From d89e2378a97fafdc74cbf997e7c88af75b81610a Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Thu, 12 Oct 2017 16:56:14 +0100 Subject: drivers: flag buses which demand DMA configuration We do not want the common dma_configure() pathway to apply indiscriminately to all devices, since there are plenty of buses which do not have DMA capability, and if their child devices were used for DMA API calls it would only be indicative of a driver bug. However, there are a number of buses for which DMA is implicitly expected even when not described by firmware - those we whitelist with an automatic opt-in to dma_configure(), assuming that the DMA address space and the physical address space are equivalent if not otherwise specified. Commit 723288836628 ("of: restrict DMA configuration") introduced a short-term fix by comparing explicit bus types, but this approach is far from pretty, doesn't scale well, and fails to cope at all with bus drivers which may be built as modules, like host1x. Let's refine things by making that opt-in a property of the bus type, which neatly addresses those problems and lets the decision of whether firmware description of DMA capability should be optional or mandatory stay internal to the bus drivers themselves. Signed-off-by: Robin Murphy Acked-by: Rob Herring Acked-by: Greg Kroah-Hartman Acked-by: Thierry Reding Signed-off-by: Christoph Hellwig --- include/linux/device.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include') diff --git a/include/linux/device.h b/include/linux/device.h index 66fe271c2544..d60f7701e245 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -97,6 +97,8 @@ extern void bus_remove_file(struct bus_type *, struct bus_attribute *); * @p: The private data of the driver core, only the driver core can * touch this. * @lock_key: Lock class key for use by the lock validator + * @force_dma: Assume devices on this bus should be set up by dma_configure() + * even if DMA capability is not explicitly described by firmware. * * A bus is a channel between the processor and one or more devices. For the * purposes of the device model, all devices are connected via a bus, even if @@ -135,6 +137,8 @@ struct bus_type { struct subsys_private *p; struct lock_class_key lock_key; + + bool force_dma; }; extern int __must_check bus_register(struct bus_type *bus); -- cgit v1.2.3 From c9eb6172c328dde7e14812f94f8da87b691e41b5 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sun, 27 Aug 2017 10:37:15 +0200 Subject: dma-mapping: turn dma_cache_sync into a dma_map_ops method After we removed all the dead wood it turns out only two architectures actually implement dma_cache_sync as a real op: mips and parisc. Add a cache_sync method to struct dma_map_ops and implement it for the mips defualt DMA ops, and the parisc pa11 ops. Note that arm, arc and openrisc support DMA_ATTR_NON_CONSISTENT, but never provided a functional dma_cache_sync implementations, which seems somewhat odd. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy --- include/linux/dma-mapping.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include') diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 29ce9815da87..028a375d240d 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -126,6 +126,8 @@ struct dma_map_ops { void (*sync_sg_for_device)(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir); + void (*cache_sync)(struct device *dev, void *vaddr, size_t size, + enum dma_data_direction direction); int (*mapping_error)(struct device *dev, dma_addr_t dma_addr); int (*dma_supported)(struct device *dev, u64 mask); #ifdef ARCH_HAS_DMA_GET_REQUIRED_MASK @@ -436,6 +438,17 @@ dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, #define dma_map_page(d, p, o, s, r) dma_map_page_attrs(d, p, o, s, r, 0) #define dma_unmap_page(d, a, s, r) dma_unmap_page_attrs(d, a, s, r, 0) +static inline void +dma_cache_sync(struct device *dev, void *vaddr, size_t size, + enum dma_data_direction dir) +{ + const struct dma_map_ops *ops = get_dma_ops(dev); + + BUG_ON(!valid_dma_direction(dir)); + if (ops->cache_sync) + ops->cache_sync(dev, vaddr, size, dir); +} + extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size); -- cgit v1.2.3