linux-kernel - [PATCH 1/2] m68k: use the generic dma coherent remap allocator

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Date:   Fri, 14 Jun 2019 12:21:25 +0200
From:   Christoph Hellwig <hch@....de>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Greg Ungerer <gerg@...ux-m68k.org>
Cc:     linux-m68k@...ts.linux-m68k.org, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] m68k: use the generic dma coherent remap allocator

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

Signed-off-by: Christoph Hellwig <hch@....de>
---
 arch/m68k/Kconfig      |  2 ++
 arch/m68k/kernel/dma.c | 59 ++++++++----------------------------------
 2 files changed, 13 insertions(+), 48 deletions(-)

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 218e037ef901..2571a8fba4b0 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -3,10 +3,12 @@ config M68K
 	bool
 	default y
 	select ARCH_32BIT_OFF_T
+	select ARCH_HAS_DMA_MMAP_PGPROT if MMU && !COLDFIRE
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if HAS_DMA
 	select ARCH_MIGHT_HAVE_PC_PARPORT if ISA
 	select ARCH_NO_COHERENT_DMA_MMAP if !MMU
 	select ARCH_NO_PREEMPT if !COLDFIRE
+	select DMA_DIRECT_REMAP if MMU && !COLDFIRE
 	select HAVE_IDE
 	select HAVE_AOUT if MMU
 	select HAVE_DEBUG_BUGVERBOSE
diff --git a/arch/m68k/kernel/dma.c b/arch/m68k/kernel/dma.c
index b4aa853051bd..9c6a350a16d8 100644
--- a/arch/m68k/kernel/dma.c
+++ b/arch/m68k/kernel/dma.c
@@ -18,57 +18,20 @@
 #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;
+	/*
+	 * XXX: this doesn't seem to handle the sun3 MMU at all.
+	 */
+	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>
-- 
2.20.1