From patchwork Mon May 8 18:16:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Conor Dooley X-Patchwork-Id: 13234801 X-Patchwork-Delegate: mail@conchuod.ie 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 A1769C7EE22 for ; Mon, 8 May 2023 18:17:19 +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-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=tnQ+AE+ABplMGKe/RRx4AMXFLjZvFTnSTJgowSK1Nz0=; b=gDPUU1Sj4UcB4u StAUsek4HNjDxsfwdj5nNnqvmczJMoBtcnrPzan4bRvkZg38VbkEG7DbBYBnn8o9eT6VLdAxri6mo 7GaF2IVCOB6n3NLAOBiAjH1G+TfMx1JNW1hVJLSMxg5MAtlaHolqmVZznhX2WLdKhyLf8I68WsuOe pXu2Eq95o9KzkK415o+JrbygXZ8cZ3pXzVP28afqtV7vdr1EW+hYLpW07RGK6ZbreaqxWMzBmk5kI lYfH6Mbb5x3Q/lglXPD2BX54GWvriH3HOGtQWT7WiaREBnAPVDoiBetPA1K9EFp8QO3DGUApx2e1F rR8dKbJRDLhNNxxYVAaQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pw5Q3-0016dQ-2w; Mon, 08 May 2023 18:17:07 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pw5Pw-0016c8-0z for linux-riscv@lists.infradead.org; Mon, 08 May 2023 18:17:05 +0000 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 dfw.source.kernel.org (Postfix) with ESMTPS id 98CA461EB2; Mon, 8 May 2023 18:16:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6522DC433A0; Mon, 8 May 2023 18:16:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1683569819; bh=05ZEnpDryaZ3pWwm2uM1BaK+nfW//+toX2uQFMeA9T4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HJGrfWGsDd1s7R5AE+0X9NTaSLnSiTl1CDjI2qlfcq8hhAqOCmAzMcydtEFIvBxYf kEQuQgx6k6zACnTIy2DQIAThvlziT4MzdAtavBoIJ+AoY6AMxPuJU2dXPxW+YKuNqX ZcWyVTekYnD9VAlWfQ/qEk0odrHvs1Z4RfkKOJ84kpsCTlZja+VwTzuSkmWSxSUY65 cAt7YdetUsJq7H6vdJPHzQtJoEEzngINLFx80lTw1eJvepAaziMwmcfh8NXI2fXban nScP2fYPcgIYUuIXBjKAceSEWgoe4x2zOVy7EpGAFoQeSPnkxqFwFQpSmiPXRRgqHR h0Yt4/U4EPHrg== From: Conor Dooley To: linux-riscv@lists.infradead.org Subject: [RFC 1/6] dt-bindings: riscv: clarify what an unversioned extension means Date: Mon, 8 May 2023 19:16:21 +0100 Message-Id: <20230508-decibel-fender-532248c8f8ed@spud> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230508-hypnotic-phobia-99598439d828@spud> References: <20230508-hypnotic-phobia-99598439d828@spud> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1402; i=conor.dooley@microchip.com; h=from:subject:message-id; bh=pGmr6rcDfQk2g8LcKq7L3T1Gg5LY7Zpc7WjhfhPcmv8=; b=owGbwMvMwCFWscWwfUFT0iXG02pJDCmRNqXs1UuN814vn8Sa0ftPPlY/qv0kw/MDHrvlzNnmL fZ+EqTUUcrCIMbBICumyJJ4u69Fav0flx3OPW9h5rAygQxh4OIUgIkYqjAy9C6zY3LI67n333be fu4JGzQVn7mGCx7aetLUcHrggz8Z6gz/E/Ncdueu3ZM/WX156Ko9SwoPMs54b6hXwKaUckDT+Fw 3NwA= X-Developer-Key: i=conor.dooley@microchip.com; a=openpgp; fpr=F9ECA03CF54F12CD01F1655722E2C55B37CF380C X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230508_111700_409074_06A3F249 X-CRM114-Status: GOOD ( 12.05 ) 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, Conor Dooley , Heiko Stuebner , conor@kernel.org, Yangyu Chen , Conor Dooley , Rob Herring , Palmer Dabbelt , Krzysztof Kozlowski , Paul Walmsley , Andrew Jones Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org From: Conor Dooley C'est la vie, the spec folks reserve the ability to make incompatible changes between major versions of an extension. Their idea of backwards compatibility appears driven by the hardware perspective - it's backwards compatible if a later version is a subset of the existing extension. IOW, if you supported `x` in vN, you still support `x` in vN+1. However in software terms, code that was built for the vN's `x` extension may not work with the new definition. Signed-off-by: Conor Dooley Acked-by: Krzysztof Kozlowski --- Documentation/devicetree/bindings/riscv/cpus.yaml | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Documentation/devicetree/bindings/riscv/cpus.yaml b/Documentation/devicetree/bindings/riscv/cpus.yaml index db5253a2a74a..405915b04d69 100644 --- a/Documentation/devicetree/bindings/riscv/cpus.yaml +++ b/Documentation/devicetree/bindings/riscv/cpus.yaml @@ -91,6 +91,9 @@ properties: Notably, riscv,isa was defined prior to the creation of the Zicsr and Zifencei extensions and thus "i" implies "zicsr_zifencei". + For the sake of backwards compatibility, an unversioned + extension means that the hart/platform is capable of + supporting version 1.0.0 of the extension. While the isa strings in ISA specification are case insensitive, letters in the riscv,isa string must be all