/*-
 * Copyright (c) 2016 Netflix, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/ioccom.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/smp.h>

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

#include <dev/pci/pcivar.h>
#include <dev/pci/pcireg.h>

#include "nvme_private.h"

#include "nvme_if.h"

#define ccb_accb_ptr spriv_ptr0
#define ccb_ctrlr_ptr spriv_ptr1
static void	nvme_sim_action(struct cam_sim *sim, union ccb *ccb);
static void	nvme_sim_poll(struct cam_sim *sim);
static int	nvme_sim_ns_added(device_t dev, struct nvme_namespace *ns);
static int	nvme_sim_ns_changed(device_t dev, uint32_t nsid);
static int	nvme_sim_ns_removed(device_t dev, struct nvme_namespace *ns);

#define sim2softc(sim)	((struct nvme_sim_softc *)cam_sim_softc(sim))
#define sim2ctrlr(sim)	(sim2softc(sim)->s_ctrlr)

struct nvme_sim_softc
{
	struct nvme_controller	*s_ctrlr;
	struct cam_sim		*s_sim;
	struct cam_path		*s_path;
};

static void
nvme_sim_nvmeio_done(void *ccb_arg, const struct nvme_completion *cpl)
{
	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 SC and SCT.
	 * We do not try to fetch additional data from the error log,
	 * though maybe we should in the future.
	 */
	memcpy(&ccb->nvmeio.cpl, cpl, sizeof(*cpl));
	ccb->ccb_h.status &= ~CAM_SIM_QUEUED;
	if (nvme_completion_is_error(cpl)) {
		ccb->ccb_h.status = CAM_NVME_STATUS_ERROR;
		xpt_done(ccb);
	} else {
		ccb->ccb_h.status = CAM_REQ_CMP;
		xpt_done_direct(ccb);
	}
}

static void
nvme_sim_nvmeio(struct cam_sim *sim, union ccb *ccb)
{
	struct ccb_nvmeio	*nvmeio = &ccb->nvmeio;
	struct nvme_request	*req;
	void			*payload;
	uint32_t		size;
	struct nvme_controller *ctrlr;

	ctrlr = sim2ctrlr(sim);
	payload = nvmeio->data_ptr;
	size = nvmeio->dxfer_len;
	/* SG LIST ??? */
	if ((nvmeio->ccb_h.flags & CAM_DATA_MASK) == CAM_DATA_BIO)
		req = nvme_allocate_request_bio((struct bio *)payload,
		    M_NOWAIT, nvme_sim_nvmeio_done, ccb);
	else if ((nvmeio->ccb_h.flags & CAM_DATA_SG) == CAM_DATA_SG)
		req = nvme_allocate_request_ccb(ccb, M_NOWAIT,
		    nvme_sim_nvmeio_done, ccb);
	else if (payload == NULL)
		req = nvme_allocate_request_null(M_NOWAIT, nvme_sim_nvmeio_done,
		    ccb);
	else
		req = nvme_allocate_request_vaddr(payload, size, M_NOWAIT,
		    nvme_sim_nvmeio_done, ccb);
	if (req == NULL) {
		nvmeio->ccb_h.status = CAM_RESRC_UNAVAIL;
		xpt_done(ccb);
		return;
	}
	ccb->ccb_h.status |= CAM_SIM_QUEUED;

	memcpy(&req->cmd, &ccb->nvmeio.cmd, sizeof(ccb->nvmeio.cmd));

	if (ccb->ccb_h.func_code == XPT_NVME_IO)
		nvme_ctrlr_submit_io_request(ctrlr, req);
	else
		nvme_ctrlr_submit_admin_request(ctrlr, req);
}

static uint32_t
nvme_link_kBps(struct nvme_controller *ctrlr)
{
	uint32_t speed, lanes, link[] = { 1, 250000, 500000, 985000, 1970000 };
	uint32_t status;

	status = pcie_read_config(ctrlr->dev, PCIER_LINK_STA, 2);
	speed = status & PCIEM_LINK_STA_SPEED;
	lanes = (status & PCIEM_LINK_STA_WIDTH) >> 4;
	/*
	 * Failsafe on link speed indicator. If it is insane report the number of
	 * lanes as the speed. Not 100% accurate, but may be diagnostic.
	 */
	if (speed >= nitems(link))
		speed = 0;
	return link[speed] * lanes;
}

static void
nvme_sim_action(struct cam_sim *sim, union ccb *ccb)
{
	struct nvme_controller *ctrlr;

	CAM_DEBUG(ccb->ccb_h.path, CAM_DEBUG_TRACE,
	    ("nvme_sim_action: func= %#x\n",
		ccb->ccb_h.func_code));

	ctrlr = sim2ctrlr(sim);

	switch (ccb->ccb_h.func_code) {
	case XPT_CALC_GEOMETRY:		/* Calculate Geometry Totally nuts ? XXX */
		/* 
		 * Only meaningful for old-school SCSI disks since only the SCSI
		 * da driver generates them. Reject all these that slip through.
		 */
		/*FALLTHROUGH*/
	case XPT_ABORT:			/* Abort the specified CCB */
		ccb->ccb_h.status = CAM_REQ_INVALID;
		break;
	case XPT_SET_TRAN_SETTINGS:
		/*
		 * NVMe doesn't really have different transfer settings, but
		 * other parts of CAM think failure here is a big deal.
		 */
		ccb->ccb_h.status = CAM_REQ_CMP;
		break;
	case XPT_PATH_INQ:		/* Path routing inquiry */
	{
		struct ccb_pathinq	*cpi = &ccb->cpi;
		device_t		dev = ctrlr->dev;

		/*
		 * For devices that are reported as children of the AHCI
		 * controller, which has no access to the config space for this
		 * controller, report the AHCI controller's data.
		 */
		if (ctrlr->quirks & QUIRK_AHCI)
			dev = device_get_parent(dev);
		cpi->version_num = 1;
		cpi->hba_inquiry = 0;
		cpi->target_sprt = 0;
		cpi->hba_misc =  PIM_UNMAPPED | PIM_NOSCAN;
		cpi->hba_eng_cnt = 0;
		cpi->max_target = 0;
		cpi->max_lun = ctrlr->cdata.nn;
		cpi->maxio = ctrlr->max_xfer_size;
		cpi->initiator_id = 0;
		cpi->bus_id = cam_sim_bus(sim);
		cpi->base_transfer_speed = nvme_link_kBps(ctrlr);
		strlcpy(cpi->sim_vid, "FreeBSD", SIM_IDLEN);
		strlcpy(cpi->hba_vid, "NVMe", HBA_IDLEN);
		strlcpy(cpi->dev_name, cam_sim_name(sim), DEV_IDLEN);
		cpi->unit_number = cam_sim_unit(sim);
		cpi->transport = XPORT_NVME;		/* XXX XPORT_PCIE ? */
		cpi->transport_version = nvme_mmio_read_4(ctrlr, vs);
		cpi->protocol = PROTO_NVME;
		cpi->protocol_version = nvme_mmio_read_4(ctrlr, vs);
		cpi->xport_specific.nvme.nsid = xpt_path_lun_id(ccb->ccb_h.path);
		cpi->xport_specific.nvme.domain = pci_get_domain(dev);
		cpi->xport_specific.nvme.bus = pci_get_bus(dev);
		cpi->xport_specific.nvme.slot = pci_get_slot(dev);
		cpi->xport_specific.nvme.function = pci_get_function(dev);
		cpi->xport_specific.nvme.progif = pci_get_progif(dev);
		strlcpy(cpi->xport_specific.nvme.dev_name, device_get_nameunit(dev),
		    sizeof(cpi->xport_specific.nvme.dev_name));
		cpi->hba_vendor = pci_get_vendor(dev);
		cpi->hba_device = pci_get_device(dev);
		cpi->hba_subvendor = pci_get_subvendor(dev);
		cpi->hba_subdevice = pci_get_subdevice(dev);
		cpi->ccb_h.status = CAM_REQ_CMP;
		break;
	}
	case XPT_GET_TRAN_SETTINGS:	/* Get transport settings */
	{
		struct ccb_trans_settings	*cts;
		struct ccb_trans_settings_nvme	*nvmep;
		struct ccb_trans_settings_nvme	*nvmex;
		device_t dev;
		uint32_t status, caps, flags;

		dev = ctrlr->dev;
		cts = &ccb->cts;
		nvmex = &cts->xport_specific.nvme;
		nvmep = &cts->proto_specific.nvme;

		nvmex->spec = nvme_mmio_read_4(ctrlr, vs);
		nvmex->valid = CTS_NVME_VALID_SPEC;
		if ((ctrlr->quirks & QUIRK_AHCI) == 0) {
			/* AHCI redirect makes it impossible to query */
			status = pcie_read_config(dev, PCIER_LINK_STA, 2);
			caps = pcie_read_config(dev, PCIER_LINK_CAP, 2);
			flags = pcie_read_config(dev, PCIER_FLAGS, 2);
			if ((flags & PCIEM_FLAGS_TYPE) == PCIEM_TYPE_ENDPOINT) {
				nvmex->valid |= CTS_NVME_VALID_LINK;
				nvmex->speed = status & PCIEM_LINK_STA_SPEED;
				nvmex->lanes = (status & PCIEM_LINK_STA_WIDTH) >> 4;
				nvmex->max_speed = caps & PCIEM_LINK_CAP_MAX_SPEED;
				nvmex->max_lanes = (caps & PCIEM_LINK_CAP_MAX_WIDTH) >> 4;
			}
		}

		/* XXX these should be something else maybe ? */
		nvmep->valid = CTS_NVME_VALID_SPEC;
		nvmep->spec = nvmex->spec;

		cts->transport = XPORT_NVME;
		cts->transport_version = nvmex->spec;
		cts->protocol = PROTO_NVME;
		cts->protocol_version = nvmex->spec;
		cts->ccb_h.status = CAM_REQ_CMP;
		break;
	}
	case XPT_TERM_IO:		/* Terminate the I/O process */
		/*
		 * every driver handles this, but nothing generates it. Assume
		 * it's OK to just say 'that worked'.
		 */
		/*FALLTHROUGH*/
	case XPT_RESET_DEV:		/* Bus Device Reset the specified device */
	case XPT_RESET_BUS:		/* Reset the specified bus */
		/*
		 * NVMe doesn't really support physically resetting the bus. It's part
		 * of the bus scanning dance, so return sucess to tell the process to
		 * proceed.
		 */
		ccb->ccb_h.status = CAM_REQ_CMP;
		break;
	case XPT_NVME_IO:		/* Execute the requested I/O operation */
		if (ctrlr->is_failed) {
			/*
			 * I/O came in while we were failing the drive, so drop
			 * it. Once falure is complete, we'll be destroyed.
			 */
			ccb->ccb_h.status = CAM_DEV_NOT_THERE;
			break;
		}
		nvme_sim_nvmeio(sim, ccb);
		return;			/* no done */
	case XPT_NVME_ADMIN:		/* or Admin operation */
		if (ctrlr->is_failed_admin) {
			/*
			 * Admin request came in when we can't send admin
			 * commands, so drop it. Once falure is complete, we'll
			 * be destroyed.
			 */
			ccb->ccb_h.status = CAM_DEV_NOT_THERE;
			break;
		}
		nvme_sim_nvmeio(sim, ccb);
		return;			/* no done */
	default:
		ccb->ccb_h.status = CAM_REQ_INVALID;
		break;
	}
	xpt_done(ccb);
}

static void
nvme_sim_poll(struct cam_sim *sim)
{
	nvme_ctrlr_poll(sim2ctrlr(sim));
}

static int
nvme_sim_probe(device_t dev)
{
	if (nvme_use_nvd)
		return (ENXIO);
	/*
	 * Only do storage devices with CAM. NVMHCI 1.0 interfaces are the only
	 * ones that have namespaces with LBA ranges on them.
	 */
	if (pci_get_progif(device_get_parent(dev)) !=
	    PCIP_STORAGE_NVM_ENTERPRISE_NVMHCI_1_0)
		return (ENXIO);

	device_set_desc(dev, "nvme cam");
	return (BUS_PROBE_DEFAULT);
}

static int
nvme_sim_attach(device_t dev)
{
	struct cam_devq *devq;
	int max_trans;
	int err = ENXIO;
	struct nvme_sim_softc *sc = device_get_softc(dev);
	struct nvme_controller	*ctrlr = device_get_ivars(dev);

	max_trans = ctrlr->max_hw_pend_io;
	devq = cam_simq_alloc(max_trans);
	if (devq == NULL)
		return (ENOMEM);

	sc->s_ctrlr = ctrlr;

	sc->s_sim = cam_sim_alloc(nvme_sim_action, nvme_sim_poll,
	    "nvme", sc, device_get_unit(dev),
	    NULL, max_trans, max_trans, devq);
	if (sc->s_sim == NULL) {
		device_printf(dev, "Failed to allocate a sim\n");
		cam_simq_free(devq);
		return (ENOMEM);
	}
	if (xpt_bus_register(sc->s_sim, dev, 0) != CAM_SUCCESS) {
		device_printf(dev, "Failed to create a bus\n");
		goto err2;
	}
	if (xpt_create_path(&sc->s_path, /*periph*/NULL, cam_sim_path(sc->s_sim),
	    CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD) != CAM_REQ_CMP) {
		device_printf(dev, "Failed to create a path\n");
		goto err3;
	}

	for (int i = 0; i < min(ctrlr->cdata.nn, NVME_MAX_NAMESPACES); i++) {
		struct nvme_namespace	*ns = &ctrlr->ns[i];

		if (ns->data.nsze == 0)
			continue;
		nvme_sim_ns_added(dev, ns);
	}

	return (0);
err3:
	xpt_bus_deregister(cam_sim_path(sc->s_sim));
err2:
	cam_sim_free(sc->s_sim, /*free_devq*/TRUE);
	return (err);
}


static int
nvme_sim_fail_all_ns(device_t dev)
{
	struct nvme_sim_softc *sc = device_get_softc(dev);
	struct nvme_controller *ctrlr = sc->s_ctrlr;

	for (int i = 0; i < min(ctrlr->cdata.nn, NVME_MAX_NAMESPACES); i++) {
		struct nvme_namespace	*ns = &ctrlr->ns[i];

		if (ns->data.nsze == 0)
			continue;
		nvme_sim_ns_removed(dev, ns);
	}
	return (0);
}

static int
nvme_sim_detach(device_t dev)
{
	return (nvme_sim_fail_all_ns(dev));
}

static int
nvme_sim_ns_added(device_t dev, struct nvme_namespace *ns)
{
	struct nvme_sim_softc *sc = device_get_softc(dev);
	union ccb *ccb;

	/*
	 * We map the NVMe namespace idea onto the CAM unit LUN. For each new
	 * namespace, scan or rescan the path to enumerate it.
	 */
	ccb = xpt_alloc_ccb();
	if (xpt_create_path(&ccb->ccb_h.path, /*periph*/NULL,
	    cam_sim_path(sc->s_sim), 0, ns->id) != CAM_REQ_CMP) {
		printf("unable to create path for rescan\n");
		return (ENOMEM);
	}
	xpt_rescan(ccb);

	return (0);
}

static int
nvme_sim_ns_removed(device_t dev, struct nvme_namespace *ns)
{
	struct nvme_sim_softc *sc = device_get_softc(dev);
	struct cam_path *tmppath;

	if (xpt_create_path(&tmppath, /*periph*/NULL,
	    cam_sim_path(sc->s_sim), 0, ns->id) != CAM_REQ_CMP) {
		printf("unable to create path for rescan\n");
		return (ENOMEM);
	}
	xpt_async(AC_LOST_DEVICE, tmppath, NULL);
	xpt_free_path(tmppath);

	return (0);
}

static int
nvme_sim_ns_changed(device_t dev, uint32_t nsid)
{
	struct nvme_sim_softc *sc = device_get_softc(dev);
	struct nvme_namespace *ns = &sc->s_ctrlr->ns[nsid - 1];

	/*
	 * These wind up being the same. For a configured cam_ed, we generate
	 * AC_GETDEV_CHANGED, but for new one we do AC_FOUND_DEVICE, but the
	 * scan is the same.
	 */
	return (nvme_sim_ns_added(dev, ns));
}

static int
nvme_sim_controller_failed(device_t dev)
{
	return (nvme_sim_fail_all_ns(dev));
}

static int
nvme_sim_handle_aen(device_t dev, const struct nvme_completion *cpl,
    uint32_t pg_nr, void *page, uint32_t page_len)
{
	/* Do nothing */
	return (0);
}

static device_method_t nvme_sim_methods[] = {
	/* Device interface */
	DEVMETHOD(device_probe,		nvme_sim_probe),
	DEVMETHOD(device_attach,	nvme_sim_attach),
	DEVMETHOD(device_detach,	nvme_sim_detach),
	/* Nvme controller messages */
	DEVMETHOD(nvme_ns_added,   	nvme_sim_ns_added),
	DEVMETHOD(nvme_ns_removed,   	nvme_sim_ns_removed),
	DEVMETHOD(nvme_ns_changed,   	nvme_sim_ns_changed),
	DEVMETHOD(nvme_controller_failed, nvme_sim_controller_failed),
	DEVMETHOD(nvme_handle_aen,   	nvme_sim_handle_aen),
	{ 0, 0 }
};

static driver_t nvme_sim_driver = {
	"nvme_sim",
	nvme_sim_methods,
	sizeof(struct nvme_sim_softc),
};

DRIVER_MODULE(nvme_sim, nvme, nvme_sim_driver, NULL, NULL);
MODULE_VERSION(nvme_shim, 1);