From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from bhuna.collabora.co.uk ([46.235.227.227]:38030 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725836AbeH3VYL (ORCPT ); Thu, 30 Aug 2018 17:24:11 -0400 From: Ezequiel Garcia To: linux-media@vger.kernel.org, linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Laurent Pinchart , Tomasz Figa , "Matwey V . Kornilov" , Alan Stern , kernel@collabora.com, Keiichi Watanabe , Ezequiel Garcia Subject: [RFC 0/3] Introduce usb_{alloc,free}_noncoherent API Date: Thu, 30 Aug 2018 14:20:27 -0300 Message-Id: <20180830172030.23344-1-ezequiel@collabora.com> Sender: linux-media-owner@vger.kernel.org List-ID: Following the discussion on PWC [1] and UVC [2] drivers, where use non-consistent mappings for the URB transfer buffers was shown to improve transfer speed significantly, here's a proposal for a non-coherent USB helpers. With this pachset, it's possible to get 360x288 raw analog video using stk1160 and a AM335x Beaglebone Black board. This isn't possible in mainline, for the same reasons Matwey has explained [1]. First patch is a hack, obviously incomplete, to add support for non-consistent mappings on ARM. The second patch introduces the usb_{alloc,free}_noncoherent API, while the third patch is an example on stk1160. I'm sending this patchset as RFC, just to get the ball rolling. [1] https://lkml.org/lkml/2018/8/21/663 [2] https://lkml.org/lkml/2018/6/27/188 Ezequiel Garcia (3): HACK: ARM: dma-mapping: Get writeback memory for non-consistent mappings USB: core: Add non-coherent buffer allocation helpers stk1160: Use non-coherent buffers for USB transfers arch/arm/include/asm/pgtable.h | 3 ++ arch/arm/mm/dma-mapping.c | 9 ++-- drivers/media/usb/stk1160/stk1160-video.c | 22 +++------ drivers/usb/core/buffer.c | 29 +++++++----- drivers/usb/core/hcd.c | 5 +- drivers/usb/core/usb.c | 56 ++++++++++++++++++++++- include/linux/usb.h | 5 ++ include/linux/usb/hcd.h | 4 +- 8 files changed, 97 insertions(+), 36 deletions(-) -- 2.18.0