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/*
* OpenRISC Linux
*
* Linux architectural port borrowing liberally from similar works of
* others. All original copyrights apply as per the original source
* declaration.
*
* Modifications for the OpenRISC architecture:
* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* DMA mapping callbacks...
* As alloc_coherent is the only DMA callback being used currently, that's
* the only thing implemented properly. The rest need looking into...
*/
#include <linux/dma-mapping.h>
#include <linux/dma-debug.h>
#include <asm/cpuinfo.h>
#include <asm/spr_defs.h>
#include <asm/tlbflush.h>
static int page_set_nocache(pte_t *pte, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
unsigned long cl;
pte_val(*pte) |= _PAGE_CI;
/*
* Flush the page out of the TLB so that the new page flags get
* picked up next time there's an access
*/
flush_tlb_page(NULL, addr);
/* Flush page out of dcache */
for (cl = __pa(addr); cl < __pa(next); cl += cpuinfo.dcache_block_size)
mtspr(SPR_DCBFR, cl);
return 0;
}
static int page_clear_nocache(pte_t *pte, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
pte_val(*pte) &= ~_PAGE_CI;
/*
* Flush the page out of the TLB so that the new page flags get
* picked up next time there's an access
*/
flush_tlb_page(NULL, addr);
return 0;
}
/*
* Alloc "coherent" memory, which for OpenRISC means simply uncached.
*
* This function effectively just calls __get_free_pages, sets the
* cache-inhibit bit on those pages, and makes sure that the pages are
* flushed out of the cache before they are used.
*
*/
void *or1k_dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp)
{
unsigned long va;
void *page;
struct mm_walk walk = {
.pte_entry = page_set_nocache,
.mm = &init_mm
};
page = alloc_pages_exact(size, gfp);
if (!page)
return NULL;
/* This gives us the real physical address of the first page. */
*dma_handle = __pa(page);
va = (unsigned long)page;
/*
* We need to iterate through the pages, clearing the dcache for
* them and setting the cache-inhibit bit.
*/
if (walk_page_range(va, va + size, &walk)) {
free_pages_exact(page, size);
return NULL;
}
return (void *)va;
}
void or1k_dma_free_coherent(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle)
{
unsigned long va = (unsigned long)vaddr;
struct mm_walk walk = {
.pte_entry = page_clear_nocache,
.mm = &init_mm
};
/* walk_page_range shouldn't be able to fail here */
WARN_ON(walk_page_range(va, va + size, &walk));
free_pages_exact(vaddr, size);
}
dma_addr_t or1k_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
struct dma_attrs *attrs)
{
unsigned long cl;
dma_addr_t addr = page_to_phys(page) + offset;
switch (dir) {
case DMA_TO_DEVICE:
/* Flush the dcache for the requested range */
for (cl = addr; cl < addr + size;
cl += cpuinfo.dcache_block_size)
mtspr(SPR_DCBFR, cl);
break;
case DMA_FROM_DEVICE:
/* Invalidate the dcache for the requested range */
for (cl = addr; cl < addr + size;
cl += cpuinfo.dcache_block_size)
mtspr(SPR_DCBIR, cl);
break;
default:
/*
* NOTE: If dir == DMA_BIDIRECTIONAL then there's no need to
* flush nor invalidate the cache here as the area will need
* to be manually synced anyway.
*/
break;
}
return addr;
}
void or1k_unmap_page(struct device *dev, dma_addr_t dma_handle,
size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs)
{
/* Nothing special to do here... */
}
void or1k_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction dir)
{
unsigned long cl;
dma_addr_t addr = dma_handle;
/* Invalidate the dcache for the requested range */
for (cl = addr; cl < addr + size; cl += cpuinfo.dcache_block_size)
mtspr(SPR_DCBIR, cl);
}
void or1k_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction dir)
{
unsigned long cl;
dma_addr_t addr = dma_handle;
/* Flush the dcache for the requested range */
for (cl = addr; cl < addr + size; cl += cpuinfo.dcache_block_size)
mtspr(SPR_DCBFR, cl);
}
/* Number of entries preallocated for DMA-API debugging */
#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
static int __init dma_init(void)
{
dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
return 0;
}
fs_initcall(dma_init);
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