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From ec52d77d077529f198fd874c550a26b9cc86a331 Mon Sep 17 00:00:00 2001
From: John Keeping <john@metanate.com>
Date: Tue, 24 Jan 2023 10:42:48 +0000
Subject: [PATCH] wifi: brcmfmac: support CQM RSSI notification with older firmware
Git-commit: ec52d77d077529f198fd874c550a26b9cc86a331
Patch-mainline: v6.4-rc1
References: git-fixes

Using the BCM4339 firmware from linux-firmware (version "BCM4339/2 wl0:
Sep  5 2019 11:05:52 version 6.37.39.113 (r722271 CY)" from
cypress/cyfmac4339-sdio.bin) the RSSI respose is only 4 bytes, which
results in an error being logged.

It seems that older devices send only the RSSI field and neither SNR nor
noise is included.  Handle this by accepting a 4 byte message and
reading only the RSSI from it.

Fixes: 7dd56ea45a66 ("brcmfmac: add support for CQM RSSI notifications")
Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230124104248.2917465-1-john@metanate.com
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 .../broadcom/brcm80211/brcmfmac/cfg80211.c         | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
index a9690ec4c850..d80d2b9b15c7 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -6489,18 +6489,20 @@ static s32 brcmf_notify_rssi(struct brcmf_if *ifp,
 {
 	struct brcmf_cfg80211_vif *vif = ifp->vif;
 	struct brcmf_rssi_be *info = data;
-	s32 rssi, snr, noise;
+	s32 rssi, snr = 0, noise = 0;
 	s32 low, high, last;
 
-	if (e->datalen < sizeof(*info)) {
+	if (e->datalen >= sizeof(*info)) {
+		rssi = be32_to_cpu(info->rssi);
+		snr = be32_to_cpu(info->snr);
+		noise = be32_to_cpu(info->noise);
+	} else if (e->datalen >= sizeof(rssi)) {
+		rssi = be32_to_cpu(*(__be32 *)data);
+	} else {
 		brcmf_err("insufficient RSSI event data\n");
 		return 0;
 	}
 
-	rssi = be32_to_cpu(info->rssi);
-	snr = be32_to_cpu(info->snr);
-	noise = be32_to_cpu(info->noise);
-
 	low = vif->cqm_rssi_low;
 	high = vif->cqm_rssi_high;
 	last = vif->cqm_rssi_last;
-- 
2.35.3