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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-mapping.h>
#include <linux/dma-direct.h>
#include <linux/bootmem.h>
#include <linux/genalloc.h>
#include <asm/dma-mapping.h>
#include <linux/module.h>
#include <asm/page.h>
#define HEXAGON_MAPPING_ERROR 0
const struct dma_map_ops *dma_ops;
EXPORT_SYMBOL(dma_ops);
static inline void *dma_addr_to_virt(dma_addr_t dma_addr)
{
return phys_to_virt((unsigned long) dma_addr);
}
static struct gen_pool *coherent_pool;
/* Allocates from a pool of uncached memory that was reserved at boot time */
static void *hexagon_dma_alloc_coherent(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;
}
static void hexagon_free_coherent(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);
}
static int check_addr(const char *name, struct device *hwdev,
dma_addr_t bus, size_t size)
{
if (hwdev && hwdev->dma_mask && !dma_capable(hwdev, bus, size)) {
if (*hwdev->dma_mask >= DMA_BIT_MASK(32))
printk(KERN_ERR
"%s: overflow %Lx+%zu of device mask %Lx\n",
name, (long long)bus, size,
(long long)*hwdev->dma_mask);
return 0;
}
return 1;
}
static int hexagon_map_sg(struct device *hwdev, struct scatterlist *sg,
int nents, enum dma_data_direction dir,
unsigned long attrs)
{
struct scatterlist *s;
int i;
WARN_ON(nents == 0 || sg[0].length == 0);
for_each_sg(sg, s, nents, i) {
s->dma_address = sg_phys(s);
if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
return 0;
s->dma_length = s->length;
if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
continue;
flush_dcache_range(dma_addr_to_virt(s->dma_address),
dma_addr_to_virt(s->dma_address + s->length));
}
return nents;
}
/*
* address is virtual
*/
static inline void dma_sync(void *addr, size_t size,
enum dma_data_direction dir)
{
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();
}
}
/**
* hexagon_map_page() - maps an address for device DMA
* @dev: pointer to DMA device
* @page: pointer to page struct of DMA memory
* @offset: offset within page
* @size: size of memory to map
* @dir: transfer direction
* @attrs: pointer to DMA attrs (not used)
*
* Called to map a memory address to a DMA address prior
* to accesses to/from device.
*
* We don't particularly have many hoops to jump through
* so far. Straight translation between phys and virtual.
*
* DMA is not cache coherent so sync is necessary; this
* seems to be a convenient place to do it.
*
*/
static dma_addr_t hexagon_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
unsigned long attrs)
{
dma_addr_t bus = page_to_phys(page) + offset;
WARN_ON(size == 0);
if (!check_addr("map_single", dev, bus, size))
return HEXAGON_MAPPING_ERROR;
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
dma_sync(dma_addr_to_virt(bus), size, dir);
return bus;
}
static void hexagon_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction dir)
{
dma_sync(dma_addr_to_virt(dma_handle), size, dir);
}
static void hexagon_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction dir)
{
dma_sync(dma_addr_to_virt(dma_handle), size, dir);
}
static int hexagon_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
return dma_addr == HEXAGON_MAPPING_ERROR;
}
const struct dma_map_ops hexagon_dma_ops = {
.alloc = hexagon_dma_alloc_coherent,
.free = hexagon_free_coherent,
.map_sg = hexagon_map_sg,
.map_page = hexagon_map_page,
.sync_single_for_cpu = hexagon_sync_single_for_cpu,
.sync_single_for_device = hexagon_sync_single_for_device,
.mapping_error = hexagon_mapping_error,
};
void __init hexagon_dma_init(void)
{
if (dma_ops)
return;
dma_ops = &hexagon_dma_ops;
}
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