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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6855CC61DB3 for ; Fri, 6 Jan 2023 21:47:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236111AbjAFVrY (ORCPT ); Fri, 6 Jan 2023 16:47:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229604AbjAFVrV (ORCPT ); Fri, 6 Jan 2023 16:47:21 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6704B12D1A; Fri, 6 Jan 2023 13:47:20 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 24ACCB81EDF; Fri, 6 Jan 2023 21:47:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57AFDC433D2; Fri, 6 Jan 2023 21:47:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673041637; bh=S5RbMSkjMYSUvEic9W15Kvy2/xK1BEwbbJpcpFh9EBI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cklrzmsgQ84R8/Wjc6mED0SgNVeYRJU9bcFLtHoR3PaPnWNKHBgDUqrdduH/KzAcD G0Sb6nqlppbL2DGVfAbsF8WkXofJIlN05MTjEwPJJnc2WJEjrbsjVA97i3IHRHI22h uOcOI3ocUkDTTVvus/oELzm3hhqc0NWh5ebmciM+MovcDzK0DTbx3o0jsnDiy/282X i6yLbrvzPJdAld8N8a9B71tnscCmxrA5OGbohDWpS8tS7P1rNiHeg2wKSg5QJBHIn3 k0OmkauwtSNv/WcFlbyGnt8xECqh+fBKVwG96i2uc3olLxxCoinFSsUmxi/Yb99Nqu ODB7bpBn6go5g== Date: Fri, 6 Jan 2023 21:47:11 +0000 From: Mark Brown To: William Zhang Cc: Linux SPI List , Broadcom Kernel List , anand.gore@broadcom.com, tomer.yacoby@broadcom.com, dan.beygelman@broadcom.com, joel.peshkin@broadcom.com, f.fainelli@gmail.com, jonas.gorski@gmail.com, kursad.oney@broadcom.com, dregan@mail.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 07/16] spi: bcm63xx-hsspi: Add polling mode support Message-ID: References: <20230106200809.330769-1-william.zhang@broadcom.com> <20230106200809.330769-8-william.zhang@broadcom.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="BZ9YTddyDyFA6Ziq" Content-Disposition: inline In-Reply-To: <20230106200809.330769-8-william.zhang@broadcom.com> X-Cookie: Do not fold, spindle or mutilate. Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --BZ9YTddyDyFA6Ziq Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Jan 06, 2023 at 12:07:59PM -0800, William Zhang wrote: > Polling mode provides better throughput in general by avoiding the > interrupt overhead as the maximum data size one interrupt can handle is > only 512 bytes. > When interrupt is not defined in the HSSPI dts node, driver switches to > polling mode for controller SPI message processing. Also add driver > banner message when the driver is loaded successfully. This should not be something the user selects via the DT, if the polling mode is better then the driver should just use it regardless of there being an interrupt wired up. Generally there's some point at which the benefits of polling become minimal (and the costs more impactful) but if the DMA setup is as bad as it sounds then the driver should just ignore the interrupt. --BZ9YTddyDyFA6Ziq Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmO4lt8ACgkQJNaLcl1U h9BtSwf9EDCxIB7GCjjTZUo4CcwKhiubo8/b3JnQ1i23/YpKRG3de6GCFJ1NFJKw DhOMbnblhK1hc9JJCAkK0CcDC4wkCrdXYicBxkTNCUBibzkdKwNHkjvfM8WrP9dJ uFO3J1hFO4F0E/MQ9E5DSeIuVXXw6QXKtYmteT11umGjZhmRX1xUWH++9S2T4zse c4c/HqoPWEElISgDKe7hyVnWmLpO1vQhPb1gkGd8NtLEv+QS3l4yV3k+qJQvHF85 bWCrWA+YT3UNag+lUlh4LfyOD8o+4i3VxcDabATMNg47nrdk/rMu3EOPXc2YIr3H peG2shfjq2Z6KLbMf/hbqeN695vbgg== =eHcH -----END PGP SIGNATURE----- --BZ9YTddyDyFA6Ziq--