HDLC WINCE6驱动设计

1、 WINCE的网络驱动结构

1.1  WINCE 网络结构

1）WINCE 的NDIS网络接口提供如下能力：

• miniport 网卡驱动接口
• 支持802.3（MAC），802.5(RING)，IRDA
• 支持广域网
• 动态绑定网卡和Plug and Play
• 支持同一个协议绑定多个网卡
• 支持网卡的MediaSense

2）WINCE的网络结构图

从该通信结构中可以看到，所有的通信协议都使用NDIS WRAPPER 作为中介和下层的硬件绑定，实现各种不同的通信。

3）NDIS Wrapper的结构

The operating system providesprotocol drivers for TCP/IP, Point-to-Point Protocol (PPP), and Infrared DataAssociation (IrDA). A protocol driver exports a set of
ProtocolXXXfunctions at its lower edge. It communicates with NDIS to send and receivenetwork packets and to bind to an underlying miniport network adapter driver orintermediate NDIS driver that exports a
MiniportXXX interface atits upper edge.

Protocol drivers that communicate with underlying NDISdrivers call NDIS library functions to send and receive packets. To send apacket to an underlying NDIS driver, a protocol driver must call the
NdisSendor NdisSendPacketsfunction. A protocol driver must call the
NdisRequestfunction to forward a request to the underlying driver that it queries for thecapabilities or status of its network adapter or that it set the state of itsnetwork adapter.

An NDIS protocol driver can support Transport DriverInterface (TDI) at its upper edge, or it could export a private interface to ahigher-level kernel-mode driver, possibly through a transport stack of drivers,including one that supports TDI at the top of
the stack. For example, an NDISprotocol driver can be the lowest module of a multi-module transportimplementation of a standard protocol, such as TCP/IP, with TDI support in thehighest module.

1.2   WINCE 中断结构

典型的中断流程如下：

The following list shows an example interrupt handling sequence:

1. If the kernel‘s exception-trapping code receives a hardware interrupt and then the kernel detects an exception, the kernel handles the hardware interrupt. Otherwise, go to the next step.
2. The kernel‘s interrupt support handler notifies the ISR to disable the specific interrupt until the required handling completes. All other interrupts remain enabled.
3. The exception handler calls the ISR to determine how to handle the interrupt.

Note   Detailsmay vary depending on the CPU architecture.

1. The kernel receives the return value from the ISR, which lets the kernel know what to do about the interrupt. The following table shows the possible responses from the kernel.

1. When the IST wakes up, the IST does whatever work it needs to do to handle the interrupt. This could mean moving data into a buffer or interpreting the data in some meaningful way.
2. As needed, the IST calls various I/O routines to access the hardware to do its work.
3. When the IST finishes its work, it notifies the kernel by calling InterruptDone.

Thekernel calls the OAL function OEMInterruptDone to complete all handling for theinterrupt. The OAL notifies the hardware to re-enable the interrupt.

1.1  MINIPORT接口介绍

1） MINIPORT 定义

Miniportdrivers directly manage network adapters that are installed on a device. At thelower edge, miniport drivers use NDIS to communicate with the adapter hardware.At the upper edge, miniport drivers present an interface to allow protocoldrivers to configure
the adapter and to send and receive packets over thenetwork.

Windows CE currently supports miniport drivers for thefollowing medium types:

• Ethernet (802.3)
• Token Ring (802.5)
• IrDA
• WAN

2） MINIPORT的主要工作

Typically, an NDIS miniport driver is a miniport NICdriver. An NDIS miniport driver the following two basic functions:

• Manages a network interface card (NIC), including sending and receiving data through the NIC
• Interfaces with higher-level drivers, such as intermediate drivers and transport protocol drivers

The following send and receive operations illustrate the interaction ofminiport NIC drivers with NDIS and with higher-level drivers:

• When a transport driver has a packet to transmit, it calls an NdisXXX
  function exported by the NDIS library. NDIS then passes the packet to the miniport by calling the appropriate
  MiniportXXX function exported by the miniport. The miniport driver then forwards the packet to the NIC for transmission by calling the appropriate
  NdisXXX function.
• When a NIC receives a packet addressed to the NIC, it can post a hardware interrupt that is handled by NDIS or the NIC‘s miniport. NDIS notifies the NIC‘s miniport by calling the appropriate
  MiniportXXX function. The miniport sets up the transfer of data from the NIC and then indicates the presence of the received packet to bound higher-level drivers by calling the appropriate
  NdisXXX function.

3） Miniport驱动的加载

All NDIS miniport and intermediate drivers must provide a DriverEntry function. When a miniport driver isloaded, the operating system creates a driver object for the miniport driverand calls the
DriverEntry function, which creates an association betweenthe miniport driver and the NDIS library and registers the miniport with NDIS.

The following parameters are passed to the DriverEntry function:

• A pointer to the driver object, which was created by the I/O system
• A pointer to the registry path, which specifies where driver-specific parameters are stored

Within the context of DriverEntry, the miniport calls the
NdisMInitializeWrapper function, and then the
NdisMRegisterMiniport function.
DriverEntryfirst calls NdisMInitializeWrapper with the parameters that are passedto
DriverEntry, which returns a wrapper handle. DriverEntry thenpasses the handle to
NdisMRegisterMiniport.

The following illustration shows the process for registering a miniportdriver and initializing the NDIS library.

1） Miniport需要实现的函数