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

Signed-off-by: Neeraj Kumar <[email protected]>
---
 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 2cf5b29cefd2..3c868c4de4ec 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3724,6 +3724,43 @@ 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 ba17fa86d249..684a0d1b441a 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -904,6 +904,7 @@ 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)
 {
@@ -926,6 +927,10 @@ 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 13d9e089ecaf..f5e3e2fca86c 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -115,15 +115,6 @@ 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
@@ -143,6 +134,15 @@ 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->ops) {
                rc = cxlmd->ops->probe(cxlmd);
                if (rc)
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index e21051d79b25..d56fdfe4b43b 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -907,6 +907,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct 
pci_device_id *id)
        struct cxl_memdev_state *mds;
        struct cxl_dev_state *cxlds;
        struct cxl_register_map map;
+       struct cxl_memdev_ops ops;
        struct cxl_memdev *cxlmd;
        int rc, pmu_count;
        unsigned int i;
@@ -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(&pdev->dev, cxlds, NULL);
+       ops.probe = cxl_region_discovery;
+       cxlmd = devm_cxl_add_memdev(&pdev->dev, cxlds, &ops);
        if (IS_ERR(cxlmd))
                return PTR_ERR(cxlmd);
 
diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
index d5fd0c5ae49b..ad98b2881fed 100644
--- a/drivers/cxl/port.c
+++ b/drivers/cxl/port.c
@@ -31,33 +31,6 @@ 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 */
@@ -83,17 +56,7 @@ 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


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