staging: wfx: relocate wfx_fill_sl_key() in secure_link.h

"Secure link" feature is not available in in-tree driver (because it
depends on mbedtls). Thus, secure_link.h only empty functions.

Module parameter "slk_key" and associated function wfx_fill_sl_key() had
an unjustifiable place in main.c. This patch relocate them to
secure_link.h.

BTW, content of wfx_fill_sl_key() is now useless. Just keep a warning if
user try to use "slk_key" attribute (unsupported by this driver).
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20191017093954.657-2-Jerome.Pouiller@silabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/main.c

@@ -44,10 +44,6 @@ static int gpio_wakeup = -2;
 module_param(gpio_wakeup, int, 0644);
 MODULE_PARM_DESC(gpio_wakeup, "gpio number for wakeup. -1 for none.");
 
-static char *slk_key;
-module_param(slk_key, charp, 0600);
-MODULE_PARM_DESC(slk_key, "secret key for secure link (expect 64 hexadecimal digits).");
-
 #define RATETAB_ENT(_rate, _rateid, _flags) { \
 	.bitrate  = (_rate),   \
 	.hw_value = (_rateid), \
@@ -194,29 +190,6 @@ struct gpio_desc *wfx_get_gpio(struct device *dev, int override, const char *lab
 	return ret;
 }
 
-static void wfx_fill_sl_key(struct device *dev, struct wfx_platform_data *pdata)
-{
-	const char *ascii_key = NULL;
-	int ret = 0;
-
-	if (slk_key)
-		ascii_key = slk_key;
-	if (!ascii_key)
-		ret = of_property_read_string(dev->of_node, "slk_key", &ascii_key);
-	if (ret == -EILSEQ || ret == -ENODATA)
-		dev_err(dev, "ignoring malformatted key from DT\n");
-	if (!ascii_key)
-		return;
-
-	ret = hex2bin(pdata->slk_key, ascii_key, sizeof(pdata->slk_key));
-	if (ret) {
-		dev_err(dev, "ignoring malformatted key: %s\n", ascii_key);
-		memset(pdata->slk_key, 0, sizeof(pdata->slk_key));
-		return;
-	}
-	dev_err(dev, "secure link is not supported by this driver, ignoring provided key\n");
-}
-
 /* NOTE: wfx_send_pds() destroy buf */
 int wfx_send_pds(struct wfx_dev *wdev, unsigned char *buf, size_t len)
 {
@@ -334,7 +307,7 @@ struct wfx_dev *wfx_init_common(struct device *dev,
 	memcpy(&wdev->pdata, pdata, sizeof(*pdata));
 	of_property_read_string(dev->of_node, "config-file", &wdev->pdata.file_pds);
 	wdev->pdata.gpio_wakeup = wfx_get_gpio(dev, gpio_wakeup, "wakeup");
-	wfx_fill_sl_key(dev, &wdev->pdata);
+	wfx_sl_fill_pdata(dev, &wdev->pdata);
 
 	mutex_init(&wdev->conf_mutex);
 	mutex_init(&wdev->rx_stats_lock);

drivers/staging/wfx/main.h

@@ -22,7 +22,6 @@ struct wfx_platform_data {
 	/* Keyset and ".sec" extention will appended to this string */
 	const char *file_fw;
 	const char *file_pds;
-	unsigned char slk_key[API_KEY_VALUE_SIZE];
 	struct gpio_desc *gpio_wakeup;
 	/*
 	 * if true HIF D_out is sampled on the rising edge of the clock

drivers/staging/wfx/secure_link.h

@@ -5,6 +5,8 @@
 #ifndef WFX_SECURE_LINK_H
 #define WFX_SECURE_LINK_H
 
+#include <linux/of.h>
+
 #include "hif_api_general.h"
 
 struct wfx_dev;
@@ -33,6 +35,13 @@ static inline int wfx_sl_check_pubkey(struct wfx_dev *wdev, uint8_t *ncp_pubkey,
 	return -EIO;
 }
 
+static inline void wfx_sl_fill_pdata(struct device *dev,
+				     struct wfx_platform_data *pdata)
+{
+	if (of_find_property(dev->of_node, "slk_key", NULL))
+		dev_err(dev, "secure link is not supported by this driver, ignoring provided key\n");
+}
+
 static inline int wfx_sl_init(struct wfx_dev *wdev)
 {
 	return -EIO;