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 /* AFU refcount management */ 58 struct cxl_afu *cxl_afu_get(struct cxl_afu *afu) 59 { 60 return (get_device(&afu->dev) == NULL) ? NULL : afu; 61 } 62 EXPORT_SYMBOL_GPL(cxl_afu_get); 63 64 void cxl_afu_put(struct cxl_afu *afu) 65 { 66 put_device(&afu->dev); 67 } 68 EXPORT_SYMBOL_GPL(cxl_afu_put); 69 70 void cxl_slbia(struct mm_struct *mm) 71 { 72 struct cxl_calls *calls; 73 74 calls = cxl_calls_get(); 75 if (!calls) 76 return; 77 78 if (cxl_ctx_in_use()) 79 calls->cxl_slbia(mm); 80 81 cxl_calls_put(calls); 82 } 83 84 int register_cxl_calls(struct cxl_calls *calls) 85 { 86 if (cxl_calls) 87 return -EBUSY; 88 89 rcu_assign_pointer(cxl_calls, calls); 90 return 0; 91 } 92 EXPORT_SYMBOL_GPL(register_cxl_calls); 93 94 void unregister_cxl_calls(struct cxl_calls *calls) 95 { 96 BUG_ON(cxl_calls->owner != calls->owner); 97 RCU_INIT_POINTER(cxl_calls, NULL); 98 synchronize_rcu(); 99 } 100 EXPORT_SYMBOL_GPL(unregister_cxl_calls); 101 102 int cxl_update_properties(struct device_node *dn, 103 struct property *new_prop) 104 { 105 return of_update_property(dn, new_prop); 106 } 107 EXPORT_SYMBOL_GPL(cxl_update_properties); 108 109 static int __init cxl_base_init(void) 110 { 111 struct device_node *np; 112 struct platform_device *dev; 113 int count = 0; 114 115 /* 116 * Scan for compatible devices in guest only 117 */ 118 if (cpu_has_feature(CPU_FTR_HVMODE)) 119 return 0; 120 121 for_each_compatible_node(np, NULL, "ibm,coherent-platform-facility") { 122 dev = of_platform_device_create(np, NULL, NULL); 123 if (dev) 124 count++; 125 } 126 pr_devel("Found %d cxl device(s)\n", count); 127 return 0; 128 } 129 device_initcall(cxl_base_init); 130