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=-2.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 BEE53CA90AF for ; Wed, 13 May 2020 11:37:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9332420753 for ; Wed, 13 May 2020 11:37:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589369821; bh=esvSPlYfmiYgql73vEjD2+5RucmuA0PgDXZlvBGj+VE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=EYIQJ2ttiuG9unWKx8r5Nq4bwUMYRdA2tPXRsWmDdK8QEKsfNTfH7pAPbL3ojFksT toJ6MMJF6a5D+3865ajBQoHkekITbvQ2aOJdAgz6j4VasS/91RTMCLdsH4YdsViGjl ygBwzib+9GNoueVyL2Snk+ehfD2wWQ8Oye6Mg0BE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730801AbgEMLhA (ORCPT ); Wed, 13 May 2020 07:37:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:34060 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727794AbgEMLhA (ORCPT ); Wed, 13 May 2020 07:37:00 -0400 Received: from localhost (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B3022206D6; Wed, 13 May 2020 11:36:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589369819; bh=esvSPlYfmiYgql73vEjD2+5RucmuA0PgDXZlvBGj+VE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EXEPmp4wRscmSOpgSsbkHiRIaecmZa09WJ0Kb2AvQ9nCRPGsSR3zseVQTSCYNqsYs nkOmpc+jTnaPWyQN/+5rGzQDmrfd+jpCWT/xDkp6bn1eVhnAXSoSK+2TW3/oixy8gP w0ifH6+8WJHCTVMQr4Me1LppjfLlROKy01S7ymhs= Date: Wed, 13 May 2020 12:36:56 +0100 From: Mark Brown To: Serge Semin Cc: Serge Semin , Georgy Vlasov , Ramil Zaripov , Alexey Malahov , Thomas Bogendoerfer , Paul Burton , Ralf Baechle , Arnd Bergmann , Allison Randal , Andy Shevchenko , Gareth Williams , Rob Herring , linux-mips@vger.kernel.org, devicetree@vger.kernel.org, Thomas Gleixner , "wuxu.wu" , Linus Walleij , linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 07/17] spi: dw: Add Tx/Rx finish wait methods to DMA Message-ID: <20200513113656.GF4803@sirena.org.uk> References: <20200508132943.9826-1-Sergey.Semin@baikalelectronics.ru> <20200508132943.9826-8-Sergey.Semin@baikalelectronics.ru> <20200508173023.GO4820@sirena.org.uk> <20200513113555.mjivjk374giopnea@mobilestation> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="O98KdSgI27dgYlM5" Content-Disposition: inline In-Reply-To: <20200513113555.mjivjk374giopnea@mobilestation> X-Cookie: Long life is in store for you. User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --O98KdSgI27dgYlM5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, May 13, 2020 at 02:35:55PM +0300, Serge Semin wrote: > On Fri, May 08, 2020 at 06:30:23PM +0100, Mark Brown wrote: > > > + while (dw_spi_dma_tx_busy(dws) && retry--) > > > + ndelay(ns); > > How deep can the FIFO be with this IP - could we end up ndelay()ing for > > non-trivial amounts of time? > According to the DW APB SSI db it can be up to 256 transfer words. So the delay > should be trivial. Yes, that should be fine. --O98KdSgI27dgYlM5 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl6729gACgkQJNaLcl1U h9AzxQf/bsWYDjXldUBZJ1fmI7RZ7yZW9/NawHY0tDiB5aidn0Qz1+0tYxPDmbhJ bUrIy7i5rEDV45LCvSLqXmOFAPs7+ic+SqlmIJFT+oHXR57351MKFSdPzc4WIbUT ZtCF2sUfQZXrk6O++CHGNwaiXkvkPxvdSw3R8AwsjUslTNHhqUH83efqIpCfu0mw Ttg/Ub0mSxEoALKiJN1T3NEH2B8qYS/J1dHGqoky8/ETQnXGR9NPTxIksgNVr42w HzXRM9gaXiBGtLAKfQqCwlRHUKqXckccJYfXN1edvFujhaXrfirs85hkEe+5CmMS OllgnBoTThVcCIvQZ+OAqp1c5UYtmw== =myKX -----END PGP SIGNATURE----- --O98KdSgI27dgYlM5--