From patchwork Fri Jan 27 21:55:01 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Anholt X-Patchwork-Id: 9542803 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 760E8604CC for ; Fri, 27 Jan 2017 21:57:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 68B32267EC for ; Fri, 27 Jan 2017 21:57:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5DA3E27F54; Fri, 27 Jan 2017 21:57:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F23CD26E77 for ; Fri, 27 Jan 2017 21:57:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752025AbdA0V5A (ORCPT ); Fri, 27 Jan 2017 16:57:00 -0500 Received: from anholt.net ([50.246.234.109]:52050 "EHLO anholt.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752032AbdA0Vzy (ORCPT ); Fri, 27 Jan 2017 16:55:54 -0500 Received: from localhost (localhost [127.0.0.1]) by anholt.net (Postfix) with ESMTP id 7316210A228A; Fri, 27 Jan 2017 13:55:07 -0800 (PST) X-Virus-Scanned: Debian amavisd-new at anholt.net Received: from anholt.net ([127.0.0.1]) by localhost (kingsolver.anholt.net [127.0.0.1]) (amavisd-new, port 10024) with LMTP id O_EVEt8Hp8R5; Fri, 27 Jan 2017 13:55:05 -0800 (PST) Received: from eliezer.anholt.net (localhost [127.0.0.1]) by anholt.net (Postfix) with ESMTP id E96CB10A1E8E; Fri, 27 Jan 2017 13:55:04 -0800 (PST) Received: by eliezer.anholt.net (Postfix, from userid 1000) id DFB232EDA39; Fri, 27 Jan 2017 13:55:03 -0800 (PST) From: Eric Anholt To: Greg Kroah-Hartman Cc: devel@driverdev.osuosl.org, linux-media@vger.kernel.org, Mauro Carvalho Chehab , linux-rpi-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Eric Anholt Subject: [PATCH 4/6] staging: bcm2835-v4l2: Add a TODO file for improvements we need. Date: Fri, 27 Jan 2017 13:55:01 -0800 Message-Id: <20170127215503.13208-5-eric@anholt.net> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170127215503.13208-1-eric@anholt.net> References: <20170127215503.13208-1-eric@anholt.net> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Signed-off-by: Eric Anholt --- drivers/staging/media/platform/bcm2835/TODO | 39 +++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 drivers/staging/media/platform/bcm2835/TODO diff --git a/drivers/staging/media/platform/bcm2835/TODO b/drivers/staging/media/platform/bcm2835/TODO new file mode 100644 index 000000000000..61a509992b9a --- /dev/null +++ b/drivers/staging/media/platform/bcm2835/TODO @@ -0,0 +1,39 @@ +1) Support dma-buf memory management. + +In order to zero-copy import camera images into the 3D or display +pipelines, we need to export our buffers through dma-buf so that the +vc4 driver can import them. This may involve bringing in the VCSM +driver (which allows long-term management of regions of memory in the +space that the VPU reserved and Linux otherwise doesn't have access +to), or building some new protocol that allows VCSM-style management +of Linux's CMA memory. + +2) Avoid extra copies for padding of images. + +We expose V4L2_PIX_FMT_* formats that have a specified stride/height +padding in the V4L2 spec, but that padding doesn't match what the +hardware can do. If we exposed the native padding requirements +through the V4L2 "multiplanar" formats, the firmware would have one +less copy it needed to do. + +3) Port to ARM64 + +The bulk_receive() does some manual cache flushing that are 32-bit ARM +only, which we should convert to proper cross-platform APIs. + +4) Convert to be a platform driver. + +Right now when the module probes, it tries to initialize VCHI and +errors out if it wasn't ready yet. If bcm2835-v4l2 was built in, then +VCHI generally isn't ready because it depends on both the firmware and +mailbox drivers having already loaded. + +We should have VCHI create a platform device once it's initialized, +and have this driver bind to it, so that we automatically load the +v4l2 module after VCHI loads. + +5) Drop the gstreamer workaround. + +This was a temporary workaround for a bug that was fixed mid-2014, and +we should remove it before stabilizing the driver. +