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// Copyright 2024-2026, Amlal El Mahrouss (amlal@nekernel.org)
// Licensed under the Apache License, Version 2.0 (see LICENSE file)
// Official repository: https://github.com/nekernel-org/nekernel
#ifndef DMAKIT_DMAPOOL_H
#define DMAKIT_DMAPOOL_H
#include <KernelKit/DebugOutput.h>
#include __nekernel_halkit_include_processor
#define kNeDMAPoolStart (__nekernel_dma_pool_start)
#define kNeDMAPoolSize (__nekernel_dma_pool_size)
#define kNeDMABestAlign (__nekernel_dma_best_align)
namespace Kernel {
/// @brief DMA pool base pointer, here we're sure that AHCI or whatever tricky standard sees it.
inline UInt8* kDmaPoolPtr = (UInt8*) kNeDMAPoolStart;
/// @brief DMA pool end pointer.
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;
}
/// Check alignement according to architecture.
if ((align % kNeDMABestAlign) != 0) {
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)) {
err_global_get() = kErrorDmaExhausted;
return nullptr;
}
kDmaPoolPtr = (UInt8*) (addr + size);
HAL::mm_memory_fence((VoidPtr) addr);
return (VoidPtr) addr;
}
/***********************************************************************************/
/// @brief Free DMA pointer.
/***********************************************************************************/
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);
}
/***********************************************************************************/
/// @brief Flush DMA pointer.
/***********************************************************************************/
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
#endif
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