libertas: add asynchronous firmware loading capability

As described at
http://article.gmane.org/gmane.linux.kernel.wireless.general/86084
libertas is taking a long time to load because it loads firmware
during module loading.

Add a new API for interface drivers to load their firmware
asynchronously. The same semantics of the firmware table are followed
like before.

Interface drivers will be converted in follow-up patches, then we can
remove the old, synchronous firmware loading function.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Acked-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/libertas/decl.h

@@ -18,6 +18,10 @@ struct lbs_fw_table {
 	const char *fwname;
 };
 
+struct lbs_private;
+typedef void (*lbs_fw_cb)(struct lbs_private *priv, int ret,
+		const struct firmware *helper, const struct firmware *mainfw);
+
 struct lbs_private;
 struct sk_buff;
 struct net_device;
@@ -70,5 +74,9 @@ int lbs_get_firmware(struct device *dev, u32 card_model,
 			const struct lbs_fw_table *fw_table,
 			const struct firmware **helper,
 			const struct firmware **mainfw);
+int lbs_get_firmware_async(struct lbs_private *priv, struct device *device,
+			   u32 card_model, const struct lbs_fw_table *fw_table,
+			   lbs_fw_cb callback);
+void lbs_wait_for_firmware_load(struct lbs_private *priv);
 
 #endif

drivers/net/wireless/libertas/dev.h

@@ -7,6 +7,7 @@
 #define _LBS_DEV_H_
 
 #include "defs.h"
+#include "decl.h"
 #include "host.h"
 
 #include <linux/kfifo.h>
@@ -180,6 +181,15 @@ struct lbs_private {
 	wait_queue_head_t scan_q;
 	/* Whether the scan was initiated internally and not by cfg80211 */
 	bool internal_scan;
+
+	/* Firmware load */
+	u32 fw_model;
+	wait_queue_head_t fw_waitq;
+	struct device *fw_device;
+	const struct firmware *helper_fw;
+	const struct lbs_fw_table *fw_table;
+	const struct lbs_fw_table *fw_iter;
+	lbs_fw_cb fw_callback;
 };
 
 extern struct cmd_confirm_sleep confirm_sleep;

drivers/net/wireless/libertas/firmware.c

@@ -2,11 +2,152 @@
  * Firmware loading and handling functions.
  */
 
+#include <linux/firmware.h>
 #include <linux/firmware.h>
 #include <linux/module.h>
 
+#include "dev.h"
 #include "decl.h"
 
+static void load_next_firmware_from_table(struct lbs_private *private);
+
+static void lbs_fw_loaded(struct lbs_private *priv, int ret,
+	const struct firmware *helper, const struct firmware *mainfw)
+{
+	unsigned long flags;
+
+	lbs_deb_fw("firmware load complete, code %d\n", ret);
+
+	/* User must free helper/mainfw */
+	priv->fw_callback(priv, ret, helper, mainfw);
+
+	spin_lock_irqsave(&priv->driver_lock, flags);
+	priv->fw_callback = NULL;
+	wake_up(&priv->fw_waitq);
+	spin_unlock_irqrestore(&priv->driver_lock, flags);
+}
+
+static void do_load_firmware(struct lbs_private *priv, const char *name,
+	void (*cb)(const struct firmware *fw, void *context))
+{
+	int ret;
+
+	lbs_deb_fw("Requesting %s\n", name);
+	ret = request_firmware_nowait(THIS_MODULE, true, name,
+			priv->fw_device, GFP_KERNEL, priv, cb);
+	if (ret) {
+		lbs_deb_fw("request_firmware_nowait error %d\n", ret);
+		lbs_fw_loaded(priv, ret, NULL, NULL);
+	}
+}
+
+static void main_firmware_cb(const struct firmware *firmware, void *context)
+{
+	struct lbs_private *priv = context;
+
+	if (!firmware) {
+		/* Failed to find firmware: try next table entry */
+		load_next_firmware_from_table(priv);
+		return;
+	}
+
+	/* Firmware found! */
+	lbs_fw_loaded(priv, 0, priv->helper_fw, firmware);
+}
+
+static void helper_firmware_cb(const struct firmware *firmware, void *context)
+{
+	struct lbs_private *priv = context;
+
+	if (!firmware) {
+		/* Failed to find firmware: try next table entry */
+		load_next_firmware_from_table(priv);
+		return;
+	}
+
+	/* Firmware found! */
+	if (priv->fw_iter->fwname) {
+		priv->helper_fw = firmware;
+		do_load_firmware(priv, priv->fw_iter->fwname, main_firmware_cb);
+	} else {
+		/* No main firmware needed for this helper --> success! */
+		lbs_fw_loaded(priv, 0, firmware, NULL);
+	}
+}
+
+static void load_next_firmware_from_table(struct lbs_private *priv)
+{
+	const struct lbs_fw_table *iter;
+
+	if (!priv->fw_iter)
+		iter = priv->fw_table;
+	else
+		iter = ++priv->fw_iter;
+
+	if (priv->helper_fw) {
+		release_firmware(priv->helper_fw);
+		priv->helper_fw = NULL;
+	}
+
+next:
+	if (!iter->helper) {
+		/* End of table hit. */
+		lbs_fw_loaded(priv, -ENOENT, NULL, NULL);
+		return;
+	}
+
+	if (iter->model != priv->fw_model) {
+		iter++;
+		goto next;
+	}
+
+	priv->fw_iter = iter;
+	do_load_firmware(priv, iter->helper, helper_firmware_cb);
+}
+
+void lbs_wait_for_firmware_load(struct lbs_private *priv)
+{
+	wait_event(priv->fw_waitq, priv->fw_callback == NULL);
+}
+
+/**
+ *  lbs_get_firmware_async - Retrieves firmware asynchronously. Can load
+ *  either a helper firmware and a main firmware (2-stage), or just the helper.
+ *
+ *  @priv:      Pointer to lbs_private instance
+ *  @dev:     	A pointer to &device structure
+ *  @card_model: Bus-specific card model ID used to filter firmware table
+ *		elements
+ *  @fw_table:	Table of firmware file names and device model numbers
+ *		terminated by an entry with a NULL helper name
+ *	@callback: User callback to invoke when firmware load succeeds or fails.
+ */
+int lbs_get_firmware_async(struct lbs_private *priv, struct device *device,
+			    u32 card_model, const struct lbs_fw_table *fw_table,
+			    lbs_fw_cb callback)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->driver_lock, flags);
+	if (priv->fw_callback) {
+		lbs_deb_fw("firmware load already in progress\n");
+		spin_unlock_irqrestore(&priv->driver_lock, flags);
+		return -EBUSY;
+	}
+
+	priv->fw_device = device;
+	priv->fw_callback = callback;
+	priv->fw_table = fw_table;
+	priv->fw_iter = NULL;
+	priv->fw_model = card_model;
+	spin_unlock_irqrestore(&priv->driver_lock, flags);
+
+	lbs_deb_fw("Starting async firmware load\n");
+	load_next_firmware_from_table(priv);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(lbs_get_firmware_async);
+
 /**
  *  lbs_get_firmware - Retrieves two-stage firmware
  *
@@ -18,6 +159,8 @@
  *  @helper:	On success, the helper firmware; caller must free
  *  @mainfw:	On success, the main firmware; caller must free
  *
+ * Deprecated: use lbs_get_firmware_async() instead.
+ *
  *  returns:		0 on success, non-zero on failure
  */
 int lbs_get_firmware(struct device *dev, u32 card_model,

drivers/net/wireless/libertas/main.c

@@ -878,6 +878,7 @@ static int lbs_init_adapter(struct lbs_private *priv)
 	priv->is_host_sleep_configured = 0;
 	priv->is_host_sleep_activated = 0;
 	init_waitqueue_head(&priv->host_sleep_q);
+	init_waitqueue_head(&priv->fw_waitq);
 	mutex_init(&priv->lock);
 
 	setup_timer(&priv->command_timer, lbs_cmd_timeout_handler,
@@ -1037,6 +1038,8 @@ void lbs_remove_card(struct lbs_private *priv)
 	if (priv->wiphy_registered)
 		lbs_scan_deinit(priv);
 
+	lbs_wait_for_firmware_load(priv);
+
 	/* worker thread destruction blocks on the in-flight command which
 	 * should have been cleared already in lbs_stop_card().
 	 */