diff mbox

[V5,2/5] arm64 : Introduce support for ACPI _CCA object

Message ID 1432159758-4486-3-git-send-email-Suravee.Suthikulpanit@amd.com (mailing list archive)
State Not Applicable
Delegated to: Herbert Xu
Headers show

Commit Message

Suravee Suthikulpanit May 20, 2015, 10:09 p.m. UTC
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. Therefore, this patch
specifies ACPI_CCA_REQUIRED in arm64 Kconfig.

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

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
---
 arch/arm64/Kconfig                   |  1 +
 arch/arm64/include/asm/dma-mapping.h | 18 ++++++-
 arch/arm64/mm/dma-mapping.c          | 92 ++++++++++++++++++++++++++++++++++++
 3 files changed, 109 insertions(+), 2 deletions(-)

Comments

Mark Salter May 29, 2015, 2:38 a.m. UTC | #1
On Wed, 2015-05-20 at 17:09 -0500, 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. Therefore, this patch
> specifies ACPI_CCA_REQUIRED in arm64 Kconfig.
> 
> In addition, to handle the case when _CCA is missing, arm64 would assign
> dummy_dma_ops to disable DMA capability of the device.
> 
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Mark Salter <msalter@redhat.com>
> Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
> ---
>  arch/arm64/Kconfig                   |  1 +
>  arch/arm64/include/asm/dma-mapping.h | 18 ++++++-
>  arch/arm64/mm/dma-mapping.c          | 92 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 109 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 4269dba..95307b4 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
> 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>
>  

^^^ This hunk causes build issues with a couple of drivers:

drivers/scsi/megaraid/megaraid_sas_fp.c:69:0: warning: "FALSE" redefined [enabled by default]
 #define FALSE 0
 ^
In file included from include/acpi/acpi.h:58:0,
                 from include/linux/acpi.h:37,
                 from ./arch/arm64/include/asm/dma-mapping.h:21,
                 from include/linux/dma-mapping.h:86,
                 from ./arch/arm64/include/asm/pci.h:7,
                 from include/linux/pci.h:1460,
                 from drivers/scsi/megaraid/megaraid_sas_fp.c:37:
include/acpi/actypes.h:433:0: note: this is the location of the previous definition
 #define FALSE                           (1 == 0)
 ^


In file included from include/acpi/acpi.h:58:0,
                 from include/linux/acpi.h:37,
                 from ./arch/arm64/include/asm/dma-mapping.h:21,
                 from include/linux/dma-mapping.h:86,
                 from include/scsi/scsi_cmnd.h:4,
                 from drivers/scsi/ufs/ufshcd.h:60,
                 from drivers/scsi/ufs/ufshcd.c:43:
include/acpi/actypes.h:433:41: error: expected identifier before ‘(’ token
 #define FALSE                           (1 == 0)
                                         ^
drivers/scsi/ufs/unipro.h:203:2: note: in expansion of macro ‘FALSE’
  FALSE = 0,
  ^

This happens because the ACPI definitions of TRUE and FALSE conflict
with local definitions in megaraid and enum declaration in ufs.


> @@ -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;


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Suravee Suthikulpanit June 3, 2015, 2:37 p.m. UTC | #2
On 5/28/2015 9:38 PM, Mark Salter wrote:
> On Wed, 2015-05-20 at 17:09 -0500, Suravee Suthikulpanit wrote:
>> >Fromhttp://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. Therefore, this patch
>> >specifies ACPI_CCA_REQUIRED in arm64 Kconfig.
>> >
>> >In addition, to handle the case when _CCA is missing, arm64 would assign
>> >dummy_dma_ops to disable DMA capability of the device.
>> >
>> >Acked-by: Catalin Marinas<catalin.marinas@arm.com>
>> >Signed-off-by: Mark Salter<msalter@redhat.com>
>> >Signed-off-by: Suravee Suthikulpanit<Suravee.Suthikulpanit@amd.com>
>> >---
>> >  arch/arm64/Kconfig                   |  1 +
>> >  arch/arm64/include/asm/dma-mapping.h | 18 ++++++-
>> >  arch/arm64/mm/dma-mapping.c          | 92 ++++++++++++++++++++++++++++++++++++
>> >  3 files changed, 109 insertions(+), 2 deletions(-)
>> >
>> >diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> >index 4269dba..95307b4 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
>> >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>
>> >
> ^^^ This hunk causes build issues with a couple of drivers:
>
> drivers/scsi/megaraid/megaraid_sas_fp.c:69:0: warning: "FALSE" redefined [enabled by default]
>   #define FALSE 0
>   ^
> In file included from include/acpi/acpi.h:58:0,
>                   from include/linux/acpi.h:37,
>                   from ./arch/arm64/include/asm/dma-mapping.h:21,
>                   from include/linux/dma-mapping.h:86,
>                   from ./arch/arm64/include/asm/pci.h:7,
>                   from include/linux/pci.h:1460,
>                   from drivers/scsi/megaraid/megaraid_sas_fp.c:37:
> include/acpi/actypes.h:433:0: note: this is the location of the previous definition
>   #define FALSE                           (1 == 0)
>   ^
>
>
> In file included from include/acpi/acpi.h:58:0,
>                   from include/linux/acpi.h:37,
>                   from ./arch/arm64/include/asm/dma-mapping.h:21,
>                   from include/linux/dma-mapping.h:86,
>                   from include/scsi/scsi_cmnd.h:4,
>                   from drivers/scsi/ufs/ufshcd.h:60,
>                   from drivers/scsi/ufs/ufshcd.c:43:
> include/acpi/actypes.h:433:41: error: expected identifier before ‘(’ token
>   #define FALSE                           (1 == 0)
>                                           ^
> drivers/scsi/ufs/unipro.h:203:2: note: in expansion of macro ‘FALSE’
>    FALSE = 0,
>    ^
>
> This happens because the ACPI definitions of TRUE and FALSE conflict
> with local definitions in megaraid and enum declaration in ufs.
>
Mark,

Thanks for pointing this out. Although, I would think that the 
megaraid_sas_fp.c should have had the #ifndef to check before defining 
the TRUE and FALSE as following.

#ifndef TRUE
#define TRUE 1
#endif
#ifndef FALSE
#define FALSE 0
#endif

This seems to be what other drivers are also doing. If this is okay, I 
can send out a fix-up patch for the megaraid driver.

Thanks,

Suravee

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Mark Salter June 3, 2015, 3:03 p.m. UTC | #3
On Wed, 2015-06-03 at 09:37 -0500, Suravee Suthikulanit wrote:
> On 5/28/2015 9:38 PM, Mark Salter wrote:
> > On Wed, 2015-05-20 at 17:09 -0500, Suravee Suthikulpanit wrote:
> >> >Fromhttp://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. Therefore, this patch
> >> >specifies ACPI_CCA_REQUIRED in arm64 Kconfig.
> >> >
> >> >In addition, to handle the case when _CCA is missing, arm64 would assign
> >> >dummy_dma_ops to disable DMA capability of the device.
> >> >
> >> >Acked-by: Catalin Marinas<catalin.marinas@arm.com>
> >> >Signed-off-by: Mark Salter<msalter@redhat.com>
> >> >Signed-off-by: Suravee Suthikulpanit<Suravee.Suthikulpanit@amd.com>
> >> >---
> >> >  arch/arm64/Kconfig                   |  1 +
> >> >  arch/arm64/include/asm/dma-mapping.h | 18 ++++++-
> >> >  arch/arm64/mm/dma-mapping.c          | 92 ++++++++++++++++++++++++++++++++++++
> >> >  3 files changed, 109 insertions(+), 2 deletions(-)
> >> >
> >> >diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> >> >index 4269dba..95307b4 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
> >> >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>
> >> >
> > ^^^ This hunk causes build issues with a couple of drivers:
> >
> > drivers/scsi/megaraid/megaraid_sas_fp.c:69:0: warning: "FALSE" redefined [enabled by default]
> >   #define FALSE 0
> >   ^
> > In file included from include/acpi/acpi.h:58:0,
> >                   from include/linux/acpi.h:37,
> >                   from ./arch/arm64/include/asm/dma-mapping.h:21,
> >                   from include/linux/dma-mapping.h:86,
> >                   from ./arch/arm64/include/asm/pci.h:7,
> >                   from include/linux/pci.h:1460,
> >                   from drivers/scsi/megaraid/megaraid_sas_fp.c:37:
> > include/acpi/actypes.h:433:0: note: this is the location of the previous definition
> >   #define FALSE                           (1 == 0)
> >   ^
> >
> >
> > In file included from include/acpi/acpi.h:58:0,
> >                   from include/linux/acpi.h:37,
> >                   from ./arch/arm64/include/asm/dma-mapping.h:21,
> >                   from include/linux/dma-mapping.h:86,
> >                   from include/scsi/scsi_cmnd.h:4,
> >                   from drivers/scsi/ufs/ufshcd.h:60,
> >                   from drivers/scsi/ufs/ufshcd.c:43:
> > include/acpi/actypes.h:433:41: error: expected identifier before ‘(’ token
> >   #define FALSE                           (1 == 0)
> >                                           ^
> > drivers/scsi/ufs/unipro.h:203:2: note: in expansion of macro ‘FALSE’
> >    FALSE = 0,
> >    ^
> >
> > This happens because the ACPI definitions of TRUE and FALSE conflict
> > with local definitions in megaraid and enum declaration in ufs.
> >
> Mark,
> 
> Thanks for pointing this out. Although, I would think that the 
> megaraid_sas_fp.c should have had the #ifndef to check before defining 
> the TRUE and FALSE as following.
> 
> #ifndef TRUE
> #define TRUE 1
> #endif
> #ifndef FALSE
> #define FALSE 0
> #endif
> 
> This seems to be what other drivers are also doing. If this is okay, I 
> can send out a fix-up patch for the megaraid driver.
> 

Yeah, or #undef them if defined so megaraid defines them as desired.
And #undef if defined would work for unipro.h as well.


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diff mbox

Patch

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 4269dba..95307b4 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
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;