diff options
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/core/hub.c | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 5219507bf227..fd1ec481aec1 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -3050,11 +3050,425 @@ void usb_root_hub_lost_power(struct usb_device *rhdev) } EXPORT_SYMBOL_GPL(usb_root_hub_lost_power); +static const char * const usb3_lpm_names[] = { + "U0", + "U1", + "U2", + "U3", +}; + +/* + * Send a Set SEL control transfer to the device, prior to enabling + * device-initiated U1 or U2. This lets the device know the exit latencies from + * the time the device initiates a U1 or U2 exit, to the time it will receive a + * packet from the host. + * + * This function will fail if the SEL or PEL values for udev are greater than + * the maximum allowed values for the link state to be enabled. + */ +static int usb_req_set_sel(struct usb_device *udev, enum usb3_link_state state) +{ + struct usb_set_sel_req *sel_values; + unsigned long long u1_sel; + unsigned long long u1_pel; + unsigned long long u2_sel; + unsigned long long u2_pel; + int ret; + + /* Convert SEL and PEL stored in ns to us */ + u1_sel = DIV_ROUND_UP(udev->u1_params.sel, 1000); + u1_pel = DIV_ROUND_UP(udev->u1_params.pel, 1000); + u2_sel = DIV_ROUND_UP(udev->u2_params.sel, 1000); + u2_pel = DIV_ROUND_UP(udev->u2_params.pel, 1000); + + /* + * Make sure that the calculated SEL and PEL values for the link + * state we're enabling aren't bigger than the max SEL/PEL + * value that will fit in the SET SEL control transfer. + * Otherwise the device would get an incorrect idea of the exit + * latency for the link state, and could start a device-initiated + * U1/U2 when the exit latencies are too high. + */ + if ((state == USB3_LPM_U1 && + (u1_sel > USB3_LPM_MAX_U1_SEL_PEL || + u1_pel > USB3_LPM_MAX_U1_SEL_PEL)) || + (state == USB3_LPM_U2 && + (u2_sel > USB3_LPM_MAX_U2_SEL_PEL || + u2_pel > USB3_LPM_MAX_U2_SEL_PEL))) { + dev_dbg(&udev->dev, "Device-initiated %s disabled due " + "to long SEL %llu ms or PEL %llu ms\n", + usb3_lpm_names[state], u1_sel, u1_pel); + return -EINVAL; + } + + /* + * If we're enabling device-initiated LPM for one link state, + * but the other link state has a too high SEL or PEL value, + * just set those values to the max in the Set SEL request. + */ + if (u1_sel > USB3_LPM_MAX_U1_SEL_PEL) + u1_sel = USB3_LPM_MAX_U1_SEL_PEL; + + if (u1_pel > USB3_LPM_MAX_U1_SEL_PEL) + u1_pel = USB3_LPM_MAX_U1_SEL_PEL; + + if (u2_sel > USB3_LPM_MAX_U2_SEL_PEL) + u2_sel = USB3_LPM_MAX_U2_SEL_PEL; + + if (u2_pel > USB3_LPM_MAX_U2_SEL_PEL) + u2_pel = USB3_LPM_MAX_U2_SEL_PEL; + + /* + * usb_enable_lpm() can be called as part of a failed device reset, + * which may be initiated by an error path of a mass storage driver. + * Therefore, use GFP_NOIO. + */ + sel_values = kmalloc(sizeof *(sel_values), GFP_NOIO); + if (!sel_values) + return -ENOMEM; + + sel_values->u1_sel = u1_sel; + sel_values->u1_pel = u1_pel; + sel_values->u2_sel = cpu_to_le16(u2_sel); + sel_values->u2_pel = cpu_to_le16(u2_pel); + + ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), + USB_REQ_SET_SEL, + USB_RECIP_DEVICE, + 0, 0, + sel_values, sizeof *(sel_values), + USB_CTRL_SET_TIMEOUT); + kfree(sel_values); + return ret; +} + +/* + * Enable or disable device-initiated U1 or U2 transitions. + */ +static int usb_set_device_initiated_lpm(struct usb_device *udev, + enum usb3_link_state state, bool enable) +{ + int ret; + int feature; + + switch (state) { + case USB3_LPM_U1: + feature = USB_DEVICE_U1_ENABLE; + break; + case USB3_LPM_U2: + feature = USB_DEVICE_U2_ENABLE; + break; + default: + dev_warn(&udev->dev, "%s: Can't %s non-U1 or U2 state.\n", + __func__, enable ? "enable" : "disable"); + return -EINVAL; + } + + if (udev->state != USB_STATE_CONFIGURED) { + dev_dbg(&udev->dev, "%s: Can't %s %s state " + "for unconfigured device.\n", + __func__, enable ? "enable" : "disable", + usb3_lpm_names[state]); + return 0; + } + + if (enable) { + /* + * First, let the device know about the exit latencies + * associated with the link state we're about to enable. + */ + ret = usb_req_set_sel(udev, state); + if (ret < 0) { + dev_warn(&udev->dev, "Set SEL for device-initiated " + "%s failed.\n", usb3_lpm_names[state]); + return -EBUSY; + } + /* + * Now send the control transfer to enable device-initiated LPM + * for either U1 or U2. + */ + ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), + USB_REQ_SET_FEATURE, + USB_RECIP_DEVICE, + feature, + 0, NULL, 0, + USB_CTRL_SET_TIMEOUT); + } else { + ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), + USB_REQ_CLEAR_FEATURE, + USB_RECIP_DEVICE, + feature, + 0, NULL, 0, + USB_CTRL_SET_TIMEOUT); + } + if (ret < 0) { + dev_warn(&udev->dev, "%s of device-initiated %s failed.\n", + enable ? "Enable" : "Disable", + usb3_lpm_names[state]); + return -EBUSY; + } + return 0; +} + +static int usb_set_lpm_timeout(struct usb_device *udev, + enum usb3_link_state state, int timeout) +{ + int ret; + int feature; + + switch (state) { + case USB3_LPM_U1: + feature = USB_PORT_FEAT_U1_TIMEOUT; + break; + case USB3_LPM_U2: + feature = USB_PORT_FEAT_U2_TIMEOUT; + break; + default: + dev_warn(&udev->dev, "%s: Can't set timeout for non-U1 or U2 state.\n", + __func__); + return -EINVAL; + } + + if (state == USB3_LPM_U1 && timeout > USB3_LPM_U1_MAX_TIMEOUT && + timeout != USB3_LPM_DEVICE_INITIATED) { + dev_warn(&udev->dev, "Failed to set %s timeout to 0x%x, " + "which is a reserved value.\n", + usb3_lpm_names[state], timeout); + return -EINVAL; + } + + ret = set_port_feature(udev->parent, + USB_PORT_LPM_TIMEOUT(timeout) | udev->portnum, + feature); + if (ret < 0) { + dev_warn(&udev->dev, "Failed to set %s timeout to 0x%x," + "error code %i\n", usb3_lpm_names[state], + timeout, ret); + return -EBUSY; + } + if (state == USB3_LPM_U1) + udev->u1_params.timeout = timeout; + else + udev->u2_params.timeout = timeout; + return 0; +} + +/* + * Enable the hub-initiated U1/U2 idle timeouts, and enable device-initiated + * U1/U2 entry. + * + * We will attempt to enable U1 or U2, but there are no guarantees that the + * control transfers to set the hub timeout or enable device-initiated U1/U2 + * will be successful. + * + * If we cannot set the parent hub U1/U2 timeout, we attempt to let the xHCI + * driver know about it. If that call fails, it should be harmless, and just + * take up more slightly more bus bandwidth for unnecessary U1/U2 exit latency. + */ +static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev, + enum usb3_link_state state) +{ + int timeout; + + /* We allow the host controller to set the U1/U2 timeout internally + * first, so that it can change its schedule to account for the + * additional latency to send data to a device in a lower power + * link state. + */ + timeout = hcd->driver->enable_usb3_lpm_timeout(hcd, udev, state); + + /* xHCI host controller doesn't want to enable this LPM state. */ + if (timeout == 0) + return; + + if (timeout < 0) { + dev_warn(&udev->dev, "Could not enable %s link state, " + "xHCI error %i.\n", usb3_lpm_names[state], + timeout); + return; + } + + if (usb_set_lpm_timeout(udev, state, timeout)) + /* If we can't set the parent hub U1/U2 timeout, + * device-initiated LPM won't be allowed either, so let the xHCI + * host know that this link state won't be enabled. + */ + hcd->driver->disable_usb3_lpm_timeout(hcd, udev, state); + + /* Only a configured device will accept the Set Feature U1/U2_ENABLE */ + else if (udev->actconfig) + usb_set_device_initiated_lpm(udev, state, true); + +} + +/* + * Disable the hub-initiated U1/U2 idle timeouts, and disable device-initiated + * U1/U2 entry. + * + * If this function returns -EBUSY, the parent hub will still allow U1/U2 entry. + * If zero is returned, the parent will not allow the link to go into U1/U2. + * + * If zero is returned, device-initiated U1/U2 entry may still be enabled, but + * it won't have an effect on the bus link state because the parent hub will + * still disallow device-initiated U1/U2 entry. + * + * If zero is returned, the xHCI host controller may still think U1/U2 entry is + * possible. The result will be slightly more bus bandwidth will be taken up + * (to account for U1/U2 exit latency), but it should be harmless. + */ +static int usb_disable_link_state(struct usb_hcd *hcd, struct usb_device *udev, + enum usb3_link_state state) +{ + int feature; + + switch (state) { + case USB3_LPM_U1: + feature = USB_PORT_FEAT_U1_TIMEOUT; + break; + case USB3_LPM_U2: + feature = USB_PORT_FEAT_U2_TIMEOUT; + break; + default: + dev_warn(&udev->dev, "%s: Can't disable non-U1 or U2 state.\n", + __func__); + return -EINVAL; + } + + if (usb_set_lpm_timeout(udev, state, 0)) + return -EBUSY; + + usb_set_device_initiated_lpm(udev, state, false); + + if (hcd->driver->disable_usb3_lpm_timeout(hcd, udev, state)) + dev_warn(&udev->dev, "Could not disable xHCI %s timeout, " + "bus schedule bandwidth may be impacted.\n", + usb3_lpm_names[state]); + return 0; +} + +/* + * Disable hub-initiated and device-initiated U1 and U2 entry. + * Caller must own the bandwidth_mutex. + * + * This will call usb_enable_lpm() on failure, which will decrement + * lpm_disable_count, and will re-enable LPM if lpm_disable_count reaches zero. + */ +int usb_disable_lpm(struct usb_device *udev) +{ + struct usb_hcd *hcd; + + if (!udev || !udev->parent || + udev->speed != USB_SPEED_SUPER || + !udev->lpm_capable) + return 0; + + hcd = bus_to_hcd(udev->bus); + if (!hcd || !hcd->driver->disable_usb3_lpm_timeout) + return 0; + + udev->lpm_disable_count++; + if ((udev->u1_params.timeout == 0 && udev->u1_params.timeout == 0)) + return 0; + + /* If LPM is enabled, attempt to disable it. */ + if (usb_disable_link_state(hcd, udev, USB3_LPM_U1)) + goto enable_lpm; + if (usb_disable_link_state(hcd, udev, USB3_LPM_U2)) + goto enable_lpm; + + return 0; + +enable_lpm: + usb_enable_lpm(udev); + return -EBUSY; +} +EXPORT_SYMBOL_GPL(usb_disable_lpm); + +/* Grab the bandwidth_mutex before calling usb_disable_lpm() */ +int usb_unlocked_disable_lpm(struct usb_device *udev) +{ + struct usb_hcd *hcd = bus_to_hcd(udev->bus); + int ret; + + if (!hcd) + return -EINVAL; + + mutex_lock(hcd->bandwidth_mutex); + ret = usb_disable_lpm(udev); + mutex_unlock(hcd->bandwidth_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(usb_unlocked_disable_lpm); + +/* + * Attempt to enable device-initiated and hub-initiated U1 and U2 entry. The + * xHCI host policy may prevent U1 or U2 from being enabled. + * + * Other callers may have disabled link PM, so U1 and U2 entry will be disabled + * until the lpm_disable_count drops to zero. Caller must own the + * bandwidth_mutex. + */ +void usb_enable_lpm(struct usb_device *udev) +{ + struct usb_hcd *hcd; + + if (!udev || !udev->parent || + udev->speed != USB_SPEED_SUPER || + !udev->lpm_capable) + return; + + udev->lpm_disable_count--; + hcd = bus_to_hcd(udev->bus); + /* Double check that we can both enable and disable LPM. + * Device must be configured to accept set feature U1/U2 timeout. + */ + if (!hcd || !hcd->driver->enable_usb3_lpm_timeout || + !hcd->driver->disable_usb3_lpm_timeout) + return; + + 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); +} +EXPORT_SYMBOL_GPL(usb_enable_lpm); + +/* Grab the bandwidth_mutex before calling usb_enable_lpm() */ +void usb_unlocked_enable_lpm(struct usb_device *udev) +{ + struct usb_hcd *hcd = bus_to_hcd(udev->bus); + + if (!hcd) + return; + + mutex_lock(hcd->bandwidth_mutex); + usb_enable_lpm(udev); + mutex_unlock(hcd->bandwidth_mutex); +} +EXPORT_SYMBOL_GPL(usb_unlocked_enable_lpm); + + #else /* CONFIG_PM */ #define hub_suspend NULL #define hub_resume NULL #define hub_reset_resume NULL + +int usb_disable_lpm(struct usb_device *udev) +{ + return 0; +} + +void usb_enable_lpm(struct usb_device *udev) { } + +int usb_unlocked_disable_lpm(struct usb_device *udev) +{ + return 0; +} + +void usb_unlocked_enable_lpm(struct usb_device *udev) { } #endif |