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.h> 11 #include <linux/of_platform.h> 12 #include "cxl.h" 13 14 /* protected by rcu */ 15 static struct cxl_calls *cxl_calls; 16 17 atomic_t cxl_use_count = ATOMIC_INIT(0); 18 EXPORT_SYMBOL(cxl_use_count); 19 20 #ifdef CONFIG_CXL_MODULE 21 22 static 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 35 static 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 45 static inline struct cxl_calls *cxl_calls_get(void) 46 { 47 return cxl_calls; 48 } 49 50 static inline void cxl_calls_put(struct cxl_calls *calls) { } 51 52 #endif /* CONFIG_CXL_MODULE */ 53 54 /* AFU refcount management */ 55 struct cxl_afu *cxl_afu_get(struct cxl_afu *afu) 56 { 57 return (get_device(&afu->dev) == NULL) ? NULL : afu; 58 } 59 EXPORT_SYMBOL_GPL(cxl_afu_get); 60 61 void cxl_afu_put(struct cxl_afu *afu) 62 { 63 put_device(&afu->dev); 64 } 65 EXPORT_SYMBOL_GPL(cxl_afu_put); 66 67 void 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 81 int 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 } 89 EXPORT_SYMBOL_GPL(register_cxl_calls); 90 91 void 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 } 97 EXPORT_SYMBOL_GPL(unregister_cxl_calls); 98 99 int cxl_update_properties(struct device_node *dn, 100 struct property *new_prop) 101 { 102 return of_update_property(dn, new_prop); 103 } 104 EXPORT_SYMBOL_GPL(cxl_update_properties); 105 106 static 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 only 114 */ 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 } 126 device_initcall(cxl_base_init); 127