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      1 /** @file
      2 
      3   This driver produces Extended SCSI Pass Thru Protocol instances for
      4   virtio-scsi devices.
      5 
      6   The implementation is basic:
      7 
      8   - No hotplug / hot-unplug.
      9 
     10   - Although EFI_EXT_SCSI_PASS_THRU_PROTOCOL.PassThru() could be a good match
     11     for multiple in-flight virtio-scsi requests, we stick to synchronous
     12     requests for now.
     13 
     14   - Timeouts are not supported for EFI_EXT_SCSI_PASS_THRU_PROTOCOL.PassThru().
     15 
     16   - Only one channel is supported. (At the time of this writing, host-side
     17     virtio-scsi supports a single channel too.)
     18 
     19   - Only one request queue is used (for the one synchronous request).
     20 
     21   - The ResetChannel() and ResetTargetLun() functions of
     22     EFI_EXT_SCSI_PASS_THRU_PROTOCOL are not supported (which is allowed by the
     23     UEFI 2.3.1 Errata C specification), although
     24     VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET could be a good match. That would
     25     however require client code for the control queue, which is deemed
     26     unreasonable for now.
     27 
     28   Copyright (C) 2012, Red Hat, Inc.
     29   Copyright (c) 2012 - 2014, Intel Corporation. All rights reserved.<BR>
     30 
     31   This program and the accompanying materials are licensed and made available
     32   under the terms and conditions of the BSD License which accompanies this
     33   distribution. The full text of the license may be found at
     34   http://opensource.org/licenses/bsd-license.php
     35 
     36   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
     37   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
     38 
     39 **/
     40 
     41 #include <IndustryStandard/VirtioScsi.h>
     42 #include <Library/BaseMemoryLib.h>
     43 #include <Library/DebugLib.h>
     44 #include <Library/MemoryAllocationLib.h>
     45 #include <Library/UefiBootServicesTableLib.h>
     46 #include <Library/UefiLib.h>
     47 #include <Library/VirtioLib.h>
     48 
     49 #include "VirtioScsi.h"
     50 
     51 /**
     52 
     53   Convenience macros to read and write configuration elements of the
     54   virtio-scsi VirtIo device.
     55 
     56   The following macros make it possible to specify only the "core parameters"
     57   for such accesses and to derive the rest. By the time VIRTIO_CFG_WRITE()
     58   returns, the transaction will have been completed.
     59 
     60   @param[in] Dev       Pointer to the VSCSI_DEV structure.
     61 
     62   @param[in] Field     A field name from VSCSI_HDR, identifying the virtio-scsi
     63                        configuration item to access.
     64 
     65   @param[in] Value     (VIRTIO_CFG_WRITE() only.) The value to write to the
     66                        selected configuration item.
     67 
     68   @param[out] Pointer  (VIRTIO_CFG_READ() only.) The object to receive the
     69                        value read from the configuration item. Its type must be
     70                        one of UINT8, UINT16, UINT32, UINT64.
     71 
     72 
     73   @return  Status codes returned by Virtio->WriteDevice() / Virtio->ReadDevice().
     74 
     75 **/
     76 
     77 #define VIRTIO_CFG_WRITE(Dev, Field, Value)  ((Dev)->VirtIo->WriteDevice (  \
     78                                                 (Dev)->VirtIo,              \
     79                                                 OFFSET_OF_VSCSI (Field),    \
     80                                                 SIZE_OF_VSCSI (Field),      \
     81                                                 (Value)                     \
     82                                                 ))
     83 
     84 #define VIRTIO_CFG_READ(Dev, Field, Pointer) ((Dev)->VirtIo->ReadDevice (   \
     85                                                 (Dev)->VirtIo,              \
     86                                                 OFFSET_OF_VSCSI (Field),    \
     87                                                 SIZE_OF_VSCSI (Field),      \
     88                                                 sizeof *(Pointer),          \
     89                                                 (Pointer)                   \
     90                                                 ))
     91 
     92 
     93 //
     94 // UEFI Spec 2.3.1 + Errata C, 14.7 Extended SCSI Pass Thru Protocol specifies
     95 // the PassThru() interface. Beside returning a status code, the function must
     96 // set some fields in the EFI_EXT_SCSI_PASS_THRU_SCSI_REQUEST_PACKET in/out
     97 // parameter on return. The following is a full list of those fields, for
     98 // easier validation of PopulateRequest(), ParseResponse(), and
     99 // VirtioScsiPassThru() below.
    100 //
    101 // - InTransferLength
    102 // - OutTransferLength
    103 // - HostAdapterStatus
    104 // - TargetStatus
    105 // - SenseDataLength
    106 // - SenseData
    107 //
    108 // On any return from the PassThru() interface, these fields must be set,
    109 // except if the returned status code is explicitly exempt. (Actually the
    110 // implementation here conservatively sets these fields even in case not all
    111 // of them would be required by the specification.)
    112 //
    113 
    114 /**
    115 
    116   Populate a virtio-scsi request from the Extended SCSI Pass Thru Protocol
    117   packet.
    118 
    119   The caller is responsible for pre-zeroing the virtio-scsi request. The
    120   Extended SCSI Pass Thru Protocol packet is modified, to be forwarded outwards
    121   by VirtioScsiPassThru(), if invalid or unsupported parameters are detected.
    122 
    123   @param[in] Dev          The virtio-scsi host device the packet targets.
    124 
    125   @param[in] Target       The SCSI target controlled by the virtio-scsi host
    126                           device.
    127 
    128   @param[in] Lun          The Logical Unit Number under the SCSI target.
    129 
    130   @param[in out] Packet   The Extended SCSI Pass Thru Protocol packet the
    131                           function translates to a virtio-scsi request. On
    132                           failure this parameter relays error contents.
    133 
    134   @param[out]    Request  The pre-zeroed virtio-scsi request to populate. This
    135                           parameter is volatile-qualified because we expect the
    136                           caller to append it to a virtio ring, thus
    137                           assignments to Request must be visible when the
    138                           function returns.
    139 
    140 
    141   @retval EFI_SUCCESS  The Extended SCSI Pass Thru Protocol packet was valid,
    142                        Request has been populated.
    143 
    144   @return              Otherwise, invalid or unsupported parameters were
    145                        detected. Status codes are meant for direct forwarding
    146                        by the EFI_EXT_SCSI_PASS_THRU_PROTOCOL.PassThru()
    147                        implementation.
    148 
    149 **/
    150 STATIC
    151 EFI_STATUS
    152 EFIAPI
    153 PopulateRequest (
    154   IN     CONST    VSCSI_DEV                                   *Dev,
    155   IN              UINT16                                      Target,
    156   IN              UINT64                                      Lun,
    157   IN OUT          EFI_EXT_SCSI_PASS_THRU_SCSI_REQUEST_PACKET  *Packet,
    158   OUT    volatile VIRTIO_SCSI_REQ                             *Request
    159   )
    160 {
    161   UINTN Idx;
    162 
    163   if (
    164       //
    165       // bidirectional transfer was requested, but the host doesn't support it
    166       //
    167       (Packet->InTransferLength > 0 && Packet->OutTransferLength > 0 &&
    168        !Dev->InOutSupported) ||
    169 
    170       //
    171       // a target / LUN was addressed that's impossible to encode for the host
    172       //
    173       Target > 0xFF || Lun >= 0x4000 ||
    174 
    175       //
    176       // Command Descriptor Block bigger than VIRTIO_SCSI_CDB_SIZE
    177       //
    178       Packet->CdbLength > VIRTIO_SCSI_CDB_SIZE ||
    179 
    180       //
    181       // From virtio-0.9.5, 2.3.2 Descriptor Table:
    182       // "no descriptor chain may be more than 2^32 bytes long in total".
    183       //
    184       (UINT64) Packet->InTransferLength + Packet->OutTransferLength > SIZE_1GB
    185       ) {
    186 
    187     //
    188     // this error code doesn't require updates to the Packet output fields
    189     //
    190     return EFI_UNSUPPORTED;
    191   }
    192 
    193   if (
    194       //
    195       // addressed invalid device
    196       //
    197       Target > Dev->MaxTarget || Lun > Dev->MaxLun ||
    198 
    199       //
    200       // invalid direction (there doesn't seem to be a macro for the "no data
    201       // transferred" "direction", eg. for TEST UNIT READY)
    202       //
    203       Packet->DataDirection > EFI_EXT_SCSI_DATA_DIRECTION_BIDIRECTIONAL ||
    204 
    205       //
    206       // trying to receive, but destination pointer is NULL, or contradicting
    207       // transfer direction
    208       //
    209       (Packet->InTransferLength > 0 &&
    210        (Packet->InDataBuffer == NULL ||
    211         Packet->DataDirection == EFI_EXT_SCSI_DATA_DIRECTION_WRITE
    212         )
    213        ) ||
    214 
    215       //
    216       // trying to send, but source pointer is NULL, or contradicting transfer
    217       // direction
    218       //
    219       (Packet->OutTransferLength > 0 &&
    220        (Packet->OutDataBuffer == NULL ||
    221         Packet->DataDirection == EFI_EXT_SCSI_DATA_DIRECTION_READ
    222         )
    223        )
    224       ) {
    225 
    226     //
    227     // this error code doesn't require updates to the Packet output fields
    228     //
    229     return EFI_INVALID_PARAMETER;
    230   }
    231 
    232   //
    233   // Catch oversized requests eagerly. If this condition evaluates to false,
    234   // then the combined size of a bidirectional request will not exceed the
    235   // virtio-scsi device's transfer limit either.
    236   //
    237   if (ALIGN_VALUE (Packet->OutTransferLength, 512) / 512
    238         > Dev->MaxSectors / 2 ||
    239       ALIGN_VALUE (Packet->InTransferLength,  512) / 512
    240         > Dev->MaxSectors / 2) {
    241     Packet->InTransferLength  = (Dev->MaxSectors / 2) * 512;
    242     Packet->OutTransferLength = (Dev->MaxSectors / 2) * 512;
    243     Packet->HostAdapterStatus =
    244                         EFI_EXT_SCSI_STATUS_HOST_ADAPTER_DATA_OVERRUN_UNDERRUN;
    245     Packet->TargetStatus      = EFI_EXT_SCSI_STATUS_TARGET_GOOD;
    246     Packet->SenseDataLength   = 0;
    247     return EFI_BAD_BUFFER_SIZE;
    248   }
    249 
    250   //
    251   // target & LUN encoding: see virtio-0.9.5, Appendix I: SCSI Host Device,
    252   // Device Operation: request queues
    253   //
    254   Request->Lun[0] = 1;
    255   Request->Lun[1] = (UINT8) Target;
    256   Request->Lun[2] = (UINT8) (((UINT32)Lun >> 8) | 0x40);
    257   Request->Lun[3] = (UINT8) Lun;
    258 
    259   //
    260   // CopyMem() would cast away the "volatile" qualifier before access, which is
    261   // undefined behavior (ISO C99 6.7.3p5)
    262   //
    263   for (Idx = 0; Idx < Packet->CdbLength; ++Idx) {
    264     Request->Cdb[Idx] = ((UINT8 *) Packet->Cdb)[Idx];
    265   }
    266 
    267   return EFI_SUCCESS;
    268 }
    269 
    270 
    271 /**
    272 
    273   Parse the virtio-scsi device's response, translate it to an EFI status code,
    274   and update the Extended SCSI Pass Thru Protocol packet, to be returned by
    275   the EFI_EXT_SCSI_PASS_THRU_PROTOCOL.PassThru() implementation.
    276 
    277   @param[in out] Packet  The Extended SCSI Pass Thru Protocol packet that has
    278                          been translated to a virtio-scsi request with
    279                          PopulateRequest(), and processed by the host. On
    280                          output this parameter is updated with response or
    281                          error contents.
    282 
    283   @param[in] Response    The virtio-scsi response structure to parse. We expect
    284                          it to come from a virtio ring, thus it is qualified
    285                          volatile.
    286 
    287 
    288   @return  PassThru() status codes mandated by UEFI Spec 2.3.1 + Errata C, 14.7
    289            Extended SCSI Pass Thru Protocol.
    290 
    291 **/
    292 STATIC
    293 EFI_STATUS
    294 EFIAPI
    295 ParseResponse (
    296   IN OUT                EFI_EXT_SCSI_PASS_THRU_SCSI_REQUEST_PACKET *Packet,
    297   IN     CONST volatile VIRTIO_SCSI_RESP                           *Response
    298   )
    299 {
    300   UINTN ResponseSenseLen;
    301   UINTN Idx;
    302 
    303   //
    304   // return sense data (length and contents) in all cases, truncated if needed
    305   //
    306   ResponseSenseLen = MIN (Response->SenseLen, VIRTIO_SCSI_SENSE_SIZE);
    307   if (Packet->SenseDataLength > ResponseSenseLen) {
    308     Packet->SenseDataLength = (UINT8) ResponseSenseLen;
    309   }
    310   for (Idx = 0; Idx < Packet->SenseDataLength; ++Idx) {
    311     ((UINT8 *) Packet->SenseData)[Idx] = Response->Sense[Idx];
    312   }
    313 
    314   //
    315   // Report actual transfer lengths. The logic below covers all three
    316   // DataDirections (read, write, bidirectional).
    317   //
    318   // -+- @ 0
    319   //  |
    320   //  | write                                       ^  @ Residual (unprocessed)
    321   //  |                                             |
    322   // -+- @ OutTransferLength                       -+- @ InTransferLength
    323   //  |                                             |
    324   //  | read                                        |
    325   //  |                                             |
    326   //  V  @ OutTransferLength + InTransferLength    -+- @ 0
    327   //
    328   if (Response->Residual <= Packet->InTransferLength) {
    329     Packet->InTransferLength  -= Response->Residual;
    330   }
    331   else {
    332     Packet->OutTransferLength -= Response->Residual - Packet->InTransferLength;
    333     Packet->InTransferLength   = 0;
    334   }
    335 
    336   //
    337   // report target status in all cases
    338   //
    339   Packet->TargetStatus = Response->Status;
    340 
    341   //
    342   // host adapter status and function return value depend on virtio-scsi
    343   // response code
    344   //
    345   switch (Response->Response) {
    346   case VIRTIO_SCSI_S_OK:
    347     Packet->HostAdapterStatus = EFI_EXT_SCSI_STATUS_HOST_ADAPTER_OK;
    348     return EFI_SUCCESS;
    349 
    350   case VIRTIO_SCSI_S_OVERRUN:
    351     Packet->HostAdapterStatus =
    352                         EFI_EXT_SCSI_STATUS_HOST_ADAPTER_DATA_OVERRUN_UNDERRUN;
    353     break;
    354 
    355   case VIRTIO_SCSI_S_BAD_TARGET:
    356     //
    357     // This is non-intuitive but explicitly required by the
    358     // EFI_EXT_SCSI_PASS_THRU_PROTOCOL.PassThru() specification for
    359     // disconnected (but otherwise valid) target / LUN addresses.
    360     //
    361     Packet->HostAdapterStatus =
    362                               EFI_EXT_SCSI_STATUS_HOST_ADAPTER_TIMEOUT_COMMAND;
    363     return EFI_TIMEOUT;
    364 
    365   case VIRTIO_SCSI_S_RESET:
    366     Packet->HostAdapterStatus = EFI_EXT_SCSI_STATUS_HOST_ADAPTER_BUS_RESET;
    367     break;
    368 
    369   case VIRTIO_SCSI_S_BUSY:
    370     Packet->HostAdapterStatus = EFI_EXT_SCSI_STATUS_HOST_ADAPTER_OK;
    371     return EFI_NOT_READY;
    372 
    373   //
    374   // Lump together the rest. The mapping for VIRTIO_SCSI_S_ABORTED is
    375   // intentional as well, not an oversight.
    376   //
    377   case VIRTIO_SCSI_S_ABORTED:
    378   case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
    379   case VIRTIO_SCSI_S_TARGET_FAILURE:
    380   case VIRTIO_SCSI_S_NEXUS_FAILURE:
    381   case VIRTIO_SCSI_S_FAILURE:
    382   default:
    383     Packet->HostAdapterStatus = EFI_EXT_SCSI_STATUS_HOST_ADAPTER_OTHER;
    384   }
    385 
    386   return EFI_DEVICE_ERROR;
    387 }
    388 
    389 
    390 //
    391 // The next seven functions implement EFI_EXT_SCSI_PASS_THRU_PROTOCOL
    392 // for the virtio-scsi HBA. Refer to UEFI Spec 2.3.1 + Errata C, sections
    393 // - 14.1 SCSI Driver Model Overview,
    394 // - 14.7 Extended SCSI Pass Thru Protocol.
    395 //
    396 
    397 EFI_STATUS
    398 EFIAPI
    399 VirtioScsiPassThru (
    400   IN     EFI_EXT_SCSI_PASS_THRU_PROTOCOL            *This,
    401   IN     UINT8                                      *Target,
    402   IN     UINT64                                     Lun,
    403   IN OUT EFI_EXT_SCSI_PASS_THRU_SCSI_REQUEST_PACKET *Packet,
    404   IN     EFI_EVENT                                  Event   OPTIONAL
    405   )
    406 {
    407   VSCSI_DEV                 *Dev;
    408   UINT16                    TargetValue;
    409   EFI_STATUS                Status;
    410   volatile VIRTIO_SCSI_REQ  Request;
    411   volatile VIRTIO_SCSI_RESP Response;
    412   DESC_INDICES              Indices;
    413 
    414   ZeroMem ((VOID*) &Request, sizeof (Request));
    415   ZeroMem ((VOID*) &Response, sizeof (Response));
    416 
    417   Dev = VIRTIO_SCSI_FROM_PASS_THRU (This);
    418   CopyMem (&TargetValue, Target, sizeof TargetValue);
    419 
    420   Status = PopulateRequest (Dev, TargetValue, Lun, Packet, &Request);
    421   if (EFI_ERROR (Status)) {
    422     return Status;
    423   }
    424 
    425   VirtioPrepare (&Dev->Ring, &Indices);
    426 
    427   //
    428   // preset a host status for ourselves that we do not accept as success
    429   //
    430   Response.Response = VIRTIO_SCSI_S_FAILURE;
    431 
    432   //
    433   // ensured by VirtioScsiInit() -- this predicate, in combination with the
    434   // lock-step progress, ensures we don't have to track free descriptors.
    435   //
    436   ASSERT (Dev->Ring.QueueSize >= 4);
    437 
    438   //
    439   // enqueue Request
    440   //
    441   VirtioAppendDesc (&Dev->Ring, (UINTN) &Request, sizeof Request,
    442     VRING_DESC_F_NEXT, &Indices);
    443 
    444   //
    445   // enqueue "dataout" if any
    446   //
    447   if (Packet->OutTransferLength > 0) {
    448     VirtioAppendDesc (&Dev->Ring, (UINTN) Packet->OutDataBuffer,
    449       Packet->OutTransferLength, VRING_DESC_F_NEXT, &Indices);
    450   }
    451 
    452   //
    453   // enqueue Response, to be written by the host
    454   //
    455   VirtioAppendDesc (&Dev->Ring, (UINTN) &Response, sizeof Response,
    456     VRING_DESC_F_WRITE | (Packet->InTransferLength > 0 ?
    457                           VRING_DESC_F_NEXT : 0),
    458     &Indices);
    459 
    460   //
    461   // enqueue "datain" if any, to be written by the host
    462   //
    463   if (Packet->InTransferLength > 0) {
    464     VirtioAppendDesc (&Dev->Ring, (UINTN) Packet->InDataBuffer,
    465       Packet->InTransferLength, VRING_DESC_F_WRITE, &Indices);
    466   }
    467 
    468   // If kicking the host fails, we must fake a host adapter error.
    469   // EFI_NOT_READY would save us the effort, but it would also suggest that the
    470   // caller retry.
    471   //
    472   if (VirtioFlush (Dev->VirtIo, VIRTIO_SCSI_REQUEST_QUEUE, &Dev->Ring,
    473         &Indices) != EFI_SUCCESS) {
    474     Packet->InTransferLength  = 0;
    475     Packet->OutTransferLength = 0;
    476     Packet->HostAdapterStatus = EFI_EXT_SCSI_STATUS_HOST_ADAPTER_OTHER;
    477     Packet->TargetStatus      = EFI_EXT_SCSI_STATUS_TARGET_GOOD;
    478     Packet->SenseDataLength   = 0;
    479     return EFI_DEVICE_ERROR;
    480   }
    481 
    482   return ParseResponse (Packet, &Response);
    483 }
    484 
    485 
    486 EFI_STATUS
    487 EFIAPI
    488 VirtioScsiGetNextTargetLun (
    489   IN     EFI_EXT_SCSI_PASS_THRU_PROTOCOL *This,
    490   IN OUT UINT8                           **TargetPointer,
    491   IN OUT UINT64                          *Lun
    492   )
    493 {
    494   UINT8     *Target;
    495   UINTN     Idx;
    496   UINT16    LastTarget;
    497   VSCSI_DEV *Dev;
    498 
    499   //
    500   // the TargetPointer input parameter is unnecessarily a pointer-to-pointer
    501   //
    502   Target = *TargetPointer;
    503 
    504   //
    505   // Search for first non-0xFF byte. If not found, return first target & LUN.
    506   //
    507   for (Idx = 0; Idx < TARGET_MAX_BYTES && Target[Idx] == 0xFF; ++Idx)
    508     ;
    509   if (Idx == TARGET_MAX_BYTES) {
    510     SetMem (Target, TARGET_MAX_BYTES, 0x00);
    511     *Lun = 0;
    512     return EFI_SUCCESS;
    513   }
    514 
    515   //
    516   // see the TARGET_MAX_BYTES check in "VirtioScsi.h"
    517   //
    518   CopyMem (&LastTarget, Target, sizeof LastTarget);
    519 
    520   //
    521   // increment (target, LUN) pair if valid on input
    522   //
    523   Dev = VIRTIO_SCSI_FROM_PASS_THRU (This);
    524   if (LastTarget > Dev->MaxTarget || *Lun > Dev->MaxLun) {
    525     return EFI_INVALID_PARAMETER;
    526   }
    527 
    528   if (*Lun < Dev->MaxLun) {
    529     ++*Lun;
    530     return EFI_SUCCESS;
    531   }
    532 
    533   if (LastTarget < Dev->MaxTarget) {
    534     *Lun = 0;
    535     ++LastTarget;
    536     CopyMem (Target, &LastTarget, sizeof LastTarget);
    537     return EFI_SUCCESS;
    538   }
    539 
    540   return EFI_NOT_FOUND;
    541 }
    542 
    543 
    544 EFI_STATUS
    545 EFIAPI
    546 VirtioScsiBuildDevicePath (
    547   IN     EFI_EXT_SCSI_PASS_THRU_PROTOCOL *This,
    548   IN     UINT8                           *Target,
    549   IN     UINT64                          Lun,
    550   IN OUT EFI_DEVICE_PATH_PROTOCOL        **DevicePath
    551   )
    552 {
    553   UINT16           TargetValue;
    554   VSCSI_DEV        *Dev;
    555   SCSI_DEVICE_PATH *ScsiDevicePath;
    556 
    557   if (DevicePath == NULL) {
    558     return EFI_INVALID_PARAMETER;
    559   }
    560 
    561   CopyMem (&TargetValue, Target, sizeof TargetValue);
    562   Dev = VIRTIO_SCSI_FROM_PASS_THRU (This);
    563   if (TargetValue > Dev->MaxTarget || Lun > Dev->MaxLun || Lun > 0xFFFF) {
    564     return EFI_NOT_FOUND;
    565   }
    566 
    567   ScsiDevicePath = AllocatePool (sizeof *ScsiDevicePath);
    568   if (ScsiDevicePath == NULL) {
    569     return EFI_OUT_OF_RESOURCES;
    570   }
    571 
    572   ScsiDevicePath->Header.Type      = MESSAGING_DEVICE_PATH;
    573   ScsiDevicePath->Header.SubType   = MSG_SCSI_DP;
    574   ScsiDevicePath->Header.Length[0] = (UINT8)  sizeof *ScsiDevicePath;
    575   ScsiDevicePath->Header.Length[1] = (UINT8) (sizeof *ScsiDevicePath >> 8);
    576   ScsiDevicePath->Pun              = TargetValue;
    577   ScsiDevicePath->Lun              = (UINT16) Lun;
    578 
    579   *DevicePath = &ScsiDevicePath->Header;
    580   return EFI_SUCCESS;
    581 }
    582 
    583 
    584 EFI_STATUS
    585 EFIAPI
    586 VirtioScsiGetTargetLun (
    587   IN  EFI_EXT_SCSI_PASS_THRU_PROTOCOL *This,
    588   IN  EFI_DEVICE_PATH_PROTOCOL        *DevicePath,
    589   OUT UINT8                           **TargetPointer,
    590   OUT UINT64                          *Lun
    591   )
    592 {
    593   SCSI_DEVICE_PATH *ScsiDevicePath;
    594   VSCSI_DEV        *Dev;
    595   UINT8            *Target;
    596 
    597   if (DevicePath == NULL || TargetPointer == NULL || *TargetPointer == NULL ||
    598       Lun == NULL) {
    599     return EFI_INVALID_PARAMETER;
    600   }
    601 
    602   if (DevicePath->Type    != MESSAGING_DEVICE_PATH ||
    603       DevicePath->SubType != MSG_SCSI_DP) {
    604     return EFI_UNSUPPORTED;
    605   }
    606 
    607   ScsiDevicePath = (SCSI_DEVICE_PATH *) DevicePath;
    608   Dev = VIRTIO_SCSI_FROM_PASS_THRU (This);
    609   if (ScsiDevicePath->Pun > Dev->MaxTarget ||
    610       ScsiDevicePath->Lun > Dev->MaxLun) {
    611     return EFI_NOT_FOUND;
    612   }
    613 
    614   //
    615   // a) the TargetPointer input parameter is unnecessarily a pointer-to-pointer
    616   // b) see the TARGET_MAX_BYTES check in "VirtioScsi.h"
    617   // c) ScsiDevicePath->Pun is an UINT16
    618   //
    619   Target = *TargetPointer;
    620   CopyMem (Target, &ScsiDevicePath->Pun, 2);
    621   SetMem (Target + 2, TARGET_MAX_BYTES - 2, 0x00);
    622 
    623   *Lun = ScsiDevicePath->Lun;
    624   return EFI_SUCCESS;
    625 }
    626 
    627 
    628 EFI_STATUS
    629 EFIAPI
    630 VirtioScsiResetChannel (
    631   IN EFI_EXT_SCSI_PASS_THRU_PROTOCOL *This
    632   )
    633 {
    634   return EFI_UNSUPPORTED;
    635 }
    636 
    637 
    638 EFI_STATUS
    639 EFIAPI
    640 VirtioScsiResetTargetLun (
    641   IN EFI_EXT_SCSI_PASS_THRU_PROTOCOL *This,
    642   IN UINT8                           *Target,
    643   IN UINT64                          Lun
    644   )
    645 {
    646   return EFI_UNSUPPORTED;
    647 }
    648 
    649 
    650 EFI_STATUS
    651 EFIAPI
    652 VirtioScsiGetNextTarget (
    653   IN EFI_EXT_SCSI_PASS_THRU_PROTOCOL *This,
    654   IN OUT UINT8                       **TargetPointer
    655   )
    656 {
    657   UINT8     *Target;
    658   UINTN     Idx;
    659   UINT16    LastTarget;
    660   VSCSI_DEV *Dev;
    661 
    662   //
    663   // the TargetPointer input parameter is unnecessarily a pointer-to-pointer
    664   //
    665   Target = *TargetPointer;
    666 
    667   //
    668   // Search for first non-0xFF byte. If not found, return first target.
    669   //
    670   for (Idx = 0; Idx < TARGET_MAX_BYTES && Target[Idx] == 0xFF; ++Idx)
    671     ;
    672   if (Idx == TARGET_MAX_BYTES) {
    673     SetMem (Target, TARGET_MAX_BYTES, 0x00);
    674     return EFI_SUCCESS;
    675   }
    676 
    677   //
    678   // see the TARGET_MAX_BYTES check in "VirtioScsi.h"
    679   //
    680   CopyMem (&LastTarget, Target, sizeof LastTarget);
    681 
    682   //
    683   // increment target if valid on input
    684   //
    685   Dev = VIRTIO_SCSI_FROM_PASS_THRU (This);
    686   if (LastTarget > Dev->MaxTarget) {
    687     return EFI_INVALID_PARAMETER;
    688   }
    689 
    690   if (LastTarget < Dev->MaxTarget) {
    691     ++LastTarget;
    692     CopyMem (Target, &LastTarget, sizeof LastTarget);
    693     return EFI_SUCCESS;
    694   }
    695 
    696   return EFI_NOT_FOUND;
    697 }
    698 
    699 
    700 STATIC
    701 EFI_STATUS
    702 EFIAPI
    703 VirtioScsiInit (
    704   IN OUT VSCSI_DEV *Dev
    705   )
    706 {
    707   UINT8      NextDevStat;
    708   EFI_STATUS Status;
    709 
    710   UINT32     Features;
    711   UINT16     MaxChannel; // for validation only
    712   UINT32     NumQueues;  // for validation only
    713   UINT16     QueueSize;
    714 
    715   //
    716   // Execute virtio-0.9.5, 2.2.1 Device Initialization Sequence.
    717   //
    718   NextDevStat = 0;             // step 1 -- reset device
    719   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
    720   if (EFI_ERROR (Status)) {
    721     goto Failed;
    722   }
    723 
    724   NextDevStat |= VSTAT_ACK;    // step 2 -- acknowledge device presence
    725   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
    726   if (EFI_ERROR (Status)) {
    727     goto Failed;
    728   }
    729 
    730   NextDevStat |= VSTAT_DRIVER; // step 3 -- we know how to drive it
    731   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
    732   if (EFI_ERROR (Status)) {
    733     goto Failed;
    734   }
    735 
    736   //
    737   // Set Page Size - MMIO VirtIo Specific
    738   //
    739   Status = Dev->VirtIo->SetPageSize (Dev->VirtIo, EFI_PAGE_SIZE);
    740   if (EFI_ERROR (Status)) {
    741     goto Failed;
    742   }
    743 
    744   //
    745   // step 4a -- retrieve and validate features
    746   //
    747   Status = Dev->VirtIo->GetDeviceFeatures (Dev->VirtIo, &Features);
    748   if (EFI_ERROR (Status)) {
    749     goto Failed;
    750   }
    751   Dev->InOutSupported = (BOOLEAN) ((Features & VIRTIO_SCSI_F_INOUT) != 0);
    752 
    753   Status = VIRTIO_CFG_READ (Dev, MaxChannel, &MaxChannel);
    754   if (EFI_ERROR (Status)) {
    755     goto Failed;
    756   }
    757   if (MaxChannel != 0) {
    758     //
    759     // this driver is for a single-channel virtio-scsi HBA
    760     //
    761     Status = EFI_UNSUPPORTED;
    762     goto Failed;
    763   }
    764 
    765   Status = VIRTIO_CFG_READ (Dev, NumQueues, &NumQueues);
    766   if (EFI_ERROR (Status)) {
    767     goto Failed;
    768   }
    769   if (NumQueues < 1) {
    770     Status = EFI_UNSUPPORTED;
    771     goto Failed;
    772   }
    773 
    774   Status = VIRTIO_CFG_READ (Dev, MaxTarget, &Dev->MaxTarget);
    775   if (EFI_ERROR (Status)) {
    776     goto Failed;
    777   }
    778   if (Dev->MaxTarget > PcdGet16 (PcdVirtioScsiMaxTargetLimit)) {
    779     Dev->MaxTarget = PcdGet16 (PcdVirtioScsiMaxTargetLimit);
    780   }
    781 
    782   Status = VIRTIO_CFG_READ (Dev, MaxLun, &Dev->MaxLun);
    783   if (EFI_ERROR (Status)) {
    784     goto Failed;
    785   }
    786   if (Dev->MaxLun > PcdGet32 (PcdVirtioScsiMaxLunLimit)) {
    787     Dev->MaxLun = PcdGet32 (PcdVirtioScsiMaxLunLimit);
    788   }
    789 
    790   Status = VIRTIO_CFG_READ (Dev, MaxSectors, &Dev->MaxSectors);
    791   if (EFI_ERROR (Status)) {
    792     goto Failed;
    793   }
    794   if (Dev->MaxSectors < 2) {
    795     //
    796     // We must be able to halve it for bidirectional transfers
    797     // (see EFI_BAD_BUFFER_SIZE in PopulateRequest()).
    798     //
    799     Status = EFI_UNSUPPORTED;
    800     goto Failed;
    801   }
    802 
    803   //
    804   // step 4b -- allocate request virtqueue
    805   //
    806   Status = Dev->VirtIo->SetQueueSel (Dev->VirtIo, VIRTIO_SCSI_REQUEST_QUEUE);
    807   if (EFI_ERROR (Status)) {
    808     goto Failed;
    809   }
    810   Status = Dev->VirtIo->GetQueueNumMax (Dev->VirtIo, &QueueSize);
    811   if (EFI_ERROR (Status)) {
    812     goto Failed;
    813   }
    814   //
    815   // VirtioScsiPassThru() uses at most four descriptors
    816   //
    817   if (QueueSize < 4) {
    818     Status = EFI_UNSUPPORTED;
    819     goto Failed;
    820   }
    821 
    822   Status = VirtioRingInit (QueueSize, &Dev->Ring);
    823   if (EFI_ERROR (Status)) {
    824     goto Failed;
    825   }
    826 
    827   //
    828   // Additional steps for MMIO: align the queue appropriately, and set the
    829   // size. If anything fails from here on, we must release the ring resources.
    830   //
    831   Status = Dev->VirtIo->SetQueueNum (Dev->VirtIo, QueueSize);
    832   if (EFI_ERROR (Status)) {
    833     goto ReleaseQueue;
    834   }
    835 
    836   Status = Dev->VirtIo->SetQueueAlign (Dev->VirtIo, EFI_PAGE_SIZE);
    837   if (EFI_ERROR (Status)) {
    838     goto ReleaseQueue;
    839   }
    840 
    841   //
    842   // step 4c -- Report GPFN (guest-physical frame number) of queue.
    843   //
    844   Status = Dev->VirtIo->SetQueueAddress (Dev->VirtIo,
    845       (UINT32) ((UINTN) Dev->Ring.Base >> EFI_PAGE_SHIFT));
    846   if (EFI_ERROR (Status)) {
    847     goto ReleaseQueue;
    848   }
    849 
    850   //
    851   // step 5 -- Report understood features and guest-tuneables. We want none of
    852   // the known (or unknown) VIRTIO_SCSI_F_* or VIRTIO_F_* capabilities (see
    853   // virtio-0.9.5, Appendices B and I), except bidirectional transfers.
    854   //
    855   Status = Dev->VirtIo->SetGuestFeatures (Dev->VirtIo,
    856       Features & VIRTIO_SCSI_F_INOUT);
    857   if (EFI_ERROR (Status)) {
    858     goto ReleaseQueue;
    859   }
    860 
    861   //
    862   // We expect these maximum sizes from the host. Since they are
    863   // guest-negotiable, ask for them rather than just checking them.
    864   //
    865   Status = VIRTIO_CFG_WRITE (Dev, CdbSize, VIRTIO_SCSI_CDB_SIZE);
    866   if (EFI_ERROR (Status)) {
    867     goto ReleaseQueue;
    868   }
    869   Status = VIRTIO_CFG_WRITE (Dev, SenseSize, VIRTIO_SCSI_SENSE_SIZE);
    870   if (EFI_ERROR (Status)) {
    871     goto ReleaseQueue;
    872   }
    873 
    874   //
    875   // step 6 -- initialization complete
    876   //
    877   NextDevStat |= VSTAT_DRIVER_OK;
    878   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
    879   if (EFI_ERROR (Status)) {
    880     goto ReleaseQueue;
    881   }
    882 
    883   //
    884   // populate the exported interface's attributes
    885   //
    886   Dev->PassThru.Mode             = &Dev->PassThruMode;
    887   Dev->PassThru.PassThru         = &VirtioScsiPassThru;
    888   Dev->PassThru.GetNextTargetLun = &VirtioScsiGetNextTargetLun;
    889   Dev->PassThru.BuildDevicePath  = &VirtioScsiBuildDevicePath;
    890   Dev->PassThru.GetTargetLun     = &VirtioScsiGetTargetLun;
    891   Dev->PassThru.ResetChannel     = &VirtioScsiResetChannel;
    892   Dev->PassThru.ResetTargetLun   = &VirtioScsiResetTargetLun;
    893   Dev->PassThru.GetNextTarget    = &VirtioScsiGetNextTarget;
    894 
    895   //
    896   // AdapterId is a target for which no handle will be created during bus scan.
    897   // Prevent any conflict with real devices.
    898   //
    899   Dev->PassThruMode.AdapterId = 0xFFFFFFFF;
    900 
    901   //
    902   // Set both physical and logical attributes for non-RAID SCSI channel. See
    903   // Driver Writer's Guide for UEFI 2.3.1 v1.01, 20.1.5 Implementing Extended
    904   // SCSI Pass Thru Protocol.
    905   //
    906   Dev->PassThruMode.Attributes = EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_PHYSICAL |
    907                                  EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_LOGICAL;
    908 
    909   //
    910   // no restriction on transfer buffer alignment
    911   //
    912   Dev->PassThruMode.IoAlign = 0;
    913 
    914   return EFI_SUCCESS;
    915 
    916 ReleaseQueue:
    917   VirtioRingUninit (&Dev->Ring);
    918 
    919 Failed:
    920   //
    921   // Notify the host about our failure to setup: virtio-0.9.5, 2.2.2.1 Device
    922   // Status. VirtIo access failure here should not mask the original error.
    923   //
    924   NextDevStat |= VSTAT_FAILED;
    925   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
    926 
    927   Dev->InOutSupported = FALSE;
    928   Dev->MaxTarget      = 0;
    929   Dev->MaxLun         = 0;
    930   Dev->MaxSectors     = 0;
    931 
    932   return Status; // reached only via Failed above
    933 }
    934 
    935 
    936 STATIC
    937 VOID
    938 EFIAPI
    939 VirtioScsiUninit (
    940   IN OUT VSCSI_DEV *Dev
    941   )
    942 {
    943   //
    944   // Reset the virtual device -- see virtio-0.9.5, 2.2.2.1 Device Status. When
    945   // VIRTIO_CFG_WRITE() returns, the host will have learned to stay away from
    946   // the old comms area.
    947   //
    948   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
    949 
    950   Dev->InOutSupported = FALSE;
    951   Dev->MaxTarget      = 0;
    952   Dev->MaxLun         = 0;
    953   Dev->MaxSectors     = 0;
    954 
    955   VirtioRingUninit (&Dev->Ring);
    956 
    957   SetMem (&Dev->PassThru,     sizeof Dev->PassThru,     0x00);
    958   SetMem (&Dev->PassThruMode, sizeof Dev->PassThruMode, 0x00);
    959 }
    960 
    961 
    962 //
    963 // Event notification function enqueued by ExitBootServices().
    964 //
    965 
    966 STATIC
    967 VOID
    968 EFIAPI
    969 VirtioScsiExitBoot (
    970   IN  EFI_EVENT Event,
    971   IN  VOID      *Context
    972   )
    973 {
    974   VSCSI_DEV *Dev;
    975 
    976   //
    977   // Reset the device. This causes the hypervisor to forget about the virtio
    978   // ring.
    979   //
    980   // We allocated said ring in EfiBootServicesData type memory, and code
    981   // executing after ExitBootServices() is permitted to overwrite it.
    982   //
    983   Dev = Context;
    984   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
    985 }
    986 
    987 
    988 //
    989 // Probe, start and stop functions of this driver, called by the DXE core for
    990 // specific devices.
    991 //
    992 // The following specifications document these interfaces:
    993 // - Driver Writer's Guide for UEFI 2.3.1 v1.01, 9 Driver Binding Protocol
    994 // - UEFI Spec 2.3.1 + Errata C, 10.1 EFI Driver Binding Protocol
    995 //
    996 // The implementation follows:
    997 // - Driver Writer's Guide for UEFI 2.3.1 v1.01
    998 //   - 5.1.3.4 OpenProtocol() and CloseProtocol()
    999 // - UEFI Spec 2.3.1 + Errata C
   1000 //   -  6.3 Protocol Handler Services
   1001 //
   1002 
   1003 EFI_STATUS
   1004 EFIAPI
   1005 VirtioScsiDriverBindingSupported (
   1006   IN EFI_DRIVER_BINDING_PROTOCOL *This,
   1007   IN EFI_HANDLE                  DeviceHandle,
   1008   IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
   1009   )
   1010 {
   1011   EFI_STATUS             Status;
   1012   VIRTIO_DEVICE_PROTOCOL *VirtIo;
   1013 
   1014   //
   1015   // Attempt to open the device with the VirtIo set of interfaces. On success,
   1016   // the protocol is "instantiated" for the VirtIo device. Covers duplicate open
   1017   // attempts (EFI_ALREADY_STARTED).
   1018   //
   1019   Status = gBS->OpenProtocol (
   1020                   DeviceHandle,               // candidate device
   1021                   &gVirtioDeviceProtocolGuid, // for generic VirtIo access
   1022                   (VOID **)&VirtIo,           // handle to instantiate
   1023                   This->DriverBindingHandle,  // requestor driver identity
   1024                   DeviceHandle,               // ControllerHandle, according to
   1025                                               // the UEFI Driver Model
   1026                   EFI_OPEN_PROTOCOL_BY_DRIVER // get exclusive VirtIo access to
   1027                                               // the device; to be released
   1028                   );
   1029   if (EFI_ERROR (Status)) {
   1030     return Status;
   1031   }
   1032 
   1033   if (VirtIo->SubSystemDeviceId != VIRTIO_SUBSYSTEM_SCSI_HOST) {
   1034     Status = EFI_UNSUPPORTED;
   1035   }
   1036 
   1037   //
   1038   // We needed VirtIo access only transitorily, to see whether we support the
   1039   // device or not.
   1040   //
   1041   gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
   1042          This->DriverBindingHandle, DeviceHandle);
   1043   return Status;
   1044 }
   1045 
   1046 
   1047 EFI_STATUS
   1048 EFIAPI
   1049 VirtioScsiDriverBindingStart (
   1050   IN EFI_DRIVER_BINDING_PROTOCOL *This,
   1051   IN EFI_HANDLE                  DeviceHandle,
   1052   IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
   1053   )
   1054 {
   1055   VSCSI_DEV  *Dev;
   1056   EFI_STATUS Status;
   1057 
   1058   Dev = (VSCSI_DEV *) AllocateZeroPool (sizeof *Dev);
   1059   if (Dev == NULL) {
   1060     return EFI_OUT_OF_RESOURCES;
   1061   }
   1062 
   1063   Status = gBS->OpenProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
   1064                   (VOID **)&Dev->VirtIo, This->DriverBindingHandle,
   1065                   DeviceHandle, EFI_OPEN_PROTOCOL_BY_DRIVER);
   1066   if (EFI_ERROR (Status)) {
   1067     goto FreeVirtioScsi;
   1068   }
   1069 
   1070   //
   1071   // VirtIo access granted, configure virtio-scsi device.
   1072   //
   1073   Status = VirtioScsiInit (Dev);
   1074   if (EFI_ERROR (Status)) {
   1075     goto CloseVirtIo;
   1076   }
   1077 
   1078   Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
   1079                   &VirtioScsiExitBoot, Dev, &Dev->ExitBoot);
   1080   if (EFI_ERROR (Status)) {
   1081     goto UninitDev;
   1082   }
   1083 
   1084   //
   1085   // Setup complete, attempt to export the driver instance's PassThru
   1086   // interface.
   1087   //
   1088   Dev->Signature = VSCSI_SIG;
   1089   Status = gBS->InstallProtocolInterface (&DeviceHandle,
   1090                   &gEfiExtScsiPassThruProtocolGuid, EFI_NATIVE_INTERFACE,
   1091                   &Dev->PassThru);
   1092   if (EFI_ERROR (Status)) {
   1093     goto CloseExitBoot;
   1094   }
   1095 
   1096   return EFI_SUCCESS;
   1097 
   1098 CloseExitBoot:
   1099   gBS->CloseEvent (Dev->ExitBoot);
   1100 
   1101 UninitDev:
   1102   VirtioScsiUninit (Dev);
   1103 
   1104 CloseVirtIo:
   1105   gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
   1106          This->DriverBindingHandle, DeviceHandle);
   1107 
   1108 FreeVirtioScsi:
   1109   FreePool (Dev);
   1110 
   1111   return Status;
   1112 }
   1113 
   1114 
   1115 EFI_STATUS
   1116 EFIAPI
   1117 VirtioScsiDriverBindingStop (
   1118   IN EFI_DRIVER_BINDING_PROTOCOL *This,
   1119   IN EFI_HANDLE                  DeviceHandle,
   1120   IN UINTN                       NumberOfChildren,
   1121   IN EFI_HANDLE                  *ChildHandleBuffer
   1122   )
   1123 {
   1124   EFI_STATUS                      Status;
   1125   EFI_EXT_SCSI_PASS_THRU_PROTOCOL *PassThru;
   1126   VSCSI_DEV                       *Dev;
   1127 
   1128   Status = gBS->OpenProtocol (
   1129                   DeviceHandle,                     // candidate device
   1130                   &gEfiExtScsiPassThruProtocolGuid, // retrieve the SCSI iface
   1131                   (VOID **)&PassThru,               // target pointer
   1132                   This->DriverBindingHandle,        // requestor driver ident.
   1133                   DeviceHandle,                     // lookup req. for dev.
   1134                   EFI_OPEN_PROTOCOL_GET_PROTOCOL    // lookup only, no new ref.
   1135                   );
   1136   if (EFI_ERROR (Status)) {
   1137     return Status;
   1138   }
   1139 
   1140   Dev = VIRTIO_SCSI_FROM_PASS_THRU (PassThru);
   1141 
   1142   //
   1143   // Handle Stop() requests for in-use driver instances gracefully.
   1144   //
   1145   Status = gBS->UninstallProtocolInterface (DeviceHandle,
   1146                   &gEfiExtScsiPassThruProtocolGuid, &Dev->PassThru);
   1147   if (EFI_ERROR (Status)) {
   1148     return Status;
   1149   }
   1150 
   1151   gBS->CloseEvent (Dev->ExitBoot);
   1152 
   1153   VirtioScsiUninit (Dev);
   1154 
   1155   gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
   1156          This->DriverBindingHandle, DeviceHandle);
   1157 
   1158   FreePool (Dev);
   1159 
   1160   return EFI_SUCCESS;
   1161 }
   1162 
   1163 
   1164 //
   1165 // The static object that groups the Supported() (ie. probe), Start() and
   1166 // Stop() functions of the driver together. Refer to UEFI Spec 2.3.1 + Errata
   1167 // C, 10.1 EFI Driver Binding Protocol.
   1168 //
   1169 STATIC EFI_DRIVER_BINDING_PROTOCOL gDriverBinding = {
   1170   &VirtioScsiDriverBindingSupported,
   1171   &VirtioScsiDriverBindingStart,
   1172   &VirtioScsiDriverBindingStop,
   1173   0x10, // Version, must be in [0x10 .. 0xFFFFFFEF] for IHV-developed drivers
   1174   NULL, // ImageHandle, to be overwritten by
   1175         // EfiLibInstallDriverBindingComponentName2() in VirtioScsiEntryPoint()
   1176   NULL  // DriverBindingHandle, ditto
   1177 };
   1178 
   1179 
   1180 //
   1181 // The purpose of the following scaffolding (EFI_COMPONENT_NAME_PROTOCOL and
   1182 // EFI_COMPONENT_NAME2_PROTOCOL implementation) is to format the driver's name
   1183 // in English, for display on standard console devices. This is recommended for
   1184 // UEFI drivers that follow the UEFI Driver Model. Refer to the Driver Writer's
   1185 // Guide for UEFI 2.3.1 v1.01, 11 UEFI Driver and Controller Names.
   1186 //
   1187 // Device type names ("Virtio SCSI Host Device") are not formatted because the
   1188 // driver supports only that device type. Therefore the driver name suffices
   1189 // for unambiguous identification.
   1190 //
   1191 
   1192 STATIC
   1193 EFI_UNICODE_STRING_TABLE mDriverNameTable[] = {
   1194   { "eng;en", L"Virtio SCSI Host Driver" },
   1195   { NULL,     NULL                   }
   1196 };
   1197 
   1198 STATIC
   1199 EFI_COMPONENT_NAME_PROTOCOL gComponentName;
   1200 
   1201 EFI_STATUS
   1202 EFIAPI
   1203 VirtioScsiGetDriverName (
   1204   IN  EFI_COMPONENT_NAME_PROTOCOL *This,
   1205   IN  CHAR8                       *Language,
   1206   OUT CHAR16                      **DriverName
   1207   )
   1208 {
   1209   return LookupUnicodeString2 (
   1210            Language,
   1211            This->SupportedLanguages,
   1212            mDriverNameTable,
   1213            DriverName,
   1214            (BOOLEAN)(This == &gComponentName) // Iso639Language
   1215            );
   1216 }
   1217 
   1218 EFI_STATUS
   1219 EFIAPI
   1220 VirtioScsiGetDeviceName (
   1221   IN  EFI_COMPONENT_NAME_PROTOCOL *This,
   1222   IN  EFI_HANDLE                  DeviceHandle,
   1223   IN  EFI_HANDLE                  ChildHandle,
   1224   IN  CHAR8                       *Language,
   1225   OUT CHAR16                      **ControllerName
   1226   )
   1227 {
   1228   return EFI_UNSUPPORTED;
   1229 }
   1230 
   1231 STATIC
   1232 EFI_COMPONENT_NAME_PROTOCOL gComponentName = {
   1233   &VirtioScsiGetDriverName,
   1234   &VirtioScsiGetDeviceName,
   1235   "eng" // SupportedLanguages, ISO 639-2 language codes
   1236 };
   1237 
   1238 STATIC
   1239 EFI_COMPONENT_NAME2_PROTOCOL gComponentName2 = {
   1240   (EFI_COMPONENT_NAME2_GET_DRIVER_NAME)     &VirtioScsiGetDriverName,
   1241   (EFI_COMPONENT_NAME2_GET_CONTROLLER_NAME) &VirtioScsiGetDeviceName,
   1242   "en" // SupportedLanguages, RFC 4646 language codes
   1243 };
   1244 
   1245 
   1246 //
   1247 // Entry point of this driver.
   1248 //
   1249 EFI_STATUS
   1250 EFIAPI
   1251 VirtioScsiEntryPoint (
   1252   IN EFI_HANDLE       ImageHandle,
   1253   IN EFI_SYSTEM_TABLE *SystemTable
   1254   )
   1255 {
   1256   return EfiLibInstallDriverBindingComponentName2 (
   1257            ImageHandle,
   1258            SystemTable,
   1259            &gDriverBinding,
   1260            ImageHandle,
   1261            &gComponentName,
   1262            &gComponentName2
   1263            );
   1264 }
   1265