diff options
| author | Felipe Balbi <felipe.balbi@linux.intel.com> | 2017-05-09 09:30:24 -0400 |
|---|---|---|
| committer | Felipe Balbi <felipe.balbi@linux.intel.com> | 2017-06-02 04:22:30 -0400 |
| commit | b0b3ddf8fb37283d0d488d667fac4c069d612ba3 (patch) | |
| tree | 334a7d90461b727dc9811a0ac1764efc424628d3 /Documentation/usb | |
| parent | 8b4cfe0bb7a4117087e2431d668ab79faabe3faa (diff) | |
usb: move ReST documentation to Documentation/driver-api/usb/
This is where all other USB ReST documentation has moved to.
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Diffstat (limited to 'Documentation/usb')
| -rw-r--r-- | Documentation/usb/typec.rst | 184 | ||||
| -rw-r--r-- | Documentation/usb/usb3-debug-port.rst | 100 |
2 files changed, 0 insertions, 284 deletions
diff --git a/Documentation/usb/typec.rst b/Documentation/usb/typec.rst deleted file mode 100644 index b67a46779de9..000000000000 --- a/Documentation/usb/typec.rst +++ /dev/null | |||
| @@ -1,184 +0,0 @@ | |||
| 1 | |||
| 2 | USB Type-C connector class | ||
| 3 | ========================== | ||
| 4 | |||
| 5 | Introduction | ||
| 6 | ------------ | ||
| 7 | |||
| 8 | The typec class is meant for describing the USB Type-C ports in a system to the | ||
| 9 | user space in unified fashion. The class is designed to provide nothing else | ||
| 10 | except the user space interface implementation in hope that it can be utilized | ||
| 11 | on as many platforms as possible. | ||
| 12 | |||
| 13 | The platforms are expected to register every USB Type-C port they have with the | ||
| 14 | class. In a normal case the registration will be done by a USB Type-C or PD PHY | ||
| 15 | driver, but it may be a driver for firmware interface such as UCSI, driver for | ||
| 16 | USB PD controller or even driver for Thunderbolt3 controller. This document | ||
| 17 | considers the component registering the USB Type-C ports with the class as "port | ||
| 18 | driver". | ||
| 19 | |||
| 20 | On top of showing the capabilities, the class also offer user space control over | ||
| 21 | the roles and alternate modes of ports, partners and cable plugs when the port | ||
| 22 | driver is capable of supporting those features. | ||
| 23 | |||
| 24 | The class provides an API for the port drivers described in this document. The | ||
| 25 | attributes are described in Documentation/ABI/testing/sysfs-class-typec. | ||
| 26 | |||
| 27 | User space interface | ||
| 28 | -------------------- | ||
| 29 | Every port will be presented as its own device under /sys/class/typec/. The | ||
| 30 | first port will be named "port0", the second "port1" and so on. | ||
| 31 | |||
| 32 | When connected, the partner will be presented also as its own device under | ||
| 33 | /sys/class/typec/. The parent of the partner device will always be the port it | ||
| 34 | is attached to. The partner attached to port "port0" will be named | ||
| 35 | "port0-partner". Full path to the device would be | ||
| 36 | /sys/class/typec/port0/port0-partner/. | ||
| 37 | |||
| 38 | The cable and the two plugs on it may also be optionally presented as their own | ||
| 39 | devices under /sys/class/typec/. The cable attached to the port "port0" port | ||
| 40 | will be named port0-cable and the plug on the SOP Prime end (see USB Power | ||
| 41 | Delivery Specification ch. 2.4) will be named "port0-plug0" and on the SOP | ||
| 42 | Double Prime end "port0-plug1". The parent of a cable will always be the port, | ||
| 43 | and the parent of the cable plugs will always be the cable. | ||
| 44 | |||
| 45 | If the port, partner or cable plug supports Alternate Modes, every supported | ||
| 46 | Alternate Mode SVID will have their own device describing them. Note that the | ||
| 47 | Alternate Mode devices will not be attached to the typec class. The parent of an | ||
| 48 | alternate mode will be the device that supports it, so for example an alternate | ||
| 49 | mode of port0-partner will be presented under /sys/class/typec/port0-partner/. | ||
| 50 | Every mode that is supported will have its own group under the Alternate Mode | ||
| 51 | device named "mode<index>", for example /sys/class/typec/port0/<alternate | ||
| 52 | mode>/mode1/. The requests for entering/exiting a mode can be done with "active" | ||
| 53 | attribute file in that group. | ||
| 54 | |||
| 55 | Driver API | ||
| 56 | ---------- | ||
| 57 | |||
| 58 | Registering the ports | ||
| 59 | ~~~~~~~~~~~~~~~~~~~~~ | ||
| 60 | |||
| 61 | The port drivers will describe every Type-C port they control with struct | ||
| 62 | typec_capability data structure, and register them with the following API: | ||
| 63 | |||
| 64 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 65 | :functions: typec_register_port typec_unregister_port | ||
| 66 | |||
| 67 | When registering the ports, the prefer_role member in struct typec_capability | ||
| 68 | deserves special notice. If the port that is being registered does not have | ||
| 69 | initial role preference, which means the port does not execute Try.SNK or | ||
| 70 | Try.SRC by default, the member must have value TYPEC_NO_PREFERRED_ROLE. | ||
| 71 | Otherwise if the port executes Try.SNK by default, the member must have value | ||
| 72 | TYPEC_DEVICE, and with Try.SRC the value must be TYPEC_HOST. | ||
| 73 | |||
| 74 | Registering Partners | ||
| 75 | ~~~~~~~~~~~~~~~~~~~~ | ||
| 76 | |||
| 77 | After successful connection of a partner, the port driver needs to register the | ||
| 78 | partner with the class. Details about the partner need to be described in struct | ||
| 79 | typec_partner_desc. The class copies the details of the partner during | ||
| 80 | registration. The class offers the following API for registering/unregistering | ||
| 81 | partners. | ||
| 82 | |||
| 83 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 84 | :functions: typec_register_partner typec_unregister_partner | ||
| 85 | |||
| 86 | The class will provide a handle to struct typec_partner if the registration was | ||
| 87 | successful, or NULL. | ||
| 88 | |||
| 89 | If the partner is USB Power Delivery capable, and the port driver is able to | ||
| 90 | show the result of Discover Identity command, the partner descriptor structure | ||
| 91 | should include handle to struct usb_pd_identity instance. The class will then | ||
| 92 | create a sysfs directory for the identity under the partner device. The result | ||
| 93 | of Discover Identity command can then be reported with the following API: | ||
| 94 | |||
| 95 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 96 | :functions: typec_partner_set_identity | ||
| 97 | |||
| 98 | Registering Cables | ||
| 99 | ~~~~~~~~~~~~~~~~~~ | ||
| 100 | |||
| 101 | After successful connection of a cable that supports USB Power Delivery | ||
| 102 | Structured VDM "Discover Identity", the port driver needs to register the cable | ||
| 103 | and one or two plugs, depending if there is CC Double Prime controller present | ||
| 104 | in the cable or not. So a cable capable of SOP Prime communication, but not SOP | ||
| 105 | Double Prime communication, should only have one plug registered. For more | ||
| 106 | information about SOP communication, please read chapter about it from the | ||
| 107 | latest USB Power Delivery specification. | ||
| 108 | |||
| 109 | The plugs are represented as their own devices. The cable is registered first, | ||
| 110 | followed by registration of the cable plugs. The cable will be the parent device | ||
| 111 | for the plugs. Details about the cable need to be described in struct | ||
| 112 | typec_cable_desc and about a plug in struct typec_plug_desc. The class copies | ||
| 113 | the details during registration. The class offers the following API for | ||
| 114 | registering/unregistering cables and their plugs: | ||
| 115 | |||
| 116 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 117 | :functions: typec_register_cable typec_unregister_cable typec_register_plug | ||
| 118 | typec_unregister_plug | ||
| 119 | |||
| 120 | The class will provide a handle to struct typec_cable and struct typec_plug if | ||
| 121 | the registration is successful, or NULL if it isn't. | ||
| 122 | |||
| 123 | If the cable is USB Power Delivery capable, and the port driver is able to show | ||
| 124 | the result of Discover Identity command, the cable descriptor structure should | ||
| 125 | include handle to struct usb_pd_identity instance. The class will then create a | ||
| 126 | sysfs directory for the identity under the cable device. The result of Discover | ||
| 127 | Identity command can then be reported with the following API: | ||
| 128 | |||
| 129 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 130 | :functions: typec_cable_set_identity | ||
| 131 | |||
| 132 | Notifications | ||
| 133 | ~~~~~~~~~~~~~ | ||
| 134 | |||
| 135 | When the partner has executed a role change, or when the default roles change | ||
| 136 | during connection of a partner or cable, the port driver must use the following | ||
| 137 | APIs to report it to the class: | ||
| 138 | |||
| 139 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 140 | :functions: typec_set_data_role typec_set_pwr_role typec_set_vconn_role | ||
| 141 | typec_set_pwr_opmode | ||
| 142 | |||
| 143 | Alternate Modes | ||
| 144 | ~~~~~~~~~~~~~~~ | ||
| 145 | |||
| 146 | USB Type-C ports, partners and cable plugs may support Alternate Modes. Each | ||
| 147 | Alternate Mode will have identifier called SVID, which is either a Standard ID | ||
| 148 | given by USB-IF or vendor ID, and each supported SVID can have 1 - 6 modes. The | ||
| 149 | class provides struct typec_mode_desc for describing individual mode of a SVID, | ||
| 150 | and struct typec_altmode_desc which is a container for all the supported modes. | ||
| 151 | |||
| 152 | Ports that support Alternate Modes need to register each SVID they support with | ||
| 153 | the following API: | ||
| 154 | |||
| 155 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 156 | :functions: typec_port_register_altmode | ||
| 157 | |||
| 158 | If a partner or cable plug provides a list of SVIDs as response to USB Power | ||
| 159 | Delivery Structured VDM Discover SVIDs message, each SVID needs to be | ||
| 160 | registered. | ||
| 161 | |||
| 162 | API for the partners: | ||
| 163 | |||
| 164 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 165 | :functions: typec_partner_register_altmode | ||
| 166 | |||
| 167 | API for the Cable Plugs: | ||
| 168 | |||
| 169 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 170 | :functions: typec_plug_register_altmode | ||
| 171 | |||
| 172 | So ports, partners and cable plugs will register the alternate modes with their | ||
| 173 | own functions, but the registration will always return a handle to struct | ||
| 174 | typec_altmode on success, or NULL. The unregistration will happen with the same | ||
| 175 | function: | ||
| 176 | |||
| 177 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 178 | :functions: typec_unregister_altmode | ||
| 179 | |||
| 180 | If a partner or cable plug enters or exits a mode, the port driver needs to | ||
| 181 | notify the class with the following API: | ||
| 182 | |||
| 183 | .. kernel-doc:: drivers/usb/typec/typec.c | ||
| 184 | :functions: typec_altmode_update_active | ||
diff --git a/Documentation/usb/usb3-debug-port.rst b/Documentation/usb/usb3-debug-port.rst deleted file mode 100644 index feb1a36a65b7..000000000000 --- a/Documentation/usb/usb3-debug-port.rst +++ /dev/null | |||
| @@ -1,100 +0,0 @@ | |||
| 1 | =============== | ||
| 2 | USB3 debug port | ||
| 3 | =============== | ||
| 4 | |||
| 5 | :Author: Lu Baolu <baolu.lu@linux.intel.com> | ||
| 6 | :Date: March 2017 | ||
| 7 | |||
| 8 | GENERAL | ||
| 9 | ======= | ||
| 10 | |||
| 11 | This is a HOWTO for using the USB3 debug port on x86 systems. | ||
| 12 | |||
| 13 | Before using any kernel debugging functionality based on USB3 | ||
| 14 | debug port, you need to:: | ||
| 15 | |||
| 16 | 1) check whether any USB3 debug port is available in | ||
| 17 | your system; | ||
| 18 | 2) check which port is used for debugging purposes; | ||
| 19 | 3) have a USB 3.0 super-speed A-to-A debugging cable. | ||
| 20 | |||
| 21 | INTRODUCTION | ||
| 22 | ============ | ||
| 23 | |||
| 24 | The xHCI debug capability (DbC) is an optional but standalone | ||
| 25 | functionality provided by the xHCI host controller. The xHCI | ||
| 26 | specification describes DbC in the section 7.6. | ||
| 27 | |||
| 28 | When DbC is initialized and enabled, it will present a debug | ||
| 29 | device through the debug port (normally the first USB3 | ||
| 30 | super-speed port). The debug device is fully compliant with | ||
| 31 | the USB framework and provides the equivalent of a very high | ||
| 32 | performance full-duplex serial link between the debug target | ||
| 33 | (the system under debugging) and a debug host. | ||
| 34 | |||
| 35 | EARLY PRINTK | ||
| 36 | ============ | ||
| 37 | |||
| 38 | DbC has been designed to log early printk messages. One use for | ||
| 39 | this feature is kernel debugging. For example, when your machine | ||
| 40 | crashes very early before the regular console code is initialized. | ||
| 41 | Other uses include simpler, lockless logging instead of a full- | ||
| 42 | blown printk console driver and klogd. | ||
| 43 | |||
| 44 | On the debug target system, you need to customize a debugging | ||
| 45 | kernel with CONFIG_EARLY_PRINTK_USB_XDBC enabled. And, add below | ||
| 46 | kernel boot parameter:: | ||
| 47 | |||
| 48 | "earlyprintk=xdbc" | ||
| 49 | |||
| 50 | If there are multiple xHCI controllers in your system, you can | ||
| 51 | append a host contoller index to this kernel parameter. This | ||
| 52 | index starts from 0. | ||
| 53 | |||
| 54 | Current design doesn't support DbC runtime suspend/resume. As | ||
| 55 | the result, you'd better disable runtime power management for | ||
| 56 | USB subsystem by adding below kernel boot parameter:: | ||
| 57 | |||
| 58 | "usbcore.autosuspend=-1" | ||
| 59 | |||
| 60 | Before starting the debug target, you should connect the debug | ||
| 61 | port to a USB port (root port or port of any external hub) on | ||
| 62 | the debug host. The cable used to connect these two ports | ||
| 63 | should be a USB 3.0 super-speed A-to-A debugging cable. | ||
| 64 | |||
| 65 | During early boot of the debug target, DbC will be detected and | ||
| 66 | initialized. After initialization, the debug host should be able | ||
| 67 | to enumerate the debug device in debug target. The debug host | ||
| 68 | will then bind the debug device with the usb_debug driver module | ||
| 69 | and create the /dev/ttyUSB device. | ||
| 70 | |||
| 71 | If the debug device enumeration goes smoothly, you should be able | ||
| 72 | to see below kernel messages on the debug host:: | ||
| 73 | |||
| 74 | # tail -f /var/log/kern.log | ||
| 75 | [ 1815.983374] usb 4-3: new SuperSpeed USB device number 4 using xhci_hcd | ||
| 76 | [ 1815.999595] usb 4-3: LPM exit latency is zeroed, disabling LPM. | ||
| 77 | [ 1815.999899] usb 4-3: New USB device found, idVendor=1d6b, idProduct=0004 | ||
| 78 | [ 1815.999902] usb 4-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3 | ||
| 79 | [ 1815.999903] usb 4-3: Product: Remote GDB | ||
| 80 | [ 1815.999904] usb 4-3: Manufacturer: Linux | ||
| 81 | [ 1815.999905] usb 4-3: SerialNumber: 0001 | ||
| 82 | [ 1816.000240] usb_debug 4-3:1.0: xhci_dbc converter detected | ||
| 83 | [ 1816.000360] usb 4-3: xhci_dbc converter now attached to ttyUSB0 | ||
| 84 | |||
| 85 | You can use any communication program, for example minicom, to | ||
| 86 | read and view the messages. Below simple bash scripts can help | ||
| 87 | you to check the sanity of the setup. | ||
| 88 | |||
| 89 | .. code-block:: sh | ||
| 90 | |||
| 91 | ===== start of bash scripts ============= | ||
| 92 | #!/bin/bash | ||
| 93 | |||
| 94 | while true ; do | ||
| 95 | while [ ! -d /sys/class/tty/ttyUSB0 ] ; do | ||
| 96 | : | ||
| 97 | done | ||
| 98 | cat /dev/ttyUSB0 | ||
| 99 | done | ||
| 100 | ===== end of bash scripts =============== | ||
