Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932828AbdCGPex (ORCPT ); Tue, 7 Mar 2017 10:34:53 -0500 Received: from foss.arm.com ([217.140.101.70]:48920 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755623AbdCGPef (ORCPT ); Tue, 7 Mar 2017 10:34:35 -0500 From: Vladimir Murzin To: linux-arm-kernel@lists.infradead.org Cc: kbuild-all@01.org, linux-kernel@vger.kernel.org, linux@armlinux.org.uk, akpm@linux-foundation.org, robin.murphy@arm.com, benjamin.gaignard@linaro.org, alexandre.torgue@st.com, sza@esh.hu Subject: [PATCH v2 5/7] ARM: NOMMU: Introduce dma operations for noMMU Date: Tue, 7 Mar 2017 11:12:32 +0000 Message-Id: <1488885154-12429-6-git-send-email-vladimir.murzin@arm.com> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1488885154-12429-1-git-send-email-vladimir.murzin@arm.com> References: <1488885154-12429-1-git-send-email-vladimir.murzin@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10324 Lines: 344 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 Tested-by: Benjamin Gaignard Tested-by: Andras Szemzo Tested-by: Alexandre TORGUE Reviewed-by: Robin Murphy Signed-off-by: Vladimir Murzin --- arch/arm/Kconfig | 1 + arch/arm/include/asm/dma-mapping.h | 2 +- arch/arm/mm/Makefile | 5 +- arch/arm/mm/dma-mapping-nommu.c | 253 +++++++++++++++++++++++++++++++++++++ 4 files changed, 257 insertions(+), 4 deletions(-) create mode 100644 arch/arm/mm/dma-mapping-nommu.c diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 6ab63fa..8f0b6ca 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -22,6 +22,7 @@ config ARM select CLONE_BACKWARDS select CPU_PM if (SUSPEND || CPU_IDLE) select DCACHE_WORD_ACCESS if HAVE_EFFICIENT_UNALIGNED_ACCESS + select DMA_NOOP_OPS if !MMU select EDAC_SUPPORT select EDAC_ATOMIC_SCRUB select GENERIC_ALLOCATOR diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index 7166569..63270de 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -20,7 +20,7 @@ static inline const struct dma_map_ops *__generic_dma_ops(struct device *dev) { if (dev && dev->dma_ops) return dev->dma_ops; - return &arm_dma_ops; + return IS_ENABLED(CONFIG_MMU) ? &arm_dma_ops : &dma_noop_ops; } static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus) diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile index 54857bc..ea80df7 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..ecbeadb --- /dev/null +++ b/arch/arm/mm/dma-mapping-nommu.c @@ -0,0 +1,253 @@ +/* + * 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); + else + 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(phys_addr_t paddr, size_t size, + enum dma_data_direction dir) +{ + dmac_map_area(__va(paddr), size, dir); + + if (dir == DMA_FROM_DEVICE) + outer_inv_range(paddr, paddr + size); + else + outer_clean_range(paddr, paddr + size); +} + +static void __dma_page_dev_to_cpu(phys_addr_t paddr, size_t size, + enum dma_data_direction dir) +{ + if (dir != DMA_TO_DEVICE) { + outer_inv_range(paddr, paddr + size); + dmac_unmap_area(__va(paddr), 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); +} + +const 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); -- 2.0.0