[RFC PATCH v7 27/27] qedn: Add support of ASYNC

[Shai Malin <smalin@marvell.com>]

From: Prabhakar Kushwaha <pkushwaha@marvell.com>

This patch implement ASYNC request and response event notification
handling at qedn driver level.

NVME Ofld layer's ASYNC request is treated similar to read with
fake CCCID. This CCCID used to route ASYNC notification back to
the NVME ofld layer.

Acked-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: Prabhakar Kushwaha <pkushwaha@marvell.com>
Signed-off-by: Omkar Kulkarni <okulkarni@marvell.com>
Signed-off-by: Michal Kalderon <mkalderon@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: Shai Malin <smalin@marvell.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/nvme/hw/qedn/qedn.h      |   8 ++
 drivers/nvme/hw/qedn/qedn_main.c |   1 +
 drivers/nvme/hw/qedn/qedn_task.c | 148 +++++++++++++++++++++++++++++--
 3 files changed, 148 insertions(+), 9 deletions(-)

diff --git a/drivers/nvme/hw/qedn/qedn.h b/drivers/nvme/hw/qedn/qedn.h
index 286d2f984a41..f50c5aa0c936 100644
--- a/drivers/nvme/hw/qedn/qedn.h
+++ b/drivers/nvme/hw/qedn/qedn.h
@@ -96,6 +96,9 @@
 #define QEDN_TASK_CLEANUP_TMO 3000 /* 3 sec */
 #define QEDN_DRAIN_TMO 1000 /* 1 sec */
 
+#define QEDN_MAX_OUTSTAND_ASYNC 32
+#define QEDN_INVALID_CCCID (-1)
+
 enum qedn_state {
 	QEDN_STATE_CORE_PROBED = 0,
 	QEDN_STATE_CORE_OPEN,
@@ -178,6 +181,7 @@ struct qedn_ctx {
 
 enum qedn_task_flags {
 	QEDN_TASK_IS_ICREQ,
+	QEDN_TASK_ASYNC,
 	QEDN_TASK_USED_BY_FW,
 	QEDN_TASK_WAIT_FOR_CLEANUP,
 };
@@ -346,6 +350,10 @@ struct qedn_conn_ctx {
 	struct nvme_tcp_icresp_pdu icresp;
 	struct qedn_icreq_padding *icreq_pad;
 
+	DECLARE_BITMAP(async_cccid_idx_map, QEDN_MAX_OUTSTAND_ASYNC);
+	/* Spinlock for fetching pseudo CCCID for async request */
+	spinlock_t async_cccid_bitmap_lock;
+
 	/* "dummy" socket */
 	struct socket *sock;
 };
diff --git a/drivers/nvme/hw/qedn/qedn_main.c b/drivers/nvme/hw/qedn/qedn_main.c
index d2f8124a8267..5d761a68a516 100644
--- a/drivers/nvme/hw/qedn/qedn_main.c
+++ b/drivers/nvme/hw/qedn/qedn_main.c
@@ -332,6 +332,7 @@ static int qedn_create_queue(struct nvme_tcp_ofld_queue *queue, int qid,
 	atomic_set(&conn_ctx->destroy_conn_indicator, 0);
 
 	spin_lock_init(&conn_ctx->conn_state_lock);
+	spin_lock_init(&conn_ctx->async_cccid_bitmap_lock);
 
 	conn_ctx->qid = qid;
 
diff --git a/drivers/nvme/hw/qedn/qedn_task.c b/drivers/nvme/hw/qedn/qedn_task.c
index 2ac41b251292..6e3347a6218f 100644
--- a/drivers/nvme/hw/qedn/qedn_task.c
+++ b/drivers/nvme/hw/qedn/qedn_task.c
@@ -260,10 +260,45 @@ void qedn_common_clear_fw_sgl(struct storage_sgl_task_params *sgl_task_params)
 	sgl_task_params->num_sges = 0;
 }
 
-inline void qedn_host_reset_cccid_itid_entry(struct qedn_conn_ctx *conn_ctx,
-					     u16 cccid)
+inline void qedn_host_reset_cccid_itid_entry(struct qedn_conn_ctx *conn_ctx, u16 cccid, bool async)
 {
 	conn_ctx->host_cccid_itid[cccid].itid = cpu_to_le16(QEDN_INVALID_ITID);
+	if (unlikely(async))
+		clear_bit(cccid - NVME_AQ_DEPTH,
+			  conn_ctx->async_cccid_idx_map);
+}
+
+static int qedn_get_free_idx(struct qedn_conn_ctx *conn_ctx, unsigned int size)
+{
+	int idx;
+
+	spin_lock(&conn_ctx->async_cccid_bitmap_lock);
+	idx = find_first_zero_bit(conn_ctx->async_cccid_idx_map, size);
+	if (unlikely(idx >= size)) {
+		idx = -1;
+		spin_unlock(&conn_ctx->async_cccid_bitmap_lock);
+		goto err_idx;
+	}
+	set_bit(idx, conn_ctx->async_cccid_idx_map);
+	spin_unlock(&conn_ctx->async_cccid_bitmap_lock);
+
+err_idx:
+
+	return idx;
+}
+
+int qedn_get_free_async_cccid(struct qedn_conn_ctx *conn_ctx)
+{
+	int async_cccid;
+
+	async_cccid =
+		qedn_get_free_idx(conn_ctx, QEDN_MAX_OUTSTAND_ASYNC);
+	if (unlikely(async_cccid == QEDN_INVALID_CCCID))
+		pr_err("No available CCCID for Async.\n");
+	else
+		async_cccid += NVME_AQ_DEPTH;
+
+	return async_cccid;
 }
 
 inline void qedn_host_set_cccid_itid_entry(struct qedn_conn_ctx *conn_ctx, u16 cccid, u16 itid)
@@ -352,10 +387,12 @@ void qedn_return_task_to_pool(struct qedn_conn_ctx *conn_ctx,
 	struct qedn_fp_queue *fp_q = conn_ctx->fp_q;
 	struct qedn_io_resources *io_resrc;
 	unsigned long lock_flags;
+	bool async;
 
 	io_resrc = &fp_q->host_resrc;
 
 	spin_lock_irqsave(&qedn_task->lock, lock_flags);
+	async = test_bit(QEDN_TASK_ASYNC, &(qedn_task)->flags);
 	qedn_task->valid = 0;
 	qedn_task->flags = 0;
 	qedn_clear_sgl(conn_ctx->qedn, qedn_task);
@@ -363,7 +400,7 @@ void qedn_return_task_to_pool(struct qedn_conn_ctx *conn_ctx,
 
 	spin_lock(&conn_ctx->task_list_lock);
 	list_del(&qedn_task->entry);
-	qedn_host_reset_cccid_itid_entry(conn_ctx, qedn_task->cccid);
+	qedn_host_reset_cccid_itid_entry(conn_ctx, qedn_task->cccid, async);
 	spin_unlock(&conn_ctx->task_list_lock);
 
 	atomic_dec(&conn_ctx->num_active_tasks);
@@ -410,6 +447,60 @@ qedn_get_free_task_from_pool(struct qedn_conn_ctx *conn_ctx, u16 cccid)
 	return qedn_task;
 }
 
+void qedn_send_async_event_cmd(struct qedn_task_ctx *qedn_task,
+			       struct qedn_conn_ctx *conn_ctx)
+{
+	struct nvme_tcp_ofld_req *async_req = qedn_task->req;
+	struct nvme_command *nvme_cmd = &async_req->nvme_cmd;
+	struct storage_sgl_task_params *sgl_task_params;
+	struct nvmetcp_task_params task_params;
+	struct nvme_tcp_cmd_pdu cmd_hdr;
+	struct nvmetcp_wqe *chain_sqe;
+	struct nvmetcp_wqe local_sqe;
+
+	set_bit(QEDN_TASK_ASYNC, &qedn_task->flags);
+	nvme_cmd->common.command_id = qedn_task->cccid;
+	qedn_task->task_size = 0;
+
+	/* Initialize sgl params */
+	sgl_task_params = &qedn_task->sgl_task_params;
+	sgl_task_params->total_buffer_size = 0;
+	sgl_task_params->num_sges = 0;
+	sgl_task_params->small_mid_sge = false;
+
+	task_params.opq.lo = cpu_to_le32(((u64)(qedn_task)) & 0xffffffff);
+	task_params.opq.hi = cpu_to_le32(((u64)(qedn_task)) >> 32);
+
+	/* Initialize task params */
+	task_params.context = qedn_task->fw_task_ctx;
+	task_params.sqe = &local_sqe;
+	task_params.tx_io_size = 0;
+	task_params.rx_io_size = 0;
+	task_params.conn_icid = (u16)conn_ctx->conn_handle;
+	task_params.itid = qedn_task->itid;
+	task_params.cq_rss_number = conn_ctx->default_cq;
+	task_params.send_write_incapsule = 0;
+
+	/* Internal impl. - async is treated like zero len read */
+	cmd_hdr.hdr.type = nvme_tcp_cmd;
+	cmd_hdr.hdr.flags = 0;
+	cmd_hdr.hdr.hlen = sizeof(cmd_hdr);
+	cmd_hdr.hdr.pdo = 0x0;
+	cmd_hdr.hdr.plen = cpu_to_le32(cmd_hdr.hdr.hlen);
+
+	qed_ops->init_read_io(&task_params, &cmd_hdr, nvme_cmd,
+			      &qedn_task->sgl_task_params);
+
+	set_bit(QEDN_TASK_USED_BY_FW, &qedn_task->flags);
+	atomic_inc(&conn_ctx->num_active_fw_tasks);
+
+	spin_lock(&conn_ctx->ep.doorbell_lock);
+	chain_sqe = qed_chain_produce(&conn_ctx->ep.fw_sq_chain);
+	memcpy(chain_sqe, &local_sqe, sizeof(local_sqe));
+	qedn_ring_doorbell(conn_ctx);
+	spin_unlock(&conn_ctx->ep.doorbell_lock);
+}
+
 int qedn_send_read_cmd(struct qedn_task_ctx *qedn_task, struct qedn_conn_ctx *conn_ctx)
 {
 	struct nvme_command *nvme_cmd = &qedn_task->req->nvme_cmd;
@@ -521,6 +612,21 @@ int qedn_send_write_cmd(struct qedn_task_ctx *qedn_task, struct qedn_conn_ctx *c
 	return 0;
 }
 
+static void qedn_return_error_req(struct nvme_tcp_ofld_req *req)
+{
+	__le16 status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
+	union nvme_result res = {};
+
+	if (!req)
+		return;
+
+	/* Call request done to compelete the request */
+	if (req->done)
+		req->done(req, &res, status);
+	else
+		pr_err("request done not set !!!\n");
+}
+
 int qedn_queue_request(struct qedn_conn_ctx *qedn_conn, struct nvme_tcp_ofld_req *req)
 {
 	struct qedn_task_ctx *qedn_task;
@@ -530,9 +636,17 @@ int qedn_queue_request(struct qedn_conn_ctx *qedn_conn, struct nvme_tcp_ofld_req
 
 	rq = blk_mq_rq_from_pdu(req);
 
-	/* Placeholder - async */
+	if (unlikely(req->async)) {
+		cccid = qedn_get_free_async_cccid(qedn_conn);
+		if (cccid == QEDN_INVALID_CCCID) {
+			qedn_return_error_req(req);
+
+			return BLK_STS_NOTSUPP;
+		}
+	} else {
+		cccid = rq->tag;
+	}
 
-	cccid = rq->tag;
 	qedn_task = qedn_get_free_task_from_pool(qedn_conn, cccid);
 	if (unlikely(!qedn_task)) {
 		pr_err("Not able to allocate task context resource\n");
@@ -543,7 +657,11 @@ int qedn_queue_request(struct qedn_conn_ctx *qedn_conn, struct nvme_tcp_ofld_req
 	req->private_data = qedn_task;
 	qedn_task->req = req;
 
-	/* Placeholder - handle (req->async) */
+	if (unlikely(req->async)) {
+		qedn_send_async_event_cmd(qedn_task, qedn_conn);
+
+		return BLK_STS_TRANSPORT;
+	}
 
 	/* Check if there are physical segments in request to determine the task size.
 	 * The logic of nvme_tcp_set_sg_null() will be implemented as part of
@@ -613,16 +731,28 @@ static inline int qedn_comp_valid_task(struct qedn_task_ctx *qedn_task,
 
 int qedn_process_nvme_cqe(struct qedn_task_ctx *qedn_task, struct nvme_completion *cqe)
 {
+	struct qedn_conn_ctx *conn_ctx = qedn_task->qedn_conn;
+	struct nvme_tcp_ofld_req *req;
 	int rc = 0;
+	bool async;
+
+	async = test_bit(QEDN_TASK_ASYNC, &(qedn_task)->flags);
 
 	/* CQE arrives swapped
 	 * Swapping requirement will be removed in future FW versions
 	 */
 	qedn_swap_bytes((u32 *)cqe, (sizeof(*cqe) / sizeof(u32)));
 
-	/* Placeholder - async */
-
-	rc = qedn_comp_valid_task(qedn_task, &cqe->result, cqe->status);
+	if (unlikely(async)) {
+		qedn_return_task_to_pool(conn_ctx, qedn_task);
+		req = qedn_task->req;
+		if (req->done)
+			req->done(req, &cqe->result, cqe->status);
+		else
+			pr_err("request done not set for async request !!!\n");
+	} else {
+		rc = qedn_comp_valid_task(qedn_task, &cqe->result, cqe->status);
+	}
 
 	return rc;
 }
-- 
2.22.0