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An EHSET test fixture is used to initiate test modes on an embedded host controller while performing the usb host compliance testing. During enumeration by the USB host this test fixture presents a VID/PID pair and this PID value corresponds to the requested testmode. Change-Id: I7558f9c1c37b3c65be2b358d964b295593c021d9 CRs-Fixed: 174266 Signed-off-by: Manu Gautam <mgautam@qualcomm.com>
69 lines
2.2 KiB
Text
69 lines
2.2 KiB
Text
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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