[PATCH ath-next 16/19] wifi: ath12k: limit number of channels per WMI command

[Baochen Qiang]

Currently the number of channels can be sent in a single WMI command is
calculated based on the maximum message length of the target, this results
in WMI exchange hang for QCC2072 as its firmware can not support those
many channels in a single command.

Add a limit to avoid this issue.

Tested-on: QCC2072 hw1.0 PCI WLAN.COL.1.0-01560-QCACOLSWPL_V1_TO_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3

Signed-off-by: Baochen Qiang <baochen.qiang at oss.qualcomm.com>
---
 drivers/net/wireless/ath/ath12k/wmi.c | 3 ++-
 drivers/net/wireless/ath/ath12k/wmi.h | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath12k/wmi.c b/drivers/net/wireless/ath/ath12k/wmi.c
index ef7690f829ca..ed2374c4aac0 100644
--- a/drivers/net/wireless/ath/ath12k/wmi.c
+++ b/drivers/net/wireless/ath/ath12k/wmi.c
@@ -2806,7 +2806,8 @@ int ath12k_wmi_send_scan_chan_list_cmd(struct ath12k *ar,
 		max_chan_limit = (wmi->wmi_ab->max_msg_len[ar->pdev_idx] - len) /
 			sizeof(*chan_info);
 
-		num_send_chans = min(arg->nallchans, max_chan_limit);
+		num_send_chans = min3(arg->nallchans, max_chan_limit,
+				      ATH12K_WMI_MAX_NUM_CHAN_PER_CMD);
 
 		arg->nallchans -= num_send_chans;
 		len += sizeof(*chan_info) * num_send_chans;
diff --git a/drivers/net/wireless/ath/ath12k/wmi.h b/drivers/net/wireless/ath/ath12k/wmi.h
index 65f0d7ed4178..daee2787cdfd 100644
--- a/drivers/net/wireless/ath/ath12k/wmi.h
+++ b/drivers/net/wireless/ath/ath12k/wmi.h
@@ -6322,6 +6322,9 @@ struct ath12k_wmi_rssi_dbm_conv_info_arg {
 	s8 min_nf_dbm;
 };
 
+/* each WMI cmd can hold 58 channel entries at most */
+#define ATH12K_WMI_MAX_NUM_CHAN_PER_CMD	58
+
 int ath12k_wmi_cmd_send(struct ath12k_wmi_pdev *wmi, struct sk_buff *skb,
 			u32 cmd_id);
 struct sk_buff *ath12k_wmi_alloc_skb(struct ath12k_wmi_base *wmi_sc, u32 len);

-- 
2.25.1