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authorIan Munsie <imunsie@au1.ibm.com>2014-10-08 19:55:05 +1100
committerMichael Ellerman <mpe@ellerman.id.au>2014-10-08 20:16:19 +1100
commita9282d01cf357379ce29103cec5e7651a53c634d (patch)
treeefbc02a23f5dbc8453cdb4584c0ac2cef1316ba0 /Documentation/ABI
parent881632c905f29fd7173250fd1d5b3a9a769d02be (diff)
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>
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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.

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