From 1dccb598df549d892b6450c261da54cdd7af44b4 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 16 Nov 2015 17:25:48 +0100 Subject: [PATCH] arm64: simplify dma_get_ops Including linux/acpi.h from asm/dma-mapping.h causes tons of compile-time warnings, e.g. drivers/isdn/mISDN/dsp_ecdis.h:43:0: warning: "FALSE" redefined drivers/isdn/mISDN/dsp_ecdis.h:44:0: warning: "TRUE" redefined drivers/net/fddi/skfp/h/targetos.h:62:0: warning: "TRUE" redefined drivers/net/fddi/skfp/h/targetos.h:63:0: warning: "FALSE" redefined However, it looks like the dependency should not even there as I do not see why __generic_dma_ops() cares about whether we have an ACPI based system or not. The current behavior is to fall back to the global dma_ops when a device has not set its own dma_ops, but only for DT based systems. This seems dangerous, as a random device might have different requirements regarding IOMMU or coherency, so we should really never have that fallback and just forbid DMA when we have not initialized DMA for a device. This removes the global dma_ops variable and the special-casing for ACPI, and just returns the dma ops that got set for the device, or the dummy_dma_ops if none were present. The original code has apparently been copied from arm32 where we rely on it for ISA devices things like the floppy controller, but we should have no such devices on ARM64. Signed-off-by: Arnd Bergmann [catalin.marinas@arm.com: removed acpi_disabled check in arch_setup_dma_ops()] Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/dma-mapping.h | 13 +++---------- arch/arm64/mm/dma-mapping.c | 16 ++++------------ 2 files changed, 7 insertions(+), 22 deletions(-) diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h index 54d0ead41afc..61e08f360e31 100644 --- a/arch/arm64/include/asm/dma-mapping.h +++ b/arch/arm64/include/asm/dma-mapping.h @@ -18,7 +18,6 @@ #ifdef __KERNEL__ -#include #include #include @@ -26,22 +25,16 @@ #include #define DMA_ERROR_CODE (~(dma_addr_t)0) -extern struct dma_map_ops *dma_ops; extern struct dma_map_ops dummy_dma_ops; static inline struct dma_map_ops *__generic_dma_ops(struct device *dev) { - if (unlikely(!dev)) - return dma_ops; - else if (dev->archdata.dma_ops) + if (dev && dev->archdata.dma_ops) return dev->archdata.dma_ops; - else if (acpi_disabled) - return dma_ops; /* - * When ACPI is enabled, if arch_set_dma_ops is not called, - * we will disable device DMA capability by setting it - * to dummy_dma_ops. + * We expect no ISA devices, and all other DMA masters are expected to + * have someone call arch_setup_dma_ops at device creation time. */ return &dummy_dma_ops; } diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 97fd714035f9..7963aa4b5d28 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -18,6 +18,7 @@ */ #include +#include #include #include #include @@ -28,9 +29,6 @@ #include -struct dma_map_ops *dma_ops; -EXPORT_SYMBOL(dma_ops); - static pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot, bool coherent) { @@ -515,13 +513,7 @@ EXPORT_SYMBOL(dummy_dma_ops); static int __init arm64_dma_init(void) { - int ret; - - dma_ops = &swiotlb_dma_ops; - - ret = atomic_pool_init(); - - return ret; + return atomic_pool_init(); } arch_initcall(arm64_dma_init); @@ -991,8 +983,8 @@ static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, struct iommu_ops *iommu, bool coherent) { - if (!acpi_disabled && !dev->archdata.dma_ops) - dev->archdata.dma_ops = dma_ops; + if (!dev->archdata.dma_ops) + dev->archdata.dma_ops = &swiotlb_dma_ops; dev->archdata.dma_coherent = coherent; __iommu_setup_dma_ops(dev, dma_base, size, iommu); -- 2.20.1