wl1271: Support for IPv4 ARP filtering

Add support for IPv4 ARP filtering in the driver. This will dramatically
reduce the number of unnecessary interrupts by the device in conqested
networks.

This patch is based on a similar patch to wl1251 by Janne Ylälehto.

Cc: Janne Ylälehto <janne.ylalehto@nokia.com>
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/wl12xx/wl1271.h

@@ -441,6 +441,8 @@ struct wl1271 {
 
 	/* Current chipset configuration */
 	struct conf_drv_settings conf;
+
+	struct list_head list;
 };
 
 int wl1271_plt_start(struct wl1271 *wl);

drivers/net/wireless/wl12xx/wl1271_acx.c

@@ -1092,3 +1092,41 @@ int wl1271_acx_bet_enable(struct wl1271 *wl, bool enable)
 	kfree(acx);
 	return ret;
 }
+
+int wl1271_acx_arp_ip_filter(struct wl1271 *wl, bool enable, u8 *address,
+			     u8 version)
+{
+	struct wl1271_acx_arp_filter *acx;
+	int ret;
+
+	wl1271_debug(DEBUG_ACX, "acx arp ip filter, enable: %d", enable);
+
+	acx = kzalloc(sizeof(*acx), GFP_KERNEL);
+	if (!acx) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	acx->version = version;
+	acx->enable = enable;
+
+	if (enable == true) {
+		if (version == ACX_IPV4_VERSION)
+			memcpy(acx->address, address, ACX_IPV4_ADDR_SIZE);
+		else if (version == ACX_IPV6_VERSION)
+			memcpy(acx->address, address, sizeof(acx->address));
+		else
+			wl1271_error("Invalid IP version");
+	}
+
+	ret = wl1271_cmd_configure(wl, ACX_ARP_IP_FILTER,
+				   acx, sizeof(*acx));
+	if (ret < 0) {
+		wl1271_warning("failed to set arp ip filter: %d", ret);
+		goto out;
+	}
+
+out:
+	kfree(acx);
+	return ret;
+}

drivers/net/wireless/wl12xx/wl1271_acx.h

@@ -955,6 +955,21 @@ struct wl1271_acx_bet_enable {
 	u8 padding[2];
 } __attribute__ ((packed));
 
+#define ACX_IPV4_VERSION 4
+#define ACX_IPV6_VERSION 6
+#define ACX_IPV4_ADDR_SIZE 4
+struct wl1271_acx_arp_filter {
+	struct acx_header header;
+	u8 version;         /* ACX_IPV4_VERSION, ACX_IPV6_VERSION */
+	u8 enable;          /* 1 to enable ARP filtering, 0 to disable */
+	u8 padding[2];
+	u8 address[16];     /* The configured device IP address - all ARP
+			       requests directed to this IP address will pass
+			       through. For IPv4, the first four bytes are
+			       used. */
+} __attribute__((packed));
+
+
 enum {
 	ACX_WAKE_UP_CONDITIONS      = 0x0002,
 	ACX_MEM_CFG                 = 0x0003,
@@ -1064,5 +1079,7 @@ int wl1271_acx_init_mem_config(struct wl1271 *wl);
 int wl1271_acx_init_rx_interrupt(struct wl1271 *wl);
 int wl1271_acx_smart_reflex(struct wl1271 *wl);
 int wl1271_acx_bet_enable(struct wl1271 *wl, bool enable);
+int wl1271_acx_arp_ip_filter(struct wl1271 *wl, bool enable, u8 *address,
+			     u8 version);
 
 #endif /* __WL1271_ACX_H__ */

drivers/net/wireless/wl12xx/wl1271_main.c

@@ -32,6 +32,7 @@
 #include <linux/etherdevice.h>
 #include <linux/vmalloc.h>
 #include <linux/spi/wl12xx.h>
+#include <linux/inetdevice.h>
 
 #include "wl1271.h"
 #include "wl12xx_80211.h"
@@ -325,6 +326,8 @@ static struct conf_drv_settings default_conf = {
 	}
 };
 
+static LIST_HEAD(wl_list);
+
 static void wl1271_conf_init(struct wl1271 *wl)
 {
 
@@ -843,6 +846,93 @@ static int wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 	return NETDEV_TX_OK;
 }
 
+static int wl1271_dev_notify(struct notifier_block *me, unsigned long what,
+			     void *arg)
+{
+	struct net_device *dev;
+	struct wireless_dev *wdev;
+	struct wiphy *wiphy;
+	struct ieee80211_hw *hw;
+	struct wl1271 *wl;
+	struct wl1271 *wl_temp;
+	struct in_device *idev;
+	struct in_ifaddr *ifa = arg;
+	int ret = 0;
+
+	/* FIXME: this ugly function should probably be implemented in the
+	 * mac80211, and here should only be a simple callback handling actual
+	 * setting of the filters. Now we need to dig up references to
+	 * various structures to gain access to what we need.
+	 * Also, because of this, there is no "initial" setting of the filter
+	 * in "op_start", because we don't want to dig up struct net_device
+	 * there - the filter will be set upon first change of the interface
+	 * IP address. */
+
+	dev = ifa->ifa_dev->dev;
+
+	wdev = dev->ieee80211_ptr;
+	if (wdev == NULL)
+		return -ENODEV;
+
+	wiphy = wdev->wiphy;
+	if (wiphy == NULL)
+		return -ENODEV;
+
+	hw = wiphy_priv(wiphy);
+	if (hw == NULL)
+		return -ENODEV;
+
+	/* Check that the interface is one supported by this driver. */
+	wl_temp = hw->priv;
+	list_for_each_entry(wl, &wl_list, list) {
+		if (wl == wl_temp)
+			break;
+	}
+	if (wl == NULL)
+		return -ENODEV;
+
+	/* Get the interface IP address for the device. "ifa" will become
+	   NULL if:
+	     - there is no IPV4 protocol address configured
+	     - there are multiple (virtual) IPV4 addresses configured
+	   When "ifa" is NULL, filtering will be disabled.
+	*/
+	ifa = NULL;
+	idev = dev->ip_ptr;
+	if (idev)
+		ifa = idev->ifa_list;
+
+	if (ifa && ifa->ifa_next)
+		ifa = NULL;
+
+	mutex_lock(&wl->mutex);
+
+	if (wl->state == WL1271_STATE_OFF)
+		goto out;
+
+	ret = wl1271_ps_elp_wakeup(wl, false);
+	if (ret < 0)
+		goto out;
+	if (ifa)
+		ret = wl1271_acx_arp_ip_filter(wl, true,
+					       (u8 *)&ifa->ifa_address,
+					       ACX_IPV4_VERSION);
+	else
+		ret = wl1271_acx_arp_ip_filter(wl, false, NULL,
+					       ACX_IPV4_VERSION);
+	wl1271_ps_elp_sleep(wl);
+
+out:
+	mutex_unlock(&wl->mutex);
+
+	return ret;
+}
+
+static struct notifier_block wl1271_dev_notifier = {
+	.notifier_call = wl1271_dev_notify,
+};
+
+
 static int wl1271_op_start(struct ieee80211_hw *hw)
 {
 	struct wl1271 *wl = hw->priv;
@@ -886,6 +976,11 @@ static int wl1271_op_start(struct ieee80211_hw *hw)
 out:
 	mutex_unlock(&wl->mutex);
 
+	if (!ret) {
+		list_add(&wl->list, &wl_list);
+		register_inetaddr_notifier(&wl1271_dev_notifier);
+	}
+
 	return ret;
 }
 
@@ -906,6 +1001,9 @@ static void wl1271_op_stop(struct ieee80211_hw *hw)
 	wl->filter_params = NULL;
 	spin_unlock_irqrestore(&wl->wl_lock, flags);
 
+	unregister_inetaddr_notifier(&wl1271_dev_notifier);
+	list_del(&wl->list);
+
 	mutex_lock(&wl->mutex);
 
 	WARN_ON(wl->state != WL1271_STATE_ON);
@@ -1754,6 +1852,8 @@ static int __devinit wl1271_probe(struct spi_device *spi)
 	wl = hw->priv;
 	memset(wl, 0, sizeof(*wl));
 
+	INIT_LIST_HEAD(&wl->list);
+
 	wl->hw = hw;
 	dev_set_drvdata(&spi->dev, wl);
 	wl->spi = spi;