[PATCH v9 06/19] cxl/port: Add 'dynamic_ram_a' to endpoint decoder mode

[Ira Weiny <ira.weiny@intel.com>]

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@intel.com>

---
Changes:
[iweiny: completely re-written]
---
 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 2b59041bb410..b2754e6047ca 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
+KernelVersion:	v6.0, v6.16 (dynamic_ram_a)
 Contact:	linux-cxl@vger.kernel.org
 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 0fd6646c1a2e..e98605bd39b4 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -125,6 +125,7 @@ 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);
@@ -219,6 +220,8 @@ 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;
 
@@ -324,6 +327,7 @@ 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,

-- 
2.49.0