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m68k: don't provide arch_dma_alloc for nommu/coldfire

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Coldfire cores configured with a data cache can't provide coherent
DMA allocations at all.

Instead of returning non-coherent kernel memory in this case,
return NULL and fail the allocation.

The only driver that used to rely on the previous behavior (fec) has
been switched to use non-coherent allocations for this case recently.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
This commit is contained in:
Christoph Hellwig 2023-10-12 09:52:27 +02:00
parent ffd32a92b3
commit 7a360df941
2 changed files with 0 additions and 24 deletions
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1
arch/m68k/Kconfig
View File

@ -6,7 +6,6 @@ config M68K
select ARCH_HAS_BINFMT_FLAT
select ARCH_HAS_CPU_FINALIZE_INIT if MMU
select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_DMA_ALLOC if M68K_NONCOHERENT_DMA && COLDFIRE
select ARCH_HAS_DMA_PREP_COHERENT if M68K_NONCOHERENT_DMA && !COLDFIRE
select ARCH_HAS_SYNC_DMA_FOR_DEVICE if M68K_NONCOHERENT_DMA
select ARCH_HAVE_NMI_SAFE_CMPXCHG if RMW_INSNS

23
arch/m68k/kernel/dma.c
View File

@ -33,29 +33,6 @@ pgprot_t pgprot_dmacoherent(pgprot_t prot)
}
return prot;
}
#else
void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
gfp_t gfp, unsigned long attrs)
{
void *ret;
if (dev == NULL || (*dev->dma_mask < 0xffffffff))
gfp |= GFP_DMA;
ret = (void *)__get_free_pages(gfp, get_order(size));
if (ret != NULL) {
memset(ret, 0, size);
*dma_handle = virt_to_phys(ret);
}
return ret;
}
void arch_dma_free(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle, unsigned long attrs)
{
free_pages((unsigned long)vaddr, get_order(size));
}
#endif /* CONFIG_MMU && !CONFIG_COLDFIRE */
void arch_sync_dma_for_device(phys_addr_t handle, size_t size,