查看“USBH internal peripheral”的源代码

==Article purpose==
The purpose of this article is to
* briefly introduce the USBH peripheral and its main features
* indicate the level of security supported by this hardware block
* explain how it can be allocated to the three runtime contexts and linked to the corresponding software components
* explain, when needed, how to configure the USBH peripheral.

==Peripheral overview==
The '''USBH''' peripheral is used to interconnect other systems with STM32 MPU devices, using USB standard.

===Features===
The '''USBH''' peripheral is a USB Host controller supporting high-speed (480 Mbit/s) using an '''EHCI''' controller, and full- and low- speeds (12 and 1.5 Mbit/s) through '''OHCI''' controller. <br>
The '''USBH''' peripheral has two physical ports providing a '''UTMI+''' physical interface, mapped on an on-chip 2-port '''[[USBPHYC internal peripheral|high-speed UTMI+ PHY]]'''. <br>
It supports the standard registers used for low- and full-speed operation ('''OHCI''' model) and high-speed operation ('''EHCI''' model) and the power management feature called Link Power Management (LPM).

The supported standards are:
* ''Universal Serial Bus Revision 2.0 Specification''<ref name="usb2_specification">[http://www.usb.org/developers/docs/usb20_docs Universal Serial Bus Revision 2.0 Specification]</ref>, Revision 2.0, April 27, 2000
* ''USB 2.0 Link Power Management Addendum Engineering Change Notice to the USB 2.0 specification''<ref name="lpm_addendum">[http://www.usb.org/developers/docs/usb20_docs ECN USB 2.0 Link Power Management Addendum]</ref>, July 16, 2007
* ''Enhanced Host Controller Interface Specification for Universal Serial Bus''<ref name="ehci_specification">[https://www.intel.com/content/www/us/en/io/universal-serial-bus/ehci-specification-for-usb.html Enhanced Host Controller Interface Specification for Universal Serial Bus]</ref>, Revision 1.0, March 12, 2002
* ''EHCI v1.1 Addendum''<ref name="ehci_addendum">[https://www.intel.com/content/www/us/en/io/universal-serial-bus/ehci-v1-1-addendum.html Enhanced Host Controller Interface Specification: Addendum]</ref>, August 2008
* ''Open Host Controller Interface Specification for USB''<ref name="ohci_specification">[https://www.usb.org Open Host Controller Interface Specification for USB]</ref>, Release 1.0a, September 14, 1999
* ''USB 2.0 Transceiver Macrocell Interface (UTMI) Specification''<ref name="utmi_specification">[https://www.intel.com/content/www/us/en/io/universal-serial-bus/usb2-transceiver-macrocell-interface-specification.html USB 2.0 Transceiver Macrocell Interface (UTMI) Specification]</ref>, Version 1.05, March 29, 2001
* ''UTMI+ Specification''<ref name="utmi+_specification">[https://www.nxp.com/docs/en/brochure/UTMI-PLUS-SPECIFICATION.pdf UTMI+ Specification]</ref>, Revision 1.0, February 25, 2004

Refer to [[STM32MP15 resources#Reference manuals|STM32MP15 reference manuals]] for the complete features list, and to the software components, introduced below, to know which features are really implemented.

===Security support===
The '''USBH''' peripheral is a '''non-secure''' peripheral.

==Peripheral usage and associated software==
===Boot time===
The '''USBH''' peripheral is usually not used at boot time. But it may be used by the SSBL (see [[Boot chain overview]]), for example to boot a kernel stored on a USB key (mass storage).

===Runtime===
====Overview====
The '''USBH''' peripheral can be allocated to the Arm<sup>&reg;</sup> Cortex<sup>&reg;</sup>-A7 non-secure core to be used under Linux<sup>&reg;</sup> with [[USB overview|USB framework]].

====Software frameworks====
{{:Internal_peripherals_software_table_template}}
 | High speed interface
 | [[USBH internal peripheral|USBH (USB Host)]]
 | 
 | [[USB overview | Linux USB framework]]
 | 
 |
 |-
 |}

====Peripheral configuration====
The configuration is applied by the firmware running in the context to which the peripheral is assigned. The configuration by itself can be performed via the [[STM32CubeMX]] tool for all internal peripherals. It can then be manually completed (especially for external peripherals) according to the information given in the corresponding software framework article.

For Linux kernel configuration, please refer to [[USBH device tree configuration|USBH device tree configuration]].

====Peripheral assignment====
{{:Internal_peripherals_assignment_table_template}}
<onlyinclude>
 | rowspan="1" | High speed interface
 | rowspan="1" | [[USBH internal peripheral|USBH (USB Host)]]
 | USBH (USB Host)
 | 
 | <span title="assignable peripheral" style="font-size:21px">☐</span>
 |
 |
 |-
</onlyinclude>
 |}

==References==
<references/>