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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 A38A7C433FF for ; Sun, 11 Aug 2019 19:50:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C46F2085B for ; Sun, 11 Aug 2019 19:50:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="BGtN/+rC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726055AbfHKTus (ORCPT ); Sun, 11 Aug 2019 15:50:48 -0400 Received: from mout.gmx.net ([212.227.15.15]:35145 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726053AbfHKTus (ORCPT ); Sun, 11 Aug 2019 15:50:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1565553020; bh=/l9xgJdATrfRjOi4+IR9VrotpqmGWD5Z3J7zZdEMGos=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=BGtN/+rCW2Qkj7QVzTKqjz/kb4szdqZcgihkHNKIa6UMyh4dZkMz1ntp8AJ732j9E n2N7S1ICaj7Ivwbp1iym08D7JtUQdeVwAp9XQElYRPCxXGjF/Nqtu0jIQqnlqr+G5v ACJHj/3vhid9+rMFHjcbgm57es2/b3RTRhJbcU68= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [192.168.1.162] ([37.4.249.106]) by mail.gmx.com (mrgmx003 [212.227.17.190]) with ESMTPSA (Nemesis) id 0LpKrt-1iTCGX2paX-00f7df; Sun, 11 Aug 2019 21:50:20 +0200 Subject: Re: [PATCH 00/10] Raspberry Pi SPI speedups To: Lukas Wunner , Mark Brown , Vinod Koul , linux-spi@vger.kernel.org, dmaengine@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, bcm-kernel-feedback-list@broadcom.com Cc: Eric Anholt , Nuno Sa , Martin Sperl , Noralf Tronnes , Robert Jarzmik , Florian Kauer , Florian Fainelli , Ray Jui , Scott Branden References: From: Stefan Wahren Message-ID: Date: Sun, 11 Aug 2019 21:50:17 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Provags-ID: V03:K1:3CK50yV8jzQB85JkuX0VH/gz4hYHd66gPR6wK5JVFZaQMmaEvPD BKy8p1ynoJsEgMfT/q21ff1F317zTg+hNQdcocVANiU89x5ivV25eHXiZU9nIfAD+oCfklK vN5oUYlw6y1FLDMxaHXnoR/HhPMKCjPQ41cQocHIeHoNvW7awXSOX1BB0QHtul6mL9IHEvP TS2/LjLtyoRsqLdWXHt9A== X-UI-Out-Filterresults: notjunk:1;V03:K0:yBVpSNGWGlM=:2+of0D0JPi5QmYjrq5E6Jq AscObkbHZhFm5nlOWg4MA/GLlTbyzKq4XyudIeUPDDCH8TmFdZo4ticc2JIqCUBDilv1mCh3D doHJv4ZvwnifE4rYenMLFga2awwADdWRJZdNpRyg39a2EFOg79ch1QoQWzEPpWmwWt3pWXma4 vWEuwwdZ1g5VafQ7h6xkIZfZIA8zL95Ge9guqccw6Y3ovHiiacZfwgIO863Z8KiakyQY14WZX O5+v0/XjWTOGkb3Yi/rIEBAudE/z7S7KCYTGCIN7VJ9ZNeACRFrBi6M7a/3VopX83foBdfS4X foHxNqj0RbD3TWmUXLf3EhYBmYZkbEcAdyErxpaK+117bb4dtzB1L4LUFn5n/Kgu8vrhMxwdm cuoCkn/u+6htEJkny0ys9RB95bPkmcIO6MYG0itqaehSATUoOLWNu9UUy3PXN3OYbZjVezRYx KtlXiL+SnBLhx9eVLtdj5yZu7g/SCEIsh9OEqELGTtKz6jH2qQb7B6wrrGQpGrDedNxG72nHn zI1Vae9hYnuf04IOBzFayJOpEldupe1eCrM7UPKamPoNEuhN/Ih/Zbd03Lx+T3YMgAmd0TnzI Ym5SxcWNiyePyLrLUMW/msBm6LxMJsrzX/fRIUPXn2C8npDjt72pZHEU8SSu4fw3buqJprEaa HEmHxJZ0EFU+txzUDVXO6iijtPcUi5haJI7OF2qnHDNachGpykh/3p8AJ5jswdsaJBiJU8dcu ujITXiVaSiOB0caU3q4t8eXSqvFvtHzBFYBgrRqodkL1RNXKXhWZLYo8xQsHxYlBqNmqQV6WI hJcxKbyY+ZN6Y+kQm0s2SVVgk50KLZUlSjkSgBkiSH3CdK5YD+mQxJuTQJzyyBefABqGGKrmQ 07VaQ+5dJfXxzd0btzk3gLH3Znm+vN2jR0o3RrIJdyL483b25DkYeEV1R0P8JQo76/e0FpKea Nb3FNPcKJyKcjugw6l9k5DAld2SgxN64AVVU7P90gqXb896tsQhqmJQQ39Sf+q0upYubeA06B JBgoJrB8SIf5QnFRyMfkyYgcIZV8CF6H+kwd1Dt0LyFLewk7LaoowpO7TqQ69HAC6GL3k2Cj0 D12rUQWYOtcfu1nkuefcyjV8abfGeJLzieQLLoahzqLRu7SammW3XYV+GdY0wUIC07Ixw82h9 XNgUw= Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org Hi Lukas, Am 03.08.19 um 12:10 schrieb Lukas Wunner: > So far the BCM2835 SPI driver cannot cope with TX-only and RX-only > transfers (rx_buf or tx_buf is NULL) when using DMA: It relies on > the SPI core to convert them to full-duplex transfers by allocating > and DMA-mapping a dummy rx_buf or tx_buf. This costs performance. > > Resolve by pre-allocating reusable DMA descriptors which cyclically > clear the RX FIFO (for TX-only transfers) or zero-fill the TX FIFO > (for RX-only transfers). Patch [07/10] provides some numbers for > the achieved latency improvement and CPU time reduction with an > SPI Ethernet controller. SPI displays should see a similar speedup. > I've also made an effort to reduce peripheral and memory bus accesses. i know the BCM2711 / Raspberry Pi 4 isn't upstreamed yet, but this series hasn't been tested with RPi 4? I only want to know.