/*   SPDX-License-Identifier: BSD-3-Clause
 *   Copyright (c) Intel Corporation. All rights reserved.
 */

#include "nvme_internal.h"

#include "spdk/endian.h"

struct nvme_discovery_ctx {
	struct spdk_nvme_ctrlr			*ctrlr;
	struct spdk_nvmf_discovery_log_page	*log_page;
	uint64_t				start_genctr;
	uint64_t				end_genctr;
	spdk_nvme_discovery_cb			cb_fn;
	void					*cb_arg;
};

static void
get_log_page_completion_final(void *cb_arg, const struct spdk_nvme_cpl *cpl)
{
	struct nvme_discovery_ctx *ctx = cb_arg;
	int rc;

	if (spdk_nvme_cpl_is_error(cpl)) {
		free(ctx->log_page);
		ctx->cb_fn(ctx->cb_arg, 0, cpl, NULL);
		free(ctx);
		return;
	}

	/* Compare original genctr with latest genctr. If it changed, we need to restart. */
	if (ctx->start_genctr == ctx->end_genctr) {
		ctx->cb_fn(ctx->cb_arg, 0, cpl, ctx->log_page);
	} else {
		free(ctx->log_page);
		rc = spdk_nvme_ctrlr_get_discovery_log_page(ctx->ctrlr, ctx->cb_fn, ctx->cb_arg);
		if (rc != 0) {
			ctx->cb_fn(ctx->cb_arg, rc, NULL, NULL);
		}
	}
	free(ctx);
}

static void
get_log_page_completion(void *cb_arg, const struct spdk_nvme_cpl *cpl)
{
	struct nvme_discovery_ctx *ctx = cb_arg;
	int rc;

	if (spdk_nvme_cpl_is_error(cpl)) {
		free(ctx->log_page);
		ctx->cb_fn(ctx->cb_arg, 0, cpl, NULL);
		free(ctx);
		return;
	}

	rc = spdk_nvme_ctrlr_cmd_get_log_page(ctx->ctrlr, SPDK_NVME_LOG_DISCOVERY, 0,
					      &ctx->end_genctr, sizeof(ctx->end_genctr), 0,
					      get_log_page_completion_final, ctx);
	if (rc != 0) {
		free(ctx->log_page);
		ctx->cb_fn(ctx->cb_arg, rc, NULL, NULL);
		free(ctx);
	}
}

static void
discovery_log_header_completion(void *cb_arg, const struct spdk_nvme_cpl *cpl)
{
	struct spdk_nvmf_discovery_log_page *new_page;
	struct nvme_discovery_ctx *ctx = cb_arg;
	size_t page_size;
	uint16_t recfmt;
	uint64_t numrec;
	int rc;

	if (spdk_nvme_cpl_is_error(cpl)) {
		/* Return without printing anything - this may not be a discovery controller */
		ctx->cb_fn(ctx->cb_arg, 0, cpl, NULL);
		free(ctx->log_page);
		free(ctx);
		return;
	}

	/* Got the first 4K of the discovery log page */
	recfmt = from_le16(&ctx->log_page->recfmt);
	if (recfmt != 0) {
		SPDK_ERRLOG("Unrecognized discovery log record format %" PRIu16 "\n", recfmt);
		ctx->cb_fn(ctx->cb_arg, -EINVAL, NULL, NULL);
		free(ctx->log_page);
		free(ctx);
		return;
	}

	numrec = from_le64(&ctx->log_page->numrec);

	if (numrec == 0) {
		/* No entries in the discovery log. So we can just return the header to the
		 * caller.
		 */
		get_log_page_completion(ctx, cpl);
		return;
	}

	ctx->start_genctr = ctx->log_page->genctr;

	/*
	 * Now that we know how many entries should be in the log page, we can allocate
	 * the full log page buffer.
	 */
	page_size = sizeof(struct spdk_nvmf_discovery_log_page);
	page_size += numrec * sizeof(struct spdk_nvmf_discovery_log_page_entry);
	new_page = realloc(ctx->log_page, page_size);
	if (new_page == NULL) {
		SPDK_ERRLOG("Could not allocate buffer for log page (%" PRIu64 " entries)\n",
			    numrec);
		ctx->cb_fn(ctx->cb_arg, -ENOMEM, NULL, NULL);
		free(ctx->log_page);
		free(ctx);
		return;
	}

	ctx->log_page = new_page;

	/* Retrieve the entire discovery log page */
	rc = spdk_nvme_ctrlr_cmd_get_log_page(ctx->ctrlr, SPDK_NVME_LOG_DISCOVERY,
					      0, (char *)ctx->log_page, page_size, 0,
					      get_log_page_completion, ctx);
	if (rc != 0) {
		free(ctx->log_page);
		ctx->cb_fn(ctx->cb_arg, rc, NULL, NULL);
		free(ctx);
	}
}

int
spdk_nvme_ctrlr_get_discovery_log_page(struct spdk_nvme_ctrlr *ctrlr,
				       spdk_nvme_discovery_cb cb_fn, void *cb_arg)
{
	struct nvme_discovery_ctx *ctx;
	int rc;

	ctx = calloc(1, sizeof(*ctx));
	if (ctx == NULL) {
		return -ENOMEM;
	}

	ctx->log_page = calloc(1, sizeof(*ctx->log_page));
	if (ctx->log_page == NULL) {
		free(ctx);
		return -ENOMEM;
	}

	ctx->ctrlr = ctrlr;
	ctx->cb_fn = cb_fn;
	ctx->cb_arg = cb_arg;

	rc = spdk_nvme_ctrlr_cmd_get_log_page(ctrlr, SPDK_NVME_LOG_DISCOVERY, 0,
					      ctx->log_page, sizeof(*ctx->log_page), 0,
					      discovery_log_header_completion, ctx);
	if (rc != 0) {
		free(ctx->log_page);
		free(ctx);
	}

	return rc;
}