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