How To Write AWindows CE SDIO Client Driver
饶大春技术专家微软中国技术中心微软(中国)有限公司
Overview
• CE SDIO Stack Features• How to write a client driver• Bluetooth code walkthrough
SDA and MMCA
• SD and MultiMediaCard Associations• SPI mode vs. SD/MMC mode• 9 pins vs. 7 pins• 4 bits vs. 1 bits• Command different• MMC,SD Memory card and IO card• RS-MMC,miniSD and TransFlash
SD(IO) Support In CE 5.0• Dynamic insert/remove
• DMA (optional in standard host spec, platform dependent)
• SDIO interrupts
• Dynamic clock control
• Error recovery
• Soft-block support
• Wake-up
• Power will be handled using CE Power Manager– Clients may be power-managed and tell the controller to put its slot into a different power
state
• Multi-function and Combo devices
• Also support MMC v3.0 basic functionality
• In the next Windows Mobile release we’re adding:– Support MMC v4.0 basic functionality
– Performance enhancements for single block cards
The Secure In SD• SDA SD Memory specification provides a mechani
sm to lock content to a specific machine
• We are not providing a block driver supporting it in 5.0 release explicitly. SDBus does allow you to build your own though
• Digital Rights Management (DRM) for all of CE is being supplied by a filesystem filter driver at a level above the SD Memory block driver
SD GPSCard
SD Host Controller
HostHost SoftwareSoftware
StackStack
HardwareHardware
ClientClientDriversDrivers
SD HostDriver
FatFS Location Services
SDBus Driver
SDIO GPSClient Driver
SD Memory(block driver)
SD MemoryCard
SD Bus Driver• Enumerates cards to determine if MMC,
SD Memory or SDIO• Determines voltage to use for card• Loads clients based on registry values• Queues bus requests• Queues asynchronous notifications from host controll
er– Bus request completion, SDIO interrupts,
device insertion/removal
• Performs error handling with retry
Standard Host Controller• SDA Host Working Group
Defined Standard Host Register Specification to standardize hardware interface from bus to controller
• Currently ratified to v1.0 by SDA executive committee
• MSFT strongly advocating this standard to all IHVs, ODMs, OEMs and Silicons
• Also support for PXa270, OMAP730, SMDK2410
Compatibility With SDIO Now!
• BSquare has an install base• PPCs on the market today• Target was to maintain client driver compatibil
ity to ensure smooth transition of marketplace• Have verified we’re compatible using SDIO N
ow!
Windows CE Provided Clients
• SD Memory (MMC support verified)• SDIO Bluetooth Type A class• SDIO GPS class• SDIO WiFi
How To Write A Client Driver
• Client Driver model• Registry loads driver• Checklist of functions
Client Driver Model
• Streams interface for API• Init, Deinit are the only ones strictly required• Suggested use of Open, Close, Read, Write, I
OControl, PowerUp/Down as appropriate
Registry EntriesCustom Driver:[HKEY_LOCAL_MACHINE\Drivers \SDCARD\ClientDrivers\Custom \MANF-02DB-CARDID-0002-FUNC-1]
"Dll"=“mydriver.dll""Prefix"=“XXX“
Class Driver:[HKEY_LOCAL_MACHINE\Drivers \SDCARD\ClientDrivers\Class\SDIO_Class\3] "Dll"=“bthsdio.dll" "Prefix"=“BSD“SD Memory and MMC have special class keys as well
Checklist• Get SDA specs and card manufacturer specs.
Use Bluetooth driver as an example• XXX_Init()• Get the unique identification handle
for the client– SDGetDeviceHandle
Checklist
• Create a function to receive asynchronous slot state change notifications
• Register the client driver with the SD Bus driver
• [SDIO] Enable the SDIO function• [SDIO] Determine which function on the card t
he driver is associated with
Slot Events
• Recommended • SlotEventCallBack()• Provides Asynchronous info about changes in
slot state – Example: SDCardEjected
SDRegisterClient
• Fill in structure with the local device context, slot event callback, and a friendly name
• Friendly name used for debug output• After successful registration, all other SD Bus
APIs may be called
SDSetCardFeature
• Configures the card– SD_IO_FUNCTION_ENABLE– SD_IO_FUNCTION_DISABLE– SD_IO_FUNCTION_SET_BLOCK_SIZE– SD_SET_CARD_INTERFACE
• Sets both the bus width and the bus clock frequency
SDCardInfoQuery• Provides information about card and host contr
oller– Function number– Host controller maximum block size– Current bus clock and width– Address of function’s SDIO CIS region– Parsed card register structures
• CSD• CID• DSR• RCA• SCR
Code Sample – Initialization
• public\common\oak\drivers\sdcard\sdclientdrivers\bluetooth\bthsdio.cpp
• CSdioDevice::Attach()
• BOOL CSdioDevice::Attach(DWORD dwContext)• {
……m_hDevice = SDGetDeviceHandle(dwContext, &m_pRegPath);
• if (NULL == m_hDevice) {• goto exit;• }• wcscpy(clientInfo.ClientName, TEXT("Bluetooth Card"));
• if (! SD_API_SUCCESS(SDRegisterClient(m_hDevice, this, &clientInfo))) {
• goto exit;• }
• if (! SD_API_SUCCESS(SDIOConnectInterrupt(m_hDevice, SDIOIsrCallBack))) {
• goto exit;• }
• functionEnable.Interval = DEFAULT_SDIO_FUNCTION_RETRY_TIMEOUT;
• functionEnable.ReadyRetryCount = DEFAULT_SDIO_FUNCTION_RETRIES;
• if (! SD_API_SUCCESS(SDSetCardFeature(m_hDevice, SD_IO_FUNCTION_ENABLE, &functionEnable, sizeof(functionEnable)))) {
• ASSERT(0);• fRetVal = FALSE;• goto exit;• }
• if (! SD_API_SUCCESS(SDCardInfoQuery(m_hDevice, SD_INFO_SDIO, &sdioInfo, sizeof(sdioInfo)))) {
• ASSERT(0);• fRetVal = FALSE;• goto exit;• }• Exit:• ……• }
Checklist
• Retrieve the host controller’s max block size– Use SDCardInfoQuery
• [SDIO] Retrieve the function’s max block size from the card tuples– Use the smaller maximum block size
• [SDIO] Set the block size on the card– Use SDSetCardFeature
SDGetTuple
• Simplifies reading tuples from the CIS• Information residing in tuples:
– Maximum block size– Power draw– Manufacturer code
Code SampleMaximum Block Size
• CSdioDevice::GetMaxBlockLen()
• BOOL CSdioDevice::GetMaxBlockLen(void)• {• ……• if (! SD_API_SUCCESS(SDGetTuple(m_hDevice, SD_CISTP
L_FUNCE, NULL, &ulLength, FALSE)) ||• (ulLength > sizeof(rgucTuple)) ) {• ASSERT(0);• fRetVal = FALSE;• goto exit;• }
• if (! SD_API_SUCCESS(SDGetTuple(m_hDevice, SD_CISTPL_FUNCE, rgucTuple, &ulLength, FALSE)) ||
• (pFunce->bType != SD_CISTPL_FUNCE_FUNCTION_TYPE) ) {
• ASSERT(0);• fRetVal = FALSE;• goto exit;• }
• usCardBlockLen = pFunce->wMaxBlkSize;
• ……• if (! SD_API_SUCCESS(SDCardInfoQuery(m_hDe
vice, SD_INFO_HOST_BLOCK_CAPABILITY, &blockCapability, sizeof(blockCapability)))) {
• goto exit;• }• m_usBlockLen = (usHostBlockLen < usCardBlockL
en) ? usHostBlockLen : usCardBlockLen;• ……• }
Checklist• [SDIO] Determine if the card supports multi-blo
ck transfers– Read from CCCR
• [SDIO] Create and register a function to receive interrupt notifications
• Transfer data via Bus Requests…
SDIO Interrupts
• Card notifies driver of Asynchronous events via SDIO interrupts
• SDIOConnectInterrupt() to register for a callback
• Client must clear the interrupt before exiting callback
• Return SD_API_STATUS_SUCCESS
Code Sample – Interrupts
• CSdioDevice::SDIOIsrCallBack()• CSdioDevice::SDIOIsrCallback_Int()
• SD_API_STATUS CSdioDevice::SDIOIsrCallback_Int(void)• {• ……• status = SDGetRegister(REG_INTRD, m_ucFunction, &ucRe
gValue, 1);• if (!SD_API_SUCCESS(status)) {
……• }• if (ucRegValue) {• SetEvent(m_hReadPacketEvent);
• // Clear INTRD register• ucRegValue = 0x01;• status = SDSetRegister(REG_INTRD, m_ucFunction, &uc
RegValue, 1);• ……• }• }• ……• }
Touching Card Registers• SDReadWriteRegistersDirect() – for multiple single-b
yte transfers• Single-byte transfers are slow so try
to avoid them• Used for doing things like:
– Determining if the card is multi-block capable (CCCR)
– Clearing and enabling card specific interrupt settings
– Setting card specific modes
– Read if data is available
Read/Write – Bus Requests• Client driver interacts with the card via the Bus driver
using Bus Requests. These requests pass the SD CMD to the card
• Sync – must wait for response before issuing subsequent commands
SDSynchronousBusRequest()• Async – subsequent commands are queued by Bus d
river. You must free the bus request after completionSDBusRequest()
• Second parameter of both is the SD CommandSDCancelBusRequest()
Sync Versus Async• Async helps the most when sending many sm
all blocks (Not multi-block)• Async will always be at least as fast or faster t
hen Sync– If you submit a bunch of async requests, they’ll be queued by
the bus driver, good because bus driver optimizes bus activity
• Sync is easier to program, less logic in client
Issuing An SDIO Command• CMDs are listed in the SDA specifications• You should build the arguments
via Macros• Two macros that build the complex command sta
tements for you:– BUILD_IO_RW_DIRECT_ARG()– BUILD_IO_RW_EXTENDED_ARG()
• Call SDSynchronousBusRequest() or SDBusRequest() with the command argument
Code Sample – Transfers
• CSdioDevice::SDSend()– Synchronous
• CSdioDevice::SDRecv()– Asynchronous
Tools & Resources
msdn.microsoft.com/msdn.microsoft.com/ embeddedembedded
microsoft.public.microsoft.public. windowsxp.embeddedwindowsxp.embedded windowsce.platbuilderwindowsce.platbuilder windowsce.embedded.vcwindowsce.embedded.vc
blogs.msdn.com/blogs.msdn.com/ mikehallmikehall
Windows CE 5.0 Eval KitWindows CE 5.0 Eval KitWindows XP Embedded Eval KitWindows XP Embedded Eval Kit
msdn.microsoft.com/msdn.microsoft.com/ mobilitymobility
microsoft.public.microsoft.public. pocketpc.developer pocketpc.developer smartphone.developer smartphone.developer dotnet.framework.compactframeworkdotnet.framework.compactframework
blogs.msdn.com/blogs.msdn.com/ windowsmobilewindowsmobile vsdteamvsdteam netcfteamnetcfteam
Windows Mobile 5.0 Eval KitWindows Mobile 5.0 Eval Kit
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