summaryrefslogtreecommitdiffhomepage
path: root/dev/kernel/DmaKit/DmaPool.h
blob: d15346b832f3ec6e06222b832baa761489c42895 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
/* -------------------------------------------

  Copyright (C) 2025, Amlal El Mahrouss , all rights reserved.

  File: FileMgr.h
  Purpose: Kernel file manager.

------------------------------------------- */

#pragma once

#include <HALKit/AMD64/Processor.h>
#include <KernelKit/DebugOutput.h>

#ifdef __NE_AMD64__
#define kNeDMAPoolStart (0x1000000)
#define kNeDMAPoolSize (0x1000000)

namespace Kernel {
/// @brief DMA pool base pointer, here we're sure that AHCI or whatever tricky standard sees it.
inline UInt8*       kDmaPoolPtr = (UInt8*) kNeDMAPoolStart;
inline const UInt8* kDmaPoolEnd = (UInt8*) (kNeDMAPoolStart + kNeDMAPoolSize);

/***********************************************************************************/
/// @brief allocate from the rtl_dma_alloc system.
/// @param size the size of the chunk to allocate.
/// @param align alignement of pointer.
/***********************************************************************************/
inline VoidPtr rtl_dma_alloc(SizeT size, SizeT align) {
  if (!size) {
    return nullptr;
  }

  UIntPtr addr = (UIntPtr) kDmaPoolPtr;

  /// here we just align the address according to a `align` variable, i'd rather be a power of two
  /// really.
  addr = (addr + (align - 1)) & ~(align - 1);

  if ((addr + size) >= reinterpret_cast<UIntPtr>(kDmaPoolEnd)) {
    kout << "DMA Pool is exhausted!\r";

    err_global_get() = kErrorDmaExhausted;

    return nullptr;
  }

  kDmaPoolPtr = (UInt8*) (addr + size);
  return (VoidPtr) addr;
}

/***********************************************************************************/
/// @brief Free DMA pointer.
/***********************************************************************************/
inline Void rtl_dma_free(SizeT size) {
  if (!size) return;

  kDmaPoolPtr = (UInt8*) (kDmaPoolPtr - size);
}

/***********************************************************************************/
/// @brief Flush DMA pointer.
/***********************************************************************************/
inline Void rtl_dma_flush(VoidPtr ptr, SizeT size_buffer) {
  if (ptr > kDmaPoolEnd) {
    return;
  }

  if (!ptr || ptr < (UInt8*) kNeDMAPoolStart) {
    return;
  }

  for (SizeT buf_idx = 0UL; buf_idx < size_buffer; ++buf_idx) {
    HAL::mm_memory_fence((VoidPtr) ((UInt8*) ptr + buf_idx));
  }
}
}  // namespace Kernel
#endif