On Thu, 23 Jun 2022 21:19:41 -0700 Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > After a region's interleave parameters (ways and granularity) are set, > add a way for regions to allocate HPA from the free capacity in their > decoder. The allocator for this capacity reuses the 'struct resource' > based allocator used for CONFIG_DEVICE_PRIVATE. > > Once the tuple of "ways, granularity, and size" is set the > region configuration transitions to the CXL_CONFIG_INTERLEAVE_ACTIVE > state which is a precursor to allowing endpoint decoders to be added to > a region. > > Co-developed-by: Ben Widawsky <bwidawsk@xxxxxxxxxx> > Signed-off-by: Ben Widawsky <bwidawsk@xxxxxxxxxx> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> A few comments on the interface inline. Thanks, Jonathan > --- > Documentation/ABI/testing/sysfs-bus-cxl | 25 ++++ > drivers/cxl/Kconfig | 3 + > drivers/cxl/core/region.c | 148 +++++++++++++++++++++++- > drivers/cxl/cxl.h | 2 + > 4 files changed, 177 insertions(+), 1 deletion(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl > index 46d5295c1149..3658facc9944 100644 > --- a/Documentation/ABI/testing/sysfs-bus-cxl > +++ b/Documentation/ABI/testing/sysfs-bus-cxl > @@ -294,3 +294,28 @@ Description: > (RW) Configures the number of devices participating in the > region is set by writing this value. Each device will provide > 1/interleave_ways of storage for the region. > + > + > +What: /sys/bus/cxl/devices/regionZ/size > +Date: May, 2022 > +KernelVersion: v5.20 > +Contact: linux-cxl@xxxxxxxxxxxxxxx > +Description: > + (RW) System physical address space to be consumed by the region. > + When written to, this attribute will allocate space out of the > + CXL root decoder's address space. When read the size of the > + address space is reported and should match the span of the > + region's resource attribute. Size shall be set after the > + interleave configuration parameters. There seem to be constraints that say you have to set this to 0 and then something else later to force a resize. That should be mentioned here or gotten rid of. > + > + > +What: /sys/bus/cxl/devices/regionZ/resource > +Date: May, 2022 > +KernelVersion: v5.20 > +Contact: linux-cxl@xxxxxxxxxxxxxxx > +Description: > + (RO) A region is a contiguous partition of a CXL root decoder > + address space. Region capacity is allocated by writing to the > + size attribute, the resulting physical address space determined > + by the driver is reflected here. It is therefore not useful to > + read this before writing a value to the size attribute. I don't much like naming a "base address" resource. I'd expect resource to contain both base and size whereas this only has the base address of the region.
