DmaPool.h

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/* ========================================
 
  Copyright (C) 2025, Amlal El Mahrouss , licensed under the Apache 2.0 license.
 
  File: DmaPool.h
  Purpose: Dma Pool Manager.
 
======================================== */
 
#pragma once
 
#include <KernelKit/DebugOutput.h>
 
#ifdef __NE_AMD64__
#include <HALKit/AMD64/Processor.h>
#define kNeDMAPoolStart (0x1000000)
#define kNeDMAPoolSize (0x1000000)
#elif defined(__NE_ARM64__)
#include <HALKit/ARM64/Processor.h>

#define kNeDMAPoolStart (0x1000000)
#define kNeDMAPoolSize (0x1000000)
#endif
 
#define kNeDMABestAlign (8)
 
namespace Kernel {
inline UInt8*       kDmaPoolPtr = (UInt8*) kNeDMAPoolStart;
inline const UInt8* kDmaPoolEnd = (UInt8*) (kNeDMAPoolStart + kNeDMAPoolSize);
 
/***********************************************************************************/
/***********************************************************************************/
inline VoidPtr rtl_dma_alloc(SizeT size, SizeT align) {
  if (!size) {
    return nullptr;
  }

  if ((align % kNeDMABestAlign) != 0) {
    return nullptr;
  }
 
  UIntPtr addr = (UIntPtr) kDmaPoolPtr;

  addr = (addr + (align - 1)) & ~(align - 1);
 
  if ((addr + size) > reinterpret_cast<UIntPtr>(kDmaPoolEnd)) {
    err_global_get() = kErrorDmaExhausted;
    return nullptr;
  }
 
  kDmaPoolPtr = (UInt8*) (addr + size);
 
  HAL::mm_memory_fence((VoidPtr) addr);
 
  return (VoidPtr) addr;
}
 
/***********************************************************************************/
/***********************************************************************************/
inline Void rtl_dma_free(SizeT size) {
  if (!size) return;
 
  auto ptr = (kDmaPoolPtr - size);
 
  if (!ptr || ptr < (UInt8*) kNeDMAPoolStart) {
    err_global_get() = kErrorDmaExhausted;
    return;
  }
 
  kDmaPoolPtr = ptr;
 
  HAL::mm_memory_fence(ptr);
}
 
/***********************************************************************************/
/***********************************************************************************/
inline Void rtl_dma_flush(VoidPtr ptr, SizeT size_buffer) {
  if (ptr > kDmaPoolEnd) {
    return;
  }
 
  if (!ptr || ptr < (UInt8*) kNeDMAPoolStart) {
    err_global_get() = kErrorDmaExhausted;
    return;
  }
 
  for (SizeT buf_idx = 0UL; buf_idx < size_buffer; ++buf_idx) {
    HAL::mm_memory_fence((VoidPtr) ((UInt8*) ptr + buf_idx));
  }
}
}  // namespace Kernel