v4.19.13 snapshot.
diff --git a/drivers/misc/cxl/base.c b/drivers/misc/cxl/base.c
new file mode 100644
index 0000000..7557835
--- /dev/null
+++ b/drivers/misc/cxl/base.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright 2014 IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/rcupdate.h>
+#include <asm/errno.h>
+#include <misc/cxl-base.h>
+#include <linux/of_platform.h>
+#include "cxl.h"
+
+/* protected by rcu */
+static struct cxl_calls *cxl_calls;
+
+atomic_t cxl_use_count = ATOMIC_INIT(0);
+EXPORT_SYMBOL(cxl_use_count);
+
+#ifdef CONFIG_CXL_MODULE
+
+static inline struct cxl_calls *cxl_calls_get(void)
+{
+ struct cxl_calls *calls = NULL;
+
+ rcu_read_lock();
+ calls = rcu_dereference(cxl_calls);
+ if (calls && !try_module_get(calls->owner))
+ calls = NULL;
+ rcu_read_unlock();
+
+ return calls;
+}
+
+static inline void cxl_calls_put(struct cxl_calls *calls)
+{
+ BUG_ON(calls != cxl_calls);
+
+ /* we don't need to rcu this, as we hold a reference to the module */
+ module_put(cxl_calls->owner);
+}
+
+#else /* !defined CONFIG_CXL_MODULE */
+
+static inline struct cxl_calls *cxl_calls_get(void)
+{
+ return cxl_calls;
+}
+
+static inline void cxl_calls_put(struct cxl_calls *calls) { }
+
+#endif /* CONFIG_CXL_MODULE */
+
+/* AFU refcount management */
+struct cxl_afu *cxl_afu_get(struct cxl_afu *afu)
+{
+ return (get_device(&afu->dev) == NULL) ? NULL : afu;
+}
+EXPORT_SYMBOL_GPL(cxl_afu_get);
+
+void cxl_afu_put(struct cxl_afu *afu)
+{
+ put_device(&afu->dev);
+}
+EXPORT_SYMBOL_GPL(cxl_afu_put);
+
+void cxl_slbia(struct mm_struct *mm)
+{
+ struct cxl_calls *calls;
+
+ calls = cxl_calls_get();
+ if (!calls)
+ return;
+
+ if (cxl_ctx_in_use())
+ calls->cxl_slbia(mm);
+
+ cxl_calls_put(calls);
+}
+
+int register_cxl_calls(struct cxl_calls *calls)
+{
+ if (cxl_calls)
+ return -EBUSY;
+
+ rcu_assign_pointer(cxl_calls, calls);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(register_cxl_calls);
+
+void unregister_cxl_calls(struct cxl_calls *calls)
+{
+ BUG_ON(cxl_calls->owner != calls->owner);
+ RCU_INIT_POINTER(cxl_calls, NULL);
+ synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(unregister_cxl_calls);
+
+int cxl_update_properties(struct device_node *dn,
+ struct property *new_prop)
+{
+ return of_update_property(dn, new_prop);
+}
+EXPORT_SYMBOL_GPL(cxl_update_properties);
+
+static int __init cxl_base_init(void)
+{
+ struct device_node *np;
+ struct platform_device *dev;
+ int count = 0;
+
+ /*
+ * Scan for compatible devices in guest only
+ */
+ if (cpu_has_feature(CPU_FTR_HVMODE))
+ return 0;
+
+ for_each_compatible_node(np, NULL, "ibm,coherent-platform-facility") {
+ dev = of_platform_device_create(np, NULL, NULL);
+ if (dev)
+ count++;
+ }
+ pr_devel("Found %d cxl device(s)\n", count);
+ return 0;
+}
+device_initcall(cxl_base_init);