Хост-контроллер USB2.0: список регистров

  Unused

  EECP

EHCI Extended Capabilities Pointer
This optional field indicates the existence of a capabilities list.
A value of 00b indicates no extended capabilities are implemented.
A non-zero value in this register indicates the offset in PCI configuration space of the first EHCI extended capabiliby.
The pointer value must be 40h or greater if implemented to maintain to consistency of the PCI header defined for this calss of device.
The value of this field is always '00b'.

  ISO_SCHED_THRESHOLD

Isochronous Scheduling Threshold
This field indicates, relative to the current position of the executing host
controller, where software can reliably update the isochronous schedule.
When bit[7] is zero, the value of the least significant 3 bits indicates the
number of micro-frames a host controller can hold a set of isochronous data
structures(one or more) before flushing the state. When bit[7] is a one, then
host software assumes the host controller may cache an isochronous data
structure for an entire frame.

  RESERV

  ASYNCH_SCHED_PARK_CAP

Asynchronous Schedule Park Capability
If this bit is set to a one, then the host controller supports the park feature
for high-speed queue heads in the Asynchronous Schedule.
The feature can be disabled or enabled and set to a specific level by using the Asynchronous
Schedule Park Mode Enable and Asynchronous Schedule Park Mode Count fields in the USBCMD register.

  PROGR_FRAME_LIST_FLG

Programmable Frame List Flag
If this bit is set to a zero, then system software must use a frame list length of 1024 elements with this host controller.
The USBCMD register Frame List Size field is a read-only register and should be set to zero.
If set to 1, then system software can specify and use the frame list in the USBCMD register Frame List Size field to cofigure the host controller.
The frame list must always aligned on a 4K page boundary.
This requirement ensures that the frame list is always physically contiguous.

  Unused

Команда U-Boot для чтения регистра

Bit fields structure

typedef union  e_hccparams
{
  struct
  {
   unsigned unused0 : 1;
   unsigned progr_frame_list_flg : 1;
   unsigned asynch_sched_park_cap : 1;
   unsigned reserv : 1;
   unsigned iso_sched_threshold : 4;
   unsigned eecp : 8;
   unsigned unused1 : 16;
  } b;
   unsigned long w;
} E_HCCPARAMS