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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/Documentation/arm/Samsung-S3C24XX/USB-Host.txt
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			S3C24XX USB Host support

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			========================

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Introduction

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------------

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  This document details the S3C2410/S3C2440 in-built OHCI USB host support.

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Configuration

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-------------

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  Enable at least the following kernel options:

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  menuconfig:

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   Device Drivers  --->

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     USB support  --->

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       <*> Support for Host-side USB

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       <*>   OHCI HCD support

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  .config:

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    CONFIG_USB

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    CONFIG_USB_OHCI_HCD

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  Once these options are configured, the standard set of USB device

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  drivers can be configured and used.

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Board Support

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-------------

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  The driver attaches to a platform device, which will need to be

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  added by the board specific support file in linux/arch/arm/mach-s3c2410,

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  such as mach-bast.c or mach-smdk2410.c

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  The platform device's platform_data field is only needed if the

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  board implements extra power control or over-current monitoring.

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  The OHCI driver does not ensure the state of the S3C2410's MISCCTRL

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  register, so if both ports are to be used for the host, then it is

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  the board support file's responsibility to ensure that the second

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  port is configured to be connected to the OHCI core.

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Platform Data

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-------------

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  See arch/arm/mach-s3c2410/include/mach/usb-control.h for the

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  descriptions of the platform device data. An implementation

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  can be found in linux/arch/arm/mach-s3c2410/usb-simtec.c .

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  The `struct s3c2410_hcd_info` contains a pair of functions

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  that get called to enable over-current detection, and to

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  control the port power status.

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  The ports are numbered 0 and 1.

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  power_control:

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    Called to enable or disable the power on the port.

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  enable_oc:

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    Called to enable or disable the over-current monitoring.

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    This should claim or release the resources being used to

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    check the power condition on the port, such as an IRQ.

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  report_oc:

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    The OHCI driver fills this field in for the over-current code

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    to call when there is a change to the over-current state on

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    an port. The ports argument is a bitmask of 1 bit per port,

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    with bit X being 1 for an over-current on port X.

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    The function s3c2410_usb_report_oc() has been provided to

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    ensure this is called correctly.

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  port[x]:

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    This is struct describes each port, 0 or 1. The platform driver

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    should set the flags field of each port to S3C_HCDFLG_USED if

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    the port is enabled.

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Document Author

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---------------

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Ben Dooks, Copyright 2005 Simtec Electronics

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