1 files changed, 126 insertions, 0 deletions
diff --git a/drivers/misc/cxl/base.c b/drivers/misc/cxl/base.c
new file mode 100644
index 0000000000..b054562c04
--- /dev/null
+++ b/drivers/misc/cxl/base.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2014 IBM Corp.
+ */
+
+#include <linux/module.h>
+#include <linux/rcupdate.h>
+#include <asm/errno.h>
+#include <misc/cxl-base.h>
+#include <linux/of.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);