1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 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_platform.h> 11 #include "cxl.h" 12 13 /* protected by rcu */ 14 static struct cxl_calls *cxl_calls; 15 16 atomic_t cxl_use_count = ATOMIC_INIT(0); 17 EXPORT_SYMBOL(cxl_use_count); 18 19 #ifdef CONFIG_CXL_MODULE 20 21 static inline struct cxl_calls *cxl_calls_get(void) 22 { 23 struct cxl_calls *calls = NULL; 24 25 rcu_read_lock(); 26 calls = rcu_dereference(cxl_calls); 27 if (calls && !try_module_get(calls->owner)) 28 calls = NULL; 29 rcu_read_unlock(); 30 31 return calls; 32 } 33 34 static inline void cxl_calls_put(struct cxl_calls *calls) 35 { 36 BUG_ON(calls != cxl_calls); 37 38 /* we don't need to rcu this, as we hold a reference to the module */ 39 module_put(cxl_calls->owner); 40 } 41 42 #else /* !defined CONFIG_CXL_MODULE */ 43 44 static inline struct cxl_calls *cxl_calls_get(void) 45 { 46 return cxl_calls; 47 } 48 49 static inline void cxl_calls_put(struct cxl_calls *calls) { } 50 51 #endif /* CONFIG_CXL_MODULE */ 52 53 /* AFU refcount management */ 54 struct cxl_afu *cxl_afu_get(struct cxl_afu *afu) 55 { 56 return (get_device(&afu->dev) == NULL) ? NULL : afu; 57 } 58 EXPORT_SYMBOL_GPL(cxl_afu_get); 59 60 void cxl_afu_put(struct cxl_afu *afu) 61 { 62 put_device(&afu->dev); 63 } 64 EXPORT_SYMBOL_GPL(cxl_afu_put); 65 66 void cxl_slbia(struct mm_struct *mm) 67 { 68 struct cxl_calls *calls; 69 70 calls = cxl_calls_get(); 71 if (!calls) 72 return; 73 74 if (cxl_ctx_in_use()) 75 calls->cxl_slbia(mm); 76 77 cxl_calls_put(calls); 78 } 79 80 int register_cxl_calls(struct cxl_calls *calls) 81 { 82 if (cxl_calls) 83 return -EBUSY; 84 85 rcu_assign_pointer(cxl_calls, calls); 86 return 0; 87 } 88 EXPORT_SYMBOL_GPL(register_cxl_calls); 89 90 void unregister_cxl_calls(struct cxl_calls *calls) 91 { 92 BUG_ON(cxl_calls->owner != calls->owner); 93 RCU_INIT_POINTER(cxl_calls, NULL); 94 synchronize_rcu(); 95 } 96 EXPORT_SYMBOL_GPL(unregister_cxl_calls); 97 98 int cxl_update_properties(struct device_node *dn, 99 struct property *new_prop) 100 { 101 return of_update_property(dn, new_prop); 102 } 103 EXPORT_SYMBOL_GPL(cxl_update_properties); 104 105 static int __init cxl_base_init(void) 106 { 107 struct device_node *np; 108 struct platform_device *dev; 109 int count = 0; 110 111 /* 112 * Scan for compatible devices in guest only 113 */ 114 if (cpu_has_feature(CPU_FTR_HVMODE)) 115 return 0; 116 117 for_each_compatible_node(np, NULL, "ibm,coherent-platform-facility") { 118 dev = of_platform_device_create(np, NULL, NULL); 119 if (dev) 120 count++; 121 } 122 pr_devel("Found %d cxl device(s)\n", count); 123 return 0; 124 } 125 device_initcall(cxl_base_init); 126