From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 396B1C2D0A3 for ; Tue, 3 Nov 2020 19:13:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C4789216C4 for ; Tue, 3 Nov 2020 19:13:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728939AbgKCTNq convert rfc822-to-8bit (ORCPT ); Tue, 3 Nov 2020 14:13:46 -0500 Received: from aposti.net ([89.234.176.197]:41592 "EHLO aposti.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725957AbgKCTNq (ORCPT ); Tue, 3 Nov 2020 14:13:46 -0500 Date: Tue, 03 Nov 2020 19:13:27 +0000 From: Paul Cercueil Subject: Re: [PATCH 3/5] drm: Add and export =?UTF-8?Q?function=0D=0A?= drm_gem_cma_mmap_noncoherent To: Christoph Hellwig Cc: David Airlie , Daniel Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , od@zcrc.me, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Message-Id: In-Reply-To: <20201103185058.GA20134@infradead.org> References: <20201102220651.22069-1-paul@crapouillou.net> <20201102220651.22069-4-paul@crapouillou.net> <20201103185058.GA20134@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Christoph, Le mar. 3 nov. 2020 à 18:50, Christoph Hellwig a écrit : > On Mon, Nov 02, 2020 at 10:06:49PM +0000, Paul Cercueil wrote: >> This function can be used by drivers that need to mmap dumb buffers >> created with non-coherent backing memory. >> >> Signed-off-by: Paul Cercueil >> --- >> drivers/gpu/drm/drm_gem_cma_helper.c | 39 >> ++++++++++++++++++++++++++++ >> include/drm/drm_gem_cma_helper.h | 2 ++ >> 2 files changed, 41 insertions(+) >> >> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c >> b/drivers/gpu/drm/drm_gem_cma_helper.c >> index 3bdd67795e20..4ed63f4896bd 100644 >> --- a/drivers/gpu/drm/drm_gem_cma_helper.c >> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c >> @@ -387,6 +387,45 @@ int drm_gem_cma_mmap(struct file *filp, struct >> vm_area_struct *vma) >> } >> EXPORT_SYMBOL_GPL(drm_gem_cma_mmap); >> >> +/** >> + * drm_gem_cma_mmap_noncoherent - memory-map a CMA GEM object with >> + * non-coherent cache attribute >> + * @filp: file object >> + * @vma: VMA for the area to be mapped >> + * >> + * Just like drm_gem_cma_mmap, but for a GEM object backed by >> non-coherent >> + * memory. >> + * >> + * Returns: >> + * 0 on success or a negative error code on failure. >> + */ >> +int drm_gem_cma_mmap_noncoherent(struct file *filp, struct >> vm_area_struct *vma) >> +{ >> + struct drm_gem_cma_object *cma_obj; >> + int ret; >> + >> + ret = drm_gem_mmap(filp, vma); >> + if (ret) >> + return ret; >> + >> + cma_obj = to_drm_gem_cma_obj(vma->vm_private_data); >> + >> + /* >> + * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and >> set the >> + * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want >> to map >> + * the whole buffer. >> + */ >> + vma->vm_flags &= ~VM_PFNMAP; >> + vma->vm_pgoff = 0; >> + vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); >> + >> + return remap_pfn_range(vma, vma->vm_start, >> + cma_obj->paddr >> PAGE_SHIFT, >> + vma->vm_end - vma->vm_start, >> + vma->vm_page_prot); > > Per patch 1 cma_obj->paddr is the dma address, while remap_pfn_range > expects a physical address. This does not work. Ok, what would be the correct way to mmap_noncoherent? -Paul