From patchwork Thu Oct 27 19:27:56 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Heiner Kallweit X-Patchwork-Id: 9400267 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E79AD60588 for ; Thu, 27 Oct 2016 19:29:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C60822A396 for ; Thu, 27 Oct 2016 19:29:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BAF642A398; Thu, 27 Oct 2016 19:29:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.3 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6C1952A396 for ; Thu, 27 Oct 2016 19:29:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754000AbcJ0T3u (ORCPT ); Thu, 27 Oct 2016 15:29:50 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:36571 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753214AbcJ0T3t (ORCPT ); Thu, 27 Oct 2016 15:29:49 -0400 Received: by mail-wm0-f68.google.com with SMTP id c17so4174047wmc.3 for ; Thu, 27 Oct 2016 12:29:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:subject:to:references:cc:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding; bh=tSaHVDSHq83+RMyh6F/bK29xlJKLMnRhzeG33aUOHl0=; b=g8WE0uXhMi6+96mjZt3ohvgQWlTesZiXULfMXPOrC68JZlzSUCe+E01Pd706vHHLyG O9NgM3O+GMytaOTOdKz9zWzNt9b2PSoakOi0H6QlAKrGbqC7bfEa8T1VdOsYNeUqE5tP z6I8eGF4KOiSTBYjVrICUWIWZ75iDt+xs4LiBluBB/Z9OOo8cP584/mHHgAUUkb6T2/w 0p0hQYw0vbv+SK2x1InLY5hYv5X4kpOAf0EFTM0Dvax3GjdqjtBpFTWb564OSc4EZDAc EFH00RNa6xZ04terGmjWDhiOHcx1yDXzKeE0B20+mvnLZsjCYeUl5aeSPY+2zyLZMRlo NTRg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:subject:to:references:cc:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=tSaHVDSHq83+RMyh6F/bK29xlJKLMnRhzeG33aUOHl0=; b=XSv6/lYdEhbUlYV32w6HgcPwhfZTBdP2zB0qYhh53wW9IB7BwWQ0uF9RSoPIUm2Qy5 ykgb6+MACC533WpzgzRTFka7hEht7A9xjBVPN+TdVIw8T1SAwC5OqQxS7FhAG+7s9M4O VLXs3Vy2hN4ib97+CvO4S4U3XhR6UWF9tLSNglMXqeiTS4vnKvvzyb0Yr0BOxIEYtRa+ A0hOMOOuZDKXax+X0Ak8CTDIqOJaeqhkQ6nT0/wtO6aFrSVsEMGRNiwAooZsMtHspOOU +6xTT0VkPHVxU8zsczMh88Y0QHEaM6lfji5JiYATR/WG07W3kPflH3k7mJv+IH+UOmlT f9dw== X-Gm-Message-State: ABUngveGgvpE+95GmI9h46qG4gwb1sWWRp1McP79RVf7Y7mus5/6BaaNiqS7vg+JwYi9hA== X-Received: by 10.28.10.202 with SMTP id 193mr40452wmk.24.1477596588118; Thu, 27 Oct 2016 12:29:48 -0700 (PDT) Received: from ?IPv6:2003:62:5f6e:ba00:49f8:f47b:2191:41c4? (p200300625F6EBA0049F8F47B219141C4.dip0.t-ipconnect.de. [2003:62:5f6e:ba00:49f8:f47b:2191:41c4]) by smtp.googlemail.com with ESMTPSA id n6sm10101310wjg.30.2016.10.27.12.29.47 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Oct 2016 12:29:47 -0700 (PDT) From: Heiner Kallweit Subject: [PATCH v2 06/09] spi: fsl-espi: make better use of the RX FIFO To: Mark Brown References: <5b98be38-17a2-79a2-14da-fb2bb6f8820f@gmail.com> Cc: "linux-spi@vger.kernel.org" Message-ID: <082fee3f-4623-2cca-803b-b0fdf7cc8ab1@gmail.com> Date: Thu, 27 Oct 2016 21:27:56 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <5b98be38-17a2-79a2-14da-fb2bb6f8820f@gmail.com> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP So far an interrupt is triggered whenever there's at least one byte in the RX FIFO. This results in a unnecessarily high number of interrupts. Change this to generate an interrupt if - RX FIFO is half full (except if all bytes to read fit into the RX FIFO anyway) - end of transfer has been reached This way the number of interrupts can be significantly reduced. Signed-off-by: Heiner Kallweit --- v2: - rebased --- drivers/spi/spi-fsl-espi.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c index ca14575..06fb185 100644 --- a/drivers/spi/spi-fsl-espi.c +++ b/drivers/spi/spi-fsl-espi.c @@ -55,9 +55,10 @@ #define CSMODE_CG(x) ((x) << 3) #define FSL_ESPI_FIFO_SIZE 32 +#define FSL_ESPI_RXTHR 15 /* Default mode/csmode for eSPI controller */ -#define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(3)) +#define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(FSL_ESPI_RXTHR)) #define CSMODE_INIT_VAL (CSMODE_POL_1 | CSMODE_BEF(0) \ | CSMODE_AFT(0) | CSMODE_CG(1)) @@ -281,6 +282,7 @@ static void fsl_espi_setup_transfer(struct spi_device *spi, static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t) { struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master); + u32 mask; int ret; mpc8xxx_spi->rx_len = t->len; @@ -295,8 +297,11 @@ static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t) fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPCOM, (SPCOM_CS(spi->chip_select) | SPCOM_TRANLEN(t->len - 1))); - /* enable rx ints */ - fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPIM, SPIM_RNE); + /* enable interrupts */ + mask = SPIM_DON; + if (mpc8xxx_spi->rx_len > FSL_ESPI_FIFO_SIZE) + mask |= SPIM_RXT; + fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPIM, mask); /* Prevent filling the fifo from getting interrupted */ spin_lock_irq(&mpc8xxx_spi->lock);