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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2000 Ani Joshi <ajoshi@unixbox.com>
* Copyright (C) 2000, 2001, 06 Ralf Baechle <ralf@linux-mips.org>
* swiped from i386, and cloned for MIPS by Geert, polished by Ralf.
*/
#include <linux/dma-direct.h>
#include <linux/dma-noncoherent.h>
#include <linux/dma-contiguous.h>
#include <linux/highmem.h>
#include <asm/cache.h>
#include <asm/cpu-type.h>
#include <asm/dma-coherence.h>
#include <asm/io.h>
/*
* The affected CPUs below in 'cpu_needs_post_dma_flush()' can speculatively
* fill random cachelines with stale data at any time, requiring an extra
* flush post-DMA.
*
* Warning on the terminology - Linux calls an uncached area coherent; MIPS
* terminology calls memory areas with hardware maintained coherency coherent.
*
* Note that the R14000 and R16000 should also be checked for in this condition.
* However this function is only called on non-I/O-coherent systems and only the
* R10000 and R12000 are used in such systems, the SGI IP28 Indigo² rsp.
* SGI IP32 aka O2.
*/
static inline bool cpu_needs_post_dma_flush(void)
{
switch (boot_cpu_type()) {
case CPU_R10000:
case CPU_R12000:
case CPU_BMIPS5000:
return true;
default:
/*
* Presence of MAARs suggests that the CPU supports
* speculatively prefetching data, and therefore requires
* the post-DMA flush/invalidate.
*/
return cpu_has_maar;
}
}
void arch_dma_prep_coherent(struct page *page, size_t size)
{
dma_cache_wback_inv((unsigned long)page_address(page), size);
}
void *uncached_kernel_address(void *addr)
{
return (void *)(__pa(addr) + UNCAC_BASE);
}
static inline void dma_sync_virt(void *addr, size_t size,
enum dma_data_direction dir)
{
switch (dir) {
case DMA_TO_DEVICE:
dma_cache_wback((unsigned long)addr, size);
break;
case DMA_FROM_DEVICE:
dma_cache_inv((unsigned long)addr, size);
break;
case DMA_BIDIRECTIONAL:
dma_cache_wback_inv((unsigned long)addr, size);
break;
default:
BUG();
}
}
/*
* A single sg entry may refer to multiple physically contiguous pages. But
* we still need to process highmem pages individually. If highmem is not
* configured then the bulk of this loop gets optimized out.
*/
static inline void dma_sync_phys(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
unsigned long offset = paddr & ~PAGE_MASK;
size_t left = size;
do {
size_t len = left;
if (PageHighMem(page)) {
void *addr;
if (offset + len > PAGE_SIZE)
len = PAGE_SIZE - offset;
addr = kmap_atomic(page);
dma_sync_virt(addr + offset, len, dir);
kunmap_atomic(addr);
} else
dma_sync_virt(page_address(page) + offset, size, dir);
offset = 0;
page++;
left -= len;
} while (left);
}
void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
dma_sync_phys(paddr, size, dir);
}
#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
if (cpu_needs_post_dma_flush())
dma_sync_phys(paddr, size, dir);
}
#endif
void arch_dma_cache_sync(struct device *dev, void *vaddr, size_t size,
enum dma_data_direction direction)
{
BUG_ON(direction == DMA_NONE);
dma_sync_virt(vaddr, size, direction);
}
#ifdef CONFIG_DMA_PERDEV_COHERENT
void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
const struct iommu_ops *iommu, bool coherent)
{
dev->dma_coherent = coherent;
}
#endif
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