Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751616AbbFRVtN (ORCPT ); Thu, 18 Jun 2015 17:49:13 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:38858 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750728AbbFRVtL (ORCPT ); Thu, 18 Jun 2015 17:49:11 -0400 From: Lorenzo Nava To: arnd@arndb.de Cc: linux@arm.linux.org.uk, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, Lorenzo Nava Subject: [RFC PATCH v3] arm DMA: Fix allocation from CMA for coherent DMA Date: Thu, 18 Jun 2015 23:44:22 +0200 Message-Id: <1434663862-17858-1-git-send-email-lorenx4@gmail.com> X-Mailer: git-send-email 1.7.10.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3486 Lines: 103 This patch allows the use of CMA for DMA coherent memory allocation. At the moment if the input parameter "is_coherent" is set to true the allocation is not made using the CMA, which I think is not the desired behaviour. Signed-off-by: Lorenzo Nava --- Changes in v2: correct __arm_dma_free() according to __dma_alloc() allocation --- Changes in v3: now __dma_alloc(), if 'is_coherent' is true, returns memory from CMA if there is no need for atomic allocation. If CMA is not available the function returns the result of __alloc_simple_buffer(). __arm_dma_free() frees memory according to the new alloc function avoiding __dma_free_remap() for coherent DMA if CMA is not enable. arm_dma_alloc() mark pages as cacheable if attrs are set by default to NULL. If attrs is not NULL, attributes are preserved in the allocation. Coherent allocation tested on Xilinx Zynq processor. --- arch/arm/mm/dma-mapping.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 7e7583d..8e7f402 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -645,15 +645,29 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, size = PAGE_ALIGN(size); want_vaddr = !dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs); - if (is_coherent || nommu()) + if (nommu()) { addr = __alloc_simple_buffer(dev, size, gfp, &page); - else if (!(gfp & __GFP_WAIT)) + goto dma_alloc_done; + } + + if (dev_get_cma_area(dev) && (gfp & __GFP_WAIT)) { + addr = __alloc_from_contiguous(dev, size, prot, &page, + caller, want_vaddr); + goto dma_alloc_done; + } + + if (is_coherent) { + addr = __alloc_simple_buffer(dev, size, gfp, &page); + goto dma_alloc_done; + } + + if (!(gfp & __GFP_WAIT)) addr = __alloc_from_pool(size, &page); - else if (!dev_get_cma_area(dev)) - addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller, want_vaddr); else - addr = __alloc_from_contiguous(dev, size, prot, &page, caller, want_vaddr); + addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, + caller, want_vaddr); +dma_alloc_done: if (page) *handle = pfn_to_dma(dev, page_to_pfn(page)); @@ -680,9 +694,14 @@ void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, static void *arm_coherent_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs) { - pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL); + pgprot_t prot; void *memory; + if (attrs == NULL) + prot = PAGE_KERNEL; + else + prot = __get_dma_pgprot(attrs, PAGE_KERNEL); + if (dma_alloc_from_coherent(dev, size, handle, &memory)) return memory; @@ -735,12 +754,12 @@ static void __arm_dma_free(struct device *dev, size_t size, void *cpu_addr, size = PAGE_ALIGN(size); - if (is_coherent || nommu()) { + if (nommu()) { __dma_free_buffer(page, size); } else if (__free_from_pool(cpu_addr, size)) { return; } else if (!dev_get_cma_area(dev)) { - if (want_vaddr) + if (want_vaddr && !is_coherent) __dma_free_remap(cpu_addr, size); __dma_free_buffer(page, size); } else { -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/