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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 72819C3A5A6 for ; Mon, 26 Aug 2019 17:12:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5499C20850 for ; Mon, 26 Aug 2019 17:12:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732351AbfHZRMy (ORCPT ); Mon, 26 Aug 2019 13:12:54 -0400 Received: from mx2.suse.de ([195.135.220.15]:47908 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727815AbfHZRMy (ORCPT ); Mon, 26 Aug 2019 13:12:54 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 7DBDEB633; Mon, 26 Aug 2019 17:12:52 +0000 (UTC) Date: Mon, 26 Aug 2019 19:12:52 +0200 Message-ID: From: Takashi Iwai To: Scott Branden Cc: Luis Chamberlain , Greg Kroah-Hartman , David Brown , Alexander Viro , Shuah Khan , bjorn.andersson@linaro.org, Shuah Khan , Arnd Bergmann , "Rafael J . Wysocki" , linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-fsdevel@vger.kernel.org, BCM Kernel Feedback , Olof Johansson , Andrew Morton , Dan Carpenter , Colin Ian King , Kees Cook , linux-kselftest@vger.kernel.org Subject: Re: [PATCH 2/7] firmware: add offset to request_firmware_into_buf In-Reply-To: <93b8285a-e5eb-d4a4-545d-426bbbeb8008@broadcom.com> References: <20190822192451.5983-1-scott.branden@broadcom.com> <20190822192451.5983-3-scott.branden@broadcom.com> <10461fcf-9eca-32b6-0f9d-23c63b3f3442@broadcom.com> <93b8285a-e5eb-d4a4-545d-426bbbeb8008@broadcom.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, 26 Aug 2019 17:41:40 +0200, Scott Branden wrote: > > HI Takashi, > > On 2019-08-26 8:20 a.m., Takashi Iwai wrote: > > On Fri, 23 Aug 2019 21:44:42 +0200, > > Scott Branden wrote: > >> Hi Takashi, > >> > >> Thanks for review.  comments below. > >> > >> On 2019-08-23 3:05 a.m., Takashi Iwai wrote: > >>> On Thu, 22 Aug 2019 21:24:46 +0200, > >>> Scott Branden wrote: > >>>> Add offset to request_firmware_into_buf to allow for portions > >>>> of firmware file to be read into a buffer. Necessary where firmware > >>>> needs to be loaded in portions from file in memory constrained systems. > >>> AFAIU, this won't work with the fallback user helper, right? > >> Seems to work fine in the fw_run_tests.sh with fallbacks. > > But how? You patch doesn't change anything about the fallback loading > > mechanism. > Correct - I didn't change any of the underlying mechanisms, > so however request_firmware_into_buf worked before it still does. > > Or, if the expected behavior is to load the whole content > > and then copy a part, what's the merit of this API? > The merit of the API is that the entire file is not copied into a buffer. > In my use case, the buffer is a memory region in PCIe space that isn't > even large enough for the whole file.  So the only way to get the file > is to read it > in portions. BTW: does the use case above mean that the firmware API directly writes onto the given PCI iomem region? If so, I'm not sure whether it would work as expected on all architectures. There must be a reason of the presence of iomem-related API like memcpy_toio()... thanks, Takashi