Step 5: Loading Drivers on the PCI Bus (Windows CE 5.0)
In this step of the driver loading process example, the PCI bus driver loads the DLL indicated by Drivers\PCI\Instance\Dll so that it can load the device drivers. This DLL is typically BusEnum.dll, the bus enumerator. BusEnum.dll examines the Instance subkeys of the Drivers\PCI key to determine which drivers to load based on their Order. If no Order is specified, the associated driver loads last. In this example, no Order is specified for any of the drivers, so the load order is arbitrary. If the serial driver is loaded first, the PCI bus driver finds the Drivers\PCI\Instance\Serial1 key and loads the corresponding DLL, if it is not loaded already. Then, it calls its default entry point, COM_Init, with the key Drivers\PCI\Instance\Serial1. Then, the driver reads its configuration information from the registry. The same driver is used for 16550 serial controllers on the built-in, ISA, and PCI buses. Because the registry key passed to the COM_Init function has all of the information the driver needs to run, it does not matter whether the registry has been populated by the OEM, the user, or by a bus enumerator such as the PCI bus driver.
For the first NE2000 driver instance, the PCI bus driver first loads NDIS.dll, if necessary, and then calls the default entry point NDIS_Init with Drivers\PCI\Instance\NE20001 passed in as a parameter. NDIS examines the registry and, because it recognizes that the MiniPort value is present, it loads NE2000.dll, if necessary. It then calls its default entry point, as defined by the NDIS driver. The same procedure is used for the second NE2000 driver instance.
Registry Keys After Driver Loading
The following registry entry example shows the state of the registry after the PCI bus driver has loaded the drivers.
[HKEY_LOCAL_MACHINE\Drivers]
"RootKey"="Drivers"
"Dll"="BusEnum.dll"
[HKEY_LOCAL_MACHINE\Drivers\Debug]
"Dll"="BusEnum.dll"
"Order"=dword:0
"Flags"=dword:1
[HKEY_LOCAL_MACHINE\Drivers\Debug\KITL]
"Flags"=dword:4
"Irq"=dword:1
"MemBase"=dword:FFBFA000
"MemLen"=dword:1000
"SysIntr"=dword:11
[HKEY_LOCAL_MACHINE\Drivers\Virtual]
"Dll"="BusEnum.dll"
"Order"=dword:1
"Flags"=dword:1
[HKEY_LOCAL_MACHINE\Drivers\Virtual\NDIS]
"Dll"="NDIS.dll"
"Order"=dword:1
"Prefix"="NDS"
"Index"=dword:0
[HKEY_LOCAL_MACHINE\Drivers\CSP]
"Dll"="BusEnum.dll"
"Order"=dword:2
"Flags"=dword:1
[HKEY_LOCAL_MACHINE\Drivers\CSP\Serial]
"Dll"="Com16550.Dll"
"Order"=dword:0
"Irq"=dword:3
"MemBase"=dword:FFBFC000
"MemLen"=dword:8
"SysIntr"=dword:13
"Prefix"="COM"
"DeviceArrayIndex"=dword:0
"Priority"=dword:0
[HKEY_LOCAL_MACHINE\Drivers\CSP\Serial\Unimodem]
"Tsp"="Unimodem.dll"
"DeviceType"=dword:0
"FriendlyName"="Serial Cable on COM1:"
"DevConfig"=hex: 10,00, 00,00, 05,00,00,00, 10,01,00,00, 00,4B,00,00
[HKEY_LOCAL_MACHINE\Drivers\ISA]
"Dll"="BusEnum.dll"
"Order"=dword:3
"Flags"=dword:1
[HKEY_LOCAL_MACHINE\Drivers\ISA\Serial]
"Dll"="Com16550.Dll"
"Order"=dword:0
"Irq"=dword:4
"IoBase"=dword:02F8
"IoLen"=dword:8
"SysIntr"=dword:14
"Prefix"="COM"
"DeviceArrayIndex"=dword:1
[HKEY_LOCAL_MACHINE\Drivers\ISA\Serial\Unimodem]
"Tsp"="Unimodem.dll"
"DeviceType"=dword:0
"FriendlyName"="Serial Cable on COM2:"
"DevConfig"=hex: 10,00, 00,00, 05,00,00,00, 10,01,00,00, 00,4B,00,00
[HKEY_LOCAL_MACHINE\Drivers\ISA\PCMCIA]
"Dll"="PCMCIA.dll"
"Order"=dword:1
"Irq"=dword:B
"SysIntr"=dword:1B
"IoBase"=dword:03e0
"IoLen"=dword:2
[HKEY_LOCAL_MACHINE\Drivers\PCI]
"Dll"="PCIbus.dll"
"Order"=dword:4
"Flags"=dword:1
"MemBase"=dword:FFC00000
"MemLen"=dword:100000
"IoBase"=dword:D000
"IoLen"=dword:3000
[HKEY_LOCAL_MACHINE\Drivers\PCI\Template\Serial]
"Dll"="Com16550.Dll"
"Class"=dword:07
"SubClass"=dword:00
"ProgIF"=dword:02
"VendorID"=multi_sz:"0AF0","B320","B320"
"DeviceID"=multi_sz:"0020","0300","0302"
"Prefix"="COM"
[HKEY_LOCAL_MACHINE\Drivers\PCI\Template\Serial\Unimodem]
"Tsp"="Unimodem.dll"
"DeviceType"=dword:0
"FriendlyName"="Serial Cable on PCI"
"DevConfig"=hex: 10,00, 00,00, 05,00,00,00, 10,01,00,00, 00,4B,00,00
[HKEY_LOCAL_MACHINE\Drivers\PCI\Instance\Serial1\Unimodem]
"FriendlyName"="Serial Cable on COM3:"
[HKEY_LOCAL_MACHINE\Drivers\PCI\Template\NE2000]
"Dll"="NDIS.dll"
"ConfigDll"="NE2000cfg.dll"
"ConfigEntry"="DeviceConfig"
"Class"=dword:02
"SubClass"=dword:00
"ProgIF"=dword:00
"MiniPort"="NE2000"
[HKEY_LOCAL_MACHINE\Drivers\PCI\Instance\Serial1]
"InstanceIndex"=dword:1
"Dll"="Com16550.Dll"
"Prefix"="COM"
"Priority"=dword:0
"Class"=dword:7
"SubClass"=dword:0
"ProgIF"=dword:2
"VendorID"=dword:B320
"DeviceID"=dword:300
"RevisionID"=dword:0
"SubVendorID"=dword:B330
"SubSystemID"=dword:300
"InterfaceType"=dword:5
"BusNumber"=dword:0
"DeviceNumber"=dword:2
"FunctionNumber"=dword:0
"IoBase"=dword:D2F8
"IoLen"=dword:8
"Irq"=dword:9
"SysIntr"=dword:19
[HKEY_LOCAL_MACHINE\Drivers\PCI\Instance\Serial1\Unimodem]
"Tsp"="Unimodem.dll"
"DeviceType"=dword:0
"FriendlyName"="Serial Cable on COM3:"
"DevConfig"=hex: 10,00, 00,00, 05,00,00,00, 10,01,00,00, 00,4B,00,00
[HKEY_LOCAL_MACHINE\Drivers\PCI\Instance\NE20001]
"InstanceIndex"=dword:1
"Dll"="NDIS.dll"
"ConfigDll"="NE2000cfg.dll"
"ConfigEntry"="DeviceConfig"
"Prefix"="COM"
"MiniPort"="NE2000"
"Class"=dword:2
"SubClass"=dword:0
"ProgIF"=dword:0
"VendorID"=dword:10EC
"DeviceID"=dword:8029
"RevisionID"=dword:0
"SubVendorID"=dword:10EC
"SubSystemID"=dword:8029
"InterfaceType"=dword:5
"BusNumber"=dword:2
"DeviceNumber"=dword:1
"FunctionNumber"=dword:0
"IoBase"=dword:D100
"IoLen"=dword:10
"Irq"=dword:A
"SysIntr"=dword:1A
[HKEY_LOCAL_MACHINE\Drivers\PCI\Instance\NE20002]
"InstanceIndex"=dword:2
"Dll"="NDIS.dll"
"ConfigDll"="NE2000cfg.dll"
"ConfigEntry"="DeviceConfig"
"Prefix"="COM"
"MiniPort"="NE2000"
"Class"=dword:2
"SubClass"=dword:0
"ProgIF"=dword:0
"VendorID"=dword:10EC
"DeviceID"=dword:8029
"RevisionID"=dword:0
"SubVendorID"=dword:10EC
"SubSystemID"=dword:8029
"InterfaceType"=dword:5
"BusNumber"=dword:3
"DeviceNumber"=dword:1
"FunctionNumber"=dword:0
"IoBase"=dword:D200
"IoLen"=dword:10
"Irq"=dword:C
"SysIntr"=dword:1C
; NE2000 common and instance specific information
[HKEY_LOCAL_MACHINE\Comm\NE2000]
"DisplayName"="NE2000 Compatible Ethernet Driver"
"Group"="NDIS"
"ImagePath"="NE2000.dll"
[HKEY_LOCAL_MACHINE\Comm\NE20001]
"DisplayName"="NE2000 Compatible Ethernet Driver 1"
[HKEY_LOCAL_MACHINE\Comm\NE20001\Parms]
"Transceiver"=dword:3
[HKEY_LOCAL_MACHINE\Comm\NE20001\Parms\TcpIp]
"EnableDHCP"=dword:1
"DefaultGateway"=""
"UseZeroBroadcast"=dword:0
"IpAddress"="0.0.0.0"
"Subnetmask"="0.0.0.0"
[HKEY_LOCAL_MACHINE\Comm\NE20002]
"DisplayName"="NE2000 Compatible Ethernet Driver 2"
[HKEY_LOCAL_MACHINE\Comm\NE20002\Parms]
"Transceiver"=dword:2
[HKEY_LOCAL_MACHINE\Comm\NE20002\Parms\TcpIp]
"EnableDHCP"=dword:0
"DefaultGateway"=""
"UseZeroBroadcast"=dword:0
"IpAddress"="157.56.148.128"
"Subnetmask"="255.255.252.0"
See Also
Example: Loading Drivers on the PCI Bus
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