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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(struct device *dev)
{
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_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
void *ret;
ret = dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);
if (!ret && !(attrs & DMA_ATTR_NON_CONSISTENT)) {
dma_cache_wback_inv((unsigned long) ret, size);
ret = (void *)UNCAC_ADDR(ret);
}
return ret;
}
void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs)
{
if (!(attrs & DMA_ATTR_NON_CONSISTENT))
cpu_addr = (void *)CAC_ADDR((unsigned long)cpu_addr);
dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs);
}
int arch_dma_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
unsigned long user_count = vma_pages(vma);
unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long addr = CAC_ADDR((unsigned long)cpu_addr);
unsigned long off = vma->vm_pgoff;
unsigned long pfn = page_to_pfn(virt_to_page((void *)addr));
int ret = -ENXIO;
if (attrs & DMA_ATTR_WRITE_COMBINE)
vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
else
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
return ret;
if (off < count && user_count <= (count - off)) {
ret = remap_pfn_range(vma, vma->vm_start,
pfn + off,
user_count << PAGE_SHIFT,
vma->vm_page_prot);
}
return ret;
}
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) {
if (offset >= PAGE_SIZE) {
page += offset >> PAGE_SHIFT;
offset &= ~PAGE_MASK;
}
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(struct device *dev, phys_addr_t paddr,
size_t size, enum dma_data_direction dir)
{
dma_sync_phys(paddr, size, dir);
}
void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
size_t size, enum dma_data_direction dir)
{
if (cpu_needs_post_dma_flush(dev))
dma_sync_phys(paddr, size, dir);
}
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);
}
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