/*-
 * Copyright (C) 2012 Intel Corporation
 * All rights reserved.
 *
 * 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.
 * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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/cdefs.h>
__FBSDID("$FreeBSD: head/sys/dev/nvme/nvme_qpair.c 241661 2012-10-18 00:40:40Z jimharris $");

#include <sys/param.h>
#include <sys/bus.h>

#include "nvme_private.h"

static boolean_t
nvme_completion_check_retry(const struct nvme_completion *cpl)
{
	/*
	 * TODO: spec is not clear how commands that are aborted due
	 *  to TLER will be marked.  So for now, it seems
	 *  NAMESPACE_NOT_READY is the only case where we should
	 *  look at the DNR bit.
	 */
	switch (cpl->sf_sct) {
	case NVME_SCT_GENERIC:
		switch (cpl->sf_sc) {
		case NVME_SC_NAMESPACE_NOT_READY:
			if (cpl->sf_dnr)
				return (0);
			else
				return (1);
		case NVME_SC_INVALID_OPCODE:
		case NVME_SC_INVALID_FIELD:
		case NVME_SC_COMMAND_ID_CONFLICT:
		case NVME_SC_DATA_TRANSFER_ERROR:
		case NVME_SC_ABORTED_POWER_LOSS:
		case NVME_SC_INTERNAL_DEVICE_ERROR:
		case NVME_SC_ABORTED_BY_REQUEST:
		case NVME_SC_ABORTED_SQ_DELETION:
		case NVME_SC_ABORTED_FAILED_FUSED:
		case NVME_SC_ABORTED_MISSING_FUSED:
		case NVME_SC_INVALID_NAMESPACE_OR_FORMAT:
		case NVME_SC_COMMAND_SEQUENCE_ERROR:
		case NVME_SC_LBA_OUT_OF_RANGE:
		case NVME_SC_CAPACITY_EXCEEDED:
		default:
			return (0);
		}
	case NVME_SCT_COMMAND_SPECIFIC:
	case NVME_SCT_MEDIA_ERROR:
	case NVME_SCT_VENDOR_SPECIFIC:
	default:
		return (0);
	}
}

struct nvme_tracker *
nvme_qpair_allocate_tracker(struct nvme_qpair *qpair)
{
	struct nvme_tracker	*tr;

	mtx_lock(&qpair->lock);

	tr = SLIST_FIRST(&qpair->free_tr);
	if (tr == NULL) {
		/* 
		 * We can't support more trackers than we have entries in
		 *  our queue, because it would generate invalid indices
		 *  into the qpair's active tracker array.
		 */
		if (qpair->num_tr == qpair->num_entries) {
			mtx_unlock(&qpair->lock);
			return (NULL);
		}

		tr = malloc(sizeof(struct nvme_tracker), M_NVME,
		    M_ZERO | M_NOWAIT);

		if (tr == NULL) {
			mtx_unlock(&qpair->lock);
			return (NULL);
		}

		bus_dmamap_create(qpair->dma_tag, 0, &tr->payload_dma_map);
		bus_dmamap_create(qpair->dma_tag, 0, &tr->prp_dma_map);

		bus_dmamap_load(qpair->dma_tag, tr->prp_dma_map, tr->prp,
		    sizeof(tr->prp), nvme_single_map, &tr->prp_bus_addr, 0);

		callout_init_mtx(&tr->timer, &qpair->lock, 0);
		tr->cid = qpair->num_tr++;
		tr->qpair = qpair;
	} else
		SLIST_REMOVE_HEAD(&qpair->free_tr, slist);

	return (tr);
}

void
nvme_qpair_process_completions(struct nvme_qpair *qpair)
{
	struct nvme_tracker	*tr;
	struct nvme_request	*req;
	struct nvme_completion	*cpl;
	boolean_t		retry, error;

	qpair->num_intr_handler_calls++;

	while (1) {
		cpl = &qpair->cpl[qpair->cq_head];

		if (cpl->p != qpair->phase)
			break;

		tr = qpair->act_tr[cpl->cid];
		req = tr->req;

		KASSERT(tr,
		    ("completion queue has entries but no active trackers\n"));

		error = cpl->sf_sc || cpl->sf_sct;
		retry = error && nvme_completion_check_retry(cpl);

		if (error) {
			nvme_dump_completion(cpl);
			nvme_dump_command(&tr->req->cmd);
		}

		qpair->act_tr[cpl->cid] = NULL;

		KASSERT(cpl->cid == tr->cmd.cid,
		    ("cpl cid does not match cmd cid\n"));

		if (req->cb_fn && !retry)
			req->cb_fn(req->cb_arg, cpl);

		qpair->sq_head = cpl->sqhd;

		mtx_lock(&qpair->lock);
		callout_stop(&tr->timer);

		if (retry)
			/* nvme_qpair_submit_cmd() will release the lock. */
			nvme_qpair_submit_cmd(qpair, tr);
		else {
			if (req->payload_size > 0 || req->uio != NULL)
				bus_dmamap_unload(qpair->dma_tag,
				    tr->payload_dma_map);

			nvme_free_request(req);
			SLIST_INSERT_HEAD(&qpair->free_tr, tr, slist);

			mtx_unlock(&qpair->lock);
		}

		if (++qpair->cq_head == qpair->num_entries) {
			qpair->cq_head = 0;
			qpair->phase = !qpair->phase;
		}

		nvme_mmio_write_4(qpair->ctrlr, doorbell[qpair->id].cq_hdbl,
		    qpair->cq_head);
	}
}

static void
nvme_qpair_msix_handler(void *arg)
{
	struct nvme_qpair *qpair = arg;

	nvme_qpair_process_completions(qpair);
}

void
nvme_qpair_construct(struct nvme_qpair *qpair, uint32_t id,
    uint16_t vector, uint32_t num_entries, uint32_t max_xfer_size,
    struct nvme_controller *ctrlr)
{

	qpair->id = id;
	qpair->vector = vector;
	qpair->num_entries = num_entries;
	qpair->max_xfer_size = max_xfer_size;
	qpair->ctrlr = ctrlr;

	/*
	 * First time through the completion queue, HW will set phase
	 *  bit on completions to 1.  So set this to 1 here, indicating
	 *  we're looking for a 1 to know which entries have completed.
	 *  we'll toggle the bit each time when the completion queue
	 *  rolls over.
	 */
	qpair->phase = 1;

	if (ctrlr->msix_enabled) {

		/*
		 * MSI-X vector resource IDs start at 1, so we add one to
		 *  the queue's vector to get the corresponding rid to use.
		 */
		qpair->rid = vector + 1;

		qpair->res = bus_alloc_resource_any(ctrlr->dev, SYS_RES_IRQ,
		    &qpair->rid, RF_ACTIVE);

		bus_setup_intr(ctrlr->dev, qpair->res,
		    INTR_TYPE_MISC | INTR_MPSAFE, NULL,
		    nvme_qpair_msix_handler, qpair, &qpair->tag);
	}

	mtx_init(&qpair->lock, "nvme qpair lock", NULL, MTX_DEF);

	bus_dma_tag_create(bus_get_dma_tag(ctrlr->dev),
	    sizeof(uint64_t), PAGE_SIZE, BUS_SPACE_MAXADDR,
	    BUS_SPACE_MAXADDR, NULL, NULL, qpair->max_xfer_size,
	    (qpair->max_xfer_size/PAGE_SIZE)+1, PAGE_SIZE, 0,
	    NULL, NULL, &qpair->dma_tag);

	qpair->num_cmds = 0;
	qpair->num_intr_handler_calls = 0;
	qpair->num_tr = 0;
	qpair->sq_head = qpair->sq_tail = qpair->cq_head = 0;

	/* TODO: error checking on contigmalloc, bus_dmamap_load calls */
	qpair->cmd = contigmalloc(qpair->num_entries *
	    sizeof(struct nvme_command), M_NVME, M_ZERO | M_NOWAIT,
	    0, BUS_SPACE_MAXADDR, PAGE_SIZE, 0);
	qpair->cpl = contigmalloc(qpair->num_entries *
	    sizeof(struct nvme_completion), M_NVME, M_ZERO | M_NOWAIT,
	    0, BUS_SPACE_MAXADDR, PAGE_SIZE, 0);

	bus_dmamap_create(qpair->dma_tag, 0, &qpair->cmd_dma_map);
	bus_dmamap_create(qpair->dma_tag, 0, &qpair->cpl_dma_map);

	bus_dmamap_load(qpair->dma_tag, qpair->cmd_dma_map,
	    qpair->cmd, qpair->num_entries * sizeof(struct nvme_command),
	    nvme_single_map, &qpair->cmd_bus_addr, 0);
	bus_dmamap_load(qpair->dma_tag, qpair->cpl_dma_map,
	    qpair->cpl, qpair->num_entries * sizeof(struct nvme_completion),
	    nvme_single_map, &qpair->cpl_bus_addr, 0);

	qpair->sq_tdbl_off = nvme_mmio_offsetof(doorbell[id].sq_tdbl);
	qpair->cq_hdbl_off = nvme_mmio_offsetof(doorbell[id].cq_hdbl);

	SLIST_INIT(&qpair->free_tr);

	qpair->act_tr = malloc(sizeof(struct nvme_tracker *) * qpair->num_entries,
	    M_NVME, M_ZERO | M_NOWAIT);
}

static void
nvme_qpair_destroy(struct nvme_qpair *qpair)
{
	struct nvme_tracker *tr;

	if (qpair->tag)
		bus_teardown_intr(qpair->ctrlr->dev, qpair->res, qpair->tag);

	if (qpair->res)
		bus_release_resource(qpair->ctrlr->dev, SYS_RES_IRQ,
		    rman_get_rid(qpair->res), qpair->res);

	if (qpair->dma_tag)
		bus_dma_tag_destroy(qpair->dma_tag);

	if (qpair->act_tr)
		free(qpair->act_tr, M_NVME);

	while (!SLIST_EMPTY(&qpair->free_tr)) {
		tr = SLIST_FIRST(&qpair->free_tr);
		SLIST_REMOVE_HEAD(&qpair->free_tr, slist);
		bus_dmamap_destroy(qpair->dma_tag, tr->payload_dma_map);
		bus_dmamap_destroy(qpair->dma_tag, tr->prp_dma_map);
		free(tr, M_NVME);
	}
}

void
nvme_admin_qpair_destroy(struct nvme_qpair *qpair)
{

	/*
	 * For NVMe, you don't send delete queue commands for the admin
	 *  queue, so we just need to unload and free the cmd and cpl memory.
	 */
	bus_dmamap_unload(qpair->dma_tag, qpair->cmd_dma_map);
	bus_dmamap_destroy(qpair->dma_tag, qpair->cmd_dma_map);

	contigfree(qpair->cmd,
	    qpair->num_entries * sizeof(struct nvme_command), M_NVME);

	bus_dmamap_unload(qpair->dma_tag, qpair->cpl_dma_map);
	bus_dmamap_destroy(qpair->dma_tag, qpair->cpl_dma_map);
	contigfree(qpair->cpl,
	    qpair->num_entries * sizeof(struct nvme_completion), M_NVME);

	nvme_qpair_destroy(qpair);
}

static void
nvme_free_cmd_ring(void *arg, const struct nvme_completion *status)
{
	struct nvme_qpair *qpair;

	qpair = (struct nvme_qpair *)arg;
	bus_dmamap_unload(qpair->dma_tag, qpair->cmd_dma_map);
	bus_dmamap_destroy(qpair->dma_tag, qpair->cmd_dma_map);
	contigfree(qpair->cmd,
	    qpair->num_entries * sizeof(struct nvme_command), M_NVME);
	qpair->cmd = NULL;
}

static void
nvme_free_cpl_ring(void *arg, const struct nvme_completion *status)
{
	struct nvme_qpair *qpair;

	qpair = (struct nvme_qpair *)arg;
	bus_dmamap_unload(qpair->dma_tag, qpair->cpl_dma_map);
	bus_dmamap_destroy(qpair->dma_tag, qpair->cpl_dma_map);
	contigfree(qpair->cpl,
	    qpair->num_entries * sizeof(struct nvme_completion), M_NVME);
	qpair->cpl = NULL;
}

void
nvme_io_qpair_destroy(struct nvme_qpair *qpair)
{
	struct nvme_controller *ctrlr = qpair->ctrlr;

	if (qpair->num_entries > 0) {

		nvme_ctrlr_cmd_delete_io_sq(ctrlr, qpair, nvme_free_cmd_ring,
		    qpair);
		/* Spin until free_cmd_ring sets qpair->cmd to NULL. */
		while (qpair->cmd)
			DELAY(5);

		nvme_ctrlr_cmd_delete_io_cq(ctrlr, qpair, nvme_free_cpl_ring,
		    qpair);
		/* Spin until free_cpl_ring sets qpair->cmd to NULL. */
		while (qpair->cpl)
			DELAY(5);

		nvme_qpair_destroy(qpair);
	}
}

static void
nvme_timeout(void *arg)
{
	/*
	 * TODO: Add explicit abort operation here, once nvme(4) supports
	 *  abort commands.
	 */
}

void
nvme_qpair_submit_cmd(struct nvme_qpair *qpair, struct nvme_tracker *tr)
{
	struct nvme_request *req;

	req = tr->req;
	req->cmd.cid = tr->cid;
	qpair->act_tr[tr->cid] = tr;

	/*
	 * TODO: rather than spin until entries free up, put this tracker
	 *  on a queue, and submit from the interrupt handler when
	 *  entries free up.
	 */
	if ((qpair->sq_tail+1) % qpair->num_entries == qpair->sq_head) {
		do {
			mtx_unlock(&qpair->lock);
			DELAY(5);
			mtx_lock(&qpair->lock);
		} while ((qpair->sq_tail+1) % qpair->num_entries == qpair->sq_head);
	}

	callout_reset(&tr->timer, NVME_TIMEOUT_IN_SEC * hz, nvme_timeout, tr);

	/* Copy the command from the tracker to the submission queue. */
	memcpy(&qpair->cmd[qpair->sq_tail], &req->cmd, sizeof(req->cmd));

	if (++qpair->sq_tail == qpair->num_entries)
		qpair->sq_tail = 0;

	wmb();
	nvme_mmio_write_4(qpair->ctrlr, doorbell[qpair->id].sq_tdbl,
	    qpair->sq_tail);

	qpair->num_cmds++;

	mtx_unlock(&qpair->lock);
}