libwd/0093-uadk-check-queue-status-before-sending-doorbells.patch

From cf6d321107cbbb91e440395c0a26075e500ed5be Mon Sep 17 00:00:00 2001
From: Weili Qian <qianweili@huawei.com>
Date: Thu, 30 Nov 2023 16:41:27 +0800
Subject: [PATCH 093/123] uadk: check queue status before sending doorbells

When the device needs to be reset, the queue status is
set to disable before resetting. The user process checks
the queue status before sending the doorbell. If the queue
is disable, the user process returns failure.

Currently, the task execution order in user mode is as follows:
1. check the queue status.
2. fill in or parse the BD.
3. send the doorbell to the hardware.

To reduce the possibility of sending doorbells during reset,
the task execution order is modified as follows:
1. fill in or parse the BD.
2. check the queue status.
3. send the doorbell to the hardware.

In addition, a rmb() is added before the doorbell is
sent to ensure that the queue status check is complete.

rmb() and wmb() can be replaced by mb() in hisi_qm_send().
Therefore, the barrier on the wd_ioread() and wd_iowrite()
can be deleted.

Signed-off-by: Weili Qian <qianweili@huawei.com>
---
 drv/hisi_qm_udrv.c | 39 ++++++++++++++++++++++++++++-----------
 include/wd.h       |  6 ++----
 2 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/drv/hisi_qm_udrv.c b/drv/hisi_qm_udrv.c
index 4c80959..d8b5271 100644
--- a/drv/hisi_qm_udrv.c
+++ b/drv/hisi_qm_udrv.c
@@ -469,11 +469,6 @@ int hisi_qm_send(handle_t h_qp, const void *req, __u16 expect, __u16 *count)
 
 	q_info = &qp->q_info;
 
-	if (unlikely(wd_ioread32(q_info->ds_tx_base) == 1)) {
-		WD_ERR("wd queue hw error happened before qm send!\n");
-		return -WD_HW_EACCESS;
-	}
-
 	pthread_spin_lock(&q_info->sd_lock);
 	free_num = get_free_num(q_info);
 	if (!free_num) {
@@ -486,14 +481,26 @@ int hisi_qm_send(handle_t h_qp, const void *req, __u16 expect, __u16 *count)
 	tail = q_info->sq_tail_index;
 	hisi_qm_fill_sqe(req, q_info, tail, send_num);
 	tail = (tail + send_num) % q_info->sq_depth;
+
+	/*
+	 * Before sending doorbell, check the queue status,
+	 * if the queue is disable, return failure.
+	 */
+	if (unlikely(wd_ioread32(q_info->ds_tx_base) == 1)) {
+		pthread_spin_unlock(&q_info->sd_lock);
+		WD_DEV_ERR(qp->h_ctx, "wd queue hw error happened before qm send!\n");
+		return -WD_HW_EACCESS;
+	}
+
+	/* Make sure sqe is filled before db ring and queue status check is complete. */
+	mb();
 	q_info->db(q_info, QM_DBELL_CMD_SQ, tail, 0);
 	q_info->sq_tail_index = tail;
 
 	/* Make sure used_num is changed before the next thread gets free sqe. */
 	__atomic_add_fetch(&q_info->used_num, send_num, __ATOMIC_RELAXED);
-	*count = send_num;
-
 	pthread_spin_unlock(&q_info->sd_lock);
+	*count = send_num;
 
 	return 0;
 }
@@ -509,6 +516,8 @@ static int hisi_qm_recv_single(struct hisi_qm_queue_info *q_info, void *resp)
 	cqe = q_info->cq_base + i * sizeof(struct cqe);
 
 	if (q_info->cqc_phase == CQE_PHASE(cqe)) {
+		/* Make sure cqe valid bit is set */
+		rmb();
 		j = CQE_SQ_HEAD_INDEX(cqe);
 		if (unlikely(j >= q_info->sq_depth)) {
 			pthread_spin_unlock(&q_info->rv_lock);
@@ -529,6 +538,18 @@ static int hisi_qm_recv_single(struct hisi_qm_queue_info *q_info, void *resp)
 		i++;
 	}
 
+	/*
+	 * Before sending doorbell, check the queue status,
+	 * if the queue is disable, return failure.
+	 */
+	if (unlikely(wd_ioread32(q_info->ds_rx_base) == 1)) {
+		pthread_spin_unlock(&q_info->rv_lock);
+		WD_DEV_ERR(qp->h_ctx, "wd queue hw error happened after qm receive!\n");
+		return -WD_HW_EACCESS;
+	}
+
+	/* Make sure queue status check is complete. */
+	rmb();
 	q_info->db(q_info, QM_DBELL_CMD_CQ, i, q_info->epoll_en);
 
 	/* only support one thread poll one queue, so no need protect */
@@ -568,10 +589,6 @@ int hisi_qm_recv(handle_t h_qp, void *resp, __u16 expect, __u16 *count)
 	}
 
 	*count = recv_num;
-	if (unlikely(wd_ioread32(q_info->ds_rx_base) == 1)) {
-		WD_DEV_ERR(qp->h_ctx, "wd queue hw error happened in qm receive!\n");
-		return -WD_HW_EACCESS;
-	}
 
 	return ret;
 }
diff --git a/include/wd.h b/include/wd.h
index 0e67cad..0a654d6 100644
--- a/include/wd.h
+++ b/include/wd.h
@@ -167,7 +167,7 @@ static inline uint32_t wd_ioread32(void *addr)
 	uint32_t ret;
 
 	ret = *((volatile uint32_t *)addr);
-	rmb();
+
 	return ret;
 }
 
@@ -176,19 +176,17 @@ static inline uint64_t wd_ioread64(void *addr)
 	uint64_t ret;
 
 	ret = *((volatile uint64_t *)addr);
-	rmb();
+
 	return ret;
 }
 
 static inline void wd_iowrite32(void *addr, uint32_t value)
 {
-	wmb();
 	*((volatile uint32_t *)addr) = value;
 }
 
 static inline void wd_iowrite64(void *addr, uint64_t value)
 {
-	wmb();
 	*((volatile uint64_t *)addr) = value;
 }
 
-- 
2.31.1.windows.1