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Subject[PATCH] usb: core: add usb3 lpm sysfs
Some usb3 devices may not support usb3 lpm well.
The patch adds a sysfs to enable/disable u1 or u2 of the port.The
settings apply to both before and after device enumeration.
Supported values are "0" - u1 and u2 are disabled, "u1" - only u1 is
enabled, "u2" - only u2 is enabled, "u1_u2" - u1 and u2 are enabled.

The interface is useful for testing some USB3 devices during
development, and provides a way to disable usb3 lpm if the issues can
not be fixed in final products.

Signed-off-by: Zhuang Jin Can <jin.can.zhuang@intel.com>
---
Documentation/ABI/testing/sysfs-bus-usb | 10 ++++
drivers/usb/core/hub.c | 16 +++++-
drivers/usb/core/hub.h | 4 ++
drivers/usb/core/port.c | 89 ++++++++++++++++++++++++++++++-
4 files changed, 116 insertions(+), 3 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index e5cc763..32fc689 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -179,3 +179,13 @@ Description:
Supported values are 0 - 15.
More information on how besl values map to microseconds can be found in
USB 2.0 ECN Errata for Link Power Management, section 4.10)
+
+What: /sys/bus/usb/devices/.../(hub interface)/portX/usb3_lpm
+Date: March 2015
+Contact: Zhuang Jin Can <jin.can.zhuang@intel.com>
+Description:
+ Some USB3.0 devices may not support usb3 lpm well.
+ usb3_lpm attribute allows enabling/disabling usb3 lpm of the port.
+ It takes effect both before and after a usb device is enumerated.
+ Supported values are "0" if u1 and u2 are disabled, "u1" if only u1 is
+ enabled, "u2" if only u2 is enabled, "u1_u2" if u1 and u2 are enabled.
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index d7c3d5a..7732a41 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3996,6 +3996,8 @@ EXPORT_SYMBOL_GPL(usb_unlocked_disable_lpm);
void usb_enable_lpm(struct usb_device *udev)
{
struct usb_hcd *hcd;
+ struct usb_hub *hub;
+ struct usb_port *port_dev;

if (!udev || !udev->parent ||
udev->speed != USB_SPEED_SUPER ||
@@ -4015,8 +4017,18 @@ void usb_enable_lpm(struct usb_device *udev)
if (udev->lpm_disable_count > 0)
return;

- usb_enable_link_state(hcd, udev, USB3_LPM_U1);
- usb_enable_link_state(hcd, udev, USB3_LPM_U2);
+ hub = usb_hub_to_struct_hub(udev->parent);
+ if (!hub) {
+ dev_err(&udev->dev, "can't enable lpm, usb_hub is null.\n");
+ return;
+ }
+ port_dev = hub->ports[udev->portnum - 1];
+
+ if (port_dev->u1_is_enabled)
+ usb_enable_link_state(hcd, udev, USB3_LPM_U1);
+
+ if (port_dev->u2_is_enabled)
+ usb_enable_link_state(hcd, udev, USB3_LPM_U2);
}
EXPORT_SYMBOL_GPL(usb_enable_lpm);

diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 688817f..1ae060e 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -92,6 +92,8 @@ struct usb_hub {
* @status_lock: synchronize port_event() vs usb_port_{suspend|resume}
* @portnum: port index num based one
* @is_superspeed cache super-speed status
+ * @u1_is_enabled: whether u1 should be enabled.
+ * @u2_is_enabled: whether u2 should be enabled.
*/
struct usb_port {
struct usb_device *child;
@@ -104,6 +106,8 @@ struct usb_port {
struct mutex status_lock;
u8 portnum;
unsigned int is_superspeed:1;
+ unsigned int u1_is_enabled:1;
+ unsigned int u2_is_enabled:1;
};

#define to_usb_port(_dev) \
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 2106183..7f4e6c7 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -50,6 +50,72 @@ static ssize_t connect_type_show(struct device *dev,
}
static DEVICE_ATTR_RO(connect_type);

+static ssize_t usb3_lpm_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct usb_port *port_dev = to_usb_port(dev);
+ const char *p;
+
+ if (port_dev->u1_is_enabled) {
+ if (port_dev->u2_is_enabled)
+ p = "u1_u2";
+ else
+ p = "u1";
+ } else {
+ if (port_dev->u2_is_enabled)
+ p = "u2";
+ else
+ p = "0";
+ }
+
+ return sprintf(buf, "%s\n", p);
+}
+
+static ssize_t usb3_lpm_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct usb_port *port_dev = to_usb_port(dev);
+ struct usb_device *udev = port_dev->child;
+ struct usb_hcd *hcd;
+
+ if (!strncmp(buf, "u1_u2", 5)) {
+ port_dev->u1_is_enabled = 1;
+ port_dev->u2_is_enabled = 1;
+
+ } else if (!strncmp(buf, "u1", 2)) {
+ port_dev->u1_is_enabled = 1;
+ port_dev->u2_is_enabled = 0;
+
+ } else if (!strncmp(buf, "u2", 2)) {
+ port_dev->u1_is_enabled = 0;
+ port_dev->u2_is_enabled = 1;
+
+ } else if (!strncmp(buf, "0", 1)) {
+ port_dev->u1_is_enabled = 0;
+ port_dev->u2_is_enabled = 0;
+ } else
+ return -EINVAL;
+
+ /* If device is connected to the port, disable & enable lpm
+ * to make new u1 u2 setting take effect immediately
+ */
+ if (udev) {
+ hcd = bus_to_hcd(udev->bus);
+ if (!hcd)
+ return -EINVAL;
+ usb_lock_device(udev);
+ mutex_lock(hcd->bandwidth_mutex);
+ if (!usb_disable_lpm(udev))
+ usb_enable_lpm(udev);
+ mutex_unlock(hcd->bandwidth_mutex);
+ usb_unlock_device(udev);
+ }
+
+ return count;
+}
+static DEVICE_ATTR_RW(usb3_lpm);
+
static struct attribute *port_dev_attrs[] = {
&dev_attr_connect_type.attr,
NULL,
@@ -64,6 +130,21 @@ static const struct attribute_group *port_dev_group[] = {
NULL,
};

+static struct attribute *port_dev_usb3_attrs[] = {
+ &dev_attr_usb3_lpm.attr,
+ NULL,
+};
+
+static struct attribute_group port_dev_usb3_attr_grp = {
+ .attrs = port_dev_usb3_attrs,
+};
+
+static const struct attribute_group *port_dev_usb3_group[] = {
+ &port_dev_attr_grp,
+ &port_dev_usb3_attr_grp,
+ NULL,
+};
+
static void usb_port_device_release(struct device *dev)
{
struct usb_port *port_dev = to_usb_port(dev);
@@ -401,6 +482,7 @@ static void find_and_link_peer(struct usb_hub *hub, int port1)
int usb_hub_create_port_device(struct usb_hub *hub, int port1)
{
struct usb_port *port_dev;
+ struct usb_device *hdev = hub->hdev;
int retval;

port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
@@ -417,7 +499,12 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
port_dev->portnum = port1;
set_bit(port1, hub->power_bits);
port_dev->dev.parent = hub->intfdev;
- port_dev->dev.groups = port_dev_group;
+ if (hub_is_superspeed(hdev)) {
+ port_dev->u1_is_enabled = 1;
+ port_dev->u2_is_enabled = 1;
+ port_dev->dev.groups = port_dev_usb3_group;
+ } else
+ port_dev->dev.groups = port_dev_group;
port_dev->dev.type = &usb_port_device_type;
port_dev->dev.driver = &usb_port_driver;
if (hub_is_superspeed(hub->hdev))
--
1.7.9.5


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