wifi: ath11k: skip status ring entry processing

If STATUS_BUFFER_DONE is not set for a monitor status ring entry,
we don't process the status ring until STATUS_BUFFER_DONE set
for that status ring entry.

During LMAC reset it may happen that hardware will not write
STATUS_BUFFER_DONE tlv in status buffer, in that case we end up
waiting for STATUS_BUFFER_DONE leading to backpressure on monitor
status ring.

To fix the issue, when HP (Head Pointer) + 1 entry is peeked and if DMA is not
done and if HP + 2 entry's DMA done is set, replenish HP + 1 entry and start
processing in next interrupt. If HP + 2 entry's DMA done is not set, poll onto
HP + 1 entry DMA done to be set.

Also, during monitor attach HP points to the end of the ring and TP (Tail
Pointer) points to the start of the ring.  Using ath11k_hal_srng_src_peek() may
result in processing invalid buffer for the very first interrupt. Since, HW
starts writing buffer from TP.

To avoid this issue call ath11k_hal_srng_src_next_peek() instead of
calling ath11k_hal_srng_src_peek().

Tested-on: IPQ5018 hw1.0 AHB WLAN.HK.2.6.0.1-00861-QCAHKSWPL_SILICONZ-1

Signed-off-by: Venkateswara Naralasetty <quic_vnaralas@quicinc.com>
Co-developed-by: Tamizh Chelvam Raja <quic_tamizhr@quicinc.com>
Signed-off-by: Tamizh Chelvam Raja <quic_tamizhr@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20240429073624.736147-1-quic_tamizhr@quicinc.com

1 files changed, 15 insertions, 1 deletions

diff --git a/drivers/net/wireless/ath/ath11k/hal.c b/drivers/net/wireless/ath/ath11k/hal.c
index f3d04568c221..f02599bd1c36 100644
--- a/drivers/net/wireless/ath/ath11k/hal.c
+++ b/drivers/net/wireless/ath/ath11k/hal.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause-Clear
 /*
  * Copyright (c) 2018-2019 The Linux Foundation. All rights reserved.
- * Copyright (c) 2021-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) 2021-2024 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 #include <linux/dma-mapping.h>
 #include "hal_tx.h"
@@ -796,6 +796,20 @@ u32 *ath11k_hal_srng_src_get_next_reaped(struct ath11k_base *ab,
 	return desc;
 }
 
+u32 *ath11k_hal_srng_src_next_peek(struct ath11k_base *ab, struct hal_srng *srng)
+{
+	u32 next_hp;
+
+	lockdep_assert_held(&srng->lock);
+
+	next_hp = (srng->u.src_ring.hp + srng->entry_size) % srng->ring_size;
+
+	if (next_hp != srng->u.src_ring.cached_tp)
+		return srng->ring_base_vaddr + next_hp;
+
+	return NULL;
+}
+
 u32 *ath11k_hal_srng_src_peek(struct ath11k_base *ab, struct hal_srng *srng)
 {
 	lockdep_assert_held(&srng->lock);