From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id 36B926B017D for ; Tue, 21 Jun 2011 07:23:47 -0400 (EDT) MIME-version: 1.0 Content-type: text/plain; charset=iso-8859-2 Received: from spt2.w1.samsung.com ([210.118.77.14]) by mailout4.w1.samsung.com (Sun Java(tm) System Messaging Server 6.3-8.04 (built Jul 29 2009; 32bit)) with ESMTP id <0LN5002UI0ZJQI60@mailout4.w1.samsung.com> for linux-mm@kvack.org; Tue, 21 Jun 2011 12:23:43 +0100 (BST) Received: from linux.samsung.com ([106.116.38.10]) by spt2.w1.samsung.com (iPlanet Messaging Server 5.2 Patch 2 (built Jul 14 2004)) with ESMTPA id <0LN500F7P0ZI4V@spt2.w1.samsung.com> for linux-mm@kvack.org; Tue, 21 Jun 2011 12:23:42 +0100 (BST) Date: Tue, 21 Jun 2011 13:23:35 +0200 From: Marek Szyprowski Subject: RE: [PATCH 7/8] common: dma-mapping: change alloc/free_coherent method to more generic alloc/free_attrs In-reply-to: Message-id: <002401cc3005$a941c010$fbc54030$%szyprowski@samsung.com> Content-language: pl Content-transfer-encoding: quoted-printable References: <1308556213-24970-1-git-send-email-m.szyprowski@samsung.com> <1308556213-24970-8-git-send-email-m.szyprowski@samsung.com> Sender: owner-linux-mm@kvack.org List-ID: To: 'KyongHo Cho' Cc: linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, 'Kyungmin Park' , 'Arnd Bergmann' , 'Joerg Roedel' , 'Russell King - ARM Linux' Hello, On Monday, June 20, 2011 4:46 PM KyongHo Cho wrote: > On Mon, Jun 20, 2011 at 4:50 PM, Marek Szyprowski > wrote: >=20 > > =A0struct dma_map_ops { > > - =A0 =A0 =A0 void* (*alloc_coherent)(struct device *dev, size_t = size, > > - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 = dma_addr_t *dma_handle, gfp_t gfp); > > - =A0 =A0 =A0 void (*free_coherent)(struct device *dev, size_t size, > > - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 void = *vaddr, dma_addr_t dma_handle); > > + =A0 =A0 =A0 void* (*alloc)(struct device *dev, size_t size, > > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 = dma_addr_t *dma_handle, gfp_t gfp, > > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 struct = dma_attrs *attrs); > > + =A0 =A0 =A0 void (*free)(struct device *dev, size_t size, > > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 void = *vaddr, dma_addr_t dma_handle, > > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 struct = dma_attrs *attrs); > > + =A0 =A0 =A0 int (*mmap)(struct device *, struct vm_area_struct *, > > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 void *, = dma_addr_t, size_t, struct dma_attrs > *attrs); > > + > > =A0 =A0 =A0 =A0dma_addr_t (*map_page)(struct device *dev, struct = page *page, > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 unsigned = long offset, size_t size, > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 enum = dma_data_direction dir, >=20 > I still don't agree with your idea that change alloc_coherent() with > alloc(). > As I said before, we actually do not need dma_alloc_writecombine() = anymore > because it is not different from dma_alloc_coherent() in ARM. You already got a reply that dropping dma_alloc_writecombine() is no go on ARM. > Most of other architectures do not have dma_alloc_writecombine(). That's not a problem. Once we agree on dma_alloc_attrs(), the drivers can be changed to use DMA_ATTR_WRITE_COMBINE attribute. If the platform doesn't support the attribute, it is just ignored. That's the whole point of the attributes extension. Once a driver is converted to=20 dma_alloc_attrs(), it can be used without any changes either on = platforms that supports some specific attributes or the one that doesn't implement support for any of them. > If you want dma_alloc_coherent() to allocate user virtual address, > I believe that it is also available with mmap() you introduced. Allocation is a separate operation from mapping to userspace. Mmap operation should just map the buffer (represented by a cookie of type dma_addr_t) to user address space. Note that some drivers (like framebuffer drivers for example) also needs to have both types of mapping - one for user space and one for kernel virtual space. Best regards --=20 Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org