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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 102DBEB64D7 for ; Fri, 30 Jun 2023 13:20:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=+6ZxquaprlHYsSwlglZz03TccPg10CmEPCThYyV3cLE=; b=TPgkpyW5576WdLqTo9/C7GmpCG nodU/50xIe8abZmyNBAVarGURvSQlCqr9jDj4ynKfSAhk3Jfv3CpQDobZelyP6YwZkA3PP9R/yMX1 1uGOPqq18nKFK6uzBD9bbfElXpdEe0BQxc2GhXBKWAvv6lQvuznKLpxuJuP7IHvRBDJKYhiXg5iE5 zg4dUD1wJo/bNiRaiSzp2EDk6Wmwky1CsF5NJ2L3EcRl4mlusVzPdKjHhgcnLEeW7jGPWXgmnusUd 6B5XKRO6nNNERf2kl3ogWICaYhPHKq3lbumvK4DQx041aXbM4HSoAtNGVHzfEwSgBTMQYSUg/W1wj CZ+80sDw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qFE2z-003kye-0T; Fri, 30 Jun 2023 13:20:25 +0000 Received: from esa.microchip.iphmx.com ([68.232.153.233]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qFE2x-003kx6-0K for linux-riscv@lists.infradead.org; Fri, 30 Jun 2023 13:20:24 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1688131223; x=1719667223; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=EaJ77L8/k3Hf0KmA9VK9enDoW0KMpkjzS7BilECDl2A=; b=o0LzK4k6ddgz4qTxH02Aw7VCv1QN6rRi5pImS9B4nRNoE2G5sr4huuK+ TwoDdWaX05/edx9u1SVCsWJIvtjmlb90C17UOrsKACHeGG0Z/7cKRGaHR QHjka/CdzG3uRnDCzQQ1rRVHfOj0lPYYI3R0baAEljxzBLp1crHT5+ghN NxDCYG1e9hyoxXXFblkAk5b9kaRHz5/125W9VSfRG5NAOAmbUxMtRNDC0 M7DhSFK9rw2ItHRimUXo02bhaVT1VfJKW1IsYhQrI/VQPvqOvGhBoeUqu eeRH4rlbE6MBbnO5PZ9z+oCFMxwYwQwdsumCcuMLlfsnE6fpCw2CNn8hF A==; X-IronPort-AV: E=Sophos;i="6.01,170,1684825200"; d="asc'?scan'208";a="221422464" X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa5.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 30 Jun 2023 06:20:18 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Fri, 30 Jun 2023 06:20:17 -0700 Received: from wendy (10.10.115.15) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21 via Frontend Transport; Fri, 30 Jun 2023 06:20:15 -0700 Date: Fri, 30 Jun 2023 14:19:46 +0100 From: Conor Dooley To: Andrew Jones Subject: Re: [PATCH v2 10/10] RISC-V: provide a Kconfig option to disable parsing "riscv,isa" Message-ID: <20230630-urgency-emission-882cd52a7a27@wendy> References: <20230629-landed-popsicle-ab46ab3b46d9@spud> <20230629-angled-gallantly-8fe7451a25fa@spud> <20230630-7d0f6fe66c9415315d491f15@orel> MIME-Version: 1.0 In-Reply-To: <20230630-7d0f6fe66c9415315d491f15@orel> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230630_062023_150948_7C2C39EA X-CRM114-Status: GOOD ( 22.97 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, aou@eecs.berkeley.edu, linux-kernel@vger.kernel.org, Palmer Dabbelt , robh+dt@kernel.org, Conor Dooley , krzysztof.kozlowski+dt@linaro.org, Paul Walmsley , linux-riscv@lists.infradead.org, heiko.stuebner@vrull.eu, Evan Green Content-Type: multipart/mixed; boundary="===============7839964902572103792==" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org --===============7839964902572103792== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="o4a1LRPZt0ieGy5D" Content-Disposition: inline --o4a1LRPZt0ieGy5D Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jun 30, 2023 at 09:46:48AM +0200, Andrew Jones wrote: > On Thu, Jun 29, 2023 at 10:44:18PM +0100, Conor Dooley wrote: > > On Thu, Jun 29, 2023 at 02:16:49PM -0700, Palmer Dabbelt wrote: > > > On Thu, 29 Jun 2023 13:20:55 PDT (-0700), Conor Dooley wrote: > ... > > > > +bool __initdata riscv_isa_fallback_cmdline =3D false; > > > > +static int __init riscv_isa_fallback_setup(char *__unused) > > >=20 > > > Maybe it's better to support =3Dtrue and =3Dfalse here? Not sure it = matters, > > > we're already down a rabbit hole ;) > >=20 > > Dunno, not implemented a cmdline param before. Seemed "cleaner" to check > > for presence, don't really care so I'll adapt to w/e. > > >=20 > I don't have a strong preference here, but to throw in more food for > thought, I see this DT-v1 vs. DT-v2 choice to be a bit analogous to the > DT vs. ACPI choice. The 'acpi' command line parameter, for RISC-V, can > be 'off', 'on', and 'force', where >=20 > off -- disable ACPI if default was on > on -- enable ACPI but allow fallback to DT > force -- enable ACPI if default was off >=20 > So, if the default of the isa fallback command line option will depend on > Kconfig, then we may also want a 'force'. I'm not sure that I understand what "force" would give us. There's 4 cases: - CONFIG_RISCV_ISA_FALLBACK is enabled, cmdline option is present: cmdline option is ignored, fallback is taken if needed. crash if neither are present. - CONFIG_RISCV_ISA_FALLBACK is enabled, cmdline option is not present: cmdline option is ignored, fallback is taken if needed. crash if neither are present. - CONFIG_RISCV_ISA_FALLBACK is disabled, cmdline option is present: cmdline option takes priority, fallback is taken if needed. crash if neither are present. - CONFIG_RISCV_ISA_FALLBACK is disabled, cmdline option is not present: fallback is never taken crash if new properties aren't present. I don't really see the value in having an equivalent to acpi=3Doff, because the order of precedence is, to use your naming, "DT-v2" falling back to "DT-v1" & the default value concerns the use of the fallback. For ACPI, it is the other way around & the option controls the use of "DT-v2"'s analogue. Trying to slot in that logic: - CONFIG_RISCV_ISA_FALLBACK is enabled, cmdline option "=3Don": cmdline option is ignored, fallback is taken if needed. crash if neither are present. - CONFIG_RISCV_ISA_FALLBACK is enabled, cmdline option "=3Doff": cmdline option is prioritised, fallback is taken if needed. crash if new properties aren't present. - CONFIG_RISCV_ISA_FALLBACK is disabled, cmdline option "=3Don": cmdline option is prioritised, fallback is taken if needed. crash if neither are present. - CONFIG_RISCV_ISA_FALLBACK is disabled, cmdline option "=3Doff": fallback is never taken crash if new properties aren't present. I think I prefer the behaviour of what I currently have & I don't really get where the "force" option is supposed to fit in either? Cheers, Conor. --o4a1LRPZt0ieGy5D Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZJ7WZwAKCRB4tDGHoIJi 0gMcAQChwEuzvhSORcS7/4Mm0GXlyvRmOlOfWOHtGmwWRFmLMgD+JzMMaxJwKmej f/W/6SoUrX44MMben0skWQdfEYtTNQo= =N0ZM -----END PGP SIGNATURE----- --o4a1LRPZt0ieGy5D-- --===============7839964902572103792== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv --===============7839964902572103792==--