Commit 015d239a authored by Kenneth Lee's avatar Kenneth Lee Committed by Herbert Xu
Browse files

uacce: add uacce driver 



Uacce (Unified/User-space-access-intended Accelerator Framework) targets to
provide Shared Virtual Addressing (SVA) between accelerators and processes.
So accelerator can access any data structure of the main cpu.
This differs from the data sharing between cpu and io device, which share
only data content rather than address.
Since unified address, hardware and user space of process can share the
same virtual address in the communication.

Uacce create a chrdev for every registration, the queue is allocated to
the process when the chrdev is opened. Then the process can access the
hardware resource by interact with the queue file. By mmap the queue
file space to user space, the process can directly put requests to the
hardware without syscall to the kernel space.

The IOMMU core only tracks mm<->device bonds at the moment, because it
only needs to handle IOTLB invalidation and PASID table entries. However
uacce needs a finer granularity since multiple queues from the same
device can be bound to an mm. When the mm exits, all bound queues must
be stopped so that the IOMMU can safely clear the PASID table entry and
reallocate the PASID.

An intermediate struct uacce_mm links uacce devices and queues.
Note that an mm may be bound to multiple devices but an uacce_mm
structure only ever belongs to a single device, because we don't need
anything more complex (if multiple devices are bound to one mm, then
we'll create one uacce_mm for each bond).

        uacce_device --+-- uacce_mm --+-- uacce_queue
                       |              '-- uacce_queue
                       |
                       '-- uacce_mm --+-- uacce_queue
                                      +-- uacce_queue
                                      '-- uacce_queue

Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarKenneth Lee <liguozhu@hisilicon.com>
Signed-off-by: default avatarZaibo Xu <xuzaibo@huawei.com>
Signed-off-by: default avatarZhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: default avatarZhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent aa017ab9

Documentation/ABI/testing/sysfs-driver-uacce

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What:           /sys/class/uacce/<dev_name>/api

Date:           Feb 2020

KernelVersion:  5.7

Contact:        linux-accelerators@lists.ozlabs.org

Description:    Api of the device

                Can be any string and up to userspace to parse.

                Application use the api to match the correct driver



What:           /sys/class/uacce/<dev_name>/flags

Date:           Feb 2020

KernelVersion:  5.7

Contact:        linux-accelerators@lists.ozlabs.org

Description:    Attributes of the device, see UACCE_DEV_xxx flag defined in uacce.h



What:           /sys/class/uacce/<dev_name>/available_instances

Date:           Feb 2020

KernelVersion:  5.7

Contact:        linux-accelerators@lists.ozlabs.org

Description:    Available instances left of the device

                Return -ENODEV if uacce_ops get_available_instances is not provided



What:           /sys/class/uacce/<dev_name>/algorithms

Date:           Feb 2020

KernelVersion:  5.7

Contact:        linux-accelerators@lists.ozlabs.org

Description:    Algorithms supported by this accelerator, separated by new line.

                Can be any string and up to userspace to parse.



What:           /sys/class/uacce/<dev_name>/region_mmio_size

Date:           Feb 2020

KernelVersion:  5.7

Contact:        linux-accelerators@lists.ozlabs.org

Description:    Size (bytes) of mmio region queue file



What:           /sys/class/uacce/<dev_name>/region_dus_size

Date:           Feb 2020

KernelVersion:  5.7

Contact:        linux-accelerators@lists.ozlabs.org

Description:    Size (bytes) of dus region queue file

drivers/misc/Kconfig

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@@ -480,4 +480,5 @@ source "drivers/misc/cxl/Kconfig" 
source "drivers/misc/ocxl/Kconfig"

source "drivers/misc/cardreader/Kconfig"

source "drivers/misc/habanalabs/Kconfig"

source "drivers/misc/uacce/Kconfig"

endmenu

drivers/misc/Makefile

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@@ -56,4 +56,5 @@ obj-$(CONFIG_OCXL) += ocxl/ 
obj-y				+= cardreader/

obj-$(CONFIG_PVPANIC)   	+= pvpanic.o

obj-$(CONFIG_HABANA_AI)		+= habanalabs/

obj-$(CONFIG_UACCE)		+= uacce/

obj-$(CONFIG_XILINX_SDFEC)	+= xilinx_sdfec.o

drivers/misc/uacce/Kconfig

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config UACCE

	tristate "Accelerator Framework for User Land"

	depends on IOMMU_API

	help

	  UACCE provides interface for the user process to access the hardware

	  without interaction with the kernel space in data path.



	  The user-space interface is described in

	  include/uapi/misc/uacce/uacce.h



	  See Documentation/misc-devices/uacce.rst for more details.



	  If you don't know what to do here, say N.

drivers/misc/uacce/Makefile

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# SPDX-License-Identifier: GPL-2.0-or-later

obj-$(CONFIG_UACCE) += uacce.o

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