usb/core: consider link speed while looking at bMaxPower

The USB 2.0 specification says that bMaxPower is the maximum power
consumption expressed in 2 mA units and the USB 3.0 specification says
that it is expressed in 8 mA units.
This patch adds a helper function usb_get_max_power() which computes the
value based on config & usb_device's speed value. The the device descriptor
dump computes the value on its own.

Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

6 files changed, 44 insertions, 15 deletions

diff --git a/drivers/usb/core/devices.c b/drivers/usb/core/devices.c
index cbacea933b18..e33224e23770 100644
--- a/drivers/usb/core/devices.c
+++ b/drivers/usb/core/devices.c
@@ -316,17 +316,23 @@ static char *usb_dump_iad_descriptor(char *start, char *end,
  */
 static char *usb_dump_config_descriptor(char *start, char *end,
                                 const struct usb_config_descriptor *desc,
-                                int active)
+                                int active, int speed)
 {
+        int mul;
+
         if (start > end)
                 return start;
+        if (speed == USB_SPEED_SUPER)
+                mul = 8;
+        else
+                mul = 2;
         start += sprintf(start, format_config,
                          /* mark active/actual/current cfg. */
                          active ? '*' : ' ',
                          desc->bNumInterfaces,
                          desc->bConfigurationValue,
                          desc->bmAttributes,
-                         desc->bMaxPower * 2);
+                         desc->bMaxPower * mul);
         return start;
 }
 
@@ -342,7 +348,8 @@ static char *usb_dump_config(int speed, char *start, char *end,
         if (!config)
                 /* getting these some in 2.3.7; none in 2.3.6 */
                 return start + sprintf(start, "(null Cfg. desc.)\n");
-        start = usb_dump_config_descriptor(start, end, &config->desc, active);
+        start = usb_dump_config_descriptor(start, end, &config->desc, active,
+                        speed);
         for (i = 0; i < USB_MAXIADS; i++) {
                 if (config->intf_assoc[i] == NULL)
                         break;
diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c
index eff2010eb63f..271e761f563e 100644
--- a/drivers/usb/core/generic.c
+++ b/drivers/usb/core/generic.c
@@ -100,7 +100,7 @@ int usb_choose_configuration(struct usb_device *udev)
                  */
 
                 /* Rule out configs that draw too much bus current */
-                if (c->desc.bMaxPower * 2 > udev->bus_mA) {
+                if (usb_get_max_power(udev, c) > udev->bus_mA) {
                         insufficient_power++;
                         continue;
                 }
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index ae10862fb041..12913306840a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -4211,7 +4211,7 @@ hub_power_remaining (struct usb_hub *hub)
                 /* Unconfigured devices may not use more than 100mA,
                  * or 8mA for OTG ports */
                 if (udev->actconfig)
-                        delta = udev->actconfig->desc.bMaxPower * 2;
+                        delta = usb_get_max_power(udev, udev->actconfig);
                 else if (port1 != udev->bus->otg_port || hdev->parent)
                         delta = 100;
                 else
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 131f73649b60..444d30e3a78b 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1751,7 +1751,7 @@ free_interfaces:
                         }
                 }
 
-                i = dev->bus_mA - cp->desc.bMaxPower * 2;
+                i = dev->bus_mA - usb_get_max_power(dev, cp);
                 if (i < 0)
                         dev_warn(&dev->dev, "new config #%d exceeds power "
                                         "limit by %dmA\n",
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 818e4a024d0d..3f81a3dc6867 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -17,7 +17,7 @@
 #include "usb.h"
 
 /* Active configuration fields */
-#define usb_actconfig_show(field, multiplier, format_string)            \
+#define usb_actconfig_show(field, format_string)                        \
 static ssize_t  show_##field(struct device *dev,                        \
                 struct device_attribute *attr, char *buf)               \
 {                                                                       \
@@ -28,18 +28,31 @@ static ssize_t  show_##field(struct device *dev,			\
         actconfig = udev->actconfig;                                    \
         if (actconfig)                                                  \
                 return sprintf(buf, format_string,                      \
-                                actconfig->desc.field * multiplier);    \
+                                actconfig->desc.field);                 \
         else                                                            \
                 return 0;                                               \
 }                                                                       \
 
-#define usb_actconfig_attr(field, multiplier, format_string)            \
-usb_actconfig_show(field, multiplier, format_string)                    \
-static DEVICE_ATTR(field, S_IRUGO, show_##field, NULL);
+#define usb_actconfig_attr(field, format_string)                \
+        usb_actconfig_show(field, format_string)                \
+        static DEVICE_ATTR(field, S_IRUGO, show_##field, NULL);
+
+usb_actconfig_attr(bNumInterfaces, "%2d\n")
+usb_actconfig_attr(bmAttributes, "%2x\n")
 
-usb_actconfig_attr(bNumInterfaces, 1, "%2d\n")
-usb_actconfig_attr(bmAttributes, 1, "%2x\n")
-usb_actconfig_attr(bMaxPower, 2, "%3dmA\n")
+static ssize_t show_bMaxPower(struct device *dev,
+                struct device_attribute *attr, char *buf)
+{
+        struct usb_device *udev;
+        struct usb_host_config *actconfig;
+
+        udev = to_usb_device(dev);
+        actconfig = udev->actconfig;
+        if (!actconfig)
+                return 0;
+        return sprintf(buf, "%dmA\n", usb_get_max_power(udev, actconfig));
+}
+static DEVICE_ATTR(bMaxPower, S_IRUGO, show_bMaxPower, NULL);
 
 static ssize_t show_configuration_string(struct device *dev,
                 struct device_attribute *attr, char *buf)
@@ -56,7 +69,7 @@ static ssize_t show_configuration_string(struct device *dev,
 static DEVICE_ATTR(configuration, S_IRUGO, show_configuration_string, NULL);
 
 /* configuration value is always present, and r/w */
-usb_actconfig_show(bConfigurationValue, 1, "%u\n");
+usb_actconfig_show(bConfigurationValue, "%u\n");
 
 static ssize_t
 set_bConfigurationValue(struct device *dev, struct device_attribute *attr,
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 1c528c1bf0be..fb7d8fcb4551 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -38,6 +38,15 @@ extern char *usb_cache_string(struct usb_device *udev, int index);
 extern int usb_set_configuration(struct usb_device *dev, int configuration);
 extern int usb_choose_configuration(struct usb_device *udev);
 
+static inline unsigned usb_get_max_power(struct usb_device *udev,
+                struct usb_host_config *c)
+{
+        /* SuperSpeed power is in 8 mA units; others are in 2 mA units */
+        unsigned mul = (udev->speed == USB_SPEED_SUPER ? 8 : 2);
+
+        return c->desc.bMaxPower * mul;
+}
+
 extern void usb_kick_khubd(struct usb_device *dev);
 extern int usb_match_one_id_intf(struct usb_device *dev,
                                  struct usb_host_interface *intf,