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Date: Fri, 08 May 2015 22:55:02 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
Cc: lenb@...nel.org, catalin.marinas@....com, will.deacon@....com,
thomas.lendacky@....com, herbert@...dor.apana.org.au,
davem@...emloft.net, arnd@...db.de, msalter@...hat.com,
hanjun.guo@...aro.org, al.stone@...aro.org,
grant.likely@...aro.org, leo.duran@....com,
linux-arm-kernel@...ts.infradead.org, linux-acpi@...r.kernel.org,
linux-kernel@...r.kernel.org, linaro-acpi@...ts.linaro.org,
netdev@...r.kernel.org, linux-crypto@...r.kernel.org
Subject: Re: [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@...hat.com>
> Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@....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;
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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