/** @file
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Copyright (c) 2017-2018, Arm Limited. All rights reserved.
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SPDX-License-Identifier: BSD-2-Clause-Patent
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System Control and Management Interface V1.0
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http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/
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DEN0056A_System_Control_and_Management_Interface.pdf
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**/
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#include <Uefi/UefiBaseType.h>
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#include <Uefi/UefiSpec.h>
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#include <Library/ArmLib.h>
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#include <Library/ArmMtlLib.h>
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#include <Library/DebugLib.h>
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#include <Library/IoLib.h>
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#include <Library/MemoryAllocationLib.h>
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#include <Library/PcdLib.h>
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#include <Library/UefiBootServicesTableLib.h>
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#include "ArmJunoMtlPrivateLib.h"
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// Each channel has a shared mailbox and a doorbell register.
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STATIC CONST MTL_CHANNEL Channels[NUM_CHANNELS] = {
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// Low priority channel.
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{
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MTL_CHANNEL_TYPE_LOW,
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(MTL_MAILBOX*)(MTL_MAILBOX_BASE),
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DOORBELL_LOW
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},
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// High priority channel
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{
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MTL_CHANNEL_TYPE_HIGH,
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(MTL_MAILBOX*)(MTL_MAILBOX_BASE + MTL_MAILBOX_HIGH_PRIORITY_OFFSET),
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DOORBELL_HIGH
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}
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};
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/** Wait until channel is free.
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@param[in] Channel Pointer to a channel.
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@param[in] TimeOutInMicroSeconds Time out in micro seconds.
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@retval EFI_SUCCESS Channel is free.
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@retval EFI_TIMEOUT Time out error.
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**/
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EFI_STATUS
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MtlWaitUntilChannelFree (
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IN MTL_CHANNEL *Channel,
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IN UINTN TimeOutInMicroSeconds
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)
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{
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while (TimeOutInMicroSeconds != 0) {
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// If channel is free then we have received the reply.
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if (Channel->MailBox->ChannelStatus == MTL_CHANNEL_FREE) {
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return EFI_SUCCESS;
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}
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if (TimeOutInMicroSeconds < MTL_POLL_WAIT_TIME) {
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gBS->Stall (TimeOutInMicroSeconds);
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break;
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}
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// Wait for some arbitrary time.
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gBS->Stall (MTL_POLL_WAIT_TIME);
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TimeOutInMicroSeconds -= MTL_POLL_WAIT_TIME;
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}
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// No response from SCP.
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if (Channel->MailBox->ChannelStatus != MTL_CHANNEL_FREE) {
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ASSERT (FALSE);
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return EFI_TIMEOUT;
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}
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return EFI_SUCCESS;
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}
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/** Return the address of the message payload.
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@param[in] Channel Pointer to a channel.
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@retval UINT32* Pointer to the payload.
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**/
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UINT32*
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MtlGetChannelPayload (
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IN MTL_CHANNEL *Channel
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)
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{
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return Channel->MailBox->Payload;
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}
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/** Return pointer to a channel for the requested channel type.
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@param[in] ChannelType ChannelType, Low or High priority channel.
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MTL_CHANNEL_TYPE_LOW or
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MTL_CHANNEL_TYPE_HIGH
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@param[out] Channel Holds pointer to the channel.
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@retval EFI_SUCCESS Pointer to channel is returned.
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@retval EFI_UNSUPPORTED Requested channel type not supported.
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**/
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EFI_STATUS
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MtlGetChannel (
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IN MTL_CHANNEL_TYPE ChannelType,
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OUT MTL_CHANNEL **Channel
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)
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{
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if (ChannelType != MTL_CHANNEL_TYPE_LOW
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&& ChannelType != MTL_CHANNEL_TYPE_HIGH) {
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return EFI_UNSUPPORTED;
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}
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*Channel = (MTL_CHANNEL*)&Channels[ChannelType];
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return EFI_SUCCESS;
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}
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/** Mark the channel busy and ring the doorbell.
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@param[in] Channel Pointer to a channel.
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@param[in] MessageHeader Message header.
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@param[out] PayloadLength Message length.
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@retval EFI_SUCCESS Message sent successfully.
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@retval EFI_DEVICE_ERROR Channel is busy.
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**/
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EFI_STATUS
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MtlSendMessage (
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IN MTL_CHANNEL *Channel,
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IN UINT32 MessageHeader,
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OUT UINT32 PayloadLength
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)
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{
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MTL_MAILBOX *MailBox = Channel->MailBox;
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if (Channel->MailBox->ChannelStatus != MTL_CHANNEL_FREE) {
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return EFI_DEVICE_ERROR;
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}
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// Mark the channel busy before ringing doorbell.
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Channel->MailBox->ChannelStatus = MTL_CHANNEL_BUSY;
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ArmDataSynchronizationBarrier ();
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MailBox->Flags = MTL_POLL;
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MailBox->MessageHeader = MessageHeader;
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// Add length of message header.
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MailBox->Length = PayloadLength + sizeof (MessageHeader);
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// Ring the doorbell. It sets SET bit of the MHU register.
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MmioWrite32 (
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Channel->DoorBell.PhysicalAddress,
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Channel->DoorBell.ModifyMask
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);
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return EFI_SUCCESS;
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}
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/** Wait for a response on a channel.
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If channel is free after sending message, it implies SCP responded
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with a response on the channel.
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@param[in] Channel Pointer to a channel.
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@retval EFI_SUCCESS Message received successfully.
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@retval EFI_TIMEOUT Time out error.
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**/
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EFI_STATUS
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MtlReceiveMessage (
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IN MTL_CHANNEL *Channel,
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OUT UINT32 *MessageHeader,
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OUT UINT32 *PayloadLength
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)
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{
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EFI_STATUS Status;
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MTL_MAILBOX *MailBox = Channel->MailBox;
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Status = MtlWaitUntilChannelFree (Channel, RESPONSE_TIMEOUT);
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if (EFI_ERROR (Status)) {
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return Status;
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}
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*MessageHeader = MailBox->MessageHeader;
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// Deduct message header length.
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*PayloadLength = MailBox->Length - sizeof (*MessageHeader);
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return EFI_SUCCESS;
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}
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