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      1 /** @file
      2 Implementation for SMBus DXE driver entry point and SMBus Host
      3 Controller protocol.
      4 
      5 Copyright (c) 2013-2015 Intel Corporation.
      6 
      7 This program and the accompanying materials
      8 are licensed and made available under the terms and conditions of the BSD License
      9 which accompanies this distribution.  The full text of the license may be found at
     10 http://opensource.org/licenses/bsd-license.php
     11 
     12 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
     13 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
     14 
     15 **/
     16 #include "CommonHeader.h"
     17 
     18 #include "DxeQNCSmbus.h"
     19 
     20 //
     21 // Interface defintion of SMBUS Host Controller Protocol.
     22 //
     23 EFI_SMBUS_HC_PROTOCOL mSmbusHc = {
     24   SmbusExecute,
     25   SmbusArpDevice,
     26   SmbusGetArpMap,
     27   SmbusNotify
     28 };
     29 
     30 //
     31 // Handle to install SMBus Host Controller protocol.
     32 //
     33 EFI_HANDLE                   mSmbusHcHandle = NULL;
     34 UINT8                        mDeviceMapEntries = 0;
     35 EFI_SMBUS_DEVICE_MAP         mDeviceMap[MAX_SMBUS_DEVICES];
     36 UINT8                        mPlatformNumRsvd = 0;
     37 UINT8                        *mPlatformAddrRsvd = NULL;
     38 
     39 //
     40 // These addresses are reserved by the SMBus 2.0 specification
     41 //
     42 UINT8    mReservedAddress[SMBUS_NUM_RESERVED] = {
     43   0x00, 0x02, 0x04, 0x06, 0x08, 0x0A, 0x0C, 0x0E, 0x10, 0x18, 0x50, 0x6E, 0xC2,
     44   0xF0, 0xF2, 0xF4, 0xF6, 0xF8, 0xFA, 0xFC, 0xFE
     45 };
     46 
     47 
     48 /**
     49   Gets Io port base address of Smbus Host Controller.
     50 
     51   This internal function depends on a feature flag named PcdIchSmbusFixedIoPortBaseAddress
     52   to retrieve Smbus Io port base. If that feature flag is true, it will get Smbus Io port base
     53   address from a preset Pcd entry named PcdIchSmbusIoPortBaseAddress; otherwise, it will always
     54   read Pci configuration space to get that value in each Smbus bus transaction.
     55 
     56   @return The Io port base address of Smbus host controller.
     57 
     58 **/
     59 UINTN
     60 GetSmbusIoPortBaseAddress (
     61   VOID
     62   )
     63 {
     64   UINTN     IoPortBaseAddress;
     65 
     66   if (FeaturePcdGet (PcdSmbaIoBaseAddressFixed)) {
     67     IoPortBaseAddress = (UINTN) PcdGet16 (PcdSmbaIoBaseAddress);
     68   } else {
     69     IoPortBaseAddress = (UINTN) LpcPciCfg32 (R_QNC_LPC_SMBUS_BASE) & B_QNC_LPC_SMBUS_BASE_MASK;
     70   }
     71 
     72   //
     73   // Make sure that the IO port base address has been properly set.
     74   //
     75   ASSERT (IoPortBaseAddress != 0);
     76 
     77   return IoPortBaseAddress;
     78 }
     79 
     80 
     81 VOID
     82 InitializeInternal (
     83   )
     84 {
     85   UINTN     IoPortBaseAddress;
     86 
     87   IoPortBaseAddress = GetSmbusIoPortBaseAddress ();
     88 
     89   //
     90   // Step1: Enable QNC SMBUS I/O space.
     91   //
     92   LpcPciCfg32Or(R_QNC_LPC_SMBUS_BASE, B_QNC_LPC_SMBUS_BASE_EN);
     93 
     94   //
     95   // Step2: Clear Status Register before anyone uses the interfaces.
     96   //
     97   IoWrite8 (IoPortBaseAddress + R_QNC_SMBUS_HSTS, B_QNC_SMBUS_HSTS_ALL);
     98 
     99   //
    100   // Step3: Program the correct smbus clock
    101   //
    102   IoWrite8 (IoPortBaseAddress + R_QNC_SMBUS_HCLK, V_QNC_SMBUS_HCLK_100KHZ);
    103 }
    104 
    105 
    106 
    107 
    108 BOOLEAN
    109 IsAddressAvailable (
    110   IN      EFI_SMBUS_DEVICE_ADDRESS  SlaveAddress
    111   )
    112 {
    113   UINT8         Index;
    114 
    115   //
    116   // See if we have already assigned this address to a device
    117   //
    118   for (Index = 0; Index < mDeviceMapEntries; Index++) {
    119     if (SlaveAddress.SmbusDeviceAddress ==
    120          mDeviceMap[Index].SmbusDeviceAddress.SmbusDeviceAddress) {
    121       return FALSE;
    122     }
    123   }
    124 
    125   //
    126   // See if this address is claimed by a platform non-ARP-capable device
    127   //
    128   for (Index = 0; Index < mPlatformNumRsvd; Index++) {
    129     if ((SlaveAddress.SmbusDeviceAddress << 1) == mPlatformAddrRsvd[Index]) {
    130       return FALSE;
    131     }
    132   }
    133 
    134   //
    135   // See if this is a reserved address
    136   //
    137   for (Index = 0; Index < SMBUS_NUM_RESERVED; Index++) {
    138     if (SlaveAddress.SmbusDeviceAddress == (UINTN) mReservedAddress[Index]) {
    139       return FALSE;
    140     }
    141   }
    142 
    143   return TRUE;
    144 }
    145 
    146 
    147 EFI_STATUS
    148 GetNextAvailableAddress (
    149   IN EFI_SMBUS_DEVICE_ADDRESS  *SlaveAddress
    150   )
    151 {
    152   for (SlaveAddress->SmbusDeviceAddress = 0x03;
    153     SlaveAddress->SmbusDeviceAddress < 0x7F;
    154     SlaveAddress->SmbusDeviceAddress++
    155     ) {
    156     if (IsAddressAvailable (*SlaveAddress)) {
    157       return EFI_SUCCESS;
    158     }
    159   }
    160 
    161   return EFI_OUT_OF_RESOURCES;
    162 }
    163 
    164 EFI_STATUS
    165 SmbusPrepareToArp (
    166   )
    167 {
    168   EFI_SMBUS_DEVICE_ADDRESS  SlaveAddress;
    169   EFI_STATUS                Status;
    170   UINTN                     Length;
    171   UINT8                     Buffer;
    172 
    173   SlaveAddress.SmbusDeviceAddress = SMBUS_ADDRESS_ARP;
    174   Length = 1;
    175   Buffer = SMBUS_DATA_PREPARE_TO_ARP;
    176 
    177   Status = Execute (
    178              SlaveAddress,
    179              0,
    180              EfiSmbusSendByte,
    181              TRUE,
    182              &Length,
    183              &Buffer
    184              );
    185   return Status;
    186 }
    187 
    188 EFI_STATUS
    189 SmbusGetUdidGeneral (
    190   IN OUT  EFI_SMBUS_DEVICE_MAP  *DeviceMap
    191   )
    192 {
    193   EFI_SMBUS_DEVICE_ADDRESS      SlaveAddress;
    194   EFI_STATUS                    Status;
    195   UINTN                         Length;
    196   UINT8                         Buffer[SMBUS_GET_UDID_LENGTH];
    197 
    198   SlaveAddress.SmbusDeviceAddress = SMBUS_ADDRESS_ARP;
    199   Length = SMBUS_GET_UDID_LENGTH;
    200 
    201   Status = Execute (
    202              SlaveAddress,
    203              SMBUS_DATA_GET_UDID_GENERAL,
    204              EfiSmbusReadBlock,
    205              TRUE,
    206              &Length,
    207              Buffer
    208              );
    209 
    210   if (!EFI_ERROR(Status)) {
    211     if (Length == SMBUS_GET_UDID_LENGTH) {
    212       DeviceMap->SmbusDeviceUdid.DeviceCapabilities = Buffer[0];
    213       DeviceMap->SmbusDeviceUdid.VendorRevision = Buffer[1];
    214       DeviceMap->SmbusDeviceUdid.VendorId = (UINT16)((Buffer[2] << 8) + Buffer[3]);
    215       DeviceMap->SmbusDeviceUdid.DeviceId = (UINT16)((Buffer[4] << 8) + Buffer[5]);
    216       DeviceMap->SmbusDeviceUdid.Interface = (UINT16)((Buffer[6] << 8) + Buffer[7]);
    217       DeviceMap->SmbusDeviceUdid.SubsystemVendorId = (UINT16)((Buffer[8] << 8) + Buffer[9]);
    218       DeviceMap->SmbusDeviceUdid.SubsystemDeviceId = (UINT16)((Buffer[10] << 8) + Buffer[11]);
    219       DeviceMap->SmbusDeviceUdid.VendorSpecificId = (UINT32)((Buffer[12] << 24) + (Buffer[13] << 16) + (Buffer[14] << 8) + Buffer[15]);
    220       DeviceMap->SmbusDeviceAddress.SmbusDeviceAddress = (UINT8)(Buffer[16] >> 1);
    221     } else {
    222       Status = EFI_DEVICE_ERROR;
    223     }
    224   }
    225 
    226   return Status;
    227 }
    228 
    229 EFI_STATUS
    230 SmbusAssignAddress (
    231   IN OUT  EFI_SMBUS_DEVICE_MAP  *DeviceMap
    232   )
    233 {
    234   EFI_SMBUS_DEVICE_ADDRESS      SlaveAddress;
    235   EFI_STATUS                    Status;
    236   UINTN                         Length;
    237   UINT8                         Buffer[SMBUS_GET_UDID_LENGTH];
    238 
    239   Buffer[0] = DeviceMap->SmbusDeviceUdid.DeviceCapabilities;
    240   Buffer[1] = DeviceMap->SmbusDeviceUdid.VendorRevision;
    241   Buffer[2] = (UINT8)(DeviceMap->SmbusDeviceUdid.VendorId >> 8);
    242   Buffer[3] = (UINT8)(DeviceMap->SmbusDeviceUdid.VendorId);
    243   Buffer[4] = (UINT8)(DeviceMap->SmbusDeviceUdid.DeviceId >> 8);
    244   Buffer[5] = (UINT8)(DeviceMap->SmbusDeviceUdid.DeviceId);
    245   Buffer[6] = (UINT8)(DeviceMap->SmbusDeviceUdid.Interface >> 8);
    246   Buffer[7] = (UINT8)(DeviceMap->SmbusDeviceUdid.Interface);
    247   Buffer[8] = (UINT8)(DeviceMap->SmbusDeviceUdid.SubsystemVendorId >> 8);
    248   Buffer[9] = (UINT8)(DeviceMap->SmbusDeviceUdid.SubsystemVendorId);
    249   Buffer[10] = (UINT8)(DeviceMap->SmbusDeviceUdid.SubsystemDeviceId >> 8);
    250   Buffer[11] = (UINT8)(DeviceMap->SmbusDeviceUdid.SubsystemDeviceId);
    251   Buffer[12] = (UINT8)(DeviceMap->SmbusDeviceUdid.VendorSpecificId >> 24);
    252   Buffer[13] = (UINT8)(DeviceMap->SmbusDeviceUdid.VendorSpecificId >> 16);
    253   Buffer[14] = (UINT8)(DeviceMap->SmbusDeviceUdid.VendorSpecificId >> 8);
    254   Buffer[15] = (UINT8)(DeviceMap->SmbusDeviceUdid.VendorSpecificId);
    255   Buffer[16] = (UINT8)(DeviceMap->SmbusDeviceAddress.SmbusDeviceAddress << 1);
    256 
    257   SlaveAddress.SmbusDeviceAddress = SMBUS_ADDRESS_ARP;
    258   Length = SMBUS_GET_UDID_LENGTH;
    259 
    260   Status = Execute (
    261              SlaveAddress,
    262              SMBUS_DATA_ASSIGN_ADDRESS,
    263              EfiSmbusWriteBlock,
    264              TRUE,
    265              &Length,
    266              Buffer
    267              );
    268   return Status;
    269 }
    270 
    271 
    272 EFI_STATUS
    273 SmbusFullArp (
    274   )
    275 {
    276   EFI_STATUS              Status;
    277   EFI_SMBUS_DEVICE_MAP    *CurrentDeviceMap;
    278 
    279   Status = SmbusPrepareToArp ();
    280   if (EFI_ERROR(Status)) {
    281     if (Status == EFI_DEVICE_ERROR) {
    282       //
    283       //  ARP is complete
    284       //
    285       return EFI_SUCCESS;
    286     } else {
    287       return Status;
    288     }
    289   }
    290 
    291   //
    292   //  Main loop to ARP all ARP-capable devices
    293   //
    294   do {
    295     CurrentDeviceMap = &mDeviceMap[mDeviceMapEntries];
    296     Status = SmbusGetUdidGeneral (CurrentDeviceMap);
    297     if (EFI_ERROR(Status)) {
    298       break;
    299     }
    300 
    301     if (CurrentDeviceMap->SmbusDeviceAddress.SmbusDeviceAddress == (0xFF >> 1)) {
    302       //
    303       // If address is unassigned, assign it
    304       //
    305       Status = GetNextAvailableAddress (
    306                  &CurrentDeviceMap->SmbusDeviceAddress
    307                  );
    308       if (EFI_ERROR(Status)) {
    309         return EFI_OUT_OF_RESOURCES;
    310       }
    311     } else if (((CurrentDeviceMap->SmbusDeviceUdid.DeviceCapabilities) & 0xC0) != 0) {
    312       //
    313       // if address is not fixed, check if the current address is available
    314       //
    315       if (!IsAddressAvailable (
    316              CurrentDeviceMap->SmbusDeviceAddress
    317              )) {
    318         //
    319         // if currently assigned address is already used, get a new one
    320         //
    321         Status = GetNextAvailableAddress (
    322                    &CurrentDeviceMap->SmbusDeviceAddress
    323                    );
    324         if (EFI_ERROR(Status)) {
    325           return EFI_OUT_OF_RESOURCES;
    326         }
    327       }
    328     }
    329 
    330     Status = SmbusAssignAddress (CurrentDeviceMap);
    331     if (EFI_ERROR(Status)) {
    332       //
    333       // If there was a device error, just continue on and try again.
    334       // Other errors should be reported.
    335       //
    336       if (Status != EFI_DEVICE_ERROR) {
    337         return Status;
    338       }
    339     } else {
    340       //
    341       // If there was no error, the address was assigned and we must update our
    342       // records.
    343       //
    344       mDeviceMapEntries++;
    345     }
    346 
    347   } while (mDeviceMapEntries < MAX_SMBUS_DEVICES);
    348 
    349   return EFI_SUCCESS;
    350 }
    351 
    352 
    353 EFI_STATUS
    354 SmbusDirectedArp (
    355   IN      EFI_SMBUS_UDID            *SmbusUdid,
    356   IN OUT  EFI_SMBUS_DEVICE_ADDRESS  *SlaveAddress
    357   )
    358 {
    359   EFI_STATUS                        Status;
    360   EFI_SMBUS_DEVICE_MAP              *CurrentDeviceMap;
    361 
    362   if (mDeviceMapEntries >= MAX_SMBUS_DEVICES) {
    363     return EFI_OUT_OF_RESOURCES;
    364   }
    365 
    366   CurrentDeviceMap = &mDeviceMap[mDeviceMapEntries];
    367 
    368   //
    369   // Find an available address to assign
    370   //
    371   Status = GetNextAvailableAddress (
    372              &CurrentDeviceMap->SmbusDeviceAddress
    373              );
    374   if (EFI_ERROR(Status)) {
    375     return EFI_OUT_OF_RESOURCES;
    376   }
    377 
    378   CurrentDeviceMap->SmbusDeviceUdid.DeviceCapabilities  = SmbusUdid->DeviceCapabilities;
    379   CurrentDeviceMap->SmbusDeviceUdid.DeviceId            = SmbusUdid->DeviceId;
    380   CurrentDeviceMap->SmbusDeviceUdid.Interface           = SmbusUdid->Interface;
    381   CurrentDeviceMap->SmbusDeviceUdid.SubsystemDeviceId   = SmbusUdid->SubsystemDeviceId;
    382   CurrentDeviceMap->SmbusDeviceUdid.SubsystemVendorId   = SmbusUdid->SubsystemVendorId;
    383   CurrentDeviceMap->SmbusDeviceUdid.VendorId            = SmbusUdid->VendorId;
    384   CurrentDeviceMap->SmbusDeviceUdid.VendorRevision      = SmbusUdid->VendorRevision;
    385   CurrentDeviceMap->SmbusDeviceUdid.VendorSpecificId    = SmbusUdid->VendorSpecificId;
    386 
    387   Status = SmbusAssignAddress (CurrentDeviceMap);
    388   if (EFI_ERROR(Status)) {
    389     return Status;
    390   }
    391 
    392   mDeviceMapEntries++;
    393   SlaveAddress->SmbusDeviceAddress = CurrentDeviceMap->SmbusDeviceAddress.SmbusDeviceAddress;
    394 
    395   return EFI_SUCCESS;
    396 }
    397 
    398 
    399 
    400 /**
    401   Executes an SMBus operation to an SMBus controller. Returns when either the command has been
    402   executed or an error is encountered in doing the operation.
    403 
    404   The Execute() function provides a standard way to execute an operation as defined in the System
    405   Management Bus (SMBus) Specification. The resulting transaction will be either that the SMBus
    406   slave devices accept this transaction or that this function returns with error.
    407 
    408   @param  This                    A pointer to the EFI_SMBUS_HC_PROTOCOL instance.
    409   @param  SlaveAddress            The SMBus slave address of the device with which to communicate.
    410   @param  Command                 This command is transmitted by the SMBus host controller to the
    411                                   SMBus slave device and the interpretation is SMBus slave device
    412                                   specific. It can mean the offset to a list of functions inside an
    413                                   SMBus slave device. Not all operations or slave devices support
    414                                   this command's registers.
    415   @param  Operation               Signifies which particular SMBus hardware protocol instance that
    416                                   it will use to execute the SMBus transactions. This SMBus
    417                                   hardware protocol is defined by the SMBus Specification and is
    418                                   not related to EFI.
    419   @param  PecCheck                Defines if Packet Error Code (PEC) checking is required for this
    420                                   operation.
    421   @param  Length                  Signifies the number of bytes that this operation will do. The
    422                                   maximum number of bytes can be revision specific and operation
    423                                   specific. This field will contain the actual number of bytes that
    424                                   are executed for this operation. Not all operations require this
    425                                   argument.
    426   @param  Buffer                  Contains the value of data to execute to the SMBus slave device.
    427                                   Not all operations require this argument. The length of this
    428                                   buffer is identified by Length.
    429 
    430   @retval EFI_SUCCESS             The last data that was returned from the access matched the poll
    431                                   exit criteria.
    432   @retval EFI_CRC_ERROR           Checksum is not correct (PEC is incorrect).
    433   @retval EFI_TIMEOUT             Timeout expired before the operation was completed. Timeout is
    434                                   determined by the SMBus host controller device.
    435   @retval EFI_OUT_OF_RESOURCES    The request could not be completed due to a lack of resources.
    436   @retval EFI_DEVICE_ERROR        The request was not completed because a failure that was
    437                                   reflected in the Host Status Register bit. Device errors are a
    438                                   result of a transaction collision, illegal command field,
    439                                   unclaimed cycle (host initiated), or bus errors (collisions).
    440   @retval EFI_INVALID_PARAMETER   Operation is not defined in EFI_SMBUS_OPERATION.
    441   @retval EFI_INVALID_PARAMETER   Length/Buffer is NULL for operations except for EfiSmbusQuickRead
    442                                   and EfiSmbusQuickWrite. Length is outside the range of valid
    443                                   values.
    444   @retval EFI_UNSUPPORTED         The SMBus operation or PEC is not supported.
    445   @retval EFI_BUFFER_TOO_SMALL    Buffer is not sufficient for this operation.
    446 
    447 **/
    448 EFI_STATUS
    449 EFIAPI
    450 SmbusExecute (
    451   IN CONST  EFI_SMBUS_HC_PROTOCOL     *This,
    452   IN CONST  EFI_SMBUS_DEVICE_ADDRESS  SlaveAddress,
    453   IN CONST  EFI_SMBUS_DEVICE_COMMAND  Command,
    454   IN CONST  EFI_SMBUS_OPERATION       Operation,
    455   IN CONST  BOOLEAN                   PecCheck,
    456   IN OUT    UINTN                     *Length,
    457   IN OUT    VOID                      *Buffer
    458   )
    459 {
    460   InitializeInternal ();
    461   return Execute (
    462            SlaveAddress,
    463            Command,
    464            Operation,
    465            PecCheck,
    466            Length,
    467            Buffer
    468            );
    469 }
    470 
    471 /**
    472   Sets the SMBus slave device addresses for the device with a given unique ID or enumerates the
    473   entire bus.
    474 
    475   The ArpDevice() function provides a standard way for a device driver to enumerate the entire
    476   SMBus or specific devices on the bus.
    477 
    478   @param  This                    A pointer to the EFI_SMBUS_HC_PROTOCOL instance.
    479   @param  ArpAll                  A Boolean expression that indicates if the host drivers need to
    480                                   enumerate all the devices or enumerate only the device that is
    481                                   identified by SmbusUdid. If ArpAll is TRUE, SmbusUdid and
    482                                   SlaveAddress are optional. If ArpAll is FALSE, ArpDevice will
    483                                   enumerate SmbusUdid and the address will be at SlaveAddress.
    484   @param  SmbusUdid               The Unique Device Identifier (UDID) that is associated with this
    485                                   device.
    486   @param  SlaveAddress            The SMBus slave address that is associated with an SMBus UDID.
    487 
    488   @retval EFI_SUCCESS             The last data that was returned from the access matched the poll
    489                                   exit criteria.
    490   @retval EFI_CRC_ERROR           Checksum is not correct (PEC is incorrect).
    491   @retval EFI_TIMEOUT             Timeout expired before the operation was completed. Timeout is
    492                                   determined by the SMBus host controller device.
    493   @retval EFI_OUT_OF_RESOURCES    The request could not be completed due to a lack of resources.
    494   @retval EFI_DEVICE_ERROR        The request was not completed because a failure that was
    495                                   reflected in the Host Status Register bit. Device errors are a
    496                                   result of a transaction collision, illegal command field,
    497                                   unclaimed cycle (host initiated), or bus errors (collisions).
    498   @retval EFI_UNSUPPORTED         The corresponding SMBus operation is not supported.
    499 
    500 **/
    501 EFI_STATUS
    502 EFIAPI
    503 SmbusArpDevice (
    504   IN CONST  EFI_SMBUS_HC_PROTOCOL     *This,
    505   IN        BOOLEAN                   ArpAll,
    506   IN        EFI_SMBUS_UDID            *SmbusUdid,   OPTIONAL
    507   IN OUT    EFI_SMBUS_DEVICE_ADDRESS  *SlaveAddress OPTIONAL
    508   )
    509 {
    510     InitializeInternal ();
    511 
    512     if (ArpAll) {
    513     return SmbusFullArp ();
    514   } else {
    515     if ((SmbusUdid == NULL) || (SlaveAddress == NULL)) {
    516       return EFI_INVALID_PARAMETER;
    517     }
    518     return SmbusDirectedArp ((EFI_SMBUS_UDID *)SmbusUdid, SlaveAddress);
    519   }
    520 }
    521 
    522 /**
    523   Returns a pointer to the Address Resolution Protocol (ARP) map that contains the ID/address pair
    524   of the slave devices that were enumerated by the SMBus host controller driver.
    525 
    526   The GetArpMap() function returns the mapping of all the SMBus devices that were enumerated by the
    527   SMBus host driver.
    528 
    529   @param  This                    A pointer to the EFI_SMBUS_HC_PROTOCOL instance.
    530   @param  Length                  Size of the buffer that contains the SMBus device map.
    531   @param  SmbusDeviceMap          The pointer to the device map as enumerated by the SMBus
    532                                   controller driver.
    533 
    534   @retval EFI_SUCCESS             The SMBus returned the current device map.
    535   @retval EFI_UNSUPPORTED         The corresponding operation is not supported.
    536 
    537 **/
    538 EFI_STATUS
    539 EFIAPI
    540 SmbusGetArpMap (
    541   IN CONST  EFI_SMBUS_HC_PROTOCOL   *This,
    542   IN OUT    UINTN                   *Length,
    543   IN OUT    EFI_SMBUS_DEVICE_MAP    **SmbusDeviceMap
    544   )
    545 {
    546   *Length = mDeviceMapEntries;
    547   *SmbusDeviceMap = mDeviceMap;
    548   return EFI_SUCCESS;
    549 }
    550 
    551 
    552 /**
    553   Allows a device driver to register for a callback when the bus driver detects a state that it
    554   needs to propagate to other drivers that are registered for a callback.
    555 
    556   The Notify() function registers all the callback functions to allow the bus driver to call these
    557   functions when the SlaveAddress/Data pair happens.
    558   If NotifyFunction is NULL, then ASSERT ().
    559 
    560   @param  This                    A pointer to the EFI_SMBUS_HC_PROTOCOL instance.
    561   @param  SlaveAddress            The SMBUS hardware address to which the SMBUS device is
    562                                   preassigned or allocated.
    563   @param  Data                    Data of the SMBus host notify command that the caller wants to be
    564                                   called.
    565   @param  NotifyFunction          The function to call when the bus driver detects the SlaveAddress
    566                                   and Data pair.
    567 
    568   @retval EFI_SUCCESS             NotifyFunction was registered.
    569   @retval EFI_UNSUPPORTED         The corresponding operation is not supported.
    570 
    571 **/
    572 EFI_STATUS
    573 EFIAPI
    574 SmbusNotify (
    575   IN CONST  EFI_SMBUS_HC_PROTOCOL     *This,
    576   IN CONST  EFI_SMBUS_DEVICE_ADDRESS  SlaveAddress,
    577   IN CONST  UINTN                     Data,
    578   IN CONST  EFI_SMBUS_NOTIFY_FUNCTION NotifyFunction
    579   )
    580 {
    581   return EFI_UNSUPPORTED;
    582 }
    583 
    584 /**
    585   Entry point to the DXE Driver that produces the SMBus Host Controller Protocol.
    586 
    587   @param  ImageHandle      ImageHandle of the loaded driver.
    588   @param  SystemTable      Pointer to the EFI System Table.
    589 
    590   @retval EFI_SUCCESS      The entry point of SMBus DXE driver is executed successfully.
    591   @retval !EFI_SUCESS      Some error occurs in the entry point of SMBus DXE driver.
    592 
    593 **/
    594 EFI_STATUS
    595 EFIAPI
    596 InitializeQNCSmbus (
    597   IN EFI_HANDLE            ImageHandle,
    598   IN EFI_SYSTEM_TABLE      *SystemTable
    599   )
    600 {
    601   EFI_STATUS    Status;
    602 
    603   mPlatformNumRsvd = (UINT8)PcdGet32 (PcdPlatformSmbusAddrNum);
    604   mPlatformAddrRsvd = (UINT8 *)(UINTN) PcdGet64 (PcdPlatformSmbusAddrTable);
    605 
    606   //
    607   // Install SMBus Host Controller protocol interface.
    608   //
    609   Status = gBS->InstallMultipleProtocolInterfaces (
    610                   &mSmbusHcHandle,
    611                   &gEfiSmbusHcProtocolGuid,
    612                   &mSmbusHc,
    613                   NULL
    614                   );
    615   ASSERT_EFI_ERROR (Status);
    616 
    617   return Status;
    618 }
    619