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91 lines
2.1 KiB
C++
91 lines
2.1 KiB
C++
/*
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* \brief Utility to allocate and locally attach a DMA buffer
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* \author Norman Feske
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* \date 2022-02-02
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*/
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/*
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* Copyright (C) 2022 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__PLATFORM_SESSION__DMA_BUFFER_H_
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#define _INCLUDE__PLATFORM_SESSION__DMA_BUFFER_H_
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/* Genode includes */
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#include <base/attached_dataspace.h>
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#include <platform_session/connection.h>
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class Platform::Dma_buffer : Noncopyable
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{
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private:
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struct Allocation
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{
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Platform::Connection &platform;
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size_t const size;
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Cache const cache;
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Ram_dataspace_capability _alloc()
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{
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return platform.retry_with_upgrade(Ram_quota{4096}, Cap_quota{2},
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[&] () { return platform.alloc_dma_buffer(size, cache); });
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}
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Ram_dataspace_capability cap = _alloc();
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addr_t const dma_addr = platform.dma_addr(cap);
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Allocation(Connection &platform, size_t size, Cache cache)
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: platform(platform), size(size), cache(cache) { }
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~Allocation() { platform.free_dma_buffer(cap); }
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} _allocation;
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Attached_dataspace _ds { _allocation.platform._rm, _allocation.cap };
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public:
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/**
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* Constructor
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*
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* \param platform platform session used for the buffer allocation
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* \param size DMA buffer size in bytes
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*
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* \throw Out_of_ram
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* \throw Out_of_caps
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* \throw Region_map::Region_conflict
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*/
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Dma_buffer(Connection &platform, size_t size, Cache cache)
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:
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_allocation(platform, size, cache)
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{ }
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/**
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* Return component-local base address
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*/
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template <typename T> T *local_addr() { return _ds.local_addr<T>(); }
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template <typename T> T const *local_addr() const { return _ds.local_addr<T>(); }
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/**
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* Return bus address to be used for DMA operations
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*/
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addr_t dma_addr() const { return _allocation.dma_addr; }
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/**
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* Return DMA-buffer size in bytes
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*/
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size_t size() const { return _allocation.size; }
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/**
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* Return DMA-buffer as dataspace capability
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*/
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Dataspace_capability cap() { return _ds.cap(); }
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};
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#endif /* _INCLUDE__PLATFORM_SESSION__DMA_BUFFER_H_ */
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