288fd4e56e
This patch extends the RAM session interface with the ability to allocate DMA buffers. The client specifies the type of RAM dataspace to allocate via the new 'cached' argument of the 'Ram_session::alloc()' function. By default, 'cached' is true, which correponds to the common case and the original behavior. When setting 'cached' to 'false', core takes the precautions needed to register the memory as uncached in the page table of each process that has the dataspace attached. Currently, the support for allocating DMA buffers is implemented for Fiasco.OC only. On x86 platforms, it is generally not needed. But on platforms with more relaxed cache coherence (such as ARM), user-level device drivers should always use uncacheable memory for DMA transactions.
149 lines
3.8 KiB
C++
149 lines
3.8 KiB
C++
/*
|
|
* \brief Core-specific instance of the IO_MEM session interface
|
|
* \author Christian Helmuth
|
|
* \date 2006-09-14
|
|
*/
|
|
|
|
/*
|
|
* Copyright (C) 2006-2012 Genode Labs GmbH
|
|
*
|
|
* This file is part of the Genode OS framework, which is distributed
|
|
* under the terms of the GNU General Public License version 2.
|
|
*/
|
|
|
|
#ifndef _CORE__INCLUDE__IO_MEM_SESSION_COMPONENT_H_
|
|
#define _CORE__INCLUDE__IO_MEM_SESSION_COMPONENT_H_
|
|
|
|
/* Genode includes */
|
|
#include <base/allocator.h>
|
|
#include <base/rpc_server.h>
|
|
#include <io_mem_session/io_mem_session.h>
|
|
|
|
/* core includes */
|
|
#include <dataspace_component.h>
|
|
|
|
namespace Genode {
|
|
|
|
class Io_mem_session_component : public Rpc_object<Io_mem_session>
|
|
{
|
|
private:
|
|
|
|
/*
|
|
* Helper class used to pass the dataspace attributes as
|
|
* parameters from the _prepare_io_mem function to the
|
|
* constructor of Dataspace_component.
|
|
*/
|
|
struct Dataspace_attr
|
|
{
|
|
size_t size;
|
|
addr_t core_local_addr;
|
|
addr_t phys_addr;
|
|
bool write_combined;
|
|
|
|
/**
|
|
* Base address of request used for freeing mem-ranges
|
|
*/
|
|
addr_t req_base;
|
|
|
|
/**
|
|
* Default constructor
|
|
*
|
|
* This constructor enables Dataspace_attr objects to be
|
|
* returned from the '_prepare_io_mem' function.
|
|
*/
|
|
Dataspace_attr() : size(0) { }
|
|
|
|
/**
|
|
* Constructor
|
|
*
|
|
* An invalid dataspace is represented by setting all
|
|
* arguments to zero.
|
|
*/
|
|
Dataspace_attr(size_t s, addr_t cla, addr_t pa, bool write_combined,
|
|
addr_t req_base)
|
|
:
|
|
size(s), core_local_addr(cla), phys_addr(pa), req_base(req_base) { }
|
|
};
|
|
|
|
struct Io_dataspace_component : Dataspace_component
|
|
{
|
|
addr_t req_base;
|
|
|
|
/**
|
|
* Constructor
|
|
*/
|
|
Io_dataspace_component(Dataspace_attr da)
|
|
:
|
|
Dataspace_component(da.size, da.core_local_addr,
|
|
da.phys_addr, da.write_combined,
|
|
true, 0),
|
|
req_base(da.req_base) { }
|
|
|
|
|
|
bool valid() { return size() != 0; }
|
|
};
|
|
|
|
Range_allocator *_io_mem_alloc;
|
|
Io_dataspace_component _ds;
|
|
Rpc_entrypoint *_ds_ep;
|
|
Io_mem_dataspace_capability _ds_cap;
|
|
bool _write_combined;
|
|
|
|
Dataspace_attr _prepare_io_mem(const char *args, Range_allocator *ram_alloc);
|
|
|
|
|
|
/********************************************
|
|
** Platform-implemented support functions **
|
|
********************************************/
|
|
|
|
/* FIXME Could this be merged with Dataspace::unmap() and friends? */
|
|
|
|
/**
|
|
* Map region locally and return local base address
|
|
*
|
|
* Both parameters - base and size - must be page-aligned.
|
|
*/
|
|
addr_t _map_local(addr_t base, size_t size);
|
|
|
|
/**
|
|
* Unmap Core-local mapping of region
|
|
*
|
|
* Both parameters - base and size - must be page-aligned.
|
|
*/
|
|
void _unmap_local(addr_t base, size_t size);
|
|
|
|
public:
|
|
|
|
/**
|
|
* Constructor
|
|
*
|
|
* \param io_mem_alloc MMIO region allocator
|
|
* \param ram_alloc RAM allocator that will be checked for
|
|
* region collisions
|
|
* \param ds_ep entry point to manage the dataspace
|
|
* corresponding the io_mem session
|
|
* \param args session construction arguments, in
|
|
* particular MMIO region base, size and
|
|
* caching demands
|
|
*/
|
|
Io_mem_session_component(Range_allocator *io_mem_alloc,
|
|
Range_allocator *ram_alloc,
|
|
Rpc_entrypoint *ds_ep,
|
|
const char *args);
|
|
|
|
/**
|
|
* Destructor
|
|
*/
|
|
~Io_mem_session_component();
|
|
|
|
|
|
/******************************
|
|
** Io-mem session interface **
|
|
******************************/
|
|
|
|
Io_mem_dataspace_capability dataspace() { return _ds_cap; }
|
|
};
|
|
}
|
|
|
|
#endif /* _CORE__INCLUDE__IO_MEM_SESSION_COMPONENT_H_ */
|