linux/Documentation/ABI/testing/sysfs-class-cxl
Ian Munsie a9282d01cf cxl: Add documentation for userspace APIs
This documentation gives an overview of the hardware architecture, userspace
APIs via /dev/cxl/afuM.N and the syfs files. It also adds a MAINTAINERS file
entry for cxl.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-08 20:16:19 +11:00

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Slave contexts (eg. /sys/class/cxl/afu0.0s):
What: /sys/class/cxl/<afu>/irqs_max
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read/write
Decimal value of maximum number of interrupts that can be
requested by userspace. The default on probe is the maximum
that hardware can support (eg. 2037). Write values will limit
userspace applications to that many userspace interrupts. Must
be >= irqs_min.
What: /sys/class/cxl/<afu>/irqs_min
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the minimum number of interrupts that
userspace must request on a CXL_START_WORK ioctl. Userspace may
omit the num_interrupts field in the START_WORK IOCTL to get
this minimum automatically.
What: /sys/class/cxl/<afu>/mmio_size
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the size of the MMIO space that may be mmaped
by userspace.
What: /sys/class/cxl/<afu>/modes_supported
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
List of the modes this AFU supports. One per line.
Valid entries are: "dedicated_process" and "afu_directed"
What: /sys/class/cxl/<afu>/mode
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read/write
The current mode the AFU is using. Will be one of the modes
given in modes_supported. Writing will change the mode
provided that no user contexts are attached.
What: /sys/class/cxl/<afu>/prefault_mode
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read/write
Set the mode for prefaulting in segments into the segment table
when performing the START_WORK ioctl. Possible values:
none: No prefaulting (default)
work_element_descriptor: Treat the work element
descriptor as an effective address and
prefault what it points to.
all: all segments process calling START_WORK maps.
What: /sys/class/cxl/<afu>/reset
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: write only
Writing 1 here will reset the AFU provided there are not
contexts active on the AFU.
What: /sys/class/cxl/<afu>/api_version
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the current version of the kernel/user API.
What: /sys/class/cxl/<afu>/api_version_com
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the the lowest version of the userspace API
this this kernel supports.
Master contexts (eg. /sys/class/cxl/afu0.0m)
What: /sys/class/cxl/<afu>m/mmio_size
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the size of the MMIO space that may be mmaped
by userspace. This includes all slave contexts space also.
What: /sys/class/cxl/<afu>m/pp_mmio_len
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the Per Process MMIO space length.
What: /sys/class/cxl/<afu>m/pp_mmio_off
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the Per Process MMIO space offset.
Card info (eg. /sys/class/cxl/card0)
What: /sys/class/cxl/<card>/caia_version
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Identifies the CAIA Version the card implements.
What: /sys/class/cxl/<card>/psl_version
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Identifies the revision level of the PSL.
What: /sys/class/cxl/<card>/base_image
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Identifies the revision level of the base image for devices
that support loadable PSLs. For FPGAs this field identifies
the image contained in the on-adapter flash which is loaded
during the initial program load.
What: /sys/class/cxl/<card>/image_loaded
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Will return "user" or "factory" depending on the image loaded
onto the card.