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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/usr/mbox/mbox_dma_buffer.C $ */
/* */
/* IBM CONFIDENTIAL */
/* */
/* COPYRIGHT International Business Machines Corp. 2012 */
/* */
/* p1 */
/* */
/* Object Code Only (OCO) source materials */
/* Licensed Internal Code Source Materials */
/* IBM HostBoot Licensed Internal Code */
/* */
/* The source code for this program is not published or otherwise */
/* divested of its trade secrets, irrespective of what has been */
/* deposited with the U.S. Copyright Office. */
/* */
/* Origin: 30 */
/* */
/* IBM_PROLOG_END_TAG */
#include "mbox_dma_buffer.H"
#include <stdlib.h>
#include <assert.h>
#include <util/align.H>
#include <trace/interface.H>
#include <kernel/pagemgr.H>
#define ALIGN_DMAPAGE(u) (((u) + (VmmManager::MBOX_DMA_PAGESIZE-1)) & \
~(VmmManager::MBOX_DMA_PAGESIZE-1))
using namespace MBOX;
// Defined in mboxdd.C
extern trace_desc_t * g_trac_mbox;
DmaBuffer::DmaBuffer() :
iv_head(NULL),
iv_dir(makeMask(VmmManager::MBOX_DMA_PAGES))
{
iv_head = reinterpret_cast<void*>(VmmManager::MBOX_DMA_ADDR);
iv_phys_head = mm_virt_to_phys(iv_head);
}
DmaBuffer::~DmaBuffer()
{
}
void DmaBuffer::release(void * i_buffer, size_t i_size)
{
if(!i_buffer)
{
return;
}
// Make sure this buffer falls inside the DMA space
// If not then it's not a DMA buffer - exit.
if(i_buffer < iv_head ||
i_buffer >= (static_cast<uint8_t*>(iv_head) +
(VmmManager::MBOX_DMA_PAGES *
VmmManager::MBOX_DMA_PAGESIZE)))
{
TRACDCOMP(g_trac_mbox,
ERR_MRK"MBOX DMA buffer address %p out of range",
i_buffer
);
return;
}
// Calculate the # of chunks
size_t chunks = ALIGN_DMAPAGE(i_size)/VmmManager::MBOX_DMA_PAGESIZE;
uint64_t offset =
(static_cast<uint8_t *>(i_buffer) - static_cast<uint8_t *>(iv_head)) /
VmmManager::MBOX_DMA_PAGESIZE;
// makeMask will assert if chunks > total possible # of chunks in the dir
uint64_t mask = makeMask(chunks);
mask >>= offset;
iv_dir |= mask;
TRACDCOMP(g_trac_mbox,"MBOX DMA free dir: %016lx",iv_dir);
}
void DmaBuffer::addBuffers(uint64_t i_map)
{
iv_dir |= i_map;
TRACDCOMP(g_trac_mbox,"MBOXDMA addBuffers. dir: %016lx",iv_dir);
}
void * DmaBuffer::getBuffer(uint64_t & io_size)
{
// Note: Due to this check, makeMask() will never assert while trying to
// make a mask for the requested size. Instead, getBuffer will just return
// NULL if the requested size is larger than the total possible DMA buffer
// space.
if(io_size == 0 ||
io_size > (VmmManager::MBOX_DMA_PAGES * VmmManager::MBOX_DMA_PAGESIZE))
{
io_size = 0;
return NULL;
}
void * r_addr = NULL;
size_t chunks = ALIGN_DMAPAGE(io_size)/VmmManager::MBOX_DMA_PAGESIZE;
size_t start_page = 0;
size_t shift_count = (MAX_MASK_SIZE + 1) - chunks;
uint64_t mask = makeMask(chunks);
io_size = 0;
// look for a contiguous block of DMA space.
// If shift_count goes to zero, the request could not be granted.
while(shift_count)
{
if((mask & iv_dir) == mask)
{
break;
}
mask >>= 1;
++start_page;
--shift_count;
}
if(shift_count)
{
iv_dir &= ~mask;
io_size = mask;
uint64_t offset = start_page * VmmManager::MBOX_DMA_PAGESIZE;
r_addr = static_cast<void*>(static_cast<uint8_t*>(iv_head) + offset);
}
TRACDCOMP(g_trac_mbox,"MBOX DMA allocate dir: %016lx",iv_dir);
return r_addr;
}
uint64_t DmaBuffer::makeMask(uint64_t i_size)
{
assert(i_size <= MAX_MASK_SIZE);
uint64_t mask = 0;
// For some reason (1ul << 64) returns 1, not zero
// The math function pow() converts things to float then back again - bad
if(i_size < MAX_MASK_SIZE)
{
mask = 1ul << i_size;
}
mask -= 1;
mask <<= MAX_MASK_SIZE - i_size;
return mask;
}
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