USB: defines for USB "Link Power Management" (LPM) ECN

There's a new PM-related change notice for the USB 2.0 specification
called "Link Power Management" (LPM).  It defines a new "L1 Suspend"
state which resembles the current (L2) suspend state, except that it
can be entered and exited much more quickly.  It should thus be more
useful for runtime PM, even though it doesn't mandate reduced power
draw from VBUS.

This patch provides the relevant #defines for usbcore.  Actually
implementing these mechanisms requires host silicon that can generate
new USB packets, plus hubs handling some new requests and peripherals
which understand the new packets.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hcd.h

@@ -28,7 +28,7 @@
 /*
  * USB Packet IDs (PIDs)
  */
-#define USB_PID_UNDEF_0			0xf0
+#define USB_PID_EXT			0xf0	/* USB 2.0 LPM ECN */
 #define USB_PID_OUT			0xe1
 #define USB_PID_ACK			0xd2
 #define USB_PID_DATA0			0xc3

drivers/usb/core/hub.h

@@ -41,9 +41,10 @@
  */
 #define USB_PORT_FEAT_CONNECTION	0
 #define USB_PORT_FEAT_ENABLE		1
-#define USB_PORT_FEAT_SUSPEND		2
+#define USB_PORT_FEAT_SUSPEND		2	/* L2 suspend */
 #define USB_PORT_FEAT_OVER_CURRENT	3
 #define USB_PORT_FEAT_RESET		4
+#define USB_PORT_FEAT_L1		5	/* L1 suspend */
 #define USB_PORT_FEAT_POWER		8
 #define USB_PORT_FEAT_LOWSPEED		9
 #define USB_PORT_FEAT_HIGHSPEED		10
@@ -54,6 +55,7 @@
 #define USB_PORT_FEAT_C_RESET		20
 #define USB_PORT_FEAT_TEST              21
 #define USB_PORT_FEAT_INDICATOR         22
+#define USB_PORT_FEAT_C_PORT_L1         23
 
 /*
  * Hub Status and Hub Change results
@@ -73,7 +75,8 @@ struct usb_port_status {
 #define USB_PORT_STAT_SUSPEND		0x0004
 #define USB_PORT_STAT_OVERCURRENT	0x0008
 #define USB_PORT_STAT_RESET		0x0010
-/* bits 5 to 7 are reserved */
+#define USB_PORT_STAT_L1		0x0020
+/* bits 6 to 7 are reserved */
 #define USB_PORT_STAT_POWER		0x0100
 #define USB_PORT_STAT_LOW_SPEED		0x0200
 #define USB_PORT_STAT_HIGH_SPEED        0x0400
@@ -91,6 +94,7 @@ struct usb_port_status {
 #define USB_PORT_STAT_C_SUSPEND		0x0004
 #define USB_PORT_STAT_C_OVERCURRENT	0x0008
 #define USB_PORT_STAT_C_RESET		0x0010
+#define USB_PORT_STAT_C_L1		0x0020
 
 /*
  * wHubCharacteristics (masks)

include/linux/usb/ch9.h

@@ -102,10 +102,16 @@
 #define USB_REQ_LOOPBACK_DATA_READ	0x16
 #define USB_REQ_SET_INTERFACE_DS	0x17
 
+/* The Link Power Mangement (LPM) ECN defines USB_REQ_TEST_AND_SET command,
+ * used by hubs to put ports into a new L1 suspend state, except that it
+ * forgot to define its number ...
+ */
+
 /*
  * USB feature flags are written using USB_REQ_{CLEAR,SET}_FEATURE, and
  * are read as a bit array returned by USB_REQ_GET_STATUS.  (So there
- * are at most sixteen features of each type.)
+ * are at most sixteen features of each type.)  Hubs may also support a
+ * new USB_REQ_TEST_AND_SET_FEATURE to put ports into L1 suspend.
  */
 #define USB_DEVICE_SELF_POWERED		0	/* (read only) */
 #define USB_DEVICE_REMOTE_WAKEUP	1	/* dev may initiate wakeup */
@@ -575,6 +581,8 @@ enum usb_device_state {
 	/* NOTE:  there are actually four different SUSPENDED
 	 * states, returning to POWERED, DEFAULT, ADDRESS, or
 	 * CONFIGURED respectively when SOF tokens flow again.
+	 * At this level there's no difference between L1 and L2
+	 * suspend states.  (L2 being original USB 1.1 suspend.)
 	 */
 };