/*-
 *   BSD LICENSE
 *
 *   Copyright (c) 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:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
 *   OWNER 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 "spdk/stdinc.h"

#include "spdk/nvme.h"
#include "spdk/env.h"

struct ctrlr_entry {
	struct spdk_nvme_ctrlr	*ctrlr;
	struct ctrlr_entry	*next;
	char			name[1024];
};

struct ns_entry {
	struct spdk_nvme_ctrlr	*ctrlr;
	struct spdk_nvme_ns	*ns;
	struct ns_entry		*next;
	struct spdk_nvme_qpair	*qpair;
};

static struct ctrlr_entry *g_controllers = NULL;
static struct ns_entry *g_namespaces = NULL;

static void
register_ns(struct spdk_nvme_ctrlr *ctrlr, struct spdk_nvme_ns *ns)
{
	struct ns_entry *entry;
	const struct spdk_nvme_ctrlr_data *cdata;

	/*
	 * spdk_nvme_ctrlr is the logical abstraction in SPDK for an NVMe
	 *  controller.  During initialization, the IDENTIFY data for the
	 *  controller is read using an NVMe admin command, and that data
	 *  can be retrieved using spdk_nvme_ctrlr_get_data() to get
	 *  detailed information on the controller.  Refer to the NVMe
	 *  specification for more details on IDENTIFY for NVMe controllers.
	 */
	cdata = spdk_nvme_ctrlr_get_data(ctrlr);

	if (!spdk_nvme_ns_is_active(ns)) {
		printf("Controller %-20.20s (%-20.20s): Skipping inactive NS %u\n",
		       cdata->mn, cdata->sn,
		       spdk_nvme_ns_get_id(ns));
		return;
	}

	entry = malloc(sizeof(struct ns_entry));
	if (entry == NULL) {
		perror("ns_entry malloc");
		exit(1);
	}

	entry->ctrlr = ctrlr;
	entry->ns = ns;
	entry->next = g_namespaces;
	g_namespaces = entry;

	printf("  Namespace ID: %d size: %juGB\n", spdk_nvme_ns_get_id(ns),
	       spdk_nvme_ns_get_size(ns) / 1000000000);
}

struct hello_world_sequence {
	struct ns_entry	*ns_entry;
	char		*buf;
	unsigned        using_cmb_io;
	int		is_completed;
};

static void
read_complete(void *arg, const struct spdk_nvme_cpl *completion)
{
	struct hello_world_sequence *sequence = arg;

	/*
	 * The read I/O has completed.  Print the contents of the
	 *  buffer, free the buffer, then mark the sequence as
	 *  completed.  This will trigger the hello_world() function
	 *  to exit its polling loop.
	 */
	printf("%s", sequence->buf);
	spdk_free(sequence->buf);
	sequence->is_completed = 1;
}

static void
write_complete(void *arg, const struct spdk_nvme_cpl *completion)
{
	struct hello_world_sequence	*sequence = arg;
	struct ns_entry			*ns_entry = sequence->ns_entry;
	int				rc;

	/*
	 * The write I/O has completed.  Free the buffer associated with
	 *  the write I/O and allocate a new zeroed buffer for reading
	 *  the data back from the NVMe namespace.
	 */
	if (sequence->using_cmb_io) {
		spdk_nvme_ctrlr_free_cmb_io_buffer(ns_entry->ctrlr, sequence->buf, 0x1000);
	} else {
		spdk_free(sequence->buf);
	}
	sequence->buf = spdk_zmalloc(0x1000, 0x1000, NULL, SPDK_ENV_SOCKET_ID_ANY, SPDK_MALLOC_DMA);

	rc = spdk_nvme_ns_cmd_read(ns_entry->ns, ns_entry->qpair, sequence->buf,
				   0, /* LBA start */
				   1, /* number of LBAs */
				   read_complete, (void *)sequence, 0);
	if (rc != 0) {
		fprintf(stderr, "starting read I/O failed\n");
		exit(1);
	}
}

static void
hello_world(void)
{
	struct ns_entry			*ns_entry;
	struct hello_world_sequence	sequence;
	int				rc;

	ns_entry = g_namespaces;
	while (ns_entry != NULL) {
		/*
		 * Allocate an I/O qpair that we can use to submit read/write requests
		 *  to namespaces on the controller.  NVMe controllers typically support
		 *  many qpairs per controller.  Any I/O qpair allocated for a controller
		 *  can submit I/O to any namespace on that controller.
		 *
		 * The SPDK NVMe driver provides no synchronization for qpair accesses -
		 *  the application must ensure only a single thread submits I/O to a
		 *  qpair, and that same thread must also check for completions on that
		 *  qpair.  This enables extremely efficient I/O processing by making all
		 *  I/O operations completely lockless.
		 */
		ns_entry->qpair = spdk_nvme_ctrlr_alloc_io_qpair(ns_entry->ctrlr, NULL, 0);
		if (ns_entry->qpair == NULL) {
			printf("ERROR: spdk_nvme_ctrlr_alloc_io_qpair() failed\n");
			return;
		}

		/*
		 * Use spdk_dma_zmalloc to allocate a 4KB zeroed buffer.  This memory
		 * will be pinned, which is required for data buffers used for SPDK NVMe
		 * I/O operations.
		 */
		sequence.using_cmb_io = 1;
		sequence.buf = spdk_nvme_ctrlr_alloc_cmb_io_buffer(ns_entry->ctrlr, 0x1000);
		if (sequence.buf == NULL) {
			sequence.using_cmb_io = 0;
			sequence.buf = spdk_zmalloc(0x1000, 0x1000, NULL, SPDK_ENV_SOCKET_ID_ANY, SPDK_MALLOC_DMA);
		}
		if (sequence.buf == NULL) {
			printf("ERROR: write buffer allocation failed\n");
			return;
		}
		if (sequence.using_cmb_io) {
			printf("INFO: using controller memory buffer for IO\n");
		} else {
			printf("INFO: using host memory buffer for IO\n");
		}
		sequence.is_completed = 0;
		sequence.ns_entry = ns_entry;

		/*
		 * Print "Hello world!" to sequence.buf.  We will write this data to LBA
		 *  0 on the namespace, and then later read it back into a separate buffer
		 *  to demonstrate the full I/O path.
		 */
		snprintf(sequence.buf, 0x1000, "%s", "Hello world!\n");

		/*
		 * Write the data buffer to LBA 0 of this namespace.  "write_complete" and
		 *  "&sequence" are specified as the completion callback function and
		 *  argument respectively.  write_complete() will be called with the
		 *  value of &sequence as a parameter when the write I/O is completed.
		 *  This allows users to potentially specify different completion
		 *  callback routines for each I/O, as well as pass a unique handle
		 *  as an argument so the application knows which I/O has completed.
		 *
		 * Note that the SPDK NVMe driver will only check for completions
		 *  when the application calls spdk_nvme_qpair_process_completions().
		 *  It is the responsibility of the application to trigger the polling
		 *  process.
		 */
		rc = spdk_nvme_ns_cmd_write(ns_entry->ns, ns_entry->qpair, sequence.buf,
					    0, /* LBA start */
					    1, /* number of LBAs */
					    write_complete, &sequence, 0);
		if (rc != 0) {
			fprintf(stderr, "starting write I/O failed\n");
			exit(1);
		}

		/*
		 * Poll for completions.  0 here means process all available completions.
		 *  In certain usage models, the caller may specify a positive integer
		 *  instead of 0 to signify the maximum number of completions it should
		 *  process.  This function will never block - if there are no
		 *  completions pending on the specified qpair, it will return immediately.
		 *
		 * When the write I/O completes, write_complete() will submit a new I/O
		 *  to read LBA 0 into a separate buffer, specifying read_complete() as its
		 *  completion routine.  When the read I/O completes, read_complete() will
		 *  print the buffer contents and set sequence.is_completed = 1.  That will
		 *  break this loop and then exit the program.
		 */
		while (!sequence.is_completed) {
			spdk_nvme_qpair_process_completions(ns_entry->qpair, 0);
		}

		/*
		 * Free the I/O qpair.  This typically is done when an application exits.
		 *  But SPDK does support freeing and then reallocating qpairs during
		 *  operation.  It is the responsibility of the caller to ensure all
		 *  pending I/O are completed before trying to free the qpair.
		 */
		spdk_nvme_ctrlr_free_io_qpair(ns_entry->qpair);
		ns_entry = ns_entry->next;
	}
}

static bool
probe_cb(void *cb_ctx, const struct spdk_nvme_transport_id *trid,
	 struct spdk_nvme_ctrlr_opts *opts)
{
	printf("Attaching to %s\n", trid->traddr);

	return true;
}

static void
attach_cb(void *cb_ctx, const struct spdk_nvme_transport_id *trid,
	  struct spdk_nvme_ctrlr *ctrlr, const struct spdk_nvme_ctrlr_opts *opts)
{
	int nsid, num_ns;
	struct ctrlr_entry *entry;
	struct spdk_nvme_ns *ns;
	const struct spdk_nvme_ctrlr_data *cdata = spdk_nvme_ctrlr_get_data(ctrlr);

	entry = malloc(sizeof(struct ctrlr_entry));
	if (entry == NULL) {
		perror("ctrlr_entry malloc");
		exit(1);
	}

	printf("Attached to %s\n", trid->traddr);

	snprintf(entry->name, sizeof(entry->name), "%-20.20s (%-20.20s)", cdata->mn, cdata->sn);

	entry->ctrlr = ctrlr;
	entry->next = g_controllers;
	g_controllers = entry;

	/*
	 * Each controller has one or more namespaces.  An NVMe namespace is basically
	 *  equivalent to a SCSI LUN.  The controller's IDENTIFY data tells us how
	 *  many namespaces exist on the controller.  For Intel(R) P3X00 controllers,
	 *  it will just be one namespace.
	 *
	 * Note that in NVMe, namespace IDs start at 1, not 0.
	 */
	num_ns = spdk_nvme_ctrlr_get_num_ns(ctrlr);
	printf("Using controller %s with %d namespaces.\n", entry->name, num_ns);
	for (nsid = 1; nsid <= num_ns; nsid++) {
		ns = spdk_nvme_ctrlr_get_ns(ctrlr, nsid);
		if (ns == NULL) {
			continue;
		}
		register_ns(ctrlr, ns);
	}
}

static void
cleanup(void)
{
	struct ns_entry *ns_entry = g_namespaces;
	struct ctrlr_entry *ctrlr_entry = g_controllers;

	while (ns_entry) {
		struct ns_entry *next = ns_entry->next;
		free(ns_entry);
		ns_entry = next;
	}

	while (ctrlr_entry) {
		struct ctrlr_entry *next = ctrlr_entry->next;

		spdk_nvme_detach(ctrlr_entry->ctrlr);
		free(ctrlr_entry);
		ctrlr_entry = next;
	}
}

int main(int argc, char **argv)
{
	int rc;
	struct spdk_env_opts opts;

	/*
	 * SPDK relies on an abstraction around the local environment
	 * named env that handles memory allocation and PCI device operations.
	 * This library must be initialized first.
	 *
	 */
	spdk_env_opts_init(&opts);
	opts.name = "hello_world";
	opts.shm_id = 0;
	if (spdk_env_init(&opts) < 0) {
		fprintf(stderr, "Unable to initialize SPDK env\n");
		return 1;
	}

	printf("Initializing NVMe Controllers\n");

	/*
	 * Start the SPDK NVMe enumeration process.  probe_cb will be called
	 *  for each NVMe controller found, giving our application a choice on
	 *  whether to attach to each controller.  attach_cb will then be
	 *  called for each controller after the SPDK NVMe driver has completed
	 *  initializing the controller we chose to attach.
	 */
	rc = spdk_nvme_probe(NULL, NULL, probe_cb, attach_cb, NULL);
	if (rc != 0) {
		fprintf(stderr, "spdk_nvme_probe() failed\n");
		cleanup();
		return 1;
	}

	if (g_controllers == NULL) {
		fprintf(stderr, "no NVMe controllers found\n");
		cleanup();
		return 1;
	}

	printf("Initialization complete.\n");
	hello_world();
	cleanup();
	return 0;
}