netdev - [PATCH 6/6] m68k: don't provide arch_dma

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Message-Id: <20231009074121.219686-7-hch@lst.de>
Date: Mon,  9 Oct 2023 09:41:21 +0200
From: Christoph Hellwig <hch@....de>
To: iommu@...ts.linux.dev
Cc: Robin Murphy <robin.murphy@....com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Wei Fang <wei.fang@....com>,
	Shenwei Wang <shenwei.wang@....com>,
	Clark Wang <xiaoning.wang@....com>,
	NXP Linux Team <linux-imx@....com>,
	linux-m68k@...ts.linux-m68k.org,
	netdev@...r.kernel.org,
	Jim Quinlan <james.quinlan@...adcom.com>
Subject: [PATCH 6/6] m68k: don't provide arch_dma_alloc for nommu/coldfire

m68knommu and coldfire can't provide coherent DMA allocations at all.
Currently they simply return normal kernel memory from
dma_alloc_coherent, which is broken and breaks the API contract.  Now
that the only DMA capable driver on these systems has been switched
to use explicitly non-coherent allocations we can drop this hack and
return NULL from dma_alloc_coherent.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 arch/m68k/Kconfig      |  1 -
 arch/m68k/kernel/dma.c | 23 -----------------------
 2 files changed, 24 deletions(-)

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 0430b8ba6b5cc6..3e318bf9504c5b 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -3,7 +3,6 @@ config M68K
 	bool
 	default y
 	select ARCH_32BIT_OFF_T
-	select ARCH_DMA_ALLOC if !MMU || COLDFIRE
 	select ARCH_HAS_BINFMT_FLAT
 	select ARCH_HAS_CPU_FINALIZE_INIT if MMU
 	select ARCH_HAS_CURRENT_STACK_POINTER
diff --git a/arch/m68k/kernel/dma.c b/arch/m68k/kernel/dma.c
index 2e192a5df949bb..eb164ef1a45ebd 100644
--- a/arch/m68k/kernel/dma.c
+++ b/arch/m68k/kernel/dma.c
@@ -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,
-- 
2.39.2