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/** @file\r
\r
  Declarations of utility functions used by virtio device drivers.\r
\r
  Copyright (C) 2012, Red Hat, Inc.\r
\r
  This program and the accompanying materials are licensed and made available\r
  under the terms and conditions of the BSD License which accompanies this\r
  distribution. The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT\r
  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#ifndef _VIRTIO_LIB_H_\r
#define _VIRTIO_LIB_H_\r
\r
#include <Protocol/PciIo.h>\r
#include <IndustryStandard/Virtio.h>\r
\r
/**\r
\r
  Write a word into Region 0 of the device specified by PciIo.\r
\r
  Region 0 must be an iomem region. This is an internal function for the\r
  driver-specific VIRTIO_CFG_WRITE() macros.\r
\r
  @param[in] PciIo        Target PCI device.\r
\r
  @param[in] FieldOffset  Destination offset.\r
\r
  @param[in] FieldSize    Destination field size, must be in { 1, 2, 4, 8 }.\r
\r
  @param[in] Value        Little endian value to write, converted to UINT64.\r
                          The least significant FieldSize bytes will be used.\r
\r
\r
  @return  Status code returned by PciIo->Io.Write().\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
VirtioWrite (\r
  IN EFI_PCI_IO_PROTOCOL *PciIo,\r
  IN UINTN               FieldOffset,\r
  IN UINTN               FieldSize,\r
  IN UINT64              Value\r
  );\r
\r
\r
/**\r
\r
  Read a word from Region 0 of the device specified by PciIo.\r
\r
  Region 0 must be an iomem region. This is an internal function for the\r
  driver-specific VIRTIO_CFG_READ() macros.\r
\r
  @param[in] PciIo        Source PCI device.\r
\r
  @param[in] FieldOffset  Source offset.\r
\r
  @param[in] FieldSize    Source field size, must be in { 1, 2, 4, 8 }.\r
\r
  @param[in] BufferSize   Number of bytes available in the target buffer. Must\r
                          equal FieldSize.\r
\r
  @param[out] Buffer      Target buffer.\r
\r
\r
  @return  Status code returned by PciIo->Io.Read().\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
VirtioRead (\r
  IN  EFI_PCI_IO_PROTOCOL *PciIo,\r
  IN  UINTN               FieldOffset,\r
  IN  UINTN               FieldSize,\r
  IN  UINTN               BufferSize,\r
  OUT VOID                *Buffer\r
  );\r
\r
\r
/**\r
\r
  Configure a virtio ring.\r
\r
  This function sets up internal storage (the guest-host communication area)\r
  and lays out several "navigation" (ie. no-ownership) pointers to parts of\r
  that storage.\r
\r
  Relevant sections from the virtio-0.9.5 spec:\r
  - 1.1 Virtqueues,\r
  - 2.3 Virtqueue Configuration.\r
\r
  @param[in]                    The number of descriptors to allocate for the\r
                                virtio ring, as requested by the host.\r
\r
  @param[out] Ring              The virtio ring to set up.\r
\r
  @retval EFI_OUT_OF_RESOURCES  AllocatePages() failed to allocate contiguous\r
                                pages for the requested QueueSize. Fields of\r
                                Ring have indeterminate value.\r
\r
  @retval EFI_SUCCESS           Allocation and setup successful. Ring->Base\r
                                (and nothing else) is responsible for\r
                                deallocation.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
VirtioRingInit (\r
  IN  UINT16 QueueSize,\r
  OUT VRING  *Ring\r
  );\r
\r
\r
/**\r
\r
  Tear down the internal resources of a configured virtio ring.\r
\r
  The caller is responsible to stop the host from using this ring before\r
  invoking this function: the VSTAT_DRIVER_OK bit must be clear in\r
  VhdrDeviceStatus.\r
\r
  @param[out] Ring  The virtio ring to clean up.\r
\r
**/\r
VOID\r
EFIAPI\r
VirtioRingUninit (\r
  IN OUT VRING *Ring\r
  );\r
\r
\r
//\r
// Internal use structure for tracking the submission of a multi-descriptor\r
// request.\r
//\r
typedef struct {\r
  UINT16 HeadIdx;\r
  UINT16 NextAvailIdx;\r
} DESC_INDICES;\r
\r
\r
/**\r
\r
  Turn off interrupt notifications from the host, and prepare for appending\r
  multiple descriptors to the virtio ring.\r
\r
  The calling driver must be in VSTAT_DRIVER_OK state.\r
\r
  @param[in out] Ring  The virtio ring we intend to append descriptors to.\r
\r
  @param[out] Indices  The DESC_INDICES structure to initialize.\r
\r
**/\r
VOID\r
EFIAPI\r
VirtioPrepare (\r
  IN OUT VRING        *Ring,\r
  OUT    DESC_INDICES *Indices\r
  );\r
\r
\r
/**\r
\r
  Append a contiguous buffer for transmission / reception via the virtio ring.\r
\r
  This function implements the following sections from virtio-0.9.5:\r
  - 2.4.1.1 Placing Buffers into the Descriptor Table\r
  - 2.4.1.2 Updating the Available Ring\r
\r
  Free space is taken as granted, since the individual drivers support only\r
  synchronous requests and host side status is processed in lock-step with\r
  request submission. It is the calling driver's responsibility to verify the\r
  ring size in advance.\r
\r
  The caller is responsible for initializing *Indices with VirtioPrepare()\r
  first.\r
\r
  @param[in out] Ring           The virtio ring to append the buffer to, as a\r
                                descriptor.\r
\r
  @param [in] BufferPhysAddr    (Guest pseudo-physical) start address of the\r
                                transmit / receive buffer.\r
\r
  @param [in] BufferSize        Number of bytes to transmit or receive.\r
\r
  @param [in] Flags             A bitmask of VRING_DESC_F_* flags. The caller\r
                                computes this mask dependent on further buffers\r
                                to append and transfer direction.\r
                                VRING_DESC_F_INDIRECT is unsupported. The\r
                                VRING_DESC.Next field is always set, but the\r
                                host only interprets it dependent on\r
                                VRING_DESC_F_NEXT.\r
\r
  In *Indices:\r
\r
  @param [in] HeadIdx           The index identifying the head buffer (first\r
                                buffer appended) belonging to this same\r
                                request.\r
\r
  @param [in out] NextAvailIdx  On input, the index identifying the next\r
                                descriptor available to carry the buffer. On\r
                                output, incremented by one, modulo 2^16.\r
\r
**/\r
VOID\r
EFIAPI\r
VirtioAppendDesc (\r
  IN OUT VRING        *Ring,\r
  IN     UINTN        BufferPhysAddr,\r
  IN     UINT32       BufferSize,\r
  IN     UINT16       Flags,\r
  IN OUT DESC_INDICES *Indices\r
  );\r
\r
\r
/**\r
\r
  Notify the host about appended descriptors and wait until it processes the\r
  last one (ie. all of them).\r
\r
  @param[in] PciIo        The target virtio PCI device to notify.\r
\r
  @param[in] VirtQueueId  Identifies the queue for the target device.\r
\r
  @param[in out] Ring     The virtio ring with descriptors to submit.\r
\r
  @param[in] Indices      The function waits until the host processes\r
                          descriptors up to Indices->NextAvailIdx.\r
\r
\r
  @return              Error code from VirtioWrite() if it fails.\r
\r
  @retval EFI_SUCCESS  Otherwise, the host processed all descriptors.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
VirtioFlush (\r
  IN     EFI_PCI_IO_PROTOCOL *PciIo,\r
  IN     UINT16              VirtQueueId,\r
  IN OUT VRING               *Ring,\r
  IN     DESC_INDICES        *Indices\r
  );\r
\r
#endif // _VIRTIO_LIB_H_\r