From patchwork Mon Jan 9 13:47:47 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Murzin X-Patchwork-Id: 9504957 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 0AB6A60757 for ; Mon, 9 Jan 2017 14:44:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F3F5C284C0 for ; Mon, 9 Jan 2017 14:44:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E8BF3284E8; Mon, 9 Jan 2017 14:44:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 2EA16284C0 for ; Mon, 9 Jan 2017 14:44:20 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cQbBI-000400-A9; Mon, 09 Jan 2017 14:44:16 +0000 Received: from merlin.infradead.org ([2001:4978:20e::2]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cQbAy-0003ZL-9G for linux-arm-kernel@bombadil.infradead.org; Mon, 09 Jan 2017 14:43:56 +0000 Received: from foss.arm.com ([217.140.101.70]) by merlin.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cQaJE-0007ha-Co for linux-arm-kernel@lists.infradead.org; Mon, 09 Jan 2017 13:48:25 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B154C1596; Mon, 9 Jan 2017 05:48:07 -0800 (PST) Received: from login2.euhpc.arm.com (login2.euhpc.arm.com [10.6.26.144]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6C90F3F242; Mon, 9 Jan 2017 05:48:06 -0800 (PST) From: Vladimir Murzin To: linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH v3 3/5] ARM: NOMMU: Introduce dma operations for noMMU Date: Mon, 9 Jan 2017 13:47:47 +0000 Message-Id: <1483969669-4636-4-git-send-email-vladimir.murzin@arm.com> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1483969669-4636-1-git-send-email-vladimir.murzin@arm.com> References: <1483969669-4636-1-git-send-email-vladimir.murzin@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170109_084824_687828_429EAB32 X-CRM114-Status: GOOD ( 23.03 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alexandre.torgue@st.com, linux@armlinux.org.uk, kbuild-all@01.org, benjamin.gaignard@linaro.org, m.szyprowski@samsung.com, robin.murphy@arm.com, sza@esh.hu MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP R/M classes of cpus can have memory covered by MPU which in turn might configure RAM as Normal i.e. bufferable and cacheable. It breaks dma_alloc_coherent() and friends, since data can stuck in caches now or be buffered. This patch factors out DMA support for NOMMU configuration into separate entity which provides dedicated dma_ops. We have to handle there several cases: - configurations with MMU/MPU setup - configurations without MMU/MPU setup - special case for M-class, since caches and MPU there are optional In general we rely on default DMA area for coherent allocations or/and per-device memory reserves suitable for coherent DMA, so if such regions are set coherent allocations go from there. In case MPU/MPU was not setup we fallback to normal page allocator for DMA memory allocation. In case we run M-class cpus, for configuration without cache support (like Cortex-M3/M4) dma operations are forced to be coherent and wired with dma-noop (such decision is made based on cacheid global variable); however, if caches are detected there and no DMA coherent region is given (either default or per-device), dma is disallowed even MPU is not set - it is because M-class implement system memory map which defines part of address space as Normal memory. Reported-by: Alexandre Torgue Reported-by: Andras Szemzo Signed-off-by: Vladimir Murzin --- arch/arm/include/asm/dma-mapping.h | 3 +- arch/arm/mm/Makefile | 5 +- arch/arm/mm/dma-mapping-nommu.c | 252 +++++++++++++++++++++++++++++++++++++ 3 files changed, 256 insertions(+), 4 deletions(-) create mode 100644 arch/arm/mm/dma-mapping-nommu.c diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index bf02dbd..559faad 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -20,7 +20,8 @@ static inline struct dma_map_ops *__generic_dma_ops(struct device *dev) { if (dev && dev->archdata.dma_ops) return dev->archdata.dma_ops; - return &arm_dma_ops; + + return IS_ENABLED(CONFIG_MMU) ? &arm_dma_ops : &dma_noop_ops; } static inline struct dma_map_ops *get_dma_ops(struct device *dev) diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile index 2ac7988..5796357 100644 --- a/arch/arm/mm/Makefile +++ b/arch/arm/mm/Makefile @@ -2,9 +2,8 @@ # Makefile for the linux arm-specific parts of the memory manager. # -obj-y := dma-mapping.o extable.o fault.o init.o \ - iomap.o - +obj-y := extable.o fault.o init.o iomap.o +obj-y += dma-mapping$(MMUEXT).o obj-$(CONFIG_MMU) += fault-armv.o flush.o idmap.o ioremap.o \ mmap.o pgd.o mmu.o pageattr.o diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c new file mode 100644 index 0000000..a5c50fb --- /dev/null +++ b/arch/arm/mm/dma-mapping-nommu.c @@ -0,0 +1,252 @@ +/* + * Based on linux/arch/arm/mm/dma-mapping.c + * + * Copyright (C) 2000-2004 Russell King + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include +#include +#include +#include + +#include +#include +#include +#include + +#include "dma.h" + +/* + * dma_noop_ops is used if + * - MMU/MPU is off + * - cpu is v7m w/o cache support + * - device is coherent + * otherwise arm_nommu_dma_ops is used. + * + * arm_nommu_dma_ops rely on consistent DMA memory (please, refer to + * [1] on how to declare such memory). + * + * [1] Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt + */ + +static void *arm_nommu_dma_alloc(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, + unsigned long attrs) + +{ + struct dma_map_ops *ops = &dma_noop_ops; + + /* + * We are here because: + * - no consistent DMA region has been defined, so we can't + * continue. + * - there is no space left in consistent DMA region, so we + * only can fallback to generic allocator if we are + * advertised that consistency is not required. + */ + + if (attrs & DMA_ATTR_NON_CONSISTENT) + return ops->alloc(dev, size, dma_handle, gfp, attrs); + + WARN_ON_ONCE(1); + return NULL; +} + +static void arm_nommu_dma_free(struct device *dev, size_t size, + void *cpu_addr, dma_addr_t dma_addr, + unsigned long attrs) +{ + struct dma_map_ops *ops = &dma_noop_ops; + + if (attrs & DMA_ATTR_NON_CONSISTENT) + ops->free(dev, size, cpu_addr, dma_addr, attrs); + + WARN_ON_ONCE(1); + return; +} + +static int arm_nommu_dma_mmap(struct device *dev, struct vm_area_struct *vma, + void *cpu_addr, dma_addr_t dma_addr, size_t size, + unsigned long attrs) +{ + struct dma_map_ops *ops = &dma_noop_ops; + int ret; + + if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret)) + return ret; + + if (attrs & DMA_ATTR_NON_CONSISTENT) + return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs); + + WARN_ON_ONCE(1); + return -ENXIO; +} + +static void __dma_page_cpu_to_dev(dma_addr_t handle, size_t size, + enum dma_data_direction dir) +{ + dmac_unmap_area(__va(handle), size, dir); + + if (dir == DMA_FROM_DEVICE) + outer_inv_range(handle, handle + size); + else + outer_clean_range(handle, handle + size); +} + +static void __dma_page_dev_to_cpu(dma_addr_t handle, size_t size, + enum dma_data_direction dir) +{ + if (dir != DMA_TO_DEVICE) { + outer_inv_range(handle, handle + size); + dmac_unmap_area(__va(handle), size, dir); + } +} + +static dma_addr_t arm_nommu_dma_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, + enum dma_data_direction dir, + unsigned long attrs) +{ + dma_addr_t handle = page_to_phys(page) + offset; + + __dma_page_cpu_to_dev(handle, size, dir); + + return handle; +} + +static void arm_nommu_dma_unmap_page(struct device *dev, dma_addr_t handle, + size_t size, enum dma_data_direction dir, + unsigned long attrs) +{ + __dma_page_dev_to_cpu(handle, size, dir); +} + + +static int arm_nommu_dma_map_sg(struct device *dev, struct scatterlist *sgl, + int nents, enum dma_data_direction dir, + unsigned long attrs) +{ + int i; + struct scatterlist *sg; + + for_each_sg(sgl, sg, nents, i) { + sg_dma_address(sg) = sg_phys(sg); + sg_dma_len(sg) = sg->length; + __dma_page_cpu_to_dev(sg_dma_address(sg), sg_dma_len(sg), dir); + } + + return nents; +} + +static void arm_nommu_dma_unmap_sg(struct device *dev, struct scatterlist *sgl, + int nents, enum dma_data_direction dir, + unsigned long attrs) +{ + struct scatterlist *sg; + int i; + + for_each_sg(sgl, sg, nents, i) + __dma_page_dev_to_cpu(sg_dma_address(sg), sg_dma_len(sg), dir); +} + +static void arm_nommu_dma_sync_single_for_device(struct device *dev, + dma_addr_t handle, size_t size, enum dma_data_direction dir) +{ + __dma_page_cpu_to_dev(handle, size, dir); +} + +static void arm_nommu_dma_sync_single_for_cpu(struct device *dev, + dma_addr_t handle, size_t size, enum dma_data_direction dir) +{ + __dma_page_cpu_to_dev(handle, size, dir); +} + +static void arm_nommu_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sgl, + int nents, enum dma_data_direction dir) +{ + struct scatterlist *sg; + int i; + + for_each_sg(sgl, sg, nents, i) + __dma_page_cpu_to_dev(sg_dma_address(sg), sg_dma_len(sg), dir); +} + +static void arm_nommu_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl, + int nents, enum dma_data_direction dir) +{ + struct scatterlist *sg; + int i; + + for_each_sg(sgl, sg, nents, i) + __dma_page_dev_to_cpu(sg_dma_address(sg), sg_dma_len(sg), dir); +} + +struct dma_map_ops arm_nommu_dma_ops = { + .alloc = arm_nommu_dma_alloc, + .free = arm_nommu_dma_free, + .mmap = arm_nommu_dma_mmap, + .map_page = arm_nommu_dma_map_page, + .unmap_page = arm_nommu_dma_unmap_page, + .map_sg = arm_nommu_dma_map_sg, + .unmap_sg = arm_nommu_dma_unmap_sg, + .sync_single_for_device = arm_nommu_dma_sync_single_for_device, + .sync_single_for_cpu = arm_nommu_dma_sync_single_for_cpu, + .sync_sg_for_device = arm_nommu_dma_sync_sg_for_device, + .sync_sg_for_cpu = arm_nommu_dma_sync_sg_for_cpu, +}; +EXPORT_SYMBOL(arm_nommu_dma_ops); + +static struct dma_map_ops *arm_nommu_get_dma_map_ops(bool coherent) +{ + return coherent ? &dma_noop_ops : &arm_nommu_dma_ops; +} + +void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, + const struct iommu_ops *iommu, bool coherent) +{ + struct dma_map_ops *dma_ops; + + if (IS_ENABLED(CONFIG_CPU_V7M)) { + /* + * Cache support for v7m is optional, so can be treated as + * coherent if no cache has been detected. Note that it is not + * enough to check if MPU is in use or not since in absense of + * MPU system memory map is used. + */ + dev->archdata.dma_coherent = (cacheid) ? coherent : true; + } else { + /* + * Assume coherent DMA in case MMU/MPU has not been set up. + */ + dev->archdata.dma_coherent = (get_cr() & CR_M) ? coherent : true; + } + + dma_ops = arm_nommu_get_dma_map_ops(dev->archdata.dma_coherent); + + set_dma_ops(dev, dma_ops); +} + +void arch_teardown_dma_ops(struct device *dev) +{ +} + +int dma_supported(struct device *dev, u64 mask) +{ + return 1; +} + +EXPORT_SYMBOL(dma_supported); + +#define PREALLOC_DMA_DEBUG_ENTRIES 4096 + +static int __init dma_debug_do_init(void) +{ + dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); + return 0; +} +core_initcall(dma_debug_do_init);