Re: [PATCH v10 06/31] cxl/port: Add 'dynamic_ram_a' to endpoint decoder mode

[Anisa Su]

On Wed, May 27, 2026 at 05:01:44PM -0700, Dave Jiang wrote:
> 
> 
> On 5/23/26 2:43 AM, Anisa Su wrote:
> > From: Ira Weiny <ira.weiny@xxxxxxxxx>
> > 
> > Endpoints can now support a single dynamic ram partition following the
> > persistent memory partition.
> > 
> > Expand the mode to allow a decoder to point to the first dynamic ram
> > partition.
> > 
> > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> 
> Need Anisa sign off
> 
> Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> 
> Just update kver and dates below.
> 
Updated!

Thanks,
Anisa
> > 
> > ---
> > Changes:
> > [anisa: rebase]
> > ---
> >  Documentation/ABI/testing/sysfs-bus-cxl | 18 +++++++++---------
> >  drivers/cxl/core/port.c                 |  4 ++++
> >  2 files changed, 13 insertions(+), 9 deletions(-)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl
> > index 3d95c325f6e0..c604c7ca6432 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-cxl
> > +++ b/Documentation/ABI/testing/sysfs-bus-cxl
> > @@ -358,22 +358,22 @@ Description:
> >  
> >  
> >  What:		/sys/bus/cxl/devices/decoderX.Y/mode
> > -Date:		May, 2022
> > -KernelVersion:	v6.0
> > +Date:		May, 2022, May 2025
> 
> A later date
> 
> > +KernelVersion:	v6.0, v6.16 (dynamic_ram_a)
> 
> 7.3 maybe?
> 
> DJ
> 
> >  Contact:	linux-cxl@xxxxxxxxxxxxxxx
> >  Description:
> >  		(RW) When a CXL decoder is of devtype "cxl_decoder_endpoint" it
> >  		translates from a host physical address range, to a device
> >  		local address range. Device-local address ranges are further
> > -		split into a 'ram' (volatile memory) range and 'pmem'
> > -		(persistent memory) range. The 'mode' attribute emits one of
> > -		'ram', 'pmem', or 'none'. The 'none' indicates the decoder is
> > -		not actively decoding, or no DPA allocation policy has been
> > -		set.
> > +		split into a 'ram' (volatile memory) range, 'pmem' (persistent
> > +		memory), and 'dynamic_ram_a' (first Dynamic RAM) range. The
> > +		'mode' attribute emits one of 'ram', 'pmem', 'dynamic_ram_a' or
> > +		'none'. The 'none' indicates the decoder is not actively
> > +		decoding, or no DPA allocation policy has been set.
> >  
> >  		'mode' can be written, when the decoder is in the 'disabled'
> > -		state, with either 'ram' or 'pmem' to set the boundaries for the
> > -		next allocation.
> > +		state, with either 'ram', 'pmem', or 'dynamic_ram_a' to set the
> > +		boundaries for the next allocation.
> >  
> >  
> >  What:		/sys/bus/cxl/devices/decoderX.Y/dpa_resource
> > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> > index 0c5957d1d329..a7f71f36531f 100644
> > --- a/drivers/cxl/core/port.c
> > +++ b/drivers/cxl/core/port.c
> > @@ -128,6 +128,7 @@ static DEVICE_ATTR_RO(name)
> >  
> >  CXL_DECODER_FLAG_ATTR(cap_pmem, CXL_DECODER_F_PMEM);
> >  CXL_DECODER_FLAG_ATTR(cap_ram, CXL_DECODER_F_RAM);
> > +CXL_DECODER_FLAG_ATTR(cap_dynamic_ram_a, CXL_DECODER_F_RAM);
> >  CXL_DECODER_FLAG_ATTR(cap_type2, CXL_DECODER_F_TYPE2);
> >  CXL_DECODER_FLAG_ATTR(cap_type3, CXL_DECODER_F_TYPE3);
> >  CXL_DECODER_FLAG_ATTR(locked, CXL_DECODER_F_LOCK);
> > @@ -222,6 +223,8 @@ static ssize_t mode_store(struct device *dev, struct device_attribute *attr,
> >  		mode = CXL_PARTMODE_PMEM;
> >  	else if (sysfs_streq(buf, "ram"))
> >  		mode = CXL_PARTMODE_RAM;
> > +	else if (sysfs_streq(buf, "dynamic_ram_a"))
> > +		mode = CXL_PARTMODE_DYNAMIC_RAM_A;
> >  	else
> >  		return -EINVAL;
> >  
> > @@ -327,6 +330,7 @@ static struct attribute_group cxl_decoder_base_attribute_group = {
> >  static struct attribute *cxl_decoder_root_attrs[] = {
> >  	&dev_attr_cap_pmem.attr,
> >  	&dev_attr_cap_ram.attr,
> > +	&dev_attr_cap_dynamic_ram_a.attr,
> >  	&dev_attr_cap_type2.attr,
> >  	&dev_attr_cap_type3.attr,
> >  	&dev_attr_target_list.attr,
>