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- // 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_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);
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