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=-12.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 D9302C43461 for ; Tue, 8 Sep 2020 16:51:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B70D2075A for ; Tue, 8 Sep 2020 16:51:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IQ7sGbx+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731952AbgIHQvS (ORCPT ); Tue, 8 Sep 2020 12:51:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34172 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732044AbgIHQsj (ORCPT ); Tue, 8 Sep 2020 12:48:39 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4187C061799; Tue, 8 Sep 2020 09:48:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=+nOSLIs9LkSjQJt0Q5qAmk8nkbWCQbovg2Llv5RLZtk=; b=IQ7sGbx+t6W2URYGAOKZfn6yYh JWIo9H8+pwAdOUvhjhfUAs2ggnOgWWcNDVAkixK61nw59vUUoSHBtr8ci/p/CkiVEZdX3lqJpc6md jCjTOziJO4l5EWDap3Wct/xQUY+QqWAoBNMLBc8/rDE3iqX1WQZwiYECBzvVAsUQ9APLCrlkKiLlF 6dktr7vivViBBmsenA50pIFoJ5de5v0CWB7/r84SPvhv2j5JdzZNmwn/fBawbYUvcOmD0+shnGlaO dEbh3gNu0J03xzwCCQtqqSTZPiAVTwKUib9PmEV3i6T6ESrjW11KLyCKDzjHow+Wrg8IsaatI+N2i eaa0CdKQ==; Received: from [2001:4bb8:184:af1:3dc3:9c83:fc6c:e0f] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFgmm-0001Qz-8R; Tue, 08 Sep 2020 16:48:00 +0000 From: Christoph Hellwig To: Tony Luck , Fenghua Yu , Thomas Bogendoerfer , iommu@lists.linux-foundation.org Cc: Tomasz Figa , Joerg Roedel , Robin Murphy , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org Subject: [PATCH 01/12] MIPS: make dma_sync_*_for_cpu a little less overzealous Date: Tue, 8 Sep 2020 18:47:47 +0200 Message-Id: <20200908164758.3177341-2-hch@lst.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908164758.3177341-1-hch@lst.de> References: <20200908164758.3177341-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When transferring DMA ownership back to the CPU there should never be any writeback from the cache, as the buffer was owned by the device until now. Instead it should just be invalidated for the mapping directions where the device could have written data. Note that the changes rely on the fact that kmap_atomic is stubbed out for the !HIGHMEM case to simplify the code a bit. Signed-off-by: Christoph Hellwig Acked-by: Thomas Bogendoerfer --- arch/mips/mm/dma-noncoherent.c | 44 +++++++++++++++++++++------------- 1 file changed, 28 insertions(+), 16 deletions(-) diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c index 563c2c0d0c8193..97a14adbafc99c 100644 --- a/arch/mips/mm/dma-noncoherent.c +++ b/arch/mips/mm/dma-noncoherent.c @@ -55,22 +55,34 @@ void *arch_dma_set_uncached(void *addr, size_t size) return (void *)(__pa(addr) + UNCAC_BASE); } -static inline void dma_sync_virt(void *addr, size_t size, +static inline void dma_sync_virt_for_device(void *addr, size_t size, enum dma_data_direction dir) { switch (dir) { case DMA_TO_DEVICE: dma_cache_wback((unsigned long)addr, size); break; - case DMA_FROM_DEVICE: dma_cache_inv((unsigned long)addr, size); break; - case DMA_BIDIRECTIONAL: dma_cache_wback_inv((unsigned long)addr, size); break; + default: + BUG(); + } +} +static inline void dma_sync_virt_for_cpu(void *addr, size_t size, + enum dma_data_direction dir) +{ + switch (dir) { + case DMA_TO_DEVICE: + break; + case DMA_FROM_DEVICE: + case DMA_BIDIRECTIONAL: + dma_cache_inv((unsigned long)addr, size); + break; default: BUG(); } @@ -82,7 +94,7 @@ static inline void dma_sync_virt(void *addr, size_t size, * configured then the bulk of this loop gets optimized out. */ static inline void dma_sync_phys(phys_addr_t paddr, size_t size, - enum dma_data_direction dir) + enum dma_data_direction dir, bool for_device) { struct page *page = pfn_to_page(paddr >> PAGE_SHIFT); unsigned long offset = paddr & ~PAGE_MASK; @@ -90,18 +102,20 @@ static inline void dma_sync_phys(phys_addr_t paddr, size_t size, do { size_t len = left; + void *addr; if (PageHighMem(page)) { - void *addr; - if (offset + len > PAGE_SIZE) len = PAGE_SIZE - offset; + } + + addr = kmap_atomic(page); + if (for_device) + dma_sync_virt_for_device(addr + offset, len, dir); + else + dma_sync_virt_for_cpu(addr + offset, len, dir); + kunmap_atomic(addr); - addr = kmap_atomic(page); - dma_sync_virt(addr + offset, len, dir); - kunmap_atomic(addr); - } else - dma_sync_virt(page_address(page) + offset, size, dir); offset = 0; page++; left -= len; @@ -111,7 +125,7 @@ static inline void dma_sync_phys(phys_addr_t paddr, size_t size, void arch_sync_dma_for_device(phys_addr_t paddr, size_t size, enum dma_data_direction dir) { - dma_sync_phys(paddr, size, dir); + dma_sync_phys(paddr, size, dir, true); } #ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU @@ -119,16 +133,14 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size, enum dma_data_direction dir) { if (cpu_needs_post_dma_flush()) - dma_sync_phys(paddr, size, dir); + dma_sync_phys(paddr, size, dir, false); } #endif void arch_dma_cache_sync(struct device *dev, void *vaddr, size_t size, enum dma_data_direction direction) { - BUG_ON(direction == DMA_NONE); - - dma_sync_virt(vaddr, size, direction); + dma_sync_virt_for_device(vaddr, size, direction); } #ifdef CONFIG_DMA_PERDEV_COHERENT -- 2.28.0