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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright 2014 IBM Corp.4 */5 6#include <linux/module.h>7#include <linux/rcupdate.h>8#include <asm/errno.h>9#include <misc/cxl-base.h>10#include <linux/of.h>11#include <linux/of_platform.h>12#include "cxl.h"13 14/* protected by rcu */15static struct cxl_calls *cxl_calls;16 17atomic_t cxl_use_count = ATOMIC_INIT(0);18EXPORT_SYMBOL(cxl_use_count);19 20#ifdef CONFIG_CXL_MODULE21 22static inline struct cxl_calls *cxl_calls_get(void)23{24 struct cxl_calls *calls = NULL;25 26 rcu_read_lock();27 calls = rcu_dereference(cxl_calls);28 if (calls && !try_module_get(calls->owner))29 calls = NULL;30 rcu_read_unlock();31 32 return calls;33}34 35static inline void cxl_calls_put(struct cxl_calls *calls)36{37 BUG_ON(calls != cxl_calls);38 39 /* we don't need to rcu this, as we hold a reference to the module */40 module_put(cxl_calls->owner);41}42 43#else /* !defined CONFIG_CXL_MODULE */44 45static inline struct cxl_calls *cxl_calls_get(void)46{47 return cxl_calls;48}49 50static inline void cxl_calls_put(struct cxl_calls *calls) { }51 52#endif /* CONFIG_CXL_MODULE */53 54/* AFU refcount management */55struct cxl_afu *cxl_afu_get(struct cxl_afu *afu)56{57 return (get_device(&afu->dev) == NULL) ? NULL : afu;58}59EXPORT_SYMBOL_GPL(cxl_afu_get);60 61void cxl_afu_put(struct cxl_afu *afu)62{63 put_device(&afu->dev);64}65EXPORT_SYMBOL_GPL(cxl_afu_put);66 67void cxl_slbia(struct mm_struct *mm)68{69 struct cxl_calls *calls;70 71 calls = cxl_calls_get();72 if (!calls)73 return;74 75 if (cxl_ctx_in_use())76 calls->cxl_slbia(mm);77 78 cxl_calls_put(calls);79}80 81int register_cxl_calls(struct cxl_calls *calls)82{83 if (cxl_calls)84 return -EBUSY;85 86 rcu_assign_pointer(cxl_calls, calls);87 return 0;88}89EXPORT_SYMBOL_GPL(register_cxl_calls);90 91void unregister_cxl_calls(struct cxl_calls *calls)92{93 BUG_ON(cxl_calls->owner != calls->owner);94 RCU_INIT_POINTER(cxl_calls, NULL);95 synchronize_rcu();96}97EXPORT_SYMBOL_GPL(unregister_cxl_calls);98 99int cxl_update_properties(struct device_node *dn,100 struct property *new_prop)101{102 return of_update_property(dn, new_prop);103}104EXPORT_SYMBOL_GPL(cxl_update_properties);105 106static int __init cxl_base_init(void)107{108 struct device_node *np;109 struct platform_device *dev;110 int count = 0;111 112 /*113 * Scan for compatible devices in guest only114 */115 if (cpu_has_feature(CPU_FTR_HVMODE))116 return 0;117 118 for_each_compatible_node(np, NULL, "ibm,coherent-platform-facility") {119 dev = of_platform_device_create(np, NULL, NULL);120 if (dev)121 count++;122 }123 pr_devel("Found %d cxl device(s)\n", count);124 return 0;125}126device_initcall(cxl_base_init);127