[PATCH v2 1/2] ath10k: search for default BDF name provided in DT

[Abhishek Kumar <kuabhs@chromium.org>]

There can be cases where the board-2.bin does not contain
any BDF matching the chip-id+board-id+variant combination.
This causes the wlan probe to fail and renders wifi unusable.
For e.g. if the board-2.bin has default BDF as:
bus=snoc,qmi-board-id=67 but for some reason the board-id
on the wlan chip is not programmed and read 0xff as the
default value. In such cases there won't be any matching BDF
because the board-2.bin will be searched with following:
bus=snoc,qmi-board-id=ff
To address these scenarios, there can be an option to provide
fallback default BDF name in the device tree. If none of the
BDF names match then the board-2.bin file can be searched with
default BDF names assigned in the device tree.

The default BDF name can be set as:
wifi@a000000 {
	status = "okay";
	qcom,ath10k-default-bdf = "bus=snoc,qmi-board-id=67";
};

Tested-on: WCN3990 hw1.0 SNOC WLAN.HL.3.2.2-00696-QCAHLSWMTPL-1
Signed-off-by: Abhishek Kumar <kuabhs@chromium.org>
---

Changes in v2: Fix printf formatting issue.

 drivers/net/wireless/ath/ath10k/core.c | 30 ++++++++++++++++++++++++++
 drivers/net/wireless/ath/ath10k/core.h |  5 +++++
 drivers/net/wireless/ath/ath10k/qmi.c  |  4 ++++
 3 files changed, 39 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index 8f5b8eb368fa..756856a8eed3 100644
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -1081,6 +1081,32 @@ int ath10k_core_check_dt(struct ath10k *ar)
 }
 EXPORT_SYMBOL(ath10k_core_check_dt);
 
+int ath10k_core_parse_default_bdf_dt(struct ath10k *ar)
+{
+	struct device_node *node;
+	const char *board_name = NULL;
+
+	ar->id.default_bdf[0] = '\0';
+
+	node = ar->dev->of_node;
+	if (!node)
+		return -ENOENT;
+
+	of_property_read_string(node, "qcom,ath10k-default-bdf",
+				&board_name);
+	if (!board_name)
+		return -ENODATA;
+
+	if (strscpy(ar->id.default_bdf,
+		    board_name, sizeof(ar->id.default_bdf)) < 0)
+		ath10k_warn(ar,
+			    "default board name is longer than allocated buffer, board_name: %s; allocated size: %ld\n",
+			    board_name, sizeof(ar->id.default_bdf));
+
+	return 0;
+}
+EXPORT_SYMBOL(ath10k_core_parse_default_bdf_dt);
+
 static int ath10k_download_fw(struct ath10k *ar)
 {
 	u32 address, data_len;
@@ -1441,6 +1467,10 @@ static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
 	if (ret == -ENOENT && fallback_boardname2)
 		ret = ath10k_core_search_bd(ar, fallback_boardname2, data, len);
 
+	/* check default BDF name if provided in device tree */
+	if (ret == -ENOENT && ar->id.default_bdf[0] != '\0')
+		ret = ath10k_core_search_bd(ar, ar->id.default_bdf, data, len);
+
 	if (ret == -ENOENT) {
 		ath10k_err(ar,
 			   "failed to fetch board data for %s from %s/%s\n",
diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
index 9f6680b3be0a..1201bb7bb8ab 100644
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -79,6 +79,9 @@
 /* The magic used by QCA spec */
 #define ATH10K_SMBIOS_BDF_EXT_MAGIC "BDF_"
 
+/* Default BDF board name buffer size */
+#define ATH10K_DEFAULT_BDF_BUFFER_SIZE 0x40
+
 /* Default Airtime weight multipler (Tuned for multiclient performance) */
 #define ATH10K_AIRTIME_WEIGHT_MULTIPLIER  4
 
@@ -1102,6 +1105,7 @@ struct ath10k {
 		bool ext_bid_supported;
 
 		char bdf_ext[ATH10K_SMBIOS_BDF_EXT_STR_LENGTH];
+		char default_bdf[ATH10K_DEFAULT_BDF_BUFFER_SIZE];
 	} id;
 
 	int fw_api;
@@ -1342,6 +1346,7 @@ int ath10k_core_register(struct ath10k *ar,
 void ath10k_core_unregister(struct ath10k *ar);
 int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type);
 int ath10k_core_check_dt(struct ath10k *ar);
+int ath10k_core_parse_default_bdf_dt(struct ath10k *ar);
 void ath10k_core_free_board_files(struct ath10k *ar);
 
 #endif /* _CORE_H_ */
diff --git a/drivers/net/wireless/ath/ath10k/qmi.c b/drivers/net/wireless/ath/ath10k/qmi.c
index 80fcb917fe4e..a57675308014 100644
--- a/drivers/net/wireless/ath/ath10k/qmi.c
+++ b/drivers/net/wireless/ath/ath10k/qmi.c
@@ -831,6 +831,10 @@ static int ath10k_qmi_fetch_board_file(struct ath10k_qmi *qmi)
 	if (ret)
 		ath10k_dbg(ar, ATH10K_DBG_QMI, "DT bdf variant name not set.\n");
 
+	ret = ath10k_core_parse_default_bdf_dt(ar);
+	if (ret)
+		ath10k_dbg(ar, ATH10K_DBG_QMI, "Default BDF name not set in device tree.\n");
+
 	return ath10k_core_fetch_board_file(qmi->ar, ATH10K_BD_IE_BOARD);
 }
 
-- 
2.34.1.575.g55b058a8bb-goog