Re: [RFC 0/5] Support non-coherent DMA on RISC-V using a global pool
On Tue, Aug 17, 2021 at 11:28 AM Atish Patra wrote: > > On Mon, Aug 16, 2021 at 6:37 PM Guo Ren wrote: > > > > 1 > > > > On Thu, Jul 29, 2021 at 2:19 PM Atish Patra wrote: > > > > > > On Wed, Jul 28, 2021 at 9:30 PM Palmer Dabbelt wrote: > > > > > > > > On Fri, 23 Jul 2021 14:40:26 PDT (-0700), Atish Patra wrote: > > > > > RISC-V privilege specification doesn't define an IOMMU or any method > > > > > modify > > > > > PMA attributes or PTE entries to allow non-coherent mappings yet. In > > > > > the beginning, this approach was adopted assuming that most of the > > > > > RISC-V > > > > > platforms would support full cache-coherent IO. Here is excerpt from > > > > > the > > > > > priv spec section 3.6.5 > > > > > > > > > > "In RISC-V platforms, the use of hardware-incoherent regions is > > > > > discouraged > > > > > due to software complexity, performance, and energy impacts." > > > > > > > > > > While some of the RISC-V platforms adhere to the above suggestion, > > > > > not all > > > > > platforms can afford to build to fully cache-coherent I/O devices. To > > > > > address DMA for non-coherent I/O devices, we need to mark a region of > > > > > memory > > > > > as non-cacheable. Some of the platforms rely on a fixed region of > > > > > uncached > > > > > memory that is remapped to the system memory while some other modify > > > > > the PTE entries to achieve that. > > > > > > > > > > The patch3 solves the issue for the fist use case by using a global > > > > > pool of memory that is reserved for DMA. The device access the > > > > > reserved area > > > > > of the region while corresponding CPU address will be from uncached > > > > > region > > > > > As the uncached region is remapped to the beginning of the system > > > > > ram, both > > > > > CPU and device get the same view. > > > > > > > > > > To facilitate streaming DMA APIs, patch 1 introduces a set of generic > > > > > cache operations. Any platform can use the generic ops to provide > > > > > platform > > > > > specific cache management operations. Once the standard RISC-V CMO > > > > > extension > > > > > is available, it will also use these generic ops. > > > > > > > > > > To address the second use case, Page Based Memory Attribute (PBMT) > > > > > extension > > > > > is proposed. Once the extension is in good shape, we can leverage that > > > > > using CONFIG_DIRECT_REMAP. Currently, it is selected via a compile > > > > > time config > > > > > option. We will probably need another arch specific hooks to know if > > > > > the > > > > > platform supports direct remap at runtime. For RISC-V, it will check > > > > > the > > > > > presence of PBMT extension while other arch function will simply > > > > > return true > > > > > > > > IIUC this is another extension that's not yet frozen or implemented in > > > > hardware? Is this one compatible with what's in the c906, or is it > > > > doing things its own way? > > > > > > Hi Palmer, > > > This series doesn't implement the PBMT extension which is still in > > > discussion. > > > It simply reuse the existing non-coherent dma mapping support in > > > upstream kernel and enable > > > it for RISC-V. The current version uses a non-coherent global pool. I > > > will update it to use arch_set_uncached > > > as per Christoph's suggestion. It solves the non-coherent DMA problem > > > for beagleV and not c906. > > > > > > I briefly mentioned the PBMT extension just to provide an idea how the > > > RISC-V Linux kernel > > > can support both unached window and PBMT extension. PBMT extension is > > > planned to be frozen > > > by the end of this year and none of the hardware has implemented it. > > > > > > The implementation in c906 is a non-standard one and will not be > > > supported by the default PBMT > > > extension implementation. > > The default PBMT & c908 PBMT are similar, only BIT definitions are > > different. I propose to support default PBMT first and give the back > > door to modify the PBMT definition during boot. > > The "protection_map[] = (__P000, __P001 ..__S000, __S001)" in > > mm/mmap.c has been modified by arch/mips, arm, sparc, x86, so I think > > it's proper solution direction. > > > > The reset problem is how to passing custom PBMT at the very early boot > > stage. Now I'm trying to use the DTS parsing instead of boot param hdr > > which Anup objected to. > > > > IIRC, c906 has a compatible mode that has the compliant PTE bit modifications. > Can you use that mode iOn the Allwinner D1 board to boot Linux ? I am > not sure if you have any fallback method for non-coherent DMA > if custom DMA_COHERENT bits are not enabled through enhanced mode ? We need custom PBMT(enhanced mode) to enable the dma driver on D1 (GMAC, USB, EMMC) or these drivers couldn't work. D1 hasn't any uncached region in SOC design. > > > ref: > > https://lore.kernel.org/linux-riscv/1623693067-53886-1-git-send-email-guo...@kernel.org/ > > > > Any comments are welcome. > > > > > > > > > > > > > > > >
Re: [RFC 0/5] Support non-coherent DMA on RISC-V using a global pool
On Mon, Aug 16, 2021 at 6:37 PM Guo Ren wrote: > > 1 > > On Thu, Jul 29, 2021 at 2:19 PM Atish Patra wrote: > > > > On Wed, Jul 28, 2021 at 9:30 PM Palmer Dabbelt wrote: > > > > > > On Fri, 23 Jul 2021 14:40:26 PDT (-0700), Atish Patra wrote: > > > > RISC-V privilege specification doesn't define an IOMMU or any method > > > > modify > > > > PMA attributes or PTE entries to allow non-coherent mappings yet. In > > > > the beginning, this approach was adopted assuming that most of the > > > > RISC-V > > > > platforms would support full cache-coherent IO. Here is excerpt from the > > > > priv spec section 3.6.5 > > > > > > > > "In RISC-V platforms, the use of hardware-incoherent regions is > > > > discouraged > > > > due to software complexity, performance, and energy impacts." > > > > > > > > While some of the RISC-V platforms adhere to the above suggestion, not > > > > all > > > > platforms can afford to build to fully cache-coherent I/O devices. To > > > > address DMA for non-coherent I/O devices, we need to mark a region of > > > > memory > > > > as non-cacheable. Some of the platforms rely on a fixed region of > > > > uncached > > > > memory that is remapped to the system memory while some other modify > > > > the PTE entries to achieve that. > > > > > > > > The patch3 solves the issue for the fist use case by using a global > > > > pool of memory that is reserved for DMA. The device access the reserved > > > > area > > > > of the region while corresponding CPU address will be from uncached > > > > region > > > > As the uncached region is remapped to the beginning of the system ram, > > > > both > > > > CPU and device get the same view. > > > > > > > > To facilitate streaming DMA APIs, patch 1 introduces a set of generic > > > > cache operations. Any platform can use the generic ops to provide > > > > platform > > > > specific cache management operations. Once the standard RISC-V CMO > > > > extension > > > > is available, it will also use these generic ops. > > > > > > > > To address the second use case, Page Based Memory Attribute (PBMT) > > > > extension > > > > is proposed. Once the extension is in good shape, we can leverage that > > > > using CONFIG_DIRECT_REMAP. Currently, it is selected via a compile time > > > > config > > > > option. We will probably need another arch specific hooks to know if the > > > > platform supports direct remap at runtime. For RISC-V, it will check the > > > > presence of PBMT extension while other arch function will simply return > > > > true > > > > > > IIUC this is another extension that's not yet frozen or implemented in > > > hardware? Is this one compatible with what's in the c906, or is it > > > doing things its own way? > > > > Hi Palmer, > > This series doesn't implement the PBMT extension which is still in > > discussion. > > It simply reuse the existing non-coherent dma mapping support in > > upstream kernel and enable > > it for RISC-V. The current version uses a non-coherent global pool. I > > will update it to use arch_set_uncached > > as per Christoph's suggestion. It solves the non-coherent DMA problem > > for beagleV and not c906. > > > > I briefly mentioned the PBMT extension just to provide an idea how the > > RISC-V Linux kernel > > can support both unached window and PBMT extension. PBMT extension is > > planned to be frozen > > by the end of this year and none of the hardware has implemented it. > > > > The implementation in c906 is a non-standard one and will not be > > supported by the default PBMT > > extension implementation. > The default PBMT & c908 PBMT are similar, only BIT definitions are > different. I propose to support default PBMT first and give the back > door to modify the PBMT definition during boot. > The "protection_map[] = (__P000, __P001 ..__S000, __S001)" in > mm/mmap.c has been modified by arch/mips, arm, sparc, x86, so I think > it's proper solution direction. > > The reset problem is how to passing custom PBMT at the very early boot > stage. Now I'm trying to use the DTS parsing instead of boot param hdr > which Anup objected to. > IIRC, c906 has a compatible mode that has the compliant PTE bit modifications. Can you use that mode in the Allwinner D1 board to boot Linux ? I am not sure if you have any fallback method for non-coherent DMA if custom DMA_COHERENT bits are not enabled through enhanced mode ? > ref: > https://lore.kernel.org/linux-riscv/1623693067-53886-1-git-send-email-guo...@kernel.org/ > > Any comments are welcome. > > > > > > > > > > > > if DIRECT_REMAP is enabled. This is required as arious different config > > > > (DIRECT_REMAP, GLOBAL_POOL) will be enabled in the defconfig so that a > > > > unified kernel image can boot on all RISC-V platforms. > > > > > > > > This patch series depends on Christoph's global pool support series[1]. > > > > Tested on Qemu, HiFive unleashed and beagleV. This series is also > > > > available > > > > at [2]. > > > > This series also solves the
Re: [RFC 0/5] Support non-coherent DMA on RISC-V using a global pool
1 On Thu, Jul 29, 2021 at 2:19 PM Atish Patra wrote: > > On Wed, Jul 28, 2021 at 9:30 PM Palmer Dabbelt wrote: > > > > On Fri, 23 Jul 2021 14:40:26 PDT (-0700), Atish Patra wrote: > > > RISC-V privilege specification doesn't define an IOMMU or any method > > > modify > > > PMA attributes or PTE entries to allow non-coherent mappings yet. In > > > the beginning, this approach was adopted assuming that most of the RISC-V > > > platforms would support full cache-coherent IO. Here is excerpt from the > > > priv spec section 3.6.5 > > > > > > "In RISC-V platforms, the use of hardware-incoherent regions is > > > discouraged > > > due to software complexity, performance, and energy impacts." > > > > > > While some of the RISC-V platforms adhere to the above suggestion, not all > > > platforms can afford to build to fully cache-coherent I/O devices. To > > > address DMA for non-coherent I/O devices, we need to mark a region of > > > memory > > > as non-cacheable. Some of the platforms rely on a fixed region of uncached > > > memory that is remapped to the system memory while some other modify > > > the PTE entries to achieve that. > > > > > > The patch3 solves the issue for the fist use case by using a global > > > pool of memory that is reserved for DMA. The device access the reserved > > > area > > > of the region while corresponding CPU address will be from uncached region > > > As the uncached region is remapped to the beginning of the system ram, > > > both > > > CPU and device get the same view. > > > > > > To facilitate streaming DMA APIs, patch 1 introduces a set of generic > > > cache operations. Any platform can use the generic ops to provide platform > > > specific cache management operations. Once the standard RISC-V CMO > > > extension > > > is available, it will also use these generic ops. > > > > > > To address the second use case, Page Based Memory Attribute (PBMT) > > > extension > > > is proposed. Once the extension is in good shape, we can leverage that > > > using CONFIG_DIRECT_REMAP. Currently, it is selected via a compile time > > > config > > > option. We will probably need another arch specific hooks to know if the > > > platform supports direct remap at runtime. For RISC-V, it will check the > > > presence of PBMT extension while other arch function will simply return > > > true > > > > IIUC this is another extension that's not yet frozen or implemented in > > hardware? Is this one compatible with what's in the c906, or is it > > doing things its own way? > > Hi Palmer, > This series doesn't implement the PBMT extension which is still in discussion. > It simply reuse the existing non-coherent dma mapping support in > upstream kernel and enable > it for RISC-V. The current version uses a non-coherent global pool. I > will update it to use arch_set_uncached > as per Christoph's suggestion. It solves the non-coherent DMA problem > for beagleV and not c906. > > I briefly mentioned the PBMT extension just to provide an idea how the > RISC-V Linux kernel > can support both unached window and PBMT extension. PBMT extension is > planned to be frozen > by the end of this year and none of the hardware has implemented it. > > The implementation in c906 is a non-standard one and will not be > supported by the default PBMT > extension implementation. The default PBMT & c908 PBMT are similar, only BIT definitions are different. I propose to support default PBMT first and give the back door to modify the PBMT definition during boot. The "protection_map[] = (__P000, __P001 ..__S000, __S001)" in mm/mmap.c has been modified by arch/mips, arm, sparc, x86, so I think it's proper solution direction. The reset problem is how to passing custom PBMT at the very early boot stage. Now I'm trying to use the DTS parsing instead of boot param hdr which Anup objected to. ref: https://lore.kernel.org/linux-riscv/1623693067-53886-1-git-send-email-guo...@kernel.org/ Any comments are welcome. > > > > > > > if DIRECT_REMAP is enabled. This is required as arious different config > > > (DIRECT_REMAP, GLOBAL_POOL) will be enabled in the defconfig so that a > > > unified kernel image can boot on all RISC-V platforms. > > > > > > This patch series depends on Christoph's global pool support series[1]. > > > Tested on Qemu, HiFive unleashed and beagleV. This series is also > > > available > > > at [2]. > > > This series also solves the non-coherent DMA support on beagleV but > > > requires > > > additional beagleV specific patches[3] which will be upstreamed soon. > > > > > > > > > [1] > > > https://lists.linuxfoundation.org/pipermail/iommu/2021-July/057266.html > > > [2] https://github.com/atishp04/linux/tree/riscv_nc_global_pool > > > [3] https://github.com/atishp04/linux/tree/wip_beaglev_dma_nc_global > > > > > > Atish Patra (5): > > > RISC-V: Implement arch_sync_dma* functions > > > of: Move of_dma_get_range to of_address.h > > > dma-mapping: Enable global non-coherent pool support for RISC-V > > >
Re: [RFC 0/5] Support non-coherent DMA on RISC-V using a global pool
On Fri, 23 Jul 2021 14:40:26 PDT (-0700), Atish Patra wrote: RISC-V privilege specification doesn't define an IOMMU or any method modify PMA attributes or PTE entries to allow non-coherent mappings yet. In the beginning, this approach was adopted assuming that most of the RISC-V platforms would support full cache-coherent IO. Here is excerpt from the priv spec section 3.6.5 "In RISC-V platforms, the use of hardware-incoherent regions is discouraged due to software complexity, performance, and energy impacts." While some of the RISC-V platforms adhere to the above suggestion, not all platforms can afford to build to fully cache-coherent I/O devices. To address DMA for non-coherent I/O devices, we need to mark a region of memory as non-cacheable. Some of the platforms rely on a fixed region of uncached memory that is remapped to the system memory while some other modify the PTE entries to achieve that. The patch3 solves the issue for the fist use case by using a global pool of memory that is reserved for DMA. The device access the reserved area of the region while corresponding CPU address will be from uncached region As the uncached region is remapped to the beginning of the system ram, both CPU and device get the same view. To facilitate streaming DMA APIs, patch 1 introduces a set of generic cache operations. Any platform can use the generic ops to provide platform specific cache management operations. Once the standard RISC-V CMO extension is available, it will also use these generic ops. To address the second use case, Page Based Memory Attribute (PBMT) extension is proposed. Once the extension is in good shape, we can leverage that using CONFIG_DIRECT_REMAP. Currently, it is selected via a compile time config option. We will probably need another arch specific hooks to know if the platform supports direct remap at runtime. For RISC-V, it will check the presence of PBMT extension while other arch function will simply return true IIUC this is another extension that's not yet frozen or implemented in hardware? Is this one compatible with what's in the c906, or is it doing things its own way? if DIRECT_REMAP is enabled. This is required as arious different config (DIRECT_REMAP, GLOBAL_POOL) will be enabled in the defconfig so that a unified kernel image can boot on all RISC-V platforms. This patch series depends on Christoph's global pool support series[1]. Tested on Qemu, HiFive unleashed and beagleV. This series is also available at [2]. This series also solves the non-coherent DMA support on beagleV but requires additional beagleV specific patches[3] which will be upstreamed soon. [1] https://lists.linuxfoundation.org/pipermail/iommu/2021-July/057266.html [2] https://github.com/atishp04/linux/tree/riscv_nc_global_pool [3] https://github.com/atishp04/linux/tree/wip_beaglev_dma_nc_global Atish Patra (5): RISC-V: Implement arch_sync_dma* functions of: Move of_dma_get_range to of_address.h dma-mapping: Enable global non-coherent pool support for RISC-V dma-direct: Allocate dma pages directly if global pool allocation fails RISC-V: Support a new config option for non-coherent DMA arch/riscv/Kconfig | 8 +++ arch/riscv/include/asm/dma-noncoherent.h | 19 +++ arch/riscv/mm/Makefile | 1 + arch/riscv/mm/dma-noncoherent.c | 66 drivers/of/of_private.h | 10 include/linux/of_address.h | 12 + kernel/dma/coherent.c| 49 +++--- kernel/dma/direct.c | 7 ++- 8 files changed, 152 insertions(+), 20 deletions(-) create mode 100644 arch/riscv/include/asm/dma-noncoherent.h create mode 100644 arch/riscv/mm/dma-noncoherent.c Can you guys please make up your minds about how this is going to be supported at the ISA level? I get a different answer every day here: sometimes it's that these systems are not compliant, sometimes that Linux is the compliance suite, sometimes that we're doing an ISA extension, and sometimes that we're doing the SBI stuff. I don't really care all that much about what the decision is, but it's impossible to move forward without some semblance of a plan. ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [RFC 0/5] Support non-coherent DMA on RISC-V using a global pool
On Wed, Jul 28, 2021 at 9:30 PM Palmer Dabbelt wrote: > > On Fri, 23 Jul 2021 14:40:26 PDT (-0700), Atish Patra wrote: > > RISC-V privilege specification doesn't define an IOMMU or any method modify > > PMA attributes or PTE entries to allow non-coherent mappings yet. In > > the beginning, this approach was adopted assuming that most of the RISC-V > > platforms would support full cache-coherent IO. Here is excerpt from the > > priv spec section 3.6.5 > > > > "In RISC-V platforms, the use of hardware-incoherent regions is discouraged > > due to software complexity, performance, and energy impacts." > > > > While some of the RISC-V platforms adhere to the above suggestion, not all > > platforms can afford to build to fully cache-coherent I/O devices. To > > address DMA for non-coherent I/O devices, we need to mark a region of memory > > as non-cacheable. Some of the platforms rely on a fixed region of uncached > > memory that is remapped to the system memory while some other modify > > the PTE entries to achieve that. > > > > The patch3 solves the issue for the fist use case by using a global > > pool of memory that is reserved for DMA. The device access the reserved area > > of the region while corresponding CPU address will be from uncached region > > As the uncached region is remapped to the beginning of the system ram, both > > CPU and device get the same view. > > > > To facilitate streaming DMA APIs, patch 1 introduces a set of generic > > cache operations. Any platform can use the generic ops to provide platform > > specific cache management operations. Once the standard RISC-V CMO extension > > is available, it will also use these generic ops. > > > > To address the second use case, Page Based Memory Attribute (PBMT) extension > > is proposed. Once the extension is in good shape, we can leverage that > > using CONFIG_DIRECT_REMAP. Currently, it is selected via a compile time > > config > > option. We will probably need another arch specific hooks to know if the > > platform supports direct remap at runtime. For RISC-V, it will check the > > presence of PBMT extension while other arch function will simply return true > > IIUC this is another extension that's not yet frozen or implemented in > hardware? Is this one compatible with what's in the c906, or is it > doing things its own way? Hi Palmer, This series doesn't implement the PBMT extension which is still in discussion. It simply reuse the existing non-coherent dma mapping support in upstream kernel and enable it for RISC-V. The current version uses a non-coherent global pool. I will update it to use arch_set_uncached as per Christoph's suggestion. It solves the non-coherent DMA problem for beagleV and not c906. I briefly mentioned the PBMT extension just to provide an idea how the RISC-V Linux kernel can support both unached window and PBMT extension. PBMT extension is planned to be frozen by the end of this year and none of the hardware has implemented it. The implementation in c906 is a non-standard one and will not be supported by the default PBMT extension implementation. > > > if DIRECT_REMAP is enabled. This is required as arious different config > > (DIRECT_REMAP, GLOBAL_POOL) will be enabled in the defconfig so that a > > unified kernel image can boot on all RISC-V platforms. > > > > This patch series depends on Christoph's global pool support series[1]. > > Tested on Qemu, HiFive unleashed and beagleV. This series is also available > > at [2]. > > This series also solves the non-coherent DMA support on beagleV but requires > > additional beagleV specific patches[3] which will be upstreamed soon. > > > > > > [1] https://lists.linuxfoundation.org/pipermail/iommu/2021-July/057266.html > > [2] https://github.com/atishp04/linux/tree/riscv_nc_global_pool > > [3] https://github.com/atishp04/linux/tree/wip_beaglev_dma_nc_global > > > > Atish Patra (5): > > RISC-V: Implement arch_sync_dma* functions > > of: Move of_dma_get_range to of_address.h > > dma-mapping: Enable global non-coherent pool support for RISC-V > > dma-direct: Allocate dma pages directly if global pool allocation > > fails > > RISC-V: Support a new config option for non-coherent DMA > > > > arch/riscv/Kconfig | 8 +++ > > arch/riscv/include/asm/dma-noncoherent.h | 19 +++ > > arch/riscv/mm/Makefile | 1 + > > arch/riscv/mm/dma-noncoherent.c | 66 > > drivers/of/of_private.h | 10 > > include/linux/of_address.h | 12 + > > kernel/dma/coherent.c| 49 +++--- > > kernel/dma/direct.c | 7 ++- > > 8 files changed, 152 insertions(+), 20 deletions(-) > > create mode 100644 arch/riscv/include/asm/dma-noncoherent.h > > create mode 100644 arch/riscv/mm/dma-noncoherent.c > > Can you guys please make up your minds about how this is going to be > supported at the ISA level? I get a different answer every day here: >
[RFC 0/5] Support non-coherent DMA on RISC-V using a global pool
RISC-V privilege specification doesn't define an IOMMU or any method modify PMA attributes or PTE entries to allow non-coherent mappings yet. In the beginning, this approach was adopted assuming that most of the RISC-V platforms would support full cache-coherent IO. Here is excerpt from the priv spec section 3.6.5 "In RISC-V platforms, the use of hardware-incoherent regions is discouraged due to software complexity, performance, and energy impacts." While some of the RISC-V platforms adhere to the above suggestion, not all platforms can afford to build to fully cache-coherent I/O devices. To address DMA for non-coherent I/O devices, we need to mark a region of memory as non-cacheable. Some of the platforms rely on a fixed region of uncached memory that is remapped to the system memory while some other modify the PTE entries to achieve that. The patch3 solves the issue for the fist use case by using a global pool of memory that is reserved for DMA. The device access the reserved area of the region while corresponding CPU address will be from uncached region As the uncached region is remapped to the beginning of the system ram, both CPU and device get the same view. To facilitate streaming DMA APIs, patch 1 introduces a set of generic cache operations. Any platform can use the generic ops to provide platform specific cache management operations. Once the standard RISC-V CMO extension is available, it will also use these generic ops. To address the second use case, Page Based Memory Attribute (PBMT) extension is proposed. Once the extension is in good shape, we can leverage that using CONFIG_DIRECT_REMAP. Currently, it is selected via a compile time config option. We will probably need another arch specific hooks to know if the platform supports direct remap at runtime. For RISC-V, it will check the presence of PBMT extension while other arch function will simply return true if DIRECT_REMAP is enabled. This is required as arious different config (DIRECT_REMAP, GLOBAL_POOL) will be enabled in the defconfig so that a unified kernel image can boot on all RISC-V platforms. This patch series depends on Christoph's global pool support series[1]. Tested on Qemu, HiFive unleashed and beagleV. This series is also available at [2]. This series also solves the non-coherent DMA support on beagleV but requires additional beagleV specific patches[3] which will be upstreamed soon. [1] https://lists.linuxfoundation.org/pipermail/iommu/2021-July/057266.html [2] https://github.com/atishp04/linux/tree/riscv_nc_global_pool [3] https://github.com/atishp04/linux/tree/wip_beaglev_dma_nc_global Atish Patra (5): RISC-V: Implement arch_sync_dma* functions of: Move of_dma_get_range to of_address.h dma-mapping: Enable global non-coherent pool support for RISC-V dma-direct: Allocate dma pages directly if global pool allocation fails RISC-V: Support a new config option for non-coherent DMA arch/riscv/Kconfig | 8 +++ arch/riscv/include/asm/dma-noncoherent.h | 19 +++ arch/riscv/mm/Makefile | 1 + arch/riscv/mm/dma-noncoherent.c | 66 drivers/of/of_private.h | 10 include/linux/of_address.h | 12 + kernel/dma/coherent.c| 49 +++--- kernel/dma/direct.c | 7 ++- 8 files changed, 152 insertions(+), 20 deletions(-) create mode 100644 arch/riscv/include/asm/dma-noncoherent.h create mode 100644 arch/riscv/mm/dma-noncoherent.c -- 2.31.1 ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
