In 84ec985944ef3, devm_cxl_add_nvdimm() sequence was changed and called
before devm_cxl_add_endpoint(). It's because cxl pmem region auto-assembly
used to get called at last in cxl_endpoint_port_probe(), which requires
cxl_nvd presence.

For cxl region persistency, region creation happens during nvdimm_probe
which need the completion of endpoint probe.

In order to accommodate both cxl pmem region auto-assembly and cxl region
persistency, refactored following

1. Re-Sequence devm_cxl_add_nvdimm() after devm_cxl_add_endpoint(). This
   will be called only after successful completion of endpoint probe.

2. Create cxl_region_discovery() which performs pmem region
   auto-assembly and remove cxl pmem region auto-assembly from
   cxl_endpoint_port_probe()

3. Register cxl_region_discovery() with devm_cxl_add_memdev() which gets
   called during cxl_pci_probe() in context of cxl_mem_probe()

4. As cxlmd->attach->probe() calls registered cxl_region_discovery(), so
   move devm_cxl_add_nvdimm() before cxlmd->attach->probe(). It guarantees
   both the completion of endpoint probe and cxl_nvd presence before
   calling cxlmd->attach->probe().

Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Neeraj Kumar <s.neeraj@samsung.com>
---
 drivers/cxl/core/region.c | 37 +++++++++++++++++++++++++++++++++++++
 drivers/cxl/cxl.h         |  5 +++++
 drivers/cxl/mem.c         | 18 +++++++++---------
 drivers/cxl/pci.c         |  4 +++-
 drivers/cxl/port.c        | 39 +--------------------------------------
 5 files changed, 55 insertions(+), 48 deletions(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index ae899f68551f..26238fb5e8cf 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3727,6 +3727,43 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
 }
 EXPORT_SYMBOL_NS_GPL(cxl_add_to_region, "CXL");
 
+static int discover_region(struct device *dev, void *unused)
+{
+	struct cxl_endpoint_decoder *cxled;
+	int rc;
+
+	if (!is_endpoint_decoder(dev))
+		return 0;
+
+	cxled = to_cxl_endpoint_decoder(dev);
+	if ((cxled->cxld.flags & CXL_DECODER_F_ENABLE) == 0)
+		return 0;
+
+	if (cxled->state != CXL_DECODER_STATE_AUTO)
+		return 0;
+
+	/*
+	 * Region enumeration is opportunistic, if this add-event fails,
+	 * continue to the next endpoint decoder.
+	 */
+	rc = cxl_add_to_region(cxled);
+	if (rc)
+		dev_dbg(dev, "failed to add to region: %#llx-%#llx\n",
+			cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end);
+
+	return 0;
+}
+
+int cxl_region_discovery(struct cxl_memdev *cxlmd)
+{
+	struct cxl_port *port = cxlmd->endpoint;
+
+	device_for_each_child(&port->dev, NULL, discover_region);
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_region_discovery, "CXL");
+
 u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint, u64 spa)
 {
 	struct cxl_region_ref *iter;
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index c796c3db36e0..86efcc4fb963 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -906,6 +906,7 @@ struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev);
 int cxl_add_to_region(struct cxl_endpoint_decoder *cxled);
 struct cxl_dax_region *to_cxl_dax_region(struct device *dev);
 u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint, u64 spa);
+int cxl_region_discovery(struct cxl_memdev *cxlmd);
 #else
 static inline bool is_cxl_pmem_region(struct device *dev)
 {
@@ -928,6 +929,10 @@ static inline u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint,
 {
 	return 0;
 }
+static inline int cxl_region_discovery(struct cxl_memdev *cxlmd)
+{
+	return 0;
+}
 #endif
 
 void cxl_endpoint_parse_cdat(struct cxl_port *port);
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 333c366b69e7..7d19528d9b55 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -114,15 +114,6 @@ static int cxl_mem_probe(struct device *dev)
 		return -ENXIO;
 	}
 
-	if (cxl_pmem_size(cxlds) && IS_ENABLED(CONFIG_CXL_PMEM)) {
-		rc = devm_cxl_add_nvdimm(parent_port, cxlmd);
-		if (rc) {
-			if (rc == -ENODEV)
-				dev_info(dev, "PMEM disabled by platform\n");
-			return rc;
-		}
-	}
-
 	if (dport->rch)
 		endpoint_parent = parent_port->uport_dev;
 	else
@@ -142,6 +133,15 @@ static int cxl_mem_probe(struct device *dev)
 			return rc;
 	}
 
+	if (cxl_pmem_size(cxlds) && IS_ENABLED(CONFIG_CXL_PMEM)) {
+		rc = devm_cxl_add_nvdimm(parent_port, cxlmd);
+		if (rc) {
+			if (rc == -ENODEV)
+				dev_info(dev, "PMEM disabled by platform\n");
+			return rc;
+		}
+	}
+
 	if (cxlmd->attach) {
 		rc = cxlmd->attach->probe(cxlmd);
 		if (rc)
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 549368a9c868..70b40a10be7a 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -903,6 +903,7 @@ __ATTRIBUTE_GROUPS(cxl_rcd);
 static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct pci_host_bridge *host_bridge = pci_find_host_bridge(pdev->bus);
+	struct cxl_memdev_attach memdev_attach = { 0 };
 	struct cxl_dpa_info range_info = { 0 };
 	struct cxl_memdev_state *mds;
 	struct cxl_dev_state *cxlds;
@@ -1006,7 +1007,8 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (rc)
 		dev_dbg(&pdev->dev, "No CXL Features discovered\n");
 
-	cxlmd = devm_cxl_add_memdev(cxlds, NULL);
+	memdev_attach.probe = cxl_region_discovery;
+	cxlmd = devm_cxl_add_memdev(cxlds, &memdev_attach);
 	if (IS_ERR(cxlmd))
 		return PTR_ERR(cxlmd);
 
diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
index 7937e7e53797..fbeff1978bfb 100644
--- a/drivers/cxl/port.c
+++ b/drivers/cxl/port.c
@@ -30,33 +30,6 @@ static void schedule_detach(void *cxlmd)
 	schedule_cxl_memdev_detach(cxlmd);
 }
 
-static int discover_region(struct device *dev, void *unused)
-{
-	struct cxl_endpoint_decoder *cxled;
-	int rc;
-
-	if (!is_endpoint_decoder(dev))
-		return 0;
-
-	cxled = to_cxl_endpoint_decoder(dev);
-	if ((cxled->cxld.flags & CXL_DECODER_F_ENABLE) == 0)
-		return 0;
-
-	if (cxled->state != CXL_DECODER_STATE_AUTO)
-		return 0;
-
-	/*
-	 * Region enumeration is opportunistic, if this add-event fails,
-	 * continue to the next endpoint decoder.
-	 */
-	rc = cxl_add_to_region(cxled);
-	if (rc)
-		dev_dbg(dev, "failed to add to region: %#llx-%#llx\n",
-			cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end);
-
-	return 0;
-}
-
 static int cxl_switch_port_probe(struct cxl_port *port)
 {
 	/* Reset nr_dports for rebind of driver */
@@ -82,17 +55,7 @@ static int cxl_endpoint_port_probe(struct cxl_port *port)
 	if (rc)
 		return rc;
 
-	rc = devm_cxl_endpoint_decoders_setup(port);
-	if (rc)
-		return rc;
-
-	/*
-	 * Now that all endpoint decoders are successfully enumerated, try to
-	 * assemble regions from committed decoders
-	 */
-	device_for_each_child(&port->dev, NULL, discover_region);
-
-	return 0;
+	return devm_cxl_endpoint_decoders_setup(port);
 }
 
 static int cxl_port_probe(struct device *dev)
-- 
2.34.1

Neeraj Kumar wrote:
> In 84ec985944ef3, devm_cxl_add_nvdimm() sequence was changed and called
> before devm_cxl_add_endpoint(). It's because cxl pmem region auto-assembly
> used to get called at last in cxl_endpoint_port_probe(), which requires
> cxl_nvd presence.

What?

> For cxl region persistency, region creation happens during nvdimm_probe
> which need the completion of endpoint probe.
> 
> In order to accommodate both cxl pmem region auto-assembly and cxl region
> persistency, refactored following
> 
> 1. Re-Sequence devm_cxl_add_nvdimm() after devm_cxl_add_endpoint(). This
>    will be called only after successful completion of endpoint probe.
> 
> 2. Create cxl_region_discovery() which performs pmem region
>    auto-assembly and remove cxl pmem region auto-assembly from
>    cxl_endpoint_port_probe()
> 
> 3. Register cxl_region_discovery() with devm_cxl_add_memdev() which gets
>    called during cxl_pci_probe() in context of cxl_mem_probe()
> 
> 4. As cxlmd->attach->probe() calls registered cxl_region_discovery(), so
>    move devm_cxl_add_nvdimm() before cxlmd->attach->probe(). It guarantees
>    both the completion of endpoint probe and cxl_nvd presence before
>    calling cxlmd->attach->probe().

This does not make sense. The whole point of having
devm_cxl_add_nvdimm() before devm_cxl_add_endpoint() is so that the
typical region discovery path can consider pre-existing decoder settings
*or* nvdimm labels in its assembly decisions.

I would be surprised if this passes existing region assembly and
ordering tests.

This reads like "do not understand current ordering, change it for thin
reasons".

On 1/23/26 4:31 AM, Neeraj Kumar wrote:
> In 84ec985944ef3, devm_cxl_add_nvdimm() sequence was changed and called
> before devm_cxl_add_endpoint(). It's because cxl pmem region auto-assembly
> used to get called at last in cxl_endpoint_port_probe(), which requires
> cxl_nvd presence.
> 
> For cxl region persistency, region creation happens during nvdimm_probe
> which need the completion of endpoint probe.
> 
> In order to accommodate both cxl pmem region auto-assembly and cxl region
> persistency, refactored following
> 
> 1. Re-Sequence devm_cxl_add_nvdimm() after devm_cxl_add_endpoint(). This
>    will be called only after successful completion of endpoint probe.
> 
> 2. Create cxl_region_discovery() which performs pmem region
>    auto-assembly and remove cxl pmem region auto-assembly from
>    cxl_endpoint_port_probe()
> 
> 3. Register cxl_region_discovery() with devm_cxl_add_memdev() which gets
>    called during cxl_pci_probe() in context of cxl_mem_probe()
> 
> 4. As cxlmd->attach->probe() calls registered cxl_region_discovery(), so
>    move devm_cxl_add_nvdimm() before cxlmd->attach->probe(). It guarantees
>    both the completion of endpoint probe and cxl_nvd presence before
>    calling cxlmd->attach->probe().
> 
> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> Signed-off-by: Neeraj Kumar <s.neeraj@samsung.com>

Hi Neeraj,
Just FYI this is the patch that breaks the auto-region assemble in cxl_test.

DJ

> ---
>  drivers/cxl/core/region.c | 37 +++++++++++++++++++++++++++++++++++++
>  drivers/cxl/cxl.h         |  5 +++++
>  drivers/cxl/mem.c         | 18 +++++++++---------
>  drivers/cxl/pci.c         |  4 +++-
>  drivers/cxl/port.c        | 39 +--------------------------------------
>  5 files changed, 55 insertions(+), 48 deletions(-)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index ae899f68551f..26238fb5e8cf 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3727,6 +3727,43 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
>  }
>  EXPORT_SYMBOL_NS_GPL(cxl_add_to_region, "CXL");
>  
> +static int discover_region(struct device *dev, void *unused)
> +{
> +	struct cxl_endpoint_decoder *cxled;
> +	int rc;
> +
> +	if (!is_endpoint_decoder(dev))
> +		return 0;
> +
> +	cxled = to_cxl_endpoint_decoder(dev);
> +	if ((cxled->cxld.flags & CXL_DECODER_F_ENABLE) == 0)
> +		return 0;
> +
> +	if (cxled->state != CXL_DECODER_STATE_AUTO)
> +		return 0;
> +
> +	/*
> +	 * Region enumeration is opportunistic, if this add-event fails,
> +	 * continue to the next endpoint decoder.
> +	 */
> +	rc = cxl_add_to_region(cxled);
> +	if (rc)
> +		dev_dbg(dev, "failed to add to region: %#llx-%#llx\n",
> +			cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end);
> +
> +	return 0;
> +}
> +
> +int cxl_region_discovery(struct cxl_memdev *cxlmd)
> +{
> +	struct cxl_port *port = cxlmd->endpoint;
> +
> +	device_for_each_child(&port->dev, NULL, discover_region);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_region_discovery, "CXL");
> +
>  u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint, u64 spa)
>  {
>  	struct cxl_region_ref *iter;
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index c796c3db36e0..86efcc4fb963 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -906,6 +906,7 @@ struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev);
>  int cxl_add_to_region(struct cxl_endpoint_decoder *cxled);
>  struct cxl_dax_region *to_cxl_dax_region(struct device *dev);
>  u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint, u64 spa);
> +int cxl_region_discovery(struct cxl_memdev *cxlmd);
>  #else
>  static inline bool is_cxl_pmem_region(struct device *dev)
>  {
> @@ -928,6 +929,10 @@ static inline u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint,
>  {
>  	return 0;
>  }
> +static inline int cxl_region_discovery(struct cxl_memdev *cxlmd)
> +{
> +	return 0;
> +}
>  #endif
>  
>  void cxl_endpoint_parse_cdat(struct cxl_port *port);
> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
> index 333c366b69e7..7d19528d9b55 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -114,15 +114,6 @@ static int cxl_mem_probe(struct device *dev)
>  		return -ENXIO;
>  	}
>  
> -	if (cxl_pmem_size(cxlds) && IS_ENABLED(CONFIG_CXL_PMEM)) {
> -		rc = devm_cxl_add_nvdimm(parent_port, cxlmd);
> -		if (rc) {
> -			if (rc == -ENODEV)
> -				dev_info(dev, "PMEM disabled by platform\n");
> -			return rc;
> -		}
> -	}
> -
>  	if (dport->rch)
>  		endpoint_parent = parent_port->uport_dev;
>  	else
> @@ -142,6 +133,15 @@ static int cxl_mem_probe(struct device *dev)
>  			return rc;
>  	}
>  
> +	if (cxl_pmem_size(cxlds) && IS_ENABLED(CONFIG_CXL_PMEM)) {
> +		rc = devm_cxl_add_nvdimm(parent_port, cxlmd);
> +		if (rc) {
> +			if (rc == -ENODEV)
> +				dev_info(dev, "PMEM disabled by platform\n");
> +			return rc;
> +		}
> +	}
> +
>  	if (cxlmd->attach) {
>  		rc = cxlmd->attach->probe(cxlmd);
>  		if (rc)
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 549368a9c868..70b40a10be7a 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -903,6 +903,7 @@ __ATTRIBUTE_GROUPS(cxl_rcd);
>  static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  {
>  	struct pci_host_bridge *host_bridge = pci_find_host_bridge(pdev->bus);
> +	struct cxl_memdev_attach memdev_attach = { 0 };
>  	struct cxl_dpa_info range_info = { 0 };
>  	struct cxl_memdev_state *mds;
>  	struct cxl_dev_state *cxlds;
> @@ -1006,7 +1007,8 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  	if (rc)
>  		dev_dbg(&pdev->dev, "No CXL Features discovered\n");
>  
> -	cxlmd = devm_cxl_add_memdev(cxlds, NULL);
> +	memdev_attach.probe = cxl_region_discovery;
> +	cxlmd = devm_cxl_add_memdev(cxlds, &memdev_attach);
>  	if (IS_ERR(cxlmd))
>  		return PTR_ERR(cxlmd);
>  
> diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
> index 7937e7e53797..fbeff1978bfb 100644
> --- a/drivers/cxl/port.c
> +++ b/drivers/cxl/port.c
> @@ -30,33 +30,6 @@ static void schedule_detach(void *cxlmd)
>  	schedule_cxl_memdev_detach(cxlmd);
>  }
>  
> -static int discover_region(struct device *dev, void *unused)
> -{
> -	struct cxl_endpoint_decoder *cxled;
> -	int rc;
> -
> -	if (!is_endpoint_decoder(dev))
> -		return 0;
> -
> -	cxled = to_cxl_endpoint_decoder(dev);
> -	if ((cxled->cxld.flags & CXL_DECODER_F_ENABLE) == 0)
> -		return 0;
> -
> -	if (cxled->state != CXL_DECODER_STATE_AUTO)
> -		return 0;
> -
> -	/*
> -	 * Region enumeration is opportunistic, if this add-event fails,
> -	 * continue to the next endpoint decoder.
> -	 */
> -	rc = cxl_add_to_region(cxled);
> -	if (rc)
> -		dev_dbg(dev, "failed to add to region: %#llx-%#llx\n",
> -			cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end);
> -
> -	return 0;
> -}
> -
>  static int cxl_switch_port_probe(struct cxl_port *port)
>  {
>  	/* Reset nr_dports for rebind of driver */
> @@ -82,17 +55,7 @@ static int cxl_endpoint_port_probe(struct cxl_port *port)
>  	if (rc)
>  		return rc;
>  
> -	rc = devm_cxl_endpoint_decoders_setup(port);
> -	if (rc)
> -		return rc;
> -
> -	/*
> -	 * Now that all endpoint decoders are successfully enumerated, try to
> -	 * assemble regions from committed decoders
> -	 */
> -	device_for_each_child(&port->dev, NULL, discover_region);
> -
> -	return 0;
> +	return devm_cxl_endpoint_decoders_setup(port);
>  }
>  
>  static int cxl_port_probe(struct device *dev)

On 1/26/26 3:48 PM, Dave Jiang wrote:
> 
> 
> On 1/23/26 4:31 AM, Neeraj Kumar wrote:
>> In 84ec985944ef3, devm_cxl_add_nvdimm() sequence was changed and called
>> before devm_cxl_add_endpoint(). It's because cxl pmem region auto-assembly
>> used to get called at last in cxl_endpoint_port_probe(), which requires
>> cxl_nvd presence.
>>
>> For cxl region persistency, region creation happens during nvdimm_probe
>> which need the completion of endpoint probe.
>>
>> In order to accommodate both cxl pmem region auto-assembly and cxl region
>> persistency, refactored following
>>
>> 1. Re-Sequence devm_cxl_add_nvdimm() after devm_cxl_add_endpoint(). This
>>    will be called only after successful completion of endpoint probe.
>>
>> 2. Create cxl_region_discovery() which performs pmem region
>>    auto-assembly and remove cxl pmem region auto-assembly from
>>    cxl_endpoint_port_probe()
>>
>> 3. Register cxl_region_discovery() with devm_cxl_add_memdev() which gets
>>    called during cxl_pci_probe() in context of cxl_mem_probe()
>>
>> 4. As cxlmd->attach->probe() calls registered cxl_region_discovery(), so
>>    move devm_cxl_add_nvdimm() before cxlmd->attach->probe(). It guarantees
>>    both the completion of endpoint probe and cxl_nvd presence before
>>    calling cxlmd->attach->probe().
>>
>> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
>> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
>> Signed-off-by: Neeraj Kumar <s.neeraj@samsung.com>
> 
> Hi Neeraj,
> Just FYI this is the patch that breaks the auto-region assemble in cxl_test.

So it's missing this part in cxl_test. cxl_test auto region is now showing up. But now I'm hitting some lockdep issues. 

---
diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
index cb87e8c0e63c..03af15edd988 100644
--- a/tools/testing/cxl/test/mem.c
+++ b/tools/testing/cxl/test/mem.c
@@ -1686,6 +1686,7 @@ static void cxl_mock_test_feat_init(struct cxl_mockmem_data *mdata)

 static int cxl_mock_mem_probe(struct platform_device *pdev)
 {
+       struct cxl_memdev_attach memdev_attach = { 0 };
        struct device *dev = &pdev->dev;
        struct cxl_memdev *cxlmd;
        struct cxl_memdev_state *mds;
@@ -1767,7 +1768,8 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)

        cxl_mock_add_event_logs(&mdata->mes);

-       cxlmd = devm_cxl_add_memdev(cxlds, NULL);
+       memdev_attach.probe = cxl_region_discovery;
+       cxlmd = devm_cxl_add_memdev(cxlds, &memdev_attach);
        if (IS_ERR(cxlmd))
                return PTR_ERR(cxlmd);

---


> 
> DJ
> 
>> ---
>>  drivers/cxl/core/region.c | 37 +++++++++++++++++++++++++++++++++++++
>>  drivers/cxl/cxl.h         |  5 +++++
>>  drivers/cxl/mem.c         | 18 +++++++++---------
>>  drivers/cxl/pci.c         |  4 +++-
>>  drivers/cxl/port.c        | 39 +--------------------------------------
>>  5 files changed, 55 insertions(+), 48 deletions(-)
>>
>> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
>> index ae899f68551f..26238fb5e8cf 100644
>> --- a/drivers/cxl/core/region.c
>> +++ b/drivers/cxl/core/region.c
>> @@ -3727,6 +3727,43 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
>>  }
>>  EXPORT_SYMBOL_NS_GPL(cxl_add_to_region, "CXL");
>>  
>> +static int discover_region(struct device *dev, void *unused)
>> +{
>> +	struct cxl_endpoint_decoder *cxled;
>> +	int rc;
>> +
>> +	if (!is_endpoint_decoder(dev))
>> +		return 0;
>> +
>> +	cxled = to_cxl_endpoint_decoder(dev);
>> +	if ((cxled->cxld.flags & CXL_DECODER_F_ENABLE) == 0)
>> +		return 0;
>> +
>> +	if (cxled->state != CXL_DECODER_STATE_AUTO)
>> +		return 0;
>> +
>> +	/*
>> +	 * Region enumeration is opportunistic, if this add-event fails,
>> +	 * continue to the next endpoint decoder.
>> +	 */
>> +	rc = cxl_add_to_region(cxled);
>> +	if (rc)
>> +		dev_dbg(dev, "failed to add to region: %#llx-%#llx\n",
>> +			cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end);
>> +
>> +	return 0;
>> +}
>> +
>> +int cxl_region_discovery(struct cxl_memdev *cxlmd)
>> +{
>> +	struct cxl_port *port = cxlmd->endpoint;
>> +
>> +	device_for_each_child(&port->dev, NULL, discover_region);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_region_discovery, "CXL");
>> +
>>  u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint, u64 spa)
>>  {
>>  	struct cxl_region_ref *iter;
>> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
>> index c796c3db36e0..86efcc4fb963 100644
>> --- a/drivers/cxl/cxl.h
>> +++ b/drivers/cxl/cxl.h
>> @@ -906,6 +906,7 @@ struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev);
>>  int cxl_add_to_region(struct cxl_endpoint_decoder *cxled);
>>  struct cxl_dax_region *to_cxl_dax_region(struct device *dev);
>>  u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint, u64 spa);
>> +int cxl_region_discovery(struct cxl_memdev *cxlmd);
>>  #else
>>  static inline bool is_cxl_pmem_region(struct device *dev)
>>  {
>> @@ -928,6 +929,10 @@ static inline u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint,
>>  {
>>  	return 0;
>>  }
>> +static inline int cxl_region_discovery(struct cxl_memdev *cxlmd)
>> +{
>> +	return 0;
>> +}
>>  #endif
>>  
>>  void cxl_endpoint_parse_cdat(struct cxl_port *port);
>> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
>> index 333c366b69e7..7d19528d9b55 100644
>> --- a/drivers/cxl/mem.c
>> +++ b/drivers/cxl/mem.c
>> @@ -114,15 +114,6 @@ static int cxl_mem_probe(struct device *dev)
>>  		return -ENXIO;
>>  	}
>>  
>> -	if (cxl_pmem_size(cxlds) && IS_ENABLED(CONFIG_CXL_PMEM)) {
>> -		rc = devm_cxl_add_nvdimm(parent_port, cxlmd);
>> -		if (rc) {
>> -			if (rc == -ENODEV)
>> -				dev_info(dev, "PMEM disabled by platform\n");
>> -			return rc;
>> -		}
>> -	}
>> -
>>  	if (dport->rch)
>>  		endpoint_parent = parent_port->uport_dev;
>>  	else
>> @@ -142,6 +133,15 @@ static int cxl_mem_probe(struct device *dev)
>>  			return rc;
>>  	}
>>  
>> +	if (cxl_pmem_size(cxlds) && IS_ENABLED(CONFIG_CXL_PMEM)) {
>> +		rc = devm_cxl_add_nvdimm(parent_port, cxlmd);
>> +		if (rc) {
>> +			if (rc == -ENODEV)
>> +				dev_info(dev, "PMEM disabled by platform\n");
>> +			return rc;
>> +		}
>> +	}
>> +
>>  	if (cxlmd->attach) {
>>  		rc = cxlmd->attach->probe(cxlmd);
>>  		if (rc)
>> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
>> index 549368a9c868..70b40a10be7a 100644
>> --- a/drivers/cxl/pci.c
>> +++ b/drivers/cxl/pci.c
>> @@ -903,6 +903,7 @@ __ATTRIBUTE_GROUPS(cxl_rcd);
>>  static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>  {
>>  	struct pci_host_bridge *host_bridge = pci_find_host_bridge(pdev->bus);
>> +	struct cxl_memdev_attach memdev_attach = { 0 };
>>  	struct cxl_dpa_info range_info = { 0 };
>>  	struct cxl_memdev_state *mds;
>>  	struct cxl_dev_state *cxlds;
>> @@ -1006,7 +1007,8 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>  	if (rc)
>>  		dev_dbg(&pdev->dev, "No CXL Features discovered\n");
>>  
>> -	cxlmd = devm_cxl_add_memdev(cxlds, NULL);
>> +	memdev_attach.probe = cxl_region_discovery;
>> +	cxlmd = devm_cxl_add_memdev(cxlds, &memdev_attach);
>>  	if (IS_ERR(cxlmd))
>>  		return PTR_ERR(cxlmd);
>>  
>> diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
>> index 7937e7e53797..fbeff1978bfb 100644
>> --- a/drivers/cxl/port.c
>> +++ b/drivers/cxl/port.c
>> @@ -30,33 +30,6 @@ static void schedule_detach(void *cxlmd)
>>  	schedule_cxl_memdev_detach(cxlmd);
>>  }
>>  
>> -static int discover_region(struct device *dev, void *unused)
>> -{
>> -	struct cxl_endpoint_decoder *cxled;
>> -	int rc;
>> -
>> -	if (!is_endpoint_decoder(dev))
>> -		return 0;
>> -
>> -	cxled = to_cxl_endpoint_decoder(dev);
>> -	if ((cxled->cxld.flags & CXL_DECODER_F_ENABLE) == 0)
>> -		return 0;
>> -
>> -	if (cxled->state != CXL_DECODER_STATE_AUTO)
>> -		return 0;
>> -
>> -	/*
>> -	 * Region enumeration is opportunistic, if this add-event fails,
>> -	 * continue to the next endpoint decoder.
>> -	 */
>> -	rc = cxl_add_to_region(cxled);
>> -	if (rc)
>> -		dev_dbg(dev, "failed to add to region: %#llx-%#llx\n",
>> -			cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end);
>> -
>> -	return 0;
>> -}
>> -
>>  static int cxl_switch_port_probe(struct cxl_port *port)
>>  {
>>  	/* Reset nr_dports for rebind of driver */
>> @@ -82,17 +55,7 @@ static int cxl_endpoint_port_probe(struct cxl_port *port)
>>  	if (rc)
>>  		return rc;
>>  
>> -	rc = devm_cxl_endpoint_decoders_setup(port);
>> -	if (rc)
>> -		return rc;
>> -
>> -	/*
>> -	 * Now that all endpoint decoders are successfully enumerated, try to
>> -	 * assemble regions from committed decoders
>> -	 */
>> -	device_for_each_child(&port->dev, NULL, discover_region);
>> -
>> -	return 0;
>> +	return devm_cxl_endpoint_decoders_setup(port);
>>  }
>>  
>>  static int cxl_port_probe(struct device *dev)
> 
>