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/*
* DMA implementation for Hexagon
*
* Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#include <linux/dma-noncoherent.h>
#include <linux/bootmem.h>
#include <linux/genalloc.h>
#include <linux/module.h>
#include <asm/page.h>
static struct gen_pool *coherent_pool;
/* Allocates from a pool of uncached memory that was reserved at boot time */
void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_addr,
gfp_t flag, unsigned long attrs)
{
void *ret;
/*
* Our max_low_pfn should have been backed off by 16MB in
* mm/init.c to create DMA coherent space. Use that as the VA
* for the pool.
*/
if (coherent_pool == NULL) {
coherent_pool = gen_pool_create(PAGE_SHIFT, -1);
if (coherent_pool == NULL)
panic("Can't create %s() memory pool!", __func__);
else
gen_pool_add(coherent_pool,
(unsigned long)pfn_to_virt(max_low_pfn),
hexagon_coherent_pool_size, -1);
}
ret = (void *) gen_pool_alloc(coherent_pool, size);
if (ret) {
memset(ret, 0, size);
*dma_addr = (dma_addr_t) virt_to_phys(ret);
} else
*dma_addr = ~0;
return ret;
}
void arch_dma_free(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_addr, unsigned long attrs)
{
gen_pool_free(coherent_pool, (unsigned long) vaddr, size);
}
void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
size_t size, enum dma_data_direction dir)
{
void *addr = phys_to_virt(paddr);
switch (dir) {
case DMA_TO_DEVICE:
hexagon_clean_dcache_range((unsigned long) addr,
(unsigned long) addr + size);
break;
case DMA_FROM_DEVICE:
hexagon_inv_dcache_range((unsigned long) addr,
(unsigned long) addr + size);
break;
case DMA_BIDIRECTIONAL:
flush_dcache_range((unsigned long) addr,
(unsigned long) addr + size);
break;
default:
BUG();
}
}
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