[V2 PATCH 2/5] arm64 : Introduce support for ACPI _CCA object

Suravee Suthikulpanit
2015-05-05T16:09:26Z

>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 this case of missing _CCA, 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>
---
arch/arm64/Kconfig | 2 +
arch/arm64/include/asm/dma-mapping.h | 18 +++++-
arch/arm64/mm/dma-mapping.c | 104 +++++++++++++++++++++++++++++++++++
3 files changed, 122 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 4269dba..4f4bbaaf 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1,7 +1,9 @@
config ARM64
def_bool y
select ACPI_GENERIC_GSI if ACPI
+ select ACPI_MUST_HAVE_CCA if ACPI
select ACPI_REDUCED_HARDWARE_ONLY if ACPI
+ select ACPI_SUPPORT_CCA_ZERO if ACPI
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_GCOV_PROFILE_ALL
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..31d2b52 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -415,6 +415,110 @@ 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_for_cpu(struct device *dev,
+ dma_addr_t dev_addr, size_t size,
+ enum dma_data_direction dir)
+{
+}
+
+static void __dummy_sync_single_for_device(struct device *dev,
+ dma_addr_t dev_addr, size_t size,
+ enum dma_data_direction dir)
+{
+}
+
+static void __dummy_sync_sg_for_cpu(struct device *dev,
+ struct scatterlist *sgl, int nelems,
+ enum dma_data_direction dir)
+{
+}
+
+static void __dummy_sync_sg_for_device(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_for_cpu,
+ .sync_single_for_device = __dummy_sync_single_for_device,
+ .sync_sg_for_cpu = __dummy_sync_sg_for_cpu,
+ .sync_sg_for_device = __dummy_sync_sg_for_device,
+ .mapping_error = __dummy_mapping_error,
+ .dma_supported = __dummy_dma_supported,
+};
+EXPORT_SYMBOL(dummy_dma_ops);
+
static int __init arm64_dma_init(void)
{
int ret;
--
2.1.0