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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 C25F6C4338F for ; Mon, 26 Jul 2021 06:58:09 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 5EF9460F23 for ; Mon, 26 Jul 2021 06:58:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5EF9460F23 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org 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=XnYzEaSvWBQ/4xV1clPlQRyCyz4tAIHDwoc9vNiLOfE=; b=nVpoCPQIg/p1rQ KZHEhZ963Y66FvajiXliT7r+Bv70WSVbKMmsLU0EMv0EZDhd9LLMFzRyOi+K7dM9ZvzCD+yD/nerV /PjESQCaoFWxlVXQKAIoTdP7dcuT/6/RfizdINl9NU5z1vRbkpeDAtTGn7a0sDlWg9F2DCNS1Y0kw XDDEycBzgRHEDPjxw/RbGIzvI3Bx6uiHcvePr4/41sCGPtL6KbVCHDX9XZ5VnGszYq9GK9Qg/03t3 v+iIinjxMHjTv0GEkdQbMJM/WaI618c4yR6tNhn2D41vKaoAcl4e8mhVrHRExtoc0TlKP08AsFtTP wFHJivGzNLXM4YpKuc6g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m7uY1-009nAC-4B; Mon, 26 Jul 2021 06:57:09 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m7uXx-009n8V-LN for linux-riscv@lists.infradead.org; Mon, 26 Jul 2021 06:57:07 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 408B168AFE; Mon, 26 Jul 2021 08:56:58 +0200 (CEST) Date: Mon, 26 Jul 2021 08:56:57 +0200 From: Christoph Hellwig To: Atish Patra Cc: linux-kernel@vger.kernel.org, Albert Ou , Christoph Hellwig , devicetree@vger.kernel.org, Dmitry Vyukov , Frank Rowand , Guo Ren , iommu@lists.linux-foundation.org, linux-riscv@lists.infradead.org, Marek Szyprowski , Palmer Dabbelt , Paul Walmsley , Rob Herring , Robin Murphy , Tobias Klauser Subject: Re: [RFC 1/5] RISC-V: Implement arch_sync_dma* functions Message-ID: <20210726065657.GA9035@lst.de> References: <20210723214031.3251801-1-atish.patra@wdc.com> <20210723214031.3251801-2-atish.patra@wdc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210723214031.3251801-2-atish.patra@wdc.com> 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-20210725_235705_906126_39CB2375 X-CRM114-Status: GOOD ( 13.43 ) 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 > +#ifdef CONFIG_RISCV_DMA_NONCOHERENT > +struct riscv_dma_cache_sync { > + void (*cache_invalidate)(phys_addr_t paddr, size_t size); > + void (*cache_clean)(phys_addr_t paddr, size_t size); > + void (*cache_flush)(phys_addr_t paddr, size_t size); > +}; > + > +void riscv_dma_cache_sync_set(struct riscv_dma_cache_sync *ops); > +#endif As told a bunch of times before: doing indirect calls here is a performance nightmare. Use something that actually does perform horribly like alternatives. Or even delay implementing that until we need it and do a plain direct call for now. static void __dma_sync(phys_addr_t paddr, size_t size, enum dma_data_direction dir) > +{ > + if ((dir == DMA_FROM_DEVICE) && (dma_cache_sync->cache_invalidate)) > + dma_cache_sync->cache_invalidate(paddr, size); > + else if ((dir == DMA_TO_DEVICE) && (dma_cache_sync->cache_clean)) > + dma_cache_sync->cache_clean(paddr, size); > + else if ((dir == DMA_BIDIRECTIONAL) && dma_cache_sync->cache_flush) > + dma_cache_sync->cache_flush(paddr, size); > +} The seletion of flush types is completely broken. Take a look at the comment in arch/arc/mm/dma.c above arch_sync_dma_for_device for a good explanation. > +void arch_dma_prep_coherent(struct page *page, size_t size) > +{ > + void *flush_addr = page_address(page); > + > + memset(flush_addr, 0, size); arch_dma_prep_coherent is not supposed to modify the content of the data. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv