From patchwork Wed Aug 19 06:55:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11722963 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 56A821575 for ; Wed, 19 Aug 2020 07:05:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C1AA208DB for ; Wed, 19 Aug 2020 07:05:13 +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="B+Kbvqdu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727986AbgHSHFH (ORCPT ); Wed, 19 Aug 2020 03:05:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727813AbgHSG5D (ORCPT ); Wed, 19 Aug 2020 02:57:03 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 88332C061389; Tue, 18 Aug 2020 23:57:00 -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=t/kUI/553mQLkPn2YstRQ1uK7QcbAe6EXdXOlcFiX/o=; b=B+Kbvqduoiia1ONSXw50+AAvII SDCx6Q5i1wD1ezj1lsE/JQF3YbqSMgFxv6KOUYJxjYqh+96u7plrV+/YdrNpz8WDFhQW1S4H5Srxd /svckscBzNBWdiFRGXc2AbTzAzlrdpesdCvrY46aj8wx3UqzriA+qG5PDFJHIufcy2Szc07uAzFjB A9bjJtEhAaOU0mBzU+YkTgw4yRv/Y0j0IVpmaClidPQq8MFJqjPcXNDdKkAEO/BSDZFQ9pgQ7EfIo NG5HP1xs9rulYgK4ERUivl4xbpNxfSmTYqP8Uxwxc0Fm5HhzEwUo1cHA/Is6oiJmP0q5bUvgMU50R pqfWn1Xg==; Received: from [2001:4bb8:198:f3b2:86b6:2277:f429:37a1] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8I16-0008NH-FO; Wed, 19 Aug 2020 06:56:12 +0000 From: Christoph Hellwig To: Mauro Carvalho Chehab , Thomas Bogendoerfer , "James E.J. Bottomley" , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , Ben Skeggs , Pawel Osciak , Marek Szyprowski , Matt Porter , iommu@lists.linux-foundation.org Cc: Tom Lendacky , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-samsung-soc@vger.kernel.org, nouveau@lists.freedesktop.org, netdev@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, linux-mm@kvack.org, alsa-devel@alsa-project.org Subject: [PATCH 08/28] MIPS: make dma_sync_*_for_cpu a little less overzealous Date: Wed, 19 Aug 2020 08:55:35 +0200 Message-Id: <20200819065555.1802761-9-hch@lst.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200819065555.1802761-1-hch@lst.de> References: <20200819065555.1802761-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@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