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author | Nicolas Boichat <drinkcat@chromium.org> | 2018-05-28 14:32:18 +0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-31 12:48:17 +0200 |
commit | 25244227158e1502062041365a439a54cb8fe673 (patch) | |
tree | 87af664545c88bc045cd1598c79caad305d77178 | |
parent | 380375b937211376f1dba4543460a14d3df9f04d (diff) | |
download | linux-stable-25244227158e1502062041365a439a54cb8fe673.tar.gz linux-stable-25244227158e1502062041365a439a54cb8fe673.tar.bz2 linux-stable-25244227158e1502062041365a439a54cb8fe673.zip |
usb: hub: Per-port setting to use old enumeration scheme
The "old" enumeration scheme is considerably faster (it takes
~244ms instead of ~356ms to get the descriptor).
It is currently only possible to use the old scheme globally
(/sys/module/usbcore/parameters/old_scheme_first), which is not
desirable as the new scheme was introduced to increase compatibility
with more devices.
However, in our case, we care about time-to-active for a specific
USB device (which we make the firmware for), on a specific port
(that is pogo-pin based: not a standard USB port). This new
sysfs option makes it possible to use the old scheme on a single
port only.
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 18 | ||||
-rw-r--r-- | drivers/usb/core/hub.c | 13 | ||||
-rw-r--r-- | drivers/usb/core/hub.h | 1 | ||||
-rw-r--r-- | drivers/usb/core/port.c | 23 | ||||
-rw-r--r-- | include/linux/usb.h | 7 |
5 files changed, 58 insertions, 4 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index c6e9b30f05b1..a31a66d62cbb 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -189,6 +189,24 @@ Description: The file will read "hotplug", "wired" and "not used" if the information is available, and "unknown" otherwise. +What: /sys/bus/usb/devices/.../(hub interface)/portX/quirks +Date: May 2018 +Contact: Nicolas Boichat <drinkcat@chromium.org> +Description: + In some cases, we care about time-to-active for devices + connected on a specific port (e.g. non-standard USB port like + pogo pins), where the device to be connected is known in + advance, and behaves well according to the specification. + This attribute is a bit-field that controls the behavior of + a specific port: + - Bit 0 of this field selects the "old" enumeration scheme, + as it is considerably faster (it only causes one USB reset + instead of 2). + The old enumeration scheme can also be selected globally + using /sys/module/usbcore/parameters/old_scheme_first, but + it is often not desirable as the new scheme was introduced to + increase compatibility with more devices. + What: /sys/bus/usb/devices/.../(hub interface)/portX/over_current_count Date: February 2018 Contact: Richard Leitner <richard.leitner@skidata.com> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index c2d993d3816f..f900f66a6285 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2636,7 +2636,7 @@ static unsigned hub_is_wusb(struct usb_hub *hub) #define SET_ADDRESS_TRIES 2 #define GET_DESCRIPTOR_TRIES 2 #define SET_CONFIG_TRIES (2 * (use_both_schemes + 1)) -#define USE_NEW_SCHEME(i) ((i) / 2 == (int)old_scheme_first) +#define USE_NEW_SCHEME(i, scheme) ((i) / 2 == (int)scheme) #define HUB_ROOT_RESET_TIME 60 /* times are in msec */ #define HUB_SHORT_RESET_TIME 10 @@ -2651,12 +2651,16 @@ static unsigned hub_is_wusb(struct usb_hub *hub) * enumeration failures, so disable this enumeration scheme for USB3 * devices. */ -static bool use_new_scheme(struct usb_device *udev, int retry) +static bool use_new_scheme(struct usb_device *udev, int retry, + struct usb_port *port_dev) { + int old_scheme_first_port = + port_dev->quirks & USB_PORT_QUIRK_OLD_SCHEME; + if (udev->speed >= USB_SPEED_SUPER) return false; - return USE_NEW_SCHEME(retry); + return USE_NEW_SCHEME(retry, old_scheme_first_port || old_scheme_first); } /* Is a USB 3.0 port in the Inactive or Compliance Mode state? @@ -4392,6 +4396,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, { struct usb_device *hdev = hub->hdev; struct usb_hcd *hcd = bus_to_hcd(hdev->bus); + struct usb_port *port_dev = hub->ports[port1 - 1]; int retries, operations, retval, i; unsigned delay = HUB_SHORT_RESET_TIME; enum usb_device_speed oldspeed = udev->speed; @@ -4513,7 +4518,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, for (retries = 0; retries < GET_DESCRIPTOR_TRIES; (++retries, msleep(100))) { bool did_new_scheme = false; - if (use_new_scheme(udev, retry_counter)) { + if (use_new_scheme(udev, retry_counter, port_dev)) { struct usb_device_descriptor *buf; int r = 0; diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h index 4dc769ee9c74..4accfb63f7dc 100644 --- a/drivers/usb/core/hub.h +++ b/drivers/usb/core/hub.h @@ -98,6 +98,7 @@ struct usb_port { struct mutex status_lock; u32 over_current_count; u8 portnum; + u32 quirks; unsigned int is_superspeed:1; unsigned int usb3_lpm_u1_permit:1; unsigned int usb3_lpm_u2_permit:1; diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c index 6979bde87d31..4a2143195395 100644 --- a/drivers/usb/core/port.c +++ b/drivers/usb/core/port.c @@ -50,6 +50,28 @@ static ssize_t over_current_count_show(struct device *dev, } static DEVICE_ATTR_RO(over_current_count); +static ssize_t quirks_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct usb_port *port_dev = to_usb_port(dev); + + return sprintf(buf, "%08x\n", port_dev->quirks); +} + +static ssize_t quirks_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct usb_port *port_dev = to_usb_port(dev); + u32 value; + + if (kstrtou32(buf, 16, &value)) + return -EINVAL; + + port_dev->quirks = value; + return count; +} +static DEVICE_ATTR_RW(quirks); + static ssize_t usb3_lpm_permit_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -118,6 +140,7 @@ static DEVICE_ATTR_RW(usb3_lpm_permit); static struct attribute *port_dev_attrs[] = { &dev_attr_connect_type.attr, + &dev_attr_quirks.attr, &dev_attr_over_current_count.attr, NULL, }; diff --git a/include/linux/usb.h b/include/linux/usb.h index beffceec4915..2ade17992ed6 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -490,6 +490,13 @@ enum usb_port_connect_type { }; /* + * USB port quirks. + */ + +/* For the given port, prefer the old (faster) enumeration scheme. */ +#define USB_PORT_QUIRK_OLD_SCHEME BIT(0) + +/* * USB 2.0 Link Power Management (LPM) parameters. */ struct usb2_lpm_parameters { |