wifi: ath10k: support board-specific firmware overrides

Different Qualcomm platforms using WCN3990 WiFI chip use SoC-specific
firmware versions with different features. For example firmware for
SDM845 doesn't use single-chan-info-per-channel feature, while firmware
for QRB2210 / QRB4210 requires that feature. Allow board DT files to
override the subdir of the fw dir used to lookup the firmware-N.bin file
decribing corresponding WiFi firmware.

For example:

- ath10k/WCN3990/hw1.0/wlanmdsp.mbn,
  ath10k/WCN3990/hw1.0/firmware-5.bin: main firmware files, used by default

- ath10k/WCN3990/hw1.0/qcm2290/wlanmdsp.mbn,
  ath10k/WCN3990/hw1.0/qcm2290/firmware-5.bin: SoC specific firmware
    with different signature and feature bits

Note, while board files lookup uses the same function and thus it is
possible to provide board-specific board-2.bin files, this is not
required in 99% of cases as board-2.bin already contains a way to
provide board-specific data with finer granularity than DT overrides.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20240306-wcn3990-firmware-path-v2-2-f89e98e71a57@linaro.org

drivers/net/wireless/ath/ath10k/core.c

@@ -942,11 +942,20 @@ static const struct firmware *ath10k_fetch_fw_file(struct ath10k *ar,
 	if (dir == NULL)
 		dir = ".";
 
+	if (ar->board_name) {
+		snprintf(filename, sizeof(filename), "%s/%s/%s",
+			 dir, ar->board_name, file);
+		ret = firmware_request_nowarn(&fw, filename, ar->dev);
+		ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot fw request '%s': %d\n",
+			   filename, ret);
+		if (!ret)
+			return fw;
+	}
+
 	snprintf(filename, sizeof(filename), "%s/%s", dir, file);
 	ret = firmware_request_nowarn(&fw, filename, ar->dev);
 	ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot fw request '%s': %d\n",
 		   filename, ret);
-
 	if (ret)
 		return ERR_PTR(ret);
 

drivers/net/wireless/ath/ath10k/core.h

@@ -1081,6 +1081,8 @@ struct ath10k {
 	 */
 	const struct ath10k_fw_components *running_fw;
 
+	const char *board_name;
+
 	const struct firmware *pre_cal_file;
 	const struct firmware *cal_file;
 

drivers/net/wireless/ath/ath10k/snoc.c

@@ -1338,6 +1338,9 @@ static void ath10k_snoc_quirks_init(struct ath10k *ar)
 	struct ath10k_snoc *ar_snoc = ath10k_snoc_priv(ar);
 	struct device *dev = &ar_snoc->dev->dev;
 
+	/* ignore errors, keep NULL if there is no property */
+	of_property_read_string(dev->of_node, "firmware-name", &ar->board_name);
+
 	if (of_property_read_bool(dev->of_node, "qcom,snoc-host-cap-8bit-quirk"))
 		set_bit(ATH10K_SNOC_FLAG_8BIT_HOST_CAP_QUIRK, &ar_snoc->flags);
 }