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>

3 files changed, 18 insertions, 6 deletions

diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index 2d1c3d5e47b8..2c086b8460b1 100644
--- a/drivers/usb/core/hcd.h
+++ b/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
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 1551aed65e05..d672cd81a3e4 100644
--- a/drivers/usb/core/hub.h
+++ b/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)
diff --git a/include/linux/usb/ch9.h b/include/linux/usb/ch9.h
index 7e1da17ca7ce..61fcbc2b97da 100644
--- a/include/linux/usb/ch9.h
+++ b/include/linux/usb/ch9.h
@@ -66,8 +66,8 @@
 #define USB_RECIP_ENDPOINT              0x02
 #define USB_RECIP_OTHER                 0x03
 /* From Wireless USB 1.0 */
-#define USB_RECIP_PORT                  0x04
-#define USB_RECIP_RPIPE                 0x05
+#define USB_RECIP_PORT                  0x04
+#define USB_RECIP_RPIPE         0x05
 
 /*
  * Standard requests, for the bRequest field of a SETUP packet.
@@ -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.)
          */
 };