Re: [Linaro-acpi] [V3 PATCH 2/5] arm64 : Introduce support for ACPI _CCA object

On Thursday, May 07, 2015 07:37:13 PM Suravee Suthikulpanit wrote:

From http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf, section 6.2.17 _CCA states that ARM platforms require ACPI _CCA object to be specified for DMA-cabpable devices. This patch introduces ACPI_MUST_HAVE_CCA in arm64 Kconfig to specify such requirement.

In case _CCA is missing, arm64 would assign dummy_dma_ops to disable DMA capability of the device.

Signed-off-by: Mark Salter msalter@redhat.com Signed-off-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com

This won't go in without any ACKs from the ARM64 maintainers.

---

arch/arm64/Kconfig | 2 + arch/arm64/include/asm/dma-mapping.h | 18 ++++++- arch/arm64/mm/dma-mapping.c | 92 ++++++++++++++++++++++++++++++++++++ 3 files changed, 110 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 4269dba..c7227e8 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1,5 +1,6 @@ config ARM64 def_bool y

• select ACPI_CCA_REQUIRED if ACPI select ACPI_GENERIC_GSI if ACPI select ACPI_REDUCED_HARDWARE_ONLY if ACPI select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE

@@ -19,6 +20,7 @@ config ARM64 select ARM_GIC_V2M if PCI_MSI select ARM_GIC_V3 select ARM_GIC_V3_ITS if PCI_MSI

• select ARM64_SUPPORT_ACPI_CCA_ZERO if ACPI select BUILDTIME_EXTABLE_SORT select CLONE_BACKWARDS select COMMON_CLK

diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h index 9437e3d..f0d6d0b 100644 --- a/arch/arm64/include/asm/dma-mapping.h +++ b/arch/arm64/include/asm/dma-mapping.h @@ -18,6 +18,7 @@ #ifdef __KERNEL__ +#include <linux/acpi.h> #include <linux/types.h> #include <linux/vmalloc.h> @@ -28,13 +29,23 @@ #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) || !dev->archdata.dma_ops)

• if (unlikely(!dev)) return dma_ops;

• else

• else if (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.
  

• */
  

• return &dummy_dma_ops;

} static inline struct dma_map_ops *get_dma_ops(struct device *dev) @@ -48,6 +59,9 @@ static inline struct dma_map_ops *get_dma_ops(struct device *dev) static inline 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;
  

• dev->archdata.dma_coherent = coherent;

} #define arch_setup_dma_ops arch_setup_dma_ops diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index ef7d112..6e6d6ad 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -415,6 +415,98 @@ out: return -ENOMEM; } +/********************************************

• • The following APIs are for dummy DMA ops *
• ********************************************/

+static void *__dummy_alloc(struct device *dev, size_t size,

• 	   dma_addr_t *dma_handle, gfp_t flags,
  

• 	   struct dma_attrs *attrs)
  

+{

• return NULL;

+}

+static void __dummy_free(struct device *dev, size_t size,

• 	 void *vaddr, dma_addr_t dma_handle,
  

• 	 struct dma_attrs *attrs)
  

+{ +}

+static int __dummy_mmap(struct device *dev,

• 	struct vm_area_struct *vma,
  

• 	void *cpu_addr, dma_addr_t dma_addr, size_t size,
  

• 	struct dma_attrs *attrs)
  

+{

• return -ENXIO;

+}

+static dma_addr_t __dummy_map_page(struct device *dev, struct page *page,

• 		   unsigned long offset, size_t size,
  

• 		   enum dma_data_direction dir,
  

• 		   struct dma_attrs *attrs)
  

+{

• return DMA_ERROR_CODE;

+}

+static void __dummy_unmap_page(struct device *dev, dma_addr_t dev_addr,

• 	       size_t size, enum dma_data_direction dir,
  

• 	       struct dma_attrs *attrs)
  

+{ +}

+static int __dummy_map_sg(struct device *dev, struct scatterlist *sgl,

• 	  int nelems, enum dma_data_direction dir,
  

• 	  struct dma_attrs *attrs)
  

+{

• return 0;

+}

+static void __dummy_unmap_sg(struct device *dev,

• 	     struct scatterlist *sgl, int nelems,
  

• 	     enum dma_data_direction dir,
  

• 	     struct dma_attrs *attrs)
  

+{ +}

+static void __dummy_sync_single(struct device *dev,

• 		dma_addr_t dev_addr, size_t size,
  

• 		enum dma_data_direction dir)
  

+{ +}

+static void __dummy_sync_sg(struct device *dev,

• 	    struct scatterlist *sgl, int nelems,
  

• 	    enum dma_data_direction dir)
  

+{ +}

+static int __dummy_mapping_error(struct device *hwdev, dma_addr_t dma_addr) +{

• return 1;

+}

+static int __dummy_dma_supported(struct device *hwdev, u64 mask) +{

• return 0;

+}

+struct dma_map_ops dummy_dma_ops = {

• .alloc = __dummy_alloc,
• .free = __dummy_free,
• .mmap = __dummy_mmap,
• .map_page = __dummy_map_page,
• .unmap_page = __dummy_unmap_page,
• .map_sg = __dummy_map_sg,
• .unmap_sg = __dummy_unmap_sg,
• .sync_single_for_cpu = __dummy_sync_single,
• .sync_single_for_device = __dummy_sync_single,
• .sync_sg_for_cpu = __dummy_sync_sg,
• .sync_sg_for_device = __dummy_sync_sg,
• .mapping_error = __dummy_mapping_error,
• .dma_supported = __dummy_dma_supported,

+}; +EXPORT_SYMBOL(dummy_dma_ops);

static int __init arm64_dma_init(void) { int ret;