Date:	Tue, 11 Dec 2012 15:26:01 +0000
From:	Steve Glendinning <steve.glendinning@...well.net>
To:	netdev@...r.kernel.org
Cc:	linux-usb@...r.kernel.org, ming.lei@...onical.com, oneukum@...e.de,
	gregkh@...uxfoundation.org,
	Steve Glendinning <steve.glendinning@...well.net>
Subject: [PATCHv2][RFC] smsc95xx: enable dynamic autosuspend

This patch enables USB dynamic autosuspend for LAN9500A.  This
saves very little power in itself, but it allows power saving
in upstream hubs/hosts.

The earlier devices in this family (LAN9500/9512/9514) do not
support this feature.

Signed-off-by: Steve Glendinning <steve.glendinning@...well.net>
---
 drivers/net/usb/smsc95xx.c |  159 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 158 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index 9b73670..bdd51fd 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -55,6 +55,13 @@
 #define FEATURE_PHY_NLP_CROSSOVER	(0x02)
 #define FEATURE_AUTOSUSPEND		(0x04)
 
+#define SUSPEND_SUSPEND0		(0x01)
+#define SUSPEND_SUSPEND1		(0x02)
+#define SUSPEND_SUSPEND2		(0x04)
+#define SUSPEND_SUSPEND3		(0x08)
+#define SUSPEND_ALLMODES		(SUSPEND_SUSPEND0 | SUSPEND_SUSPEND1 | \
+					 SUSPEND_SUSPEND2 | SUSPEND_SUSPEND3)
+
 struct smsc95xx_priv {
 	u32 mac_cr;
 	u32 hash_hi;
@@ -62,6 +69,7 @@ struct smsc95xx_priv {
 	u32 wolopts;
 	spinlock_t mac_cr_lock;
 	u8 features;
+	u8 suspend_flags;
 };
 
 static bool turbo_mode = true;
@@ -1341,6 +1349,8 @@ static int smsc95xx_enter_suspend0(struct usbnet *dev)
 	if (ret < 0)
 		netdev_warn(dev->net, "Error reading PM_CTRL\n");
 
+	pdata->suspend_flags |= SUSPEND_SUSPEND0;
+
 	return ret;
 }
 
@@ -1393,11 +1403,14 @@ static int smsc95xx_enter_suspend1(struct usbnet *dev)
 	if (ret < 0)
 		netdev_warn(dev->net, "Error writing PM_CTRL\n");
 
+	pdata->suspend_flags |= SUSPEND_SUSPEND1;
+
 	return ret;
 }
 
 static int smsc95xx_enter_suspend2(struct usbnet *dev)
 {
+	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
 	u32 val;
 	int ret;
 
@@ -1414,9 +1427,105 @@ static int smsc95xx_enter_suspend2(struct usbnet *dev)
 	if (ret < 0)
 		netdev_warn(dev->net, "Error writing PM_CTRL\n");
 
+	pdata->suspend_flags |= SUSPEND_SUSPEND2;
+
 	return ret;
 }
 
+static int smsc95xx_enter_suspend3(struct usbnet *dev)
+{
+	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
+	u32 val;
+	int ret;
+
+	ret = smsc95xx_read_reg_nopm(dev, RX_FIFO_INF, &val);
+	if (ret < 0) {
+		netdev_warn(dev->net, "Error reading RX_FIFO_INF");
+		return ret;
+	}
+
+	if (val & 0xFFFF) {
+		netdev_info(dev->net, "rx fifo not empty in autosuspend");
+		return -EBUSY;
+	}
+
+	ret = smsc95xx_read_reg_nopm(dev, PM_CTRL, &val);
+	if (ret < 0) {
+		netdev_warn(dev->net, "Error reading PM_CTRL");
+		return ret;
+	}
+
+	val &= ~(PM_CTL_SUS_MODE_ | PM_CTL_WUPS_ | PM_CTL_PHY_RST_);
+	val |= PM_CTL_SUS_MODE_3 | PM_CTL_RES_CLR_WKP_STS;
+
+	ret = smsc95xx_write_reg_nopm(dev, PM_CTRL, val);
+	if (ret < 0) {
+		netdev_warn(dev->net, "Error writing PM_CTRL");
+		return ret;
+	}
+
+	/* clear wol status */
+	val &= ~PM_CTL_WUPS_;
+	val |= PM_CTL_WUPS_WOL_;
+
+	ret = smsc95xx_write_reg_nopm(dev, PM_CTRL, val);
+	if (ret < 0) {
+		netdev_warn(dev->net, "Error writing PM_CTRL");
+		return ret;
+	}
+
+	pdata->suspend_flags |= SUSPEND_SUSPEND3;
+
+	return 0;
+}
+
+static int smsc95xx_autosuspend(struct usbnet *dev, u32 link_up)
+{
+	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
+	int ret;
+
+	if (!netif_running(dev->net)) {
+		/* interface is ifconfig down so fully power down hw */
+		netdev_dbg(dev->net, "autosuspend entering SUSPEND2");
+		return smsc95xx_enter_suspend2(dev);
+	}
+
+	if (!link_up) {
+		/* link is down so enter EDPD mode, but only if device can
+		 * reliably resume from it.  This check should be redundant
+		 * as current FEATURE_AUTOSUSPEND parts also support
+		 * FEATURE_PHY_NLP_CROSSOVER but it's included for clarity */
+		if (!(pdata->features & FEATURE_PHY_NLP_CROSSOVER)) {
+			netdev_warn(dev->net, "EDPD not supported");
+			return -EBUSY;
+		}
+
+		netdev_dbg(dev->net, "autosuspend entering SUSPEND1");
+
+		/* enable PHY wakeup events for if cable is attached */
+		ret = smsc95xx_enable_phy_wakeup_interrupts(dev,
+			PHY_INT_MASK_ANEG_COMP_);
+		if (ret < 0) {
+			netdev_warn(dev->net, "error enabling PHY wakeup ints");
+			return ret;
+		}
+
+		netdev_info(dev->net, "entering SUSPEND1 mode");
+		return smsc95xx_enter_suspend1(dev);
+	}
+
+	/* enable PHY wakeup events so we remote wakeup if cable is pulled */
+	ret = smsc95xx_enable_phy_wakeup_interrupts(dev,
+		PHY_INT_MASK_LINK_DOWN_);
+	if (ret < 0) {
+		netdev_warn(dev->net, "error enabling PHY wakeup ints");
+		return ret;
+	}
+
+	netdev_dbg(dev->net, "autosuspend entering SUSPEND3");
+	return smsc95xx_enter_suspend3(dev);
+}
+
 static int smsc95xx_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	struct usbnet *dev = usb_get_intfdata(intf);
@@ -1424,15 +1533,35 @@ static int smsc95xx_suspend(struct usb_interface *intf, pm_message_t message)
 	u32 val, link_up;
 	int ret;
 
+	/* TODO: don't indicate this feature to usb framework if
+	 * our current hardware doesn't have the capability
+	 */
+	if ((message.event == PM_EVENT_AUTO_SUSPEND) &&
+	    (!(pdata->features & FEATURE_AUTOSUSPEND))) {
+		netdev_warn(dev->net, "autosuspend not supported");
+		return -EBUSY;
+	}
+
 	ret = usbnet_suspend(intf, message);
 	if (ret < 0) {
 		netdev_warn(dev->net, "usbnet_suspend error\n");
 		return ret;
 	}
 
+	if (pdata->suspend_flags) {
+		netdev_warn(dev->net, "error during last resume");
+		pdata->suspend_flags = 0;
+	}
+
 	/* determine if link is up using only _nopm functions */
 	link_up = smsc95xx_link_ok_nopm(dev);
 
+	if (message.event == PM_EVENT_AUTO_SUSPEND) {
+		ret = smsc95xx_autosuspend(dev, link_up);
+		goto done;
+	}
+
+	/* if we get this far we're not autosuspending */
 	/* if no wol options set, or if link is down and we're not waking on
 	 * PHY activity, enter lowest power SUSPEND2 mode
 	 */
@@ -1694,12 +1823,18 @@ static int smsc95xx_resume(struct usb_interface *intf)
 {
 	struct usbnet *dev = usb_get_intfdata(intf);
 	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
+	u8 suspend_flags = pdata->suspend_flags;
 	int ret;
 	u32 val;
 
 	BUG_ON(!dev);
 
-	if (pdata->wolopts) {
+	netdev_dbg(dev->net, "resume suspend_flags=0x%02x", suspend_flags);
+
+	/* do this first to ensure it's cleared even in error case */
+	pdata->suspend_flags = 0;
+
+	if (suspend_flags & SUSPEND_ALLMODES) {
 		/* clear wake-up sources */
 		ret = smsc95xx_read_reg_nopm(dev, WUCSR, &val);
 		if (ret < 0) {
@@ -1891,6 +2026,26 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
 	return skb;
 }
 
+static int smsc95xx_manage_power(struct usbnet *dev, int on)
+{
+	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
+
+	dev->intf->needs_remote_wakeup = on;
+
+	if (pdata->features & FEATURE_AUTOSUSPEND)
+		return 0;
+
+	/* this chip revision doesn't support autosuspend */
+	netdev_info(dev->net, "hardware doesn't support USB autosuspend\n");
+
+	if (on)
+		usb_autopm_get_interface_no_resume(dev->intf);
+	else
+		usb_autopm_put_interface_no_suspend(dev->intf);
+
+	return 0;
+}
+
 static const struct driver_info smsc95xx_info = {
 	.description	= "smsc95xx USB 2.0 Ethernet",
 	.bind		= smsc95xx_bind,
@@ -1900,6 +2055,7 @@ static const struct driver_info smsc95xx_info = {
 	.rx_fixup	= smsc95xx_rx_fixup,
 	.tx_fixup	= smsc95xx_tx_fixup,
 	.status		= smsc95xx_status,
+	.manage_power	= smsc95xx_manage_power,
 	.flags		= FLAG_ETHER | FLAG_SEND_ZLP | FLAG_LINK_INTR,
 };
 
@@ -2007,6 +2163,7 @@ static struct usb_driver smsc95xx_driver = {
 	.reset_resume	= smsc95xx_resume,
 	.disconnect	= usbnet_disconnect,
 	.disable_hub_initiated_lpm = 1,
+	.supports_autosuspend = 1,
 };
 
 module_usb_driver(smsc95xx_driver);
-- 
1.7.10.4

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