From a558ccdcc71c7770c5e80c926a31cfe8a3892a09 Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Thu, 23 May 2013 17:14:30 +0300 Subject: usb: xhci: add USB2 Link power management BESL support usb 2.0 devices with link power managment (LPM) can describe their idle link timeouts either in BESL or HIRD format, so far xHCI has only supported HIRD but later xHCI errata add BESL support as well BESL timeouts need to inform exit latency changes with an evaluate context command the same way USB 3.0 link PM code does. The same xhci_change_max_exit_latency() function is used as with USB3 but code is pulled out from #ifdef CONFIG_PM as USB2.0 BESL LPM funcionality does not depend on CONFIG_PM. Signed-off-by: Mathias Nyman Signed-off-by: Sarah Sharp --- include/linux/usb.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/usb.h b/include/linux/usb.h index b424e5318f20..fe444989668a 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -468,6 +468,7 @@ struct usb3_lpm_parameters { * @wusb: device is Wireless USB * @lpm_capable: device supports LPM * @usb2_hw_lpm_capable: device can perform USB2 hardware LPM + * @usb2_hw_lpm_besl_capable: device can perform USB2 hardware BESL LPM * @usb2_hw_lpm_enabled: USB2 hardware LPM enabled * @usb3_lpm_enabled: USB3 hardware LPM enabled * @string_langid: language ID for strings @@ -538,6 +539,7 @@ struct usb_device { unsigned wusb:1; unsigned lpm_capable:1; unsigned usb2_hw_lpm_capable:1; + unsigned usb2_hw_lpm_besl_capable:1; unsigned usb2_hw_lpm_enabled:1; unsigned usb3_lpm_enabled:1; int string_langid; -- cgit v1.2.3 From 17f34867e98d2fb0c03918faab79efb989fa134b Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Thu, 23 May 2013 17:14:31 +0300 Subject: usb: add usb2 Link PM variables to sysfs and usb_device Adds abitilty to tune L1 timeout (inactivity timer for usb2 link sleep) and BESL (best effort service latency)via sysfs. This also adds a new usb2_lpm_parameters structure with those variables to struct usb_device. Signed-off-by: Mathias Nyman Signed-off-by: Sarah Sharp --- Documentation/ABI/testing/sysfs-bus-usb | 27 +++++++++++++++++ drivers/usb/core/sysfs.c | 54 +++++++++++++++++++++++++++++++++ drivers/usb/host/xhci.c | 6 ++-- include/linux/usb.h | 18 +++++++++++ 4 files changed, 103 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index f093e59cbe5f..9759b8c91332 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -236,3 +236,30 @@ Description: This attribute is to expose these information to user space. The file will read "hotplug", "wired" and "not used" if the information is available, and "unknown" otherwise. + +What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout +Date: May 2013 +Contact: Mathias Nyman +Description: + USB 2.0 devices may support hardware link power management (LPM) + L1 sleep state. The usb2_lpm_l1_timeout attribute allows + tuning the timeout for L1 inactivity timer (LPM timer), e.g. + needed inactivity time before host requests the device to go to L1 sleep. + Useful for power management tuning. + Supported values are 0 - 65535 microseconds. + +What: /sys/bus/usb/devices/.../power/usb2_lpm_besl +Date: May 2013 +Contact: Mathias Nyman +Description: + USB 2.0 devices that support hardware link power management (LPM) + L1 sleep state now use a best effort service latency value (BESL) to + indicate the best effort to resumption of service to the device after the + initiation of the resume event. + If the device does not have a preferred besl value then the host can select + one instead. This usb2_lpm_besl attribute allows to tune the host selected besl + value in order to tune power saving and service latency. + + 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) diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c index aa38db44818a..d9284b998bd7 100644 --- a/drivers/usb/core/sysfs.c +++ b/drivers/usb/core/sysfs.c @@ -497,8 +497,62 @@ set_usb2_hardware_lpm(struct device *dev, struct device_attribute *attr, static DEVICE_ATTR(usb2_hardware_lpm, S_IRUGO | S_IWUSR, show_usb2_hardware_lpm, set_usb2_hardware_lpm); +static ssize_t +show_usb2_lpm_l1_timeout(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct usb_device *udev = to_usb_device(dev); + return sprintf(buf, "%d\n", udev->l1_params.timeout); +} + +static ssize_t +set_usb2_lpm_l1_timeout(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct usb_device *udev = to_usb_device(dev); + u16 timeout; + + if (kstrtou16(buf, 0, &timeout)) + return -EINVAL; + + udev->l1_params.timeout = timeout; + + return count; +} + +static DEVICE_ATTR(usb2_lpm_l1_timeout, S_IRUGO | S_IWUSR, + show_usb2_lpm_l1_timeout, set_usb2_lpm_l1_timeout); + +static ssize_t +show_usb2_lpm_besl(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct usb_device *udev = to_usb_device(dev); + return sprintf(buf, "%d\n", udev->l1_params.besl); +} + +static ssize_t +set_usb2_lpm_besl(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct usb_device *udev = to_usb_device(dev); + u8 besl; + + if (kstrtou8(buf, 0, &besl) || besl > 15) + return -EINVAL; + + udev->l1_params.besl = besl; + + return count; +} + +static DEVICE_ATTR(usb2_lpm_besl, S_IRUGO | S_IWUSR, + show_usb2_lpm_besl, set_usb2_lpm_besl); + static struct attribute *usb2_hardware_lpm_attr[] = { &dev_attr_usb2_hardware_lpm.attr, + &dev_attr_usb2_lpm_l1_timeout.attr, + &dev_attr_usb2_lpm_besl.attr, NULL, }; static struct attribute_group usb2_hardware_lpm_attr_group = { diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 3d34a0eed088..8be34f838bd4 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -3917,7 +3917,7 @@ static int xhci_calculate_usb2_hw_lpm_params(struct usb_device *udev) field = le32_to_cpu(udev->bos->ext_cap->bmAttributes); /* xHCI l1 is set in steps of 256us, xHCI 1.0 section 5.4.11.2 */ - l1 = XHCI_L1_TIMEOUT / 256; + l1 = udev->l1_params.timeout / 256; /* device has preferred BESLD */ if (field & USB_BESL_DEEP_VALID) { @@ -4101,7 +4101,7 @@ int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd, (field & USB_BESL_BASELINE_VALID)) hird = USB_GET_BESL_BASELINE(field); else - hird = XHCI_DEFAULT_BESL; + hird = udev->l1_params.besl; exit_latency = xhci_besl_encoding[hird]; spin_unlock_irqrestore(&xhci->lock, flags); @@ -4191,6 +4191,8 @@ int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev) if (xhci->hw_lpm_support == 1 && xhci_check_usb2_port_capability(xhci, portnum, XHCI_HLC)) { udev->usb2_hw_lpm_capable = 1; + udev->l1_params.timeout = XHCI_L1_TIMEOUT; + udev->l1_params.besl = XHCI_DEFAULT_BESL; if (xhci_check_usb2_port_capability(xhci, portnum, XHCI_BLC)) udev->usb2_hw_lpm_besl_capable = 1; diff --git a/include/linux/usb.h b/include/linux/usb.h index fe444989668a..a232b7ece1f6 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -393,6 +393,22 @@ enum usb_port_connect_type { USB_PORT_NOT_USED, }; +/* + * USB 2.0 Link Power Management (LPM) parameters. + */ +struct usb2_lpm_parameters { + /* Best effort service latency indicate how long the host will drive + * resume on an exit from L1. + */ + unsigned int besl; + + /* Timeout value in microseconds for the L1 inactivity (LPM) timer. + * When the timer counts to zero, the parent hub will initiate a LPM + * transition to L1. + */ + int timeout; +}; + /* * USB 3.0 Link Power Management (LPM) parameters. * @@ -488,6 +504,7 @@ struct usb3_lpm_parameters { * specific data for the device. * @slot_id: Slot ID assigned by xHCI * @removable: Device can be physically removed from this port + * @l1_params: best effor service latency for USB2 L1 LPM state, and L1 timeout. * @u1_params: exit latencies for USB3 U1 LPM state, and hub-initiated timeout. * @u2_params: exit latencies for USB3 U2 LPM state, and hub-initiated timeout. * @lpm_disable_count: Ref count used by usb_disable_lpm() and usb_enable_lpm() @@ -568,6 +585,7 @@ struct usb_device { struct wusb_dev *wusb_dev; int slot_id; enum usb_device_removable removable; + struct usb2_lpm_parameters l1_params; struct usb3_lpm_parameters u1_params; struct usb3_lpm_parameters u2_params; unsigned lpm_disable_count; -- cgit v1.2.3