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[efi] Add a USB host controller driver based on EFI_USB_IO_PROTOCOL

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Allow iPXE to coexist with other USB device drivers, by attaching to
the EFI_USB_IO_PROTOCOL instances provided by the UEFI platform
firmware.

The EFI_USB_IO_PROTOCOL is an unsurprisingly badly designed
abstraction of a USB device.  The poor design choices intrinsic in the
UEFI specification prevent efficient operation as a network device,
with the result that devices operated using the EFI_USB_IO_PROTOCOL
operate approximately two orders of magnitude slower than devices
operated using our native EHCI or xHCI host controller drivers.

Since the performance is so abysmally slow, and since the underlying
problems are due to fundamental architectural mistakes in the UEFI
specification, support for the EFI_USB_IO_PROTOCOL host controller
driver is left as disabled by default.  Users are advised to use the
native iPXE host controller drivers instead.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2015-09-04 02:26:01 +01:00
parent 5cea7bdb2a
commit 15a8800a98
6 changed files with 1884 additions and 1 deletions
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3
src/config/config_usb.c
View File

@@ -43,6 +43,9 @@ REQUIRE_OBJECT ( ehci );
#ifdef USB_HCD_UHCI
REQUIRE_OBJECT ( uhci );
#endif
#ifdef USB_HCD_USBIO
REQUIRE_OBJECT ( usbio );
#endif
/*
* Drag in USB peripherals

1
src/config/usb.h
View File

@@ -18,6 +18,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
//#undef USB_HCD_XHCI /* xHCI USB host controller */
//#undef USB_HCD_EHCI /* EHCI USB host controller */
//#undef USB_HCD_UHCI /* UHCI USB host controller */
//#define USB_HCD_USBIO /* Very slow EFI USB host controller */
/*
* USB peripherals