Re: [PATCH v4 04/10] hw/mem/cxl_type3: Add support to create DC regions to type3 memory devices

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Wed, 21 Feb 2024 10:15:57 -0800
nifan.cxl@gmail.com wrote:

> From: Fan Ni <fan.ni@samsung.com>
> 
> With the change, when setting up memory for type3 memory device, we can
> create DC regions.
> A property 'num-dc-regions' is added to ct3_props to allow users to pass the
> number of DC regions to create. To make it easier, other region parameters
> like region base, length, and block size are hard coded. If needed,
> these parameters can be added easily.
> 
> With the change, we can create DC regions with proper kernel side
> support like below:
> 
> region=$(cat /sys/bus/cxl/devices/decoder0.0/create_dc_region)
> echo $region > /sys/bus/cxl/devices/decoder0.0/create_dc_region
> echo 256 > /sys/bus/cxl/devices/$region/interleave_granularity
> echo 1 > /sys/bus/cxl/devices/$region/interleave_ways
> 
> echo "dc0" >/sys/bus/cxl/devices/decoder2.0/mode
> echo 0x40000000 >/sys/bus/cxl/devices/decoder2.0/dpa_size
> 
> echo 0x40000000 > /sys/bus/cxl/devices/$region/size
> echo  "decoder2.0" > /sys/bus/cxl/devices/$region/target0
> echo 1 > /sys/bus/cxl/devices/$region/commit
> echo $region > /sys/bus/cxl/drivers/cxl_region/bind
> 

I'd be tempted to delete the rest of this description.

> However, we cannot really read/write to the DC regions due to lack of

"However, we cannot yet read/write ..."

> 1. host backend and address space setup for DC regions;
> 2. mailbox command support for adding/releasing DC extents.

"This will be added later in the series."

> 
> Signed-off-by: Fan Ni <fan.ni@samsung.com>

Without the above additions it sounds like this patch series only partly
does the job :)

A forwards reference is good, or just don't mention it.
No guarantee of code doing anything useful, beyond not crashing
at mid point of a series.

Jonathan