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 27C8EC02183 for ; Fri, 17 Jan 2025 09:58:45 +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:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Tiv9IhPb3TGJCjMZXEKnO/z1q/has7l9wjvra6B6t/0=; b=BYThk2QUUVnafu C+FdfCmBXVjipuunJH3i00iOr3rZWlRo0J6qsofubTqzPq9KynCzBrO71Dv1LCRCCELTFzYxZhPUH dNaHzBcYeRFc8hIbxz6kXoUG4rhQ0rBcWKjvNIqrJZ2xHbAguPESuCBG6UbpFITIHuD5ZI9GzVvM2 f/l7yNKHgPs+5rYTWZkZXJ8CB4Aj9o5KL6vozjSSv8y2UZSmCAuWrX2DUO8dx/k1rISmd5qMh7nY7 GNx6aZ/Ihv7Ac3dKNEgE74K9PoNUpVi7OGybvzVcSJhFIqHBsYBzbUJBWmbu5NTVfe7OEHoNum4jI NVpNUGE/wYNA+AXH+BZQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tYj7g-0000000HW9s-2ZTR; Fri, 17 Jan 2025 09:58:40 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tYj7e-0000000HW93-3L9o for linux-riscv@lists.infradead.org; Fri, 17 Jan 2025 09:58:40 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 81DB168BEB; Fri, 17 Jan 2025 10:58:32 +0100 (CET) Date: Fri, 17 Jan 2025 10:58:32 +0100 From: Christoph Hellwig To: Sergey Matyukevich Cc: Christoph Hellwig , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Palmer Dabbelt , Paul Walmsley , Albert Ou , Alexandre Ghiti , Conor Dooley , Robin Murphy , Lad Prabhakar , Geert Uytterhoeven Subject: Re: [PATCH] riscv: select DMA_DIRECT_REMAP by RISCV_ISA_SVPBMT and ERRATA_THEAD_MAE Message-ID: <20250117095832.GB2585@lst.de> References: <20250116172950.1989748-1-geomatsi@gmail.com> <20250117075238.GA25422@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250117_015838_988851_EED007C1 X-CRM114-Status: GOOD ( 15.94 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Fri, Jan 17, 2025 at 11:38:47AM +0300, Sergey Matyukevich wrote: > > Please explain what this is supposed to solve, because the above > > explanation dosn't make any sense. DMA_DIRECT_REMAP is one > > of the implementations supporting dma coherent allocatiosn for > > non-coherent devices. So selecting it from something that > > just keyes off support for an extension, but not the dma > > implementation is wrong. > > Now DMA_DIRECT_REMAP is selected either by Zicbom (standard) or XTheadCmo > (vendor) RISC-V extensions. Because they need DMA_DIRECT_REMAP to implement DMA coherent. > However neither of them can help to implement > DMA_DIRECT_REMAP on RISC-V. So selection of DMA_DIRECT_REMAP has been > moved in Kconfigs to Svpbmt and XTheadMae extensions. But Svpbmt does not imply that you even need DMA_DIRECT_REMAP. Are you tying to solve a problem here? If so can you explain it? _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv