cxl/acpi: Simplify cxl_nvdimm_bridge probing

The 'struct cxl_nvdimm_bridge' object advertises platform CXL PMEM
resources. It coordinates with libnvdimm to attach nvdimm devices and
regions for each corresponding CXL object. That coordination is
complicated, i.e. difficult to reason about, and it turns out redundant.
It is already the case that the CXL core knows how to tear down a
cxl_region when a cxl_memdev goes through ->remove(), so that pathway
can be extended to directly cleanup cxl_nvdimm and cxl_pmem_region
objects.

Towards the goal of ripping out the cxl_nvdimm_bridge state machine,
arrange for cxl_acpi to optionally pre-load the cxl_pmem driver so that
the nvdimm bridge is active synchronously with
devm_cxl_add_nvdimm_bridge(), and remove all the bind attributes for the
cxl_nvdimm* objects since the cxl root device and cxl_memdev bind
attributes are sufficient.
Tested-by: Robert Richter <rrichter@amd.com>
Link: https://lore.kernel.org/r/166993040668.1882361.7450361097265836752.stgit@dwillia2-xfh.jf.intel.comReviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/acpi.c

@@ -539,3 +539,4 @@ module_platform_driver(cxl_acpi_driver);
 MODULE_LICENSE("GPL v2");
 MODULE_IMPORT_NS(CXL);
 MODULE_IMPORT_NS(ACPI);
+MODULE_SOFTDEP("pre: cxl_pmem");

drivers/cxl/pmem.c

@@ -99,6 +99,9 @@ static struct cxl_driver cxl_nvdimm_driver = {
 	.name = "cxl_nvdimm",
 	.probe = cxl_nvdimm_probe,
 	.id = CXL_DEVICE_NVDIMM,
+	.drv = {
+		.suppress_bind_attrs = true,
+	},
 };
 
 static int cxl_pmem_get_config_size(struct cxl_dev_state *cxlds,
@@ -360,6 +363,9 @@ static struct cxl_driver cxl_nvdimm_bridge_driver = {
 	.probe = cxl_nvdimm_bridge_probe,
 	.remove = cxl_nvdimm_bridge_remove,
 	.id = CXL_DEVICE_NVDIMM_BRIDGE,
+	.drv = {
+		.suppress_bind_attrs = true,
+	},
 };
 
 static int match_cxl_nvdimm(struct device *dev, void *data)
@@ -583,6 +589,9 @@ static struct cxl_driver cxl_pmem_region_driver = {
 	.name = "cxl_pmem_region",
 	.probe = cxl_pmem_region_probe,
 	.id = CXL_DEVICE_PMEM_REGION,
+	.drv = {
+		.suppress_bind_attrs = true,
+	},
 };
 
 /*