1 /* 2 * Copyright 2014 IBM Corp. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 */ 9 10 #include <linux/module.h> 11 #include <linux/rcupdate.h> 12 #include <asm/errno.h> 13 #include <misc/cxl-base.h> 14 #include <linux/of_platform.h> 15 #include "cxl.h" 16 17 /* protected by rcu */ 18 static struct cxl_calls *cxl_calls; 19 20 atomic_t cxl_use_count = ATOMIC_INIT(0); 21 EXPORT_SYMBOL(cxl_use_count); 22 23 #ifdef CONFIG_CXL_MODULE 24 25 static inline struct cxl_calls *cxl_calls_get(void) 26 { 27 struct cxl_calls *calls = NULL; 28 29 rcu_read_lock(); 30 calls = rcu_dereference(cxl_calls); 31 if (calls && !try_module_get(calls->owner)) 32 calls = NULL; 33 rcu_read_unlock(); 34 35 return calls; 36 } 37 38 static inline void cxl_calls_put(struct cxl_calls *calls) 39 { 40 BUG_ON(calls != cxl_calls); 41 42 /* we don't need to rcu this, as we hold a reference to the module */ 43 module_put(cxl_calls->owner); 44 } 45 46 #else /* !defined CONFIG_CXL_MODULE */ 47 48 static inline struct cxl_calls *cxl_calls_get(void) 49 { 50 return cxl_calls; 51 } 52 53 static inline void cxl_calls_put(struct cxl_calls *calls) { } 54 55 #endif /* CONFIG_CXL_MODULE */ 56 57 void cxl_slbia(struct mm_struct *mm) 58 { 59 struct cxl_calls *calls; 60 61 calls = cxl_calls_get(); 62 if (!calls) 63 return; 64 65 if (cxl_ctx_in_use()) 66 calls->cxl_slbia(mm); 67 68 cxl_calls_put(calls); 69 } 70 71 int register_cxl_calls(struct cxl_calls *calls) 72 { 73 if (cxl_calls) 74 return -EBUSY; 75 76 rcu_assign_pointer(cxl_calls, calls); 77 return 0; 78 } 79 EXPORT_SYMBOL_GPL(register_cxl_calls); 80 81 void unregister_cxl_calls(struct cxl_calls *calls) 82 { 83 BUG_ON(cxl_calls->owner != calls->owner); 84 RCU_INIT_POINTER(cxl_calls, NULL); 85 synchronize_rcu(); 86 } 87 EXPORT_SYMBOL_GPL(unregister_cxl_calls); 88 89 int cxl_update_properties(struct device_node *dn, 90 struct property *new_prop) 91 { 92 return of_update_property(dn, new_prop); 93 } 94 EXPORT_SYMBOL_GPL(cxl_update_properties); 95 96 static int __init cxl_base_init(void) 97 { 98 struct device_node *np = NULL; 99 struct platform_device *dev; 100 int count = 0; 101 102 /* 103 * Scan for compatible devices in guest only 104 */ 105 if (cpu_has_feature(CPU_FTR_HVMODE)) 106 return 0; 107 108 while ((np = of_find_compatible_node(np, NULL, 109 "ibm,coherent-platform-facility"))) { 110 dev = of_platform_device_create(np, NULL, NULL); 111 if (dev) 112 count++; 113 } 114 pr_devel("Found %d cxl device(s)\n", count); 115 return 0; 116 } 117 118 module_init(cxl_base_init); 119