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,URIBL_BLOCKED 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 B14D4C3524A for ; Tue, 4 Feb 2020 08:02:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 90FFF21582 for ; Tue, 4 Feb 2020 08:02:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726730AbgBDICI (ORCPT ); Tue, 4 Feb 2020 03:02:08 -0500 Received: from mail-oi1-f193.google.com ([209.85.167.193]:44017 "EHLO mail-oi1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726000AbgBDICI (ORCPT ); Tue, 4 Feb 2020 03:02:08 -0500 Received: by mail-oi1-f193.google.com with SMTP id p125so17544249oif.10; Tue, 04 Feb 2020 00:02:07 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dum+o5gu2gGFpSl+O8wsomQ94Fs2sL9d8ohYuPebAnY=; b=ns192hVFZLPa4xwD+cCtN++jd0e7NrjqVwQ2e49oDjaLNhpOUm/Bu5kJ5a4d1lgosZ TVlJ/oOUVGyp5LEq+2VxMJRPMh8sLMzj3oi+ms1wJ7GiTdLp0+pop+ISVGvhyPILgUZI 1k7J2R1U6/1y8Qfqd5XeKpshgkilbPJiOsB32iW8KxoZG4nXFqeG05SceaVXIPGY/1Nz GzGWAIHK0r7SXnIGwuSv8BePCNKYWBW3GgPmEkDMWRbx/pUkfK41/5hSbwlqYNnGyg34 0aDiv+dpr8yazbNJdtwXU2Oefr8FCq/cEo4rJmfe2yjTjSX6QaWZl6X0JwRfCtmGpSsN SHnQ== X-Gm-Message-State: APjAAAUQGwSL/O+4LDLfB9hZmiUtemXsVbAEjPbZVlgohb0erih9g1mw 9fQg+VLAuAfxF5RtnjkEEqCOhYHg1LjMMX+A7Mg= X-Google-Smtp-Source: APXvYqzzEX39mrChEWmOwQfxI4cvrJqp32wsemcpmKn2mv1qMu0WlwDSpDrURvjggP7ZnFmlvGoXXaie/JESZoxAYEY= X-Received: by 2002:a54:4707:: with SMTP id k7mr2486144oik.153.1580803327484; Tue, 04 Feb 2020 00:02:07 -0800 (PST) MIME-Version: 1.0 References: <20200203101806.2441-1-peter.ujfalusi@ti.com> <701ab186-c240-3c37-2c0b-8ac195f8073f@ti.com> <38f686ae-66fa-0e3a-ec2e-a09fc4054ac4@physik.fu-berlin.de> In-Reply-To: From: Geert Uytterhoeven Date: Tue, 4 Feb 2020 09:01:55 +0100 Message-ID: Subject: Re: [PATCH 0/3] dmaengine: Stear users towards dma_request_slave_chan() To: Peter Ujfalusi Cc: John Paul Adrian Glaubitz , Andy Shevchenko , Vinod Koul , dmaengine , Linux Kernel Mailing List , Dan Williams , Linux-sh list , Linux-Renesas Content-Type: text/plain; charset="UTF-8" Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org Hi Peter, On Tue, Feb 4, 2020 at 7:52 AM Peter Ujfalusi wrote: > On 03/02/2020 22.34, Geert Uytterhoeven wrote: > > On Mon, Feb 3, 2020 at 9:21 PM John Paul Adrian Glaubitz > > wrote: > >> On 2/3/20 2:32 PM, Geert Uytterhoeven wrote: > >>> Both rspi and sh-msiof have users on legacy SH (i.e. without DT): > >> > >> FWIW, there is a patch set by Yoshinori Sato to add device tree support > >> for classical SuperH hardware. It was never merged, unfortunately :(. > > > > True. > > > >>> Anyone who cares for DMA on SuperH? > >> > >> What is DMA used for on SuperH? Wouldn't dropping it cut support for > >> essential hardware features? > > > > It may make a few things slower. > > I would not drop DMA support but I would suggest to add dma_slave_map > for non DT boot so the _compat() can be dropped. Which is similar in spirit to gpiod_lookup and clk_register_clkdev(), right? > Imho on lower spec SoC (and I believe SuperH is) the DMA makes big > difference offloading data movement from the CPU. Assumed it is actually used... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds