linux-surface/patches/4.19/0014-ath10k-firmware-override.patch

From df9ba74e96a8e1818028ea6f4a066a2388075377 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sat, 27 Feb 2021 00:45:52 +0100
Subject: [PATCH] ath10k: Add module parameters to override board files

Some Surface devices, specifically the Surface Go and AMD version of the
Surface Laptop 3 (wich both come with QCA6174 WiFi chips), work better
with a different board file, as it seems that the firmeware included
upstream is buggy.

As it is generally not a good idea to randomly overwrite files, let
alone doing so via packages, we add module parameters to override those
file names in the driver. This allows us to package/deploy the override
via a modprobe.d config.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: ath10k-firmware-override
---
 drivers/net/wireless/ath/ath10k/core.c | 58 ++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index 436eac342b62..c9028d59bfe2 100644
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -41,6 +41,9 @@ static bool uart_print;
 static bool skip_otp;
 static bool rawmode;
 
+static char *override_board = "";
+static char *override_board2 = "";
+
 unsigned long ath10k_coredump_mask = BIT(ATH10K_FW_CRASH_DUMP_REGISTERS) |
 				     BIT(ATH10K_FW_CRASH_DUMP_CE_DATA);
 
@@ -52,6 +55,9 @@ module_param(skip_otp, bool, 0644);
 module_param(rawmode, bool, 0644);
 module_param_named(coredump_mask, ath10k_coredump_mask, ulong, 0444);
 
+module_param(override_board, charp, 0644);
+module_param(override_board2, charp, 0644);
+
 MODULE_PARM_DESC(debug_mask, "Debugging mask");
 MODULE_PARM_DESC(uart_print, "Uart target debugging");
 MODULE_PARM_DESC(skip_otp, "Skip otp failure for calibration in testmode");
@@ -59,6 +65,9 @@ MODULE_PARM_DESC(cryptmode, "Crypto mode: 0-hardware, 1-software");
 MODULE_PARM_DESC(rawmode, "Use raw 802.11 frame datapath");
 MODULE_PARM_DESC(coredump_mask, "Bitfield of what to include in firmware crash file");
 
+MODULE_PARM_DESC(override_board, "Override for board.bin file");
+MODULE_PARM_DESC(override_board2, "Override for board-2.bin file");
+
 static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 	{
 		.id = QCA988X_HW_2_0_VERSION,
@@ -705,6 +714,42 @@ static int ath10k_init_configure_target(struct ath10k *ar)
 	return 0;
 }
 
+static const char *ath10k_override_board_fw_file(struct ath10k *ar,
+						 const char *file)
+{
+	if (strcmp(file, "board.bin") == 0) {
+		if (strcmp(override_board, "") == 0)
+			return file;
+
+		if (strcmp(override_board, "none") == 0) {
+			dev_info(ar->dev, "firmware override: pretending 'board.bin' does not exist\n");
+			return NULL;
+		}
+
+		dev_info(ar->dev, "firmware override: replacing 'board.bin' with '%s'\n",
+			 override_board);
+
+		return override_board;
+	}
+
+	if (strcmp(file, "board-2.bin") == 0) {
+		if (strcmp(override_board2, "") == 0)
+			return file;
+
+		if (strcmp(override_board2, "none") == 0) {
+			dev_info(ar->dev, "firmware override: pretending 'board-2.bin' does not exist\n");
+			return NULL;
+		}
+
+		dev_info(ar->dev, "firmware override: replacing 'board-2.bin' with '%s'\n",
+			 override_board2);
+
+		return override_board2;
+	}
+
+	return file;
+}
+
 static const struct firmware *ath10k_fetch_fw_file(struct ath10k *ar,
 						   const char *dir,
 						   const char *file)
@@ -719,6 +764,19 @@ static const struct firmware *ath10k_fetch_fw_file(struct ath10k *ar,
 	if (dir == NULL)
 		dir = ".";
 
+	/* HACK: Override board.bin and board-2.bin files if specified.
+	 *
+	 * Some Surface devices perform better with a different board
+	 * configuration. To this end, one would need to replace the board.bin
+	 * file with the modified config and remove the board-2.bin file.
+	 * Unfortunately, that's not a solution that we can easily package. So
+	 * we add module options to perform these overrides here.
+	 */
+
+	file = ath10k_override_board_fw_file(ar, file);
+	if (!file)
+		return ERR_PTR(-ENOENT);
+
 	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",
-- 
2.33.0