From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Szyprowski Subject: Re: [PATCH/RFC 0/4] Re: dma_mmap_coherent / ARCH_HAS_DMA_MMAP_COHERENT Date: Wed, 02 Jan 2013 15:39:55 +0100 Message-ID: <50E446BB.7090609@samsung.com> References: <1356722614-18224-1-git-send-email-geert@linux-m68k.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mailout1.w1.samsung.com ([210.118.77.11]:31142 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752677Ab3ABOkA (ORCPT ); Wed, 2 Jan 2013 09:40:00 -0500 In-reply-to: <1356722614-18224-1-git-send-email-geert@linux-m68k.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Geert Uytterhoeven Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-m68k@vger.kernel.org Hello, On 12/28/2012 8:23 PM, Geert Uytterhoeven wrote: > On Sun, Dec 16, 2012 at 5:03 PM, Geert Uytterhoeven > wrote: > > drivers/media/v4l2-core/videobuf2-dma-contig.c: In function =E2=80=98= vb2_dc_mmap=E2=80=99: > > drivers/media/v4l2-core/videobuf2-dma-contig.c:204: error: implicit= declaration of function =E2=80=98dma_mmap_coherent=E2=80=99 > > drivers/media/v4l2-core/videobuf2-dma-contig.c: In function =E2=80=98= vb2_dc_get_base_sgt=E2=80=99: > > drivers/media/v4l2-core/videobuf2-dma-contig.c:387: error: implicit= declaration of function =E2=80=98dma_get_sgtable=E2=80=99 > > make[6]: *** [drivers/media/v4l2-core/videobuf2-dma-contig.o] Error= 1 > > make[6]: Target `__build' not remade because of errors. > > make[5]: *** [drivers/media/v4l2-core] Error 2 > > > > Both dma_mmap_coherent() and dma_get_sgtable() are defined in > > include/asm-generic/dma-mapping-common.h only, which is included by > > on alpha, arm, arm64, hexagon, ia64, microblaze= , mips, > > openrisc, powerpc, s390, sh, sparc, tile, unicore32, x86. > > Should the remaining architectures include this, too? > > Should it be moved to ? > > I came up with an RFC-solution for this in [PATCH/RFC 3/4] > ("avr32/bfin/c6x/cris/frv/m68k/mn10300/parisc/xtensa: Add dummy get_d= ma_ops()") > and [PATCH/RFC 4/4] ("common: dma-mapping: Move dma_common_*() to > ") of this series. > > > Furthermore, there's ARCH_HAS_DMA_MMAP_COHERENT, which is defined > > by powerpc only: > > arch/powerpc/include/asm/dma-mapping.h:#define ARCH_HAS_DMA_MMAP_CO= HERENT > > > > and handled in some fishy way in sound/core/pcm_native.c: > > > > #ifndef ARCH_HAS_DMA_MMAP_COHERENT > > /* This should be defined / handled globally! */ > > #ifdef CONFIG_ARM > > #define ARCH_HAS_DMA_MMAP_COHERENT > > #endif > > #endif > > > > /* > > * mmap the DMA buffer on RAM > > */ > > int snd_pcm_lib_default_mmap(struct snd_pcm_substream *substream, > > struct vm_area_struct *area) > > { > > area->vm_flags |=3D VM_DONTEXPAND | VM_DONTDUMP; > > #ifdef ARCH_HAS_DMA_MMAP_COHERENT > > if (!substream->ops->page && > > substream->dma_buffer.dev.type =3D=3D SNDRV_DMA_TYPE_DE= V) > > return dma_mmap_coherent(substream->dma_buffer.dev.= dev, > > area, > > substream->runtime->dma_ar= ea, > > substream->runtime->dma_ad= dr, > > area->vm_end - area->vm_st= art); > > #elif defined(CONFIG_MIPS) && defined(CONFIG_DMA_NONCOHERENT) > > if (substream->dma_buffer.dev.type =3D=3D SNDRV_DMA_TYPE_DE= V && > > !plat_device_is_coherent(substream->dma_buffer.dev.dev)= ) > > area->vm_page_prot =3D pgprot_noncached(area->vm_pa= ge_prot); > > #endif /* ARCH_HAS_DMA_MMAP_COHERENT */ > > /* mmap with fault handler */ > > area->vm_ops =3D &snd_pcm_vm_ops_data_fault; > > return 0; > > } > > EXPORT_SYMBOL_GPL(snd_pcm_lib_default_mmap); > > > > What's up here? > > Probably an easy solution here is to kill ARCH_HAS_DMA_MMAP_COHERENT = and > change the code to > > #if defined(CONFIG_MIPS) && defined(CONFIG_DMA_NONCOHERENT) > if (substream->dma_buffer.dev.type =3D=3D SNDRV_DMA_TYPE_DEV && > !plat_device_is_coherent(substream->dma_buffer.dev.dev)) > area->vm_page_prot =3D pgprot_noncached(area->vm_page_prot); > #else > if (!substream->ops->page && > substream->dma_buffer.dev.type =3D=3D SNDRV_DMA_TYPE_DEV) > return dma_mmap_coherent(substream->dma_buffer.dev.dev, > area, > substream->runtime->dma_area, > substream->runtime->dma_addr, > area->vm_end - area->vm_start); > #endif > > but obviously I don't like the test for CONFIG_MIPS in generic code..= =2E I think that the best way of handling it would be to move this code to = MIPS specific dma_mmap_coherent() implementation. Best regards --=20 Marek Szyprowski Samsung Poland R&D Center