From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 77255142E89; Mon, 8 Apr 2024 16:40:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712594438; cv=none; b=iDa/CCykDQkHlcG38KSImDcajC1gELrGnEVNM5FWCk1EZOJVYx2q9C0AEukIvEqTCtL5W565K3bEdatIvWWsz2ZtmoetOyv4S0e8Z7FVojSgUyJS5VpqCnpr0croUed1vSVbVSmrg5eCq/hEOYvlk/RHr+7jM4H7iaN2E991DHM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712594438; c=relaxed/simple; bh=zVJ8/8JF/gNZWXlENelkKttfECw64CDIpT9zFq/bhs0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=j5a0fL73kwxsDJ980HTP5pHjtqBrcoXxahbopa6bIYZwgVj9dyKJqvNty8MQEumG26hYV7ipZJnX3j0Idf9Y0OB/ApHyWLl2LawEo6e15cFbOOQ3udaHh8vCcdxLuuqnMngfC27fvUEQWrwiJOt0LoTwy7B/nDHa/r6EduMz7bI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JP6xPkUw; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JP6xPkUw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA102C43394; Mon, 8 Apr 2024 16:40:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712594438; bh=zVJ8/8JF/gNZWXlENelkKttfECw64CDIpT9zFq/bhs0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JP6xPkUwBtjv6T+eAipVp5ljfUCrfuPItz9Wptzf1fFqDwjwiWvAZ8SC0e6jir7uz XpmTI8mSro0C73h2Z9F5kk9ZG+FJkqWQEfsdxPi5epkx7dng6wzlrRplAHVB9BqZ21 FERX6QitVmn3Q4uY4zxf1WSZeikKnNXZ504UHd9jDrjt2DE8U0xB5EwHVnS2Hv99e7 raYoHX9X65Ga/A5OZqsUw0ZbI9+5Cl57MnN01+qoaj8bhoZ2MJg+XbUs1KjjMGDm64 GkShWhq0tsaQK0w+J2mc/Vca12LyhqVOLWejtEYkkBiKrhl0HBr8kyBoH+Yle1GV8k Ttz2D+r36fkgQ== Date: Mon, 8 Apr 2024 17:40:32 +0100 From: Mark Brown To: =?iso-8859-1?Q?Th=E9o?= Lebrun Cc: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Vaishnav Achath , Thomas Bogendoerfer , Rob Herring , linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, Vladimir Kondratiev , Gregory CLEMENT , Thomas Petazzoni , Tawfik Bayouk Subject: Re: [PATCH v2 08/11] spi: cadence-qspi: add early busywait to cqspi_wait_for_bit() Message-ID: <9cb48440-c71e-4a73-8104-4780f0e98e72@sirena.org.uk> References: <20240405-cdns-qspi-mbly-v2-0-956679866d6d@bootlin.com> <20240405-cdns-qspi-mbly-v2-8-956679866d6d@bootlin.com> <1f7087ad-824e-47fe-9953-ed5152c8f18f@sirena.org.uk> Precedence: bulk X-Mailing-List: linux-mips@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="XV9SnMR4fo1ciYdI" Content-Disposition: inline In-Reply-To: X-Cookie: Drive defensively. Buy a tank. --XV9SnMR4fo1ciYdI Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Apr 08, 2024 at 04:42:43PM +0200, Th=E9o Lebrun wrote: > On Mon Apr 8, 2024 at 4:16 PM CEST, Mark Brown wrote: > > On Fri, Apr 05, 2024 at 05:02:18PM +0200, Th=E9o Lebrun wrote: > > > The reason is to avoid hrtimer interrupts on the system. All read > > > operations take less than 100=B5s. > > Why would this be platform specific, this seems like a very standard > > optimisation technique? > It does not make sense if you know that all read operations take more > than 100=B5s. I preferred being conservative. If you confirm it makes > sense I'll remove the quirk. It does seem plausible at least, and the time could be made a tuneable with quirks or otherwise if that's needed. I think I'd expect the MIPS platform you're working with to be towards the lower end of performance for systems that are new enough to have this hardware. --XV9SnMR4fo1ciYdI Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmYUHf8ACgkQJNaLcl1U h9D8hQf/dyR3L/vGJrr9ULKPcOdslJpST3OzjYPpEwGbLVohTyQDYK+D5/rh9TYt pOS8YnUr8YjkaanYNAmYO7wqHO5GPDJPm+tzIJYdn0fHYO0R4maXcSA2DytEbt5W re5OHsqLX8xH1T7qqgXEwlCONUQhncFIRkxaMYpcXasAqWOP4tOKsO57TH2xh3kx KRqpRTVMS9qSkGt5a0YtULVEbERcxOLn2XVthGc5OnKnwvOUU77xHJ5ucCQ86+1z z0qEm9RSSUIgSlPEq5BXd7wkDlBzkojoywBBltNCSg9R2NlLkHRmYtaSrL6MLE24 q8by3s66tiuvwmZSNttQEwdrovLgOA== =rNjJ -----END PGP SIGNATURE----- --XV9SnMR4fo1ciYdI--