[PATCH] ath79: fix ath10k caldata extraction on some D-Link DIR-842 C3 devices

[Paul Fertser]

According to forum threads [0][1] and a report on IRC by Doc-Saintly
some of those boards have calibration data in a different place. Only
one alternative location is known.

Without proper board calibration data (board.bin having all 0xff bytes)
ath10k firmware still tries to load but crashes on startup with a
confusing error message.

If you're applying this patch manually on your device do not forget to
remove /lib/firmware/ath10k/pre-cal-pci-0000:00:00.0.bin and reboot to
force caldata re-extraction.

[0] https://forum.openwrt.org/t/support-for-d-link-dir842-rev-c3/41654
[1] https://forum.openwrt.org/t/d-link-dir-842-cant-access-firmware-upload-form/65454

Signed-off-by: Paul Fertser <fercerpav at gmail.com>
---
 .../generic/base-files/etc/hotplug.d/firmware/11-ath10k-caldata  | 1 +
 1 file changed, 1 insertion(+)

diff --git a/target/linux/ath79/generic/base-files/etc/hotplug.d/firmware/11-ath10k-caldata b/target/linux/ath79/generic/base-files/etc/hotplug.d/firmware/11-ath10k-caldata
index 25e864ba72..79003929df 100644
--- a/target/linux/ath79/generic/base-files/etc/hotplug.d/firmware/11-ath10k-caldata
+++ b/target/linux/ath79/generic/base-files/etc/hotplug.d/firmware/11-ath10k-caldata
@@ -170,6 +170,7 @@ case "$FIRMWARE" in
 	dlink,dir-842-c3|\
 	nec,wg1200cr)
 		caldata_extract "art" 0x5000 0x2f20
+		caldata_valid "202f" || caldata_extract "reserved" 0x15000 0x2f20
 		ath10k_patch_mac $(mtd_get_mac_ascii devdata wlan5mac)
 		ln -sf /lib/firmware/ath10k/pre-cal-pci-0000\:00\:00.0.bin \
 			/lib/firmware/ath10k/QCA9888/hw2.0/board.bin
-- 
2.20.1