mwifiex: Select firmware based on strapping

Some WiFi/Bluetooth modules might have different host connection
options, allowing to either use SDIO for both WiFi and Bluetooth,
or SDIO for WiFi and UART for Bluetooth. It is possible to detect
whether a module has SDIO-SDIO or SDIO-UART connection by reading
its host strap register.

This change introduces a way to automatically select appropriate
firmware depending of the connection method, and removes a need
of symlinking or overwriting the original firmware file with a
required one.

Host strap register used in this commit comes from the NXP driver [1]
hosted at Code Aurora.

[1] https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/net/wireless/nxp/mxm_wifiex/wlan_src/mlinux/moal_sdio_mmc.c?h=rel_imx_5.4.70_2.3.2&id=688b67b2c7220b01521ffe560da7eee33042c7bd#n1274

Signed-off-by: Andrejs Cainikovs <andrejs.cainikovs@toradex.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220422090313.125857-2-andrejs.cainikovs@toradex.com

drivers/net/wireless/marvell/mwifiex/sdio.c

@@ -182,6 +182,9 @@ static const struct mwifiex_sdio_card_reg mwifiex_reg_sd8997 = {
 	.host_int_rsr_reg = 0x4,
 	.host_int_status_reg = 0x0C,
 	.host_int_mask_reg = 0x08,
+	.host_strap_reg = 0xF4,
+	.host_strap_mask = 0x01,
+	.host_strap_value = 0x00,
 	.status_reg_0 = 0xE8,
 	.status_reg_1 = 0xE9,
 	.sdio_int_mask = 0xff,
@@ -283,6 +286,9 @@ static const struct mwifiex_sdio_card_reg mwifiex_reg_sd8987 = {
 	.host_int_rsr_reg = 0x4,
 	.host_int_status_reg = 0x0C,
 	.host_int_mask_reg = 0x08,
+	.host_strap_reg = 0xF4,
+	.host_strap_mask = 0x01,
+	.host_strap_value = 0x00,
 	.status_reg_0 = 0xE8,
 	.status_reg_1 = 0xE9,
 	.sdio_int_mask = 0xff,
@@ -536,6 +542,7 @@ mwifiex_sdio_probe(struct sdio_func *func, const struct sdio_device_id *id)
 		struct mwifiex_sdio_device *data = (void *)id->driver_data;
 
 		card->firmware = data->firmware;
+		card->firmware_sdiouart = data->firmware_sdiouart;
 		card->reg = data->reg;
 		card->max_ports = data->max_ports;
 		card->mp_agg_pkt_limit = data->mp_agg_pkt_limit;
@@ -2439,6 +2446,7 @@ static int mwifiex_register_dev(struct mwifiex_adapter *adapter)
 	int ret;
 	struct sdio_mmc_card *card = adapter->card;
 	struct sdio_func *func = card->func;
+	const char *firmware = card->firmware;
 
 	/* save adapter pointer in card */
 	card->adapter = adapter;
@@ -2455,7 +2463,18 @@ static int mwifiex_register_dev(struct mwifiex_adapter *adapter)
 		return ret;
 	}
 
-	strcpy(adapter->fw_name, card->firmware);
+	/* Select correct firmware (sdsd or sdiouart) firmware based on the strapping
+	 * option
+	 */
+	if (card->firmware_sdiouart) {
+		u8 val;
+
+		mwifiex_read_reg(adapter, card->reg->host_strap_reg, &val);
+		if ((val & card->reg->host_strap_mask) == card->reg->host_strap_value)
+			firmware = card->firmware_sdiouart;
+	}
+	strcpy(adapter->fw_name, firmware);
+
 	if (card->fw_dump_enh) {
 		adapter->mem_type_mapping_tbl = generic_mem_type_map;
 		adapter->num_mem_types = 1;

drivers/net/wireless/marvell/mwifiex/sdio.h

@@ -196,6 +196,9 @@ struct mwifiex_sdio_card_reg {
 	u8 host_int_rsr_reg;
 	u8 host_int_status_reg;
 	u8 host_int_mask_reg;
+	u8 host_strap_reg;
+	u8 host_strap_mask;
+	u8 host_strap_value;
 	u8 status_reg_0;
 	u8 status_reg_1;
 	u8 sdio_int_mask;
@@ -241,6 +244,7 @@ struct sdio_mmc_card {
 
 	struct completion fw_done;
 	const char *firmware;
+	const char *firmware_sdiouart;
 	const struct mwifiex_sdio_card_reg *reg;
 	u8 max_ports;
 	u8 mp_agg_pkt_limit;
@@ -274,6 +278,7 @@ struct sdio_mmc_card {
 
 struct mwifiex_sdio_device {
 	const char *firmware;
+	const char *firmware_sdiouart;
 	const struct mwifiex_sdio_card_reg *reg;
 	u8 max_ports;
 	u8 mp_agg_pkt_limit;