;
	int max_trans;

	dev = ctrlr->dev;
	max_trans = ctrlr->max_hw_pend_io;
	if ((devq = cam_simq_alloc(max_trans)) == NULL) {
		printf("Failed to allocate a simq\n");
		return (ENOMEM);
	}

	ctrlr->ufshci_sim = cam_sim_alloc(ufshci_cam_action, ufshci_cam_poll,
	    "ufshci", ctrlr, device_get_unit(dev), &ctrlr->sc_mtx, max_trans,
	    max_trans, devq);
	if (ctrlr->ufshci_sim == NULL) {
		printf("Failed to allocate a sim\n");
		cam_simq_free(devq);
		return (ENOMEM);
	}

	mtx_lock(&ctrlr->sc_mtx);
	if (xpt_bus_register(ctrlr->ufshci_sim, ctrlr->dev, 0) != CAM_SUCCESS) {
		cam_sim_free(ctrlr->ufshci_sim, /*free_devq*/ TRUE);
		cam_simq_free(devq);
		mtx_unlock(&ctrlr->sc_mtx);
		printf("Failed to create a bus\n");
		return (ENOMEM);
	}

	if (xpt_create_path(&ctrlr->ufshci_path, /*periph*/ NULL,
		cam_sim_path(ctrlr->ufshci_sim), CAM_TARGET_WILDCARD,
		CAM_LUN_WILDCARD) != CAM_REQ_CMP) {
		xpt_bus_deregister(cam_sim_path(ctrlr->ufshci_sim));
		cam_sim_free(ctrlr->ufshci_sim, /*free_devq*/ TRUE);
		cam_simq_free(devq);
		mtx_unlock(&ctrlr->sc_mtx);
		printf("Failed to create a path\n");
		return (ENOMEM);
	}
	mtx_unlock(&ctrlr->sc_mtx);

	return (0);
}

void
ufshci_sim_detach(struct ufshci_controller *ctrlr)
{
	int error;

	if (ctrlr->ufshci_path != NULL) {
		xpt_free_path(ctrlr->ufshci_path);
		ctrlr->ufshci_path = NULL;
	}

	if (ctrlr->ufshci_sim != NULL) {
		error = xpt_bus_deregister(cam_sim_path(ctrlr->ufshci_sim));
		if (error == 0) {
			/* accessing the softc is not possible after this */
			ctrlr->ufshci_sim->softc = NULL;
			ufshci_printf(ctrlr,
			    "%s: %s:%d:%d caling "
			    "cam_sim_free sim %p refc %u mtx %p\n",
			    __func__, ctrlr->sc_name,
			    cam_sim_path(ctrlr->ufshci_sim), ctrlr->sc_unit,
			    ctrlr->ufshci_sim, ctrlr->ufshci_sim->refcount,
			    ctrlr->ufshci_sim->mtx);
		} else {
			panic("%s: %s: CAM layer is busy: errno %d\n", __func__,
			    ctrlr->sc_name, error);
		}

		cam_sim_free(ctrlr->ufshci_sim, /* free_devq */ TRUE);
		ctrlr->ufshci_sim = NULL;
	}
}