Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753535AbaLLWMQ (ORCPT ); Fri, 12 Dec 2014 17:12:16 -0500 Received: from mail-pd0-f169.google.com ([209.85.192.169]:48320 "EHLO mail-pd0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752615AbaLLWIg (ORCPT ); Fri, 12 Dec 2014 17:08:36 -0500 From: Kevin Cernekee To: ralf@linux-mips.org Cc: f.fainelli@gmail.com, tglx@linutronix.de, jason@lakedaemon.net, jogo@openwrt.org, arnd@arndb.de, computersforpeace@gmail.com, linux-mips@linux-mips.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V5 13/23] MIPS: BMIPS: Flush the readahead cache after DMA Date: Fri, 12 Dec 2014 14:07:04 -0800 Message-Id: <1418422034-17099-14-git-send-email-cernekee@gmail.com> X-Mailer: git-send-email 2.1.1 In-Reply-To: <1418422034-17099-1-git-send-email-cernekee@gmail.com> References: <1418422034-17099-1-git-send-email-cernekee@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org BMIPS 3300/435x/438x CPUs have a readahead cache that is separate from the L1/L2. During a DMA operation, accesses adjacent to a DMA buffer may cause parts of the DMA buffer to be prefetched into the RAC. To avoid possible coherency problems, flush the RAC upon DMA completion. Signed-off-by: Kevin Cernekee --- arch/mips/mm/dma-default.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c index af5f046..ee6d12c 100644 --- a/arch/mips/mm/dma-default.c +++ b/arch/mips/mm/dma-default.c @@ -18,6 +18,7 @@ #include #include +#include #include #include #include @@ -69,6 +70,18 @@ static inline struct page *dma_addr_to_page(struct device *dev, */ static inline int cpu_needs_post_dma_flush(struct device *dev) { + if (boot_cpu_type() == CPU_BMIPS3300 || + boot_cpu_type() == CPU_BMIPS4350 || + boot_cpu_type() == CPU_BMIPS4380) { + void __iomem *cbr = BMIPS_GET_CBR(); + + /* Flush stale data out of the readahead cache */ + __raw_writel(0x100, cbr + BMIPS_RAC_CONFIG); + __raw_readl(cbr + BMIPS_RAC_CONFIG); + + return 0; + } + return !plat_device_is_coherent(dev) && (boot_cpu_type() == CPU_R10000 || boot_cpu_type() == CPU_R12000 || -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/