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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 07954C43387 for ; Fri, 11 Jan 2019 09:09:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D589220870 for ; Fri, 11 Jan 2019 09:09:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729070AbfAKJJX (ORCPT ); Fri, 11 Jan 2019 04:09:23 -0500 Received: from mail-vk1-f193.google.com ([209.85.221.193]:46584 "EHLO mail-vk1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728943AbfAKJJX (ORCPT ); Fri, 11 Jan 2019 04:09:23 -0500 Received: by mail-vk1-f193.google.com with SMTP id j23so3116807vke.13; Fri, 11 Jan 2019 01:09:22 -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=Qt6zskZA+p1wMhnOKt8vxLu8Eo4w3/AfDj5WnKkwDN4=; b=JOBTo53oQmYQBNbm+7DfSbneMBXa3qmS8XVXhaWzp+cvNQGXmn8zqOLL3tay5C3l+S LJGF0Kah+aVayDKR2OSf2jwy+lQGlJSuIOnAUFaeasVQKCs1nALY/hjEaYRO4kkC2auE W8V9Avk6g690A4Chb1SNpI6JhzHjJkmmgLrQLofEEK4aSzOqpyFgeUspA+OrOUQlOg/l nZkwzO7tUcrBZxZ+fpQBfBO2ut0hfU/9cPMkp4koytIc9RhlKPTpJkYzt4Ym9ZP2Gd0y D3hemltoW3wWidoouA/yCY1UEQq8vgg15G4AlUCBpjATXJmZFUHyLQ2NcJBJKZ5CiaR6 6ocg== X-Gm-Message-State: AJcUukdYszZcb7MpY3ZV38ZNpOqNLbzq/2PfulmDLxgndxTaiXjd2mMm 6Vf0YhxCGHfmclxF3pQ+UFQs1pQD5MmhaCQVFgw= X-Google-Smtp-Source: ALg8bN6HX7NI18UC2RVz+yYrES37MFMX4XO4PqQZGrT2nphEaJQNGZfhfwqY0wfcZ63ZcAS0JI6DIv0mUedlEoS8k4Y= X-Received: by 2002:a1f:2145:: with SMTP id h66mr5412639vkh.65.1547197762058; Fri, 11 Jan 2019 01:09:22 -0800 (PST) MIME-Version: 1.0 References: <1547197109-637-1-git-send-email-na-hoan@jinso.co.jp> <1547197109-637-2-git-send-email-na-hoan@jinso.co.jp> In-Reply-To: <1547197109-637-2-git-send-email-na-hoan@jinso.co.jp> From: Geert Uytterhoeven Date: Fri, 11 Jan 2019 10:09:10 +0100 Message-ID: Subject: Re: [PATCH 2/2] spi: sh-msiof: Use DMA if possible To: Nguyen An Hoan Cc: Linux-Renesas , Mark Brown , Geert Uytterhoeven , Magnus Damm , linux-spi , Kuninori Morimoto , Yoshihiro Shimoda , =?UTF-8?B?56iy5ZCJ?= , =?UTF-8?B?RHVuZ++8muS6uuOCvQ==?= , =?UTF-8?B?44Kr44Kq44O744O044Kh44Oz44O744OJ44Oz?= 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 Hoan-san, On Fri, Jan 11, 2019 at 9:59 AM Nguyen An Hoan wrote: > From: Hoan Nguyen An > > Currently, this driver only supports feature for DMA 32-bits. > In this case, only if the data length is divisible by 4 to use > DMA, otherwise PIO will be used. This patch will suggest use > the DMA 32-bits with 4bytes of words, then the remaining data > will be transmitted by PIO mode. > > Signed-off-by: Hoan Nguyen An Thanks for your patch, that's a great idea! Reviewed-by: Geert Uytterhoeven with a small suggestion below. > --- a/drivers/spi/spi-sh-msiof.c > +++ b/drivers/spi/spi-sh-msiof.c > @@ -937,17 +937,13 @@ static int sh_msiof_transfer_one(struct spi_master *master, > unsigned int l = 0; > > if (tx_buf) > - l = min(len, p->tx_fifo_size * 4); > + l = min(len - len % 4, p->tx_fifo_size * 4); I think this would be easier to read when written as: l = min(round_down(len, 4), p->tx_fifo_size * 4); > if (rx_buf) > - l = min(len, p->rx_fifo_size * 4); > + l = min(len - len % 4, p->rx_fifo_size * 4); Likewise, 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