From patchwork Sat Nov 7 08:13:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Damien Le Moal X-Patchwork-Id: 321514 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=-12.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 D025CC388F9 for ; Sat, 7 Nov 2020 08:14:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9BE56221FA for ; Sat, 7 Nov 2020 08:14:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b="ioChVHyc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727833AbgKGIOi (ORCPT ); Sat, 7 Nov 2020 03:14:38 -0500 Received: from esa3.hgst.iphmx.com ([216.71.153.141]:57208 "EHLO esa3.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727810AbgKGIOi (ORCPT ); Sat, 7 Nov 2020 03:14:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1604736877; x=1636272877; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=6b+MfY7Lnw6uLwvcAlOQrQcVcVnJvNY26Ca7SXPyL/Q=; b=ioChVHyc7hSArtXZbt9ah29uDuB+BbTtOKe7jrQto0USnRsvOhwZlb47 r+FT8gH8x5RfsXW6PXHrv+bSyPgfC23zHRaZtBz+JGG4f4M9UPaU8Osw7 aKAmIVPpWj3dBY/yveKvkTJq/q+ImKJ/5eqzZZuI0ePvCCeKqvAFjLSXS BbUeA+VVPIzGQSg74IGGULogi7DgnayjqDG5Ji7+WRQgvKPa+Hhiw/mSW fBn1B2UfyvJPV3G9uVHaTxUYuTEpWBCIbjsNdGQ3Rr7Rrae5Z/HY/1jX8 9X+T3i1n+RT1Yzfqe5rwmF1x3KvUDqvlGN66PptxsB4YiHUf1YRMBekVg A==; IronPort-SDR: TAn5cp3r5TAU4Oto8TkIMU+ST3Z49BoyXXJzjYo4l2iN4hrSVl8wtGPS6z4C23YWBOKRTuS9tN kbocRFoNmPPGLiMEDuowHz2Q5YLiqEB81uTqsB7OLy+Y2e70c1eNvg7JUrIA9GcjkPgsHB20Vq CGu+79NkmvwNr3onpglZSGQhPhGLNTvcodtxAAwbiNgCe2cEScdIPMpmes2enD8eGr6d+ggsSm QNbeTMdtaE0UL1kzQljjQaOwziytCBkbhea1wAZRbtffKjl72lsmFFqyNvs8fQpGnJVfL47PDx S+E= X-IronPort-AV: E=Sophos;i="5.77,459,1596470400"; d="scan'208";a="156564367" Received: from h199-255-45-15.hgst.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 07 Nov 2020 16:14:37 +0800 IronPort-SDR: OJ2ye+09Fu47BaM8gl+/I/TCLcSl/QL8cB5d98MKKUk7aebTyytPcVL8cBUrt073p7vw/EprZ2 pDN2c2aCWDuaxwLftiWDlUyINoDrKPJkL1JKvuXzU0aEjd1qFbHrsHa+4ccacFgjDTauxjCuDc EwtJYWlRt8Ksa5mQjdKtdZoh3XcdaU+xiI9ABi6CTY+0qLNR3zrEGUXzveXjqCI5VqwNR9t0mB PguDwiBMUxW8R+SyI/ffG5p61KsPgkY76SYUZnwpH29rS09KFUZQRYX6ZqODcz8EUyRzDoHK+Z l9dcAq+MSwH/SA5/V8dGlrVY Received: from uls-op-cesaip01.wdc.com ([10.248.3.36]) by uls-op-cesaep02.wdc.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Nov 2020 23:59:28 -0800 IronPort-SDR: NSr+fi+441D/Y1RoTNH84IS+7KXzRlrA3vPMRV0+N1CX0PR26ZSjF+sMYjPwDRUPIEcZkz2Rbf jOMvNeSaoWy5oTVBlfqzCSFG+qD34T8/i7rhLqC5WioI2B6JKCjiAldHzLUdDiP+K0dRgmzVR5 G7hWuCLS6zsopefhObrpOae58CT5kaAQcUMZlbU/y2+dGZTsv1TbDx3jfSG5IMmNBjkZE5nMhn hSsR1Y1ir8AlX6JL+I/oSvG69ZIVrsLipi/Dyaa0esLFacgkelsNRm8M5rORI1GwilWaJfkd0d Ex8= WDCIronportException: Internal Received: from hdrdzf2.ad.shared (HELO twashi.fujisawa.hgst.com) ([10.84.71.85]) by uls-op-cesaip01.wdc.com with ESMTP; 07 Nov 2020 00:14:35 -0800 From: Damien Le Moal To: Palmer Dabbelt , linux-riscv@lists.infradead.org, Rob Herring , Frank Rowand , devicetree@vger.kernel.org, Serge Semin , Mark Brown , linux-spi@vger.kernel.org, Stephen Boyd , linux-clk@vger.kernel.org, Linus Walleij , linux-gpio@vger.kernel.org, Philipp Zabel Cc: Sean Anderson Subject: [PATCH 05/32] spi: dw: Introduce DW_SPI_CAP_POLL_NODELAY Date: Sat, 7 Nov 2020 17:13:53 +0900 Message-Id: <20201107081420.60325-6-damien.lemoal@wdc.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201107081420.60325-1-damien.lemoal@wdc.com> References: <20201107081420.60325-1-damien.lemoal@wdc.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On slow systems, i.e. systems with a slow CPU resulting in slow context switches, calling spi_delay_exec() when executing polled transfers using dw_spi_poll_transfer() can lead to RX FIFO overflows. Allow platforms to opt out of delayed polling by introducing the DW_SPI_CAP_POLL_NODELAY DW SPI capability flag to disable the execution of spi_delay_exec() in dw_spi_poll_transfer(). Signed-off-by: Damien Le Moal --- drivers/spi/spi-dw-core.c | 12 ++++++++---- drivers/spi/spi-dw.h | 1 + 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c index c2ef1d8d46d5..16a6fd569145 100644 --- a/drivers/spi/spi-dw-core.c +++ b/drivers/spi/spi-dw-core.c @@ -385,14 +385,18 @@ static int dw_spi_poll_transfer(struct dw_spi *dws, u16 nbits; int ret; - delay.unit = SPI_DELAY_UNIT_SCK; - nbits = dws->n_bytes * BITS_PER_BYTE; + if (!(dws->caps & DW_SPI_CAP_POLL_NODELAY)) { + delay.unit = SPI_DELAY_UNIT_SCK; + nbits = dws->n_bytes * BITS_PER_BYTE; + } do { dw_writer(dws); - delay.value = nbits * (dws->rx_len - dws->tx_len); - spi_delay_exec(&delay, transfer); + if (!(dws->caps & DW_SPI_CAP_POLL_NODELAY)) { + delay.value = nbits * (dws->rx_len - dws->tx_len); + spi_delay_exec(&delay, transfer); + } dw_reader(dws); diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h index 48a11a51a407..25f6372b993a 100644 --- a/drivers/spi/spi-dw.h +++ b/drivers/spi/spi-dw.h @@ -130,6 +130,7 @@ enum dw_ssi_type { #define DW_SPI_CAP_KEEMBAY_MST BIT(1) #define DW_SPI_CAP_DWC_SSI BIT(2) #define DW_SPI_CAP_DFS_32 BIT(3) +#define DW_SPI_CAP_POLL_NODELAY BIT(4) /* Slave spi_transfer/spi_mem_op related */ struct dw_spi_cfg {