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=-8.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 39D24C47E4F for ; Thu, 15 Jul 2021 16:42:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 212A86128D for ; Thu, 15 Jul 2021 16:42:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233314AbhGOQpO (ORCPT ); Thu, 15 Jul 2021 12:45:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:45428 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233179AbhGOQpN (ORCPT ); Thu, 15 Jul 2021 12:45:13 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5915F613C7; Thu, 15 Jul 2021 16:42:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626367339; bh=OSCJzfXQGA+YDCBz4k6NI4Wz/foAucQOhPRZx0QmPvc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mYg8LIH1LSYEYk9U2bYBFYieR/HtJMamAaRpOa4VlW6s0maPdvQF/Q81q15KRYdcf il5tc3SLAmxMWU1Zwh99kpDEPJHRQEUkAPgkFDTrRLwvZZLLDoZid51DA3pleSnMgR KHNhjHS2MLAsz7TGHkLJyHt5yifuIlQFiR7wywcYu05giVS0JBLjeNf++651W+YyTA cqjk98WdcGRXIbxN1odR2kTCb2QrLZbLewWpETLVj2gOW/HgBWvHozuoE6q6gNe12E E1+gdJom/fNM2+vaEIOy/hA7d1DgMEnla2QbCir+v9OnKWCjyBMSngKStEhKfpWYge tAmBqw4GVHNGw== Date: Thu, 15 Jul 2021 17:41:42 +0100 From: Mark Brown To: Apurva Nandan Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, Pratyush Yadav , Vignesh Raghavendra Subject: Re: [PATCH 1/2] spi: cadence-quadspi: Disable Auto-HW polling Message-ID: <20210715164142.GB27092@sirena.org.uk> References: <20210713125743.1540-1-a-nandan@ti.com> <20210713125743.1540-2-a-nandan@ti.com> <20210713182550.GG4098@sirena.org.uk> <20210714162805.GE4719@sirena.org.uk> <1cebc261-e0aa-572a-8083-1e3ec0d09195@ti.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="7iMSBzlTiPOCCT2k" Content-Disposition: inline In-Reply-To: <1cebc261-e0aa-572a-8083-1e3ec0d09195@ti.com> X-Cookie: The world is not octal despite DEC. User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --7iMSBzlTiPOCCT2k Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Jul 15, 2021 at 09:57:51PM +0530, Apurva Nandan wrote: > Now, whether the poll instruction should have an address phase or not > depends on the connected flash chip, which the controller wouldn't be > aware of as it only takes in a spimem op from the flash cores for execution. ... > More to this, not just address phase but any kind of variation in the > read register operation would result in polling failure. That seems like something that should be fixed since it means that no controller will be able to support a feature like this - it needs to get enough information passed to it to allow it to poll correctly. > Any SPI operation that is going underneath the visibility of flash core > can can problems. I agree offloading the status polling process to > controller HW is beneficial but on the other hand it restricts the flash > on having a fixed type of polling operation. This would reduce the > number of flash devices it will support (out of the box). > What should be the right way out for this situation? One idea would be to have something that takes both the operation itself and the operation that's used to poll for status (with expected result), the controller can then check the poll operation and either tell the core it's not supported or go ahead and do the polling. Or simpler just a separate poll operation which is fully specified enough. Not actually looked at the code to see how tasteful that is though... --7iMSBzlTiPOCCT2k Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmDwZUUACgkQJNaLcl1U h9CR8wf9HFBUJpyZ9REhkBSs3yZmc22r6CesOEcEeQ6HB3q7uYeuhjZhNoHxb2N9 ZeX1Ipz7anyQu9vYnObDIAKIJG/ir7mwjBHlrb3eiZXBbdWIIdxuM9r/C+kuYxYO isCC1pD/EkVIq9/cKjEWCX40jfAYUf2OcHFdiklk2zakGwp15JWJz5DrRm3fwOiw sS3Kg10/OxBBWGVzRN7YcHPNfNMKI9/+RlItI31gFJp5pPWUeb00lFMBSgPrT8R4 4P6qwpwxOCJ76tDMsixyB/SivVpZ1bKQ75ulgfcMUR2SgFTwJjTPGDMT/v4wpCjE 3+pth9xq9Kg6rQNdZ/L6rGGGZYZ7Vw== =SyFR -----END PGP SIGNATURE----- --7iMSBzlTiPOCCT2k--