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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
*
* DMA mapping callbacks...
*/
#include <linux/dma-noncoherent.h>
#include <linux/pagewalk.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;
struct cpuinfo_or1k *cpuinfo = &cpuinfo_or1k[smp_processor_id()];
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 const struct mm_walk_ops set_nocache_walk_ops = {
.pte_entry = page_set_nocache,
};
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;
}
static const struct mm_walk_ops clear_nocache_walk_ops = {
.pte_entry = page_clear_nocache,
};
void *arch_dma_set_uncached(void *cpu_addr, size_t size)
{
unsigned long va = (unsigned long)cpu_addr;
int error;
/*
* We need to iterate through the pages, clearing the dcache for
* them and setting the cache-inhibit bit.
*/
mmap_read_lock(&init_mm);
error = walk_page_range(&init_mm, va, va + size, &set_nocache_walk_ops,
NULL);
mmap_read_unlock(&init_mm);
if (error)
return ERR_PTR(error);
return cpu_addr;
}
void arch_dma_clear_uncached(void *cpu_addr, size_t size)
{
unsigned long va = (unsigned long)cpu_addr;
mmap_read_lock(&init_mm);
/* walk_page_range shouldn't be able to fail here */
WARN_ON(walk_page_range(&init_mm, va, va + size,
&clear_nocache_walk_ops, NULL));
mmap_read_unlock(&init_mm);
}
void arch_sync_dma_for_device(phys_addr_t addr, size_t size,
enum dma_data_direction dir)
{
unsigned long cl;
struct cpuinfo_or1k *cpuinfo = &cpuinfo_or1k[smp_processor_id()];
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;
}
}
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