[PATCH edk2-platforms v4 16/17] ARM/JunoPkg: Adding SCMI MTL library

[Girish Pathak <girish.pathak@arm.com>]

This change adds a new Mailbox Transport Layer library for the Juno
platform. This library is required for ArmScmiDxe driver communication
with the SCP.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Girish Pathak <girish.pathak@arm.com>
---

Notes:
    v3:
    - Please rename this library *instance* to something
      Juno-specific, e.g., ArmJunoMtlLib                    [Ard]
    
      Renamed to ArmJunoMtlLib                              [Girish]

 Platform/ARM/JunoPkg/ArmJuno.dec                                  |   9 +-
 Platform/ARM/JunoPkg/ArmJuno.dsc                                  |   5 +-
 Platform/ARM/JunoPkg/Library/ArmJunoLib/ArmJunoMem.c              |   8 +-
 Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlLib.c        | 198 ++++++++++++++++++++
 Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlLib.inf      |  39 ++++
 Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlPrivateLib.h |  94 ++++++++++
 6 files changed, 349 insertions(+), 4 deletions(-)

diff --git a/Platform/ARM/JunoPkg/ArmJuno.dec b/Platform/ARM/JunoPkg/ArmJuno.dec
index 60cef6d23a2d904103b9806d871fd2b89fff51c3..fdb56fccb2b259301fd787016a9c4de7ab3c356d 100644
--- a/Platform/ARM/JunoPkg/ArmJuno.dec
+++ b/Platform/ARM/JunoPkg/ArmJuno.dec
@@ -1,5 +1,5 @@
 #
-#  Copyright (c) 2013-2015, ARM Limited. All rights reserved.
+#  Copyright (c) 2013-2018, ARM Limited. All rights reserved.
 #
 #  This program and the accompanying materials
 #  are licensed and made available under the terms and conditions of the BSD License
@@ -46,3 +46,10 @@ [PcdsFixedAtBuild.common]
   # Juno Device Trees are loaded from NOR Flash
   gArmJunoTokenSpaceGuid.PcdJunoFdtDevicePath|L"VenHw(E7223039-5836-41E1-B542-D7EC736C5E59)/board.dtb"|VOID*|0x00000008
 
+  # MHU Register base used by SCMI Mailbox transport
+  gArmJunoTokenSpaceGuid.PcdArmMtlDoorBell|0x2B1F0000|UINT64|0x00000024
+
+  # ARM_JUNO_NON_SECURE_SRAM_BASE used by SCMI Mailbox transport
+  gArmJunoTokenSpaceGuid.PcdArmMtlMailBoxBase|0x2E000000|UINT64|0x00000025
+  gArmJunoTokenSpaceGuid.PcdArmMtlMailBoxSize|0x80|UINT32|0x00000026
+
diff --git a/Platform/ARM/JunoPkg/ArmJuno.dsc b/Platform/ARM/JunoPkg/ArmJuno.dsc
index 9d7317683ef39ab47429234b98d94c04953b41cb..851dc0f04ad693e4a88cee070b205f0234687d81 100644
--- a/Platform/ARM/JunoPkg/ArmJuno.dsc
+++ b/Platform/ARM/JunoPkg/ArmJuno.dsc
@@ -1,5 +1,5 @@
 #
-#  Copyright (c) 2013-2017, ARM Limited. All rights reserved.
+#  Copyright (c) 2013-2018, ARM Limited. All rights reserved.
 #
 #  This program and the accompanying materials
 #  are licensed and made available under the terms and conditions of the BSD License
@@ -47,6 +47,9 @@ [LibraryClasses.common]
   # USB Requirements
   UefiUsbLib|MdePkg/Library/UefiUsbLib/UefiUsbLib.inf
 
+  # SCMI Mailbox Transport Layer
+  ArmMtlLib|Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlLib.inf
+
 [LibraryClasses.common.SEC]
   PrePiLib|EmbeddedPkg/Library/PrePiLib/PrePiLib.inf
   ExtractGuidedSectionLib|EmbeddedPkg/Library/PrePiExtractGuidedSectionLib/PrePiExtractGuidedSectionLib.inf
diff --git a/Platform/ARM/JunoPkg/Library/ArmJunoLib/ArmJunoMem.c b/Platform/ARM/JunoPkg/Library/ArmJunoLib/ArmJunoMem.c
index 2d9c2c95a80d9c34ba4a1a526950537a97ec5d10..2cac815e96104e74c9ceae2c4140bcab535432a8 100644
--- a/Platform/ARM/JunoPkg/Library/ArmJunoLib/ArmJunoMem.c
+++ b/Platform/ARM/JunoPkg/Library/ArmJunoLib/ArmJunoMem.c
@@ -1,6 +1,6 @@
 /** @file
 *
-*  Copyright (c) 2013-2015, ARM Limited. All rights reserved.
+*  Copyright (c) 2013-2018, ARM Limited. All rights reserved.
 *
 *  This program and the accompanying materials
 *  are licensed and made available under the terms and conditions of the BSD License
@@ -107,7 +107,11 @@ ArmPlatformGetVirtualMemoryMap (
   VirtualMemoryTable[++Index].PhysicalBase  = ARM_JUNO_NON_SECURE_SRAM_BASE;
   VirtualMemoryTable[Index].VirtualBase     = ARM_JUNO_NON_SECURE_SRAM_BASE;
   VirtualMemoryTable[Index].Length          = ARM_JUNO_NON_SECURE_SRAM_SZ;
-  VirtualMemoryTable[Index].Attributes      = CacheAttributes;
+  // This memory is shared between the application processor
+  // and the SCP. To avoid coherency problems, map it as uncached memory.
+  // NOTE: The attribute value is misleading, it indicates memory map type as
+  // an un-cached, un-buffered but allows buffering and reordering.
+  VirtualMemoryTable[Index].Attributes      = ARM_MEMORY_REGION_ATTRIBUTE_UNCACHED_UNBUFFERED;
 
   // PCI Root Complex
   VirtualMemoryTable[++Index].PhysicalBase  = PcdGet64 (PcdPcieControlBaseAddress);
diff --git a/Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlLib.c b/Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlLib.c
new file mode 100644
index 0000000000000000000000000000000000000000..ee1efe1574c124c7f7cf1fb345b46806bc3a4466
--- /dev/null
+++ b/Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlLib.c
@@ -0,0 +1,198 @@
+/** @file
+
+  Copyright (c) 2017-2018, Arm Limited. All rights reserved.
+
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+  System Control and Management Interface V1.0
+    http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/
+    DEN0056A_System_Control_and_Management_Interface.pdf
+**/
+
+#include <Uefi/UefiBaseType.h>
+#include <Uefi/UefiSpec.h>
+#include <Library/ArmLib.h>
+#include <Library/ArmMtlLib.h>
+#include <Library/DebugLib.h>
+#include <Library/IoLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/PcdLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+
+#include "ArmJunoMtlPrivateLib.h"
+
+// Each channel has a shared mailbox and a doorbell register.
+STATIC CONST MTL_CHANNEL Channels[NUM_CHANNELS] = {
+    // Low priority channel.
+    {
+      MTL_CHANNEL_TYPE_LOW,
+      (MTL_MAILBOX*)(MTL_MAILBOX_BASE),
+      DOORBELL_LOW
+    },
+    // High priority channel
+    {
+      MTL_CHANNEL_TYPE_HIGH,
+      (MTL_MAILBOX*)(MTL_MAILBOX_BASE + MTL_MAILBOX_HIGH_PRIORITY_OFFSET),
+      DOORBELL_HIGH
+    }
+  };
+
+/** Wait until channel is free.
+
+  @param[in] Channel                Pointer to a channel.
+  @param[in] TimeOutInMicroSeconds  Time out in micro seconds.
+
+  @retval EFI_SUCCESS               Channel is free.
+  @retval EFI_TIMEOUT               Time out error.
+**/
+EFI_STATUS
+MtlWaitUntilChannelFree (
+  IN MTL_CHANNEL  *Channel,
+  IN UINTN        TimeOutInMicroSeconds
+  )
+{
+  while (TimeOutInMicroSeconds != 0) {
+    // If channel is free then we have received the reply.
+    if (Channel->MailBox->ChannelStatus == MTL_CHANNEL_FREE) {
+      return EFI_SUCCESS;
+    }
+    if (TimeOutInMicroSeconds < MTL_POLL_WAIT_TIME) {
+      gBS->Stall (TimeOutInMicroSeconds);
+      break;
+    }
+    // Wait for some arbitrary time.
+    gBS->Stall (MTL_POLL_WAIT_TIME);
+    TimeOutInMicroSeconds -= MTL_POLL_WAIT_TIME;
+  }
+
+  // No response from SCP.
+  if (Channel->MailBox->ChannelStatus != MTL_CHANNEL_FREE) {
+    ASSERT (FALSE);
+    return EFI_TIMEOUT;
+  }
+
+  return EFI_SUCCESS;
+}
+
+/** Return the address of the message payload.
+
+  @param[in] Channel   Pointer to a channel.
+
+  @retval UINT32*      Pointer to the payload.
+**/
+UINT32*
+MtlGetChannelPayload (
+  IN  MTL_CHANNEL  *Channel
+  )
+{
+  return Channel->MailBox->Payload;
+}
+
+/** Return pointer to a channel for the requested channel type.
+
+  @param[in] ChannelType        ChannelType, Low or High priority channel.
+                                MTL_CHANNEL_TYPE_LOW or
+                                MTL_CHANNEL_TYPE_HIGH
+
+  @param[out] Channel           Holds pointer to the channel.
+
+  @retval EFI_SUCCESS           Pointer to channel is returned.
+  @retval EFI_UNSUPPORTED       Requested channel type not supported.
+**/
+EFI_STATUS
+MtlGetChannel (
+  IN  MTL_CHANNEL_TYPE  ChannelType,
+  OUT MTL_CHANNEL       **Channel
+  )
+{
+  if (ChannelType != MTL_CHANNEL_TYPE_LOW
+    && ChannelType != MTL_CHANNEL_TYPE_HIGH) {
+    return EFI_UNSUPPORTED;
+  }
+
+  *Channel = (MTL_CHANNEL*)&Channels[ChannelType];
+
+  return EFI_SUCCESS;
+}
+
+/** Mark the channel busy and ring the doorbell.
+
+  @param[in] Channel               Pointer to a channel.
+  @param[in] MessageHeader         Message header.
+
+  @param[out] PayloadLength        Message length.
+
+  @retval EFI_SUCCESS              Message sent successfully.
+  @retval EFI_DEVICE_ERROR         Channel is busy.
+**/
+EFI_STATUS
+MtlSendMessage (
+  IN  MTL_CHANNEL  *Channel,
+  IN  UINT32       MessageHeader,
+  OUT UINT32       PayloadLength
+  )
+{
+  MTL_MAILBOX *MailBox = Channel->MailBox;
+
+  if (Channel->MailBox->ChannelStatus != MTL_CHANNEL_FREE) {
+    return EFI_DEVICE_ERROR;
+  }
+
+  // Mark the channel busy before ringing doorbell.
+  Channel->MailBox->ChannelStatus = MTL_CHANNEL_BUSY;
+  ArmDataSynchronizationBarrier ();
+
+  MailBox->Flags         = MTL_POLL;
+  MailBox->MessageHeader = MessageHeader;
+
+  // Add length of message header.
+  MailBox->Length = PayloadLength + sizeof (MessageHeader);
+
+  // Ring the doorbell. It sets SET bit of the MHU register.
+  MmioWrite32 (
+    Channel->DoorBell.PhysicalAddress,
+    Channel->DoorBell.ModifyMask
+    );
+
+  return EFI_SUCCESS;
+}
+
+/** Wait for a response on a channel.
+
+  If channel is free after sending message, it implies SCP responded
+  with a response on the channel.
+
+  @param[in] Channel               Pointer to a channel.
+
+  @retval EFI_SUCCESS              Message received successfully.
+  @retval EFI_TIMEOUT              Time out error.
+**/
+EFI_STATUS
+MtlReceiveMessage (
+  IN  MTL_CHANNEL  *Channel,
+  OUT UINT32       *MessageHeader,
+  OUT UINT32       *PayloadLength
+  )
+{
+  EFI_STATUS Status;
+
+  MTL_MAILBOX *MailBox = Channel->MailBox;
+
+  Status = MtlWaitUntilChannelFree (Channel, RESPONSE_TIMEOUT);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  *MessageHeader = MailBox->MessageHeader;
+
+  // Deduct message header length.
+  *PayloadLength = MailBox->Length - sizeof (*MessageHeader);
+
+  return EFI_SUCCESS;
+}
diff --git a/Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlLib.inf b/Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlLib.inf
new file mode 100644
index 0000000000000000000000000000000000000000..4b46c8071db1dbb5c740576c75461f65216c7a95
--- /dev/null
+++ b/Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlLib.inf
@@ -0,0 +1,39 @@
+#/** @file
+#  Copyright (c) 2017-2018, Arm Limited. All rights reserved.
+#
+#  This program and the accompanying materials
+#  are licensed and made available under the terms and conditions of the BSD License
+#  which accompanies this distribution.  The full text of the license may be found at
+#  http://opensource.org/licenses/bsd-license.php
+#
+#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+#**/
+
+[Defines]
+  INF_VERSION                    = 0x00010019
+  BASE_NAME                      = ArmJunoMtlLib
+  FILE_GUID                      = 21FB2D8F-C6C8-4B2C-A616-A30CB2FBA277
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = ArmMtlLib
+
+[Sources.common]
+  ArmJunoMtlLib.c
+
+[Packages]
+  ArmPkg/ArmPkg.dec
+  ArmPlatformPkg/ArmPlatformPkg.dec
+  MdePkg/MdePkg.dec
+  Platform/ARM/JunoPkg/ArmJuno.dec
+
+[LibraryClasses]
+  ArmLib
+  DebugLib
+  IoLib
+  UefiBootServicesTableLib
+
+[FixedPcd.common]
+  gArmJunoTokenSpaceGuid.PcdArmMtlDoorBell
+  gArmJunoTokenSpaceGuid.PcdArmMtlMailBoxBase
+  gArmJunoTokenSpaceGuid.PcdArmMtlMailBoxSize
diff --git a/Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlPrivateLib.h b/Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlPrivateLib.h
new file mode 100644
index 0000000000000000000000000000000000000000..b2bac5e513e93b412307bff24298bbecc083d30c
--- /dev/null
+++ b/Platform/ARM/JunoPkg/Library/ArmJunoMtlLib/ArmJunoMtlPrivateLib.h
@@ -0,0 +1,94 @@
+/** @file
+
+  Copyright (c) 2017-2018, Arm Limited. All rights reserved.
+
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+  System Control and Management Interface V1.0
+    http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/
+    DEN0056A_System_Control_and_Management_Interface.pdf
+
+  Juno ARM Development Platform SoC
+    https://www.arm.com/files/pdf/
+    DDI0515D1a_juno_arm_development_platform_soc_trm.pdf
+**/
+
+#ifndef ARM_JUNO_MTL_PRIVATE_LIB_H_
+#define ARM_JUNO_MTL_PRIVATE_LIB_H_
+
+// Mailbox transport layer.
+#define MTL_DOORBELL_MODIFY_MASK   (0x00000001U)
+#define MTL_DOORBELL_PRESERVE_MASK (~MTL_DOORBELL_MODIFY_MASK)
+
+#define MTL_DOORBELL_BASE    (FixedPcdGet64 (PcdArmMtlDoorBell))
+#define MTL_MAILBOX_BASE     (FixedPcdGet64 (PcdArmMtlMailBoxBase))
+#define MTL_MAILBOX_SIZE     (FixedPcdGet32 (PcdArmMtlMailBoxSize))
+
+#define MTL_POLL         0
+#define MTL_INTR         1
+
+/* For Juno, the mailbox for high priority is non-trusted SRAM + 256.
+
+   NOTE: Below is not documented anywhere (yet)
+
+   The payload sizes are 128 bytes.
+
+   There are two channels:
+
+   Channel 0
+    - Agent (OS) to Platform (SCP) memory base: non-trusted SRAM + 0
+    - Platform (SCP) to Agent (OS) memory base: non-trusted SRAM + 128
+    - Doorbell (both directions): MHU, bit 0
+
+   Channel 1
+    - Agent (OS) to Platform (SCP) memory base: non-trusted SRAM + 256
+    - Platform (SCP) to Agent (OS) memory base: non-trusted SRAM + 384
+    - Doorbell (both directions): MHU, bit 0
+*/
+#define MTL_MAILBOX_HIGH_PRIORITY_OFFSET (MTL_MAILBOX_SIZE * 2)
+
+// ARM MHU interrupt registers.
+#define CPU_INTR_L_SET  0x108
+#define CPU_INTR_H_SET  0x128
+
+// MTL uses MHU interrupt registers for communication with the SCP.
+#define MTL_DOORBELL_REGISTER_LOW   (MTL_DOORBELL_BASE + CPU_INTR_L_SET)
+#define MTL_DOORBELL_REGISTER_HIGH  (MTL_DOORBELL_BASE + CPU_INTR_H_SET)
+
+#define MTL_CHANNEL_BUSY    0
+#define MTL_CHANNEL_FREE    1
+
+// Response time out value on a MHU channel 20ms.
+#define  RESPONSE_TIMEOUT  20000
+
+/* As per SCMI spec. as a agent UEFI(or OS) can access only two channels
+   (low or high priority) secure channel is only accessible
+   to ARM Trusted firmware. */
+#define  NUM_CHANNELS      2
+
+/* Each channel must use a doorbell register to interrupt the SCP firmware.
+   on Juno these are MHU interrupt registers for low and high priority
+   channels. */
+#define  DOORBELL_LOW   {                                \
+                          MTL_DOORBELL_REGISTER_LOW,     \
+                          MTL_DOORBELL_MODIFY_MASK,      \
+                          MTL_DOORBELL_PRESERVE_MASK     \
+                        }
+
+#define  DOORBELL_HIGH  {                                \
+                          MTL_DOORBELL_REGISTER_HIGH,    \
+                          MTL_DOORBELL_MODIFY_MASK,      \
+                          MTL_DOORBELL_PRESERVE_MASK     \
+                        }
+
+// Arbitarary poll time.
+#define MTL_POLL_WAIT_TIME 100
+
+#endif /* ARM_JUNO_MTL_PRIVATE_LIB_H_ */
+
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'