From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lgeamrelo01.lge.com (lgeamrelo01.lge.com [156.147.1.125]) by lists.ozlabs.org (Postfix) with ESMTP id 2258A1A054F for ; Thu, 12 Jun 2014 13:17:52 +1000 (EST) From: Joonsoo Kim To: Andrew Morton , "Aneesh Kumar K.V" , Marek Szyprowski , Michal Nazarewicz Subject: [PATCH v2 04/10] DMA, CMA: support alignment constraint on cma region Date: Thu, 12 Jun 2014 12:21:41 +0900 Message-Id: <1402543307-29800-5-git-send-email-iamjoonsoo.kim@lge.com> In-Reply-To: <1402543307-29800-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1402543307-29800-1-git-send-email-iamjoonsoo.kim@lge.com> Cc: Russell King - ARM Linux , kvm@vger.kernel.org, linux-mm@kvack.org, Gleb Natapov , Greg Kroah-Hartman , Alexander Graf , kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org, Minchan Kim , Paul Mackerras , Paolo Bonzini , Joonsoo Kim , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , ppc kvm's cma area management needs alignment constraint on cma region. So support it to prepare generalization of cma area management functionality. Additionally, add some comments which tell us why alignment constraint is needed on cma region. Signed-off-by: Joonsoo Kim diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c index 8a44c82..bc4c171 100644 --- a/drivers/base/dma-contiguous.c +++ b/drivers/base/dma-contiguous.c @@ -32,6 +32,7 @@ #include #include #include +#include struct cma { unsigned long base_pfn; @@ -219,6 +220,7 @@ core_initcall(cma_init_reserved_areas); * @size: Size of the reserved area (in bytes), * @base: Base address of the reserved area optional, use 0 for any * @limit: End address of the reserved memory (optional, 0 for any). + * @alignment: Alignment for the contiguous memory area, should be power of 2 * @res_cma: Pointer to store the created cma region. * @fixed: hint about where to place the reserved area * @@ -233,15 +235,15 @@ core_initcall(cma_init_reserved_areas); */ static int __init __dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, phys_addr_t limit, + phys_addr_t alignment, struct cma **res_cma, bool fixed) { struct cma *cma = &cma_areas[cma_area_count]; - phys_addr_t alignment; int ret = 0; - pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__, - (unsigned long)size, (unsigned long)base, - (unsigned long)limit); + pr_debug("%s(size %lx, base %08lx, limit %08lx align_order %08lx)\n", + __func__, (unsigned long)size, (unsigned long)base, + (unsigned long)limit, (unsigned long)alignment); /* Sanity checks */ if (cma_area_count == ARRAY_SIZE(cma_areas)) { @@ -253,8 +255,17 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size, if (!size) return -EINVAL; - /* Sanitise input arguments */ - alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order); + if (alignment && !is_power_of_2(alignment)) + return -EINVAL; + + /* + * Sanitise input arguments. + * CMA area should be at least MAX_ORDER - 1 aligned. Otherwise, + * CMA area could be merged into other MIGRATE_TYPE by buddy mechanism + * and CMA property will be broken. + */ + alignment = max(alignment, + (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order)); base = ALIGN(base, alignment); size = ALIGN(size, alignment); limit &= ~(alignment - 1); @@ -302,7 +313,8 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, { int ret; - ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed); + ret = __dma_contiguous_reserve_area(size, base, limit, 0, + res_cma, fixed); if (ret) return ret; -- 1.7.9.5