From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 9FAE31A0E91 for ; Fri, 20 Feb 2015 19:35:44 +1100 (AEDT) Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id E1EB714018C for ; Fri, 20 Feb 2015 19:35:43 +1100 (AEDT) Message-ID: <1424421330.27448.42.camel@kernel.crashing.org> Subject: [PATCH 2/3] powerpc/dma: Support 32-bit coherent mask with 64-bit dma_mask From: Benjamin Herrenschmidt To: linuxppc-dev@ozlabs.org Date: Fri, 20 Feb 2015 19:35:30 +1100 Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: Scott Wood , Anton Blanchard , Brian J King List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Some drivers try to use a 64-bit dma_mask and a smaller (32-bit typically) coherent dma mask. We don't currently support that on platforms that do direct DMA because: - We use the generic dma_set_coherent_mask() - It will use dma_supported() with the provided mask - Our imlpementation of the latter in dma_set_our dma_direct_dma_supported() will fail if the mask passed isn't big enough to cover all of memory (+ DMA offset) This fixes it by making dma_direct_dma_supported() use the ZONE_DMA32 limit when it's enabled, and removing the ifdef CONFIG_FSL_SOC around the code in dma_direct_alloc_coherent() that supports allocating from the 32-bit zone. (Nowadays, most drivers have been fixed). This carries an additional change which is to generalize the test against memblock_end_of_DRAM() + "dma_offset" to 32-bit platforms, instead of just unconditionally returning 1 for these. This should work since the rest of the code in the direct DMA ops assume this is true anyway. Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/pgtable.h | 1 + arch/powerpc/kernel/dma.c | 21 ++++++--------------- arch/powerpc/mm/mem.c | 5 +++++ 3 files changed, 12 insertions(+), 15 deletions(-) diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h index 9835ac4..a3680b8 100644 --- a/arch/powerpc/include/asm/pgtable.h +++ b/arch/powerpc/include/asm/pgtable.h @@ -217,6 +217,7 @@ extern pgd_t swapper_pg_dir[]; void limit_zone_pfn(enum zone_type zone, unsigned long max_pfn); int dma_pfn_limit_to_zone(u64 pfn_limit); +u64 dma_get_zone_limit(int zone); extern void paging_init(void); /* diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c index 484b2d4..e24e0ae 100644 --- a/arch/powerpc/kernel/dma.c +++ b/arch/powerpc/kernel/dma.c @@ -53,16 +53,9 @@ void *dma_direct_alloc_coherent(struct device *dev, size_t size, #else struct page *page; int node = dev_to_node(dev); -#ifdef CONFIG_FSL_SOC u64 pfn = get_pfn_limit(dev); int zone; - /* - * This code should be OK on other platforms, but we have drivers that - * don't set coherent_dma_mask. As a workaround we just ifdef it. This - * whole routine needs some serious cleanup. - */ - zone = dma_pfn_limit_to_zone(pfn); if (zone < 0) { dev_err(dev, "%s: No suitable zone for pfn %#llx\n", @@ -80,7 +73,6 @@ void *dma_direct_alloc_coherent(struct device *dev, size_t size, break; #endif }; -#endif /* CONFIG_FSL_SOC */ /* ignore region specifiers */ flag &= ~(__GFP_HIGHMEM); @@ -149,14 +141,13 @@ static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg, static int dma_direct_dma_supported(struct device *dev, u64 mask) { -#ifdef CONFIG_PPC64 - /* Could be improved so platforms can set the limit in case - * they have limited DMA windows - */ - return mask >= get_dma_offset(dev) + (memblock_end_of_DRAM() - 1); -#else - return 1; + u64 offset = get_dma_offset(dev); + u64 limit = offset + memblock_end_of_DRAM() - 1; + +#if defined(CONFIG_ZONE_DMA32) + limit = offset + dma_get_zone_limit(ZONE_DMA32); #endif + return mask >= limit; } static u64 dma_direct_get_required_mask(struct device *dev) diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index f146ef0..a7f15e2 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -277,6 +277,11 @@ int dma_pfn_limit_to_zone(u64 pfn_limit) return -EPERM; } +u64 dma_get_zone_limit(int zone) +{ + return max_zone_pfns[zone] << PAGE_SHIFT; +} + /* * paging_init() sets up the page tables - in fact we've already done this. */