brcmfmac: use ISO3166 country code and 0 rev as fallback on some devices

This is a second attempt at honering the country code send out by access
points. This was first added in commit b0b524f0 ("brcmfmac: use
ISO3166 country code and 0 rev as fallback").

Subsequently this was reverted in commit 151a7c12 ("Revert "brcmfmac:
use ISO3166 country code and 0 rev as fallback""), because it was causing
issues with AP mode on some brcmfmac models (specifically on BCM4359/9).

Many devices ship with a nvram ccode value of X2/XT/XU/XV/ALL which are
all special world-wide compatibility ccode-s. Most of these world-wide
ccode-s allow passive scan mode only for 2.4GHz channels 12-14,
only enabling them when an AP is seen on them.

But at least on brcmfmac43455 devices this is not working correctly, these
do not see accesspoints on channels 12-14 unless the ccode is changes to
a country where these channels are allowed.

Translating received country codes to an ISO3166 country code and 0 rev
ccreq fixes devices using a brcmfmac43455 with a X2/XT/XU/XV/ALL ccode
not seeing accesspoints on channels 12-14.

To avoid this causing issues on other brcmfmac models again, the
fallback is limited to only brcmfmac4345* chips this time.

Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Soeren Moch <smoch@web.de>
Cc: Fabio Aiuto <fabioaiuto83@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Soeren Moch <smoch@web.de>  # on BCM4359/9
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20211218185643.158182-1-hdegoede@redhat.com

drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c

@@ -16,6 +16,7 @@
 #include <brcmu_utils.h>
 #include <defs.h>
 #include <brcmu_wifi.h>
+#include <brcm_hw_ids.h>
 #include "core.h"
 #include "debug.h"
 #include "tracepoint.h"
@@ -7476,6 +7477,16 @@ int brcmf_cfg80211_wait_vif_event(struct brcmf_cfg80211_info *cfg,
 				  vif_event_equals(event, action), timeout);
 }
 
+static bool brmcf_use_iso3166_ccode_fallback(struct brcmf_pub *drvr)
+{
+	switch (drvr->bus_if->chip) {
+	case BRCM_CC_4345_CHIP_ID:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static s32 brcmf_translate_country_code(struct brcmf_pub *drvr, char alpha2[2],
 					struct brcmf_fil_country_le *ccreq)
 {
@@ -7484,18 +7495,28 @@ static s32 brcmf_translate_country_code(struct brcmf_pub *drvr, char alpha2[2],
 	s32 found_index;
 	int i;
 
-	country_codes = drvr->settings->country_codes;
-	if (!country_codes) {
-		brcmf_dbg(TRACE, "No country codes configured for device\n");
-		return -EINVAL;
-	}
-
 	if ((alpha2[0] == ccreq->country_abbrev[0]) &&
 	    (alpha2[1] == ccreq->country_abbrev[1])) {
 		brcmf_dbg(TRACE, "Country code already set\n");
 		return -EAGAIN;
 	}
 
+	country_codes = drvr->settings->country_codes;
+	if (!country_codes) {
+		if (brmcf_use_iso3166_ccode_fallback(drvr)) {
+			brcmf_dbg(TRACE, "No country codes configured for device, using ISO3166 code and 0 rev\n");
+			memset(ccreq, 0, sizeof(*ccreq));
+			ccreq->country_abbrev[0] = alpha2[0];
+			ccreq->country_abbrev[1] = alpha2[1];
+			ccreq->ccode[0] = alpha2[0];
+			ccreq->ccode[1] = alpha2[1];
+			return 0;
+		}
+
+		brcmf_dbg(TRACE, "No country codes configured for device\n");
+		return -EINVAL;
+	}
+
 	found_index = -1;
 	for (i = 0; i < country_codes->table_size; i++) {
 		cc = &country_codes->table[i];