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m68k: Use the generic dma coherent remap allocator

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This switches m68k to using common code for the DMA allocations,
including potential use of the CMA allocator if configured.
Also add a comment where the existing behavior seems to be lacking.

Switching to the generic code enables DMA allocations from atomic
context, which is required by the DMA API documentation, and also
adds various other minor features drivers start relying upon.  It
also makes sure we have a tested code base for all architectures
that require uncached pte bits for coherent DMA allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
This commit is contained in:
Christoph Hellwig
2019-06-25 11:01:34 +02:00
committed by Geert Uytterhoeven
parent f67d667213
commit 34dc63a5fb
2 changed files with 10 additions and 48 deletions
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56
arch/m68k/kernel/dma.c
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@@ -18,57 +18,17 @@
#include <asm/pgalloc.h>
#if defined(CONFIG_MMU) && !defined(CONFIG_COLDFIRE)
void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
gfp_t flag, unsigned long attrs)
pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot,
unsigned long attrs)
{
struct page *page, **map;
pgprot_t pgprot;
void *addr;
int i, order;
pr_debug("dma_alloc_coherent: %d,%x\n", size, flag);
size = PAGE_ALIGN(size);
order = get_order(size);
page = alloc_pages(flag | __GFP_ZERO, order);
if (!page)
return NULL;
*handle = page_to_phys(page);
map = kmalloc(sizeof(struct page *) << order, flag & ~__GFP_DMA);
if (!map) {
__free_pages(page, order);
return NULL;
if (CPU_IS_040_OR_060) {
pgprot_val(prot) &= ~_PAGE_CACHE040;
pgprot_val(prot) |= _PAGE_GLOBAL040 | _PAGE_NOCACHE_S;
} else {
pgprot_val(prot) |= _PAGE_NOCACHE030;
}
split_page(page, order);
order = 1 << order;
size >>= PAGE_SHIFT;
map[0] = page;
for (i = 1; i < size; i++)
map[i] = page + i;
for (; i < order; i++)
__free_page(page + i);
pgprot = __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY);
if (CPU_IS_040_OR_060)
pgprot_val(pgprot) |= _PAGE_GLOBAL040 | _PAGE_NOCACHE_S;
else
pgprot_val(pgprot) |= _PAGE_NOCACHE030;
addr = vmap(map, size, VM_MAP, pgprot);
kfree(map);
return addr;
return prot;
}
void arch_dma_free(struct device *dev, size_t size, void *addr,
dma_addr_t handle, unsigned long attrs)
{
pr_debug("dma_free_coherent: %p, %x\n", addr, handle);
vfree(addr);
}
#else
#include <asm/cacheflush.h>