| Introduction |
| ============ |
| |
| A USB high speed host must pass electrical compliance tests defined |
| by the USB-IF. These compliance tests require the host controller to |
| support various test modes defined by the USB 2.0 specification. |
| |
| USB-IF defines a standard method to initiate the test modes on an |
| embedded host controller by using a test fixture. During enumeration |
| by the USB host, this test fixture provides a Vendor-Id/Product-Id |
| (or VID/PID) pair which is used by the host to initiate a particular |
| test mode as each VID/PID pair corresponds to a unique test mode. |
| |
| Hardware description |
| ==================== |
| |
| The driver doesn't require any new hardware and is like any other |
| USB host class driver. It gets notified when a Test Fixture device is |
| connected to the host. |
| |
| The test modes that can be initiated are specific to the high speed |
| hosts controllers only. |
| |
| Software description |
| ==================== |
| |
| This EHSET (or Embedded High Speed Electrical Test) driver registers |
| itself with USB core as the preferred driver for the Test Fixture |
| device. During registration it provides the list of the various |
| VID/PID pairs which the Test Fixture may present during enumeration. |
| The VID is always 0x1A0A, and the PIDs presented by the Test Fixture |
| correspond to the following test modes: |
| |
| __________________________________________________ |
| PID Test Mode |
| -------------------------------------------------- |
| 0x0101 TEST_SE0_NAK |
| 0x0102 TEST_J |
| 0x0103 TEST_K |
| 0x0104 TEST_PACKET |
| 0x0106 HS_HOST_PORT_SUSPEND_RESUME |
| 0x0107 SINGLE_STEP_GET_DEV_DESC |
| 0x0108 SINGLE_STEP_SET_FEATURE |
| -------------------------------------------------- |
| |
| The control flow is as follows: |
| |
| 1. USB core notifies the ehset driver when a device (Test Fixture) is |
| attached to the host having the VID/PID pair as one of the specified |
| above. |
| |
| 2. EHSET driver checks the PID which the Test Fixture presented during |
| enumeration and then initiates the corresponding test mode. |
| |
| |
| Dependencies |
| ============ |
| |
| The driver depends on the USB EHCI Host support. |
| |
| Other |
| ===== |
| |
| The driver's code shall be added as a new file in the |
| /kernel/drivers/usb/misc directory. |
| |
| Embedded High-speed Electrical Test Procedure document is available |
| at: |
| http://www.usb.org/developers/onthego/EHSET_v1.01.pdf |
