1 /* SPDX-License-Identifier: MIT */ 2 /* 3 * Copyright © 2024 Intel Corporation 4 */ 5 6 #ifndef _XE_ARGS_H_ 7 #define _XE_ARGS_H_ 8 9 #include <linux/args.h> 10 11 /* 12 * Why don't the following macros have the XE prefix? 13 * 14 * Once we find more potential users outside of the Xe driver, we plan to move 15 * all of the following macros unchanged to linux/args.h. 16 */ 17 18 /** 19 * CALL_ARGS - Invoke a macro, but allow parameters to be expanded beforehand. 20 * @f: name of the macro to invoke 21 * @args: arguments for the macro 22 * 23 * This macro allows calling macros which names might generated or we want to 24 * make sure it's arguments will be correctly expanded. 25 * 26 * Example: 27 * 28 * #define foo X,Y,Z,Q 29 * #define bar COUNT_ARGS(foo) 30 * #define buz CALL_ARGS(COUNT_ARGS, foo) 31 * 32 * With above definitions bar expands to 1 while buz expands to 4. 33 */ 34 #define CALL_ARGS(f, args...) __CALL_ARGS(f, args) 35 #define __CALL_ARGS(f, args...) f(args) 36 37 /** 38 * DROP_FIRST_ARG - Returns all arguments except the first one. 39 * @args: arguments 40 * 41 * This helper macro allows manipulation the argument list before passing it 42 * to the next level macro. 43 * 44 * Example: 45 * 46 * #define foo X,Y,Z,Q 47 * #define bar CALL_ARGS(COUNT_ARGS, DROP_FIRST_ARG(foo)) 48 * 49 * With above definitions bar expands to 3. 50 */ 51 #define DROP_FIRST_ARG(args...) __DROP_FIRST_ARG(args) 52 #define __DROP_FIRST_ARG(a, b...) b 53 54 /** 55 * FIRST_ARG - Returns the first argument. 56 * @args: arguments 57 * 58 * This helper macro allows manipulation the argument list before passing it 59 * to the next level macro. 60 * 61 * Example: 62 * 63 * #define foo X,Y,Z,Q 64 * #define bar FIRST_ARG(foo) 65 * 66 * With above definitions bar expands to X. 67 */ 68 #define FIRST_ARG(args...) __FIRST_ARG(args) 69 #define __FIRST_ARG(a, b...) a 70 71 /** 72 * LAST_ARG - Returns the last argument. 73 * @args: arguments 74 * 75 * This helper macro allows manipulation the argument list before passing it 76 * to the next level macro. 77 * 78 * Like COUNT_ARGS() this macro works up to 12 arguments. 79 * 80 * Example: 81 * 82 * #define foo X,Y,Z,Q 83 * #define bar LAST_ARG(foo) 84 * 85 * With above definitions bar expands to Q. 86 */ 87 #define LAST_ARG(args...) __LAST_ARG(args) 88 #define __LAST_ARG(args...) PICK_ARG(COUNT_ARGS(args), args) 89 90 /** 91 * PICK_ARG - Returns the n-th argument. 92 * @n: argument number to be returned 93 * @args: arguments 94 * 95 * This helper macro allows manipulation the argument list before passing it 96 * to the next level macro. 97 * 98 * Like COUNT_ARGS() this macro supports n up to 12. 99 * Specialized macros PICK_ARG1() to PICK_ARG12() are also available. 100 * 101 * Example: 102 * 103 * #define foo X,Y,Z,Q 104 * #define bar PICK_ARG(2, foo) 105 * #define buz PICK_ARG3(foo) 106 * 107 * With above definitions bar expands to Y and buz expands to Z. 108 */ 109 #define PICK_ARG(n, args...) __PICK_ARG(n, args) 110 #define __PICK_ARG(n, args...) CALL_ARGS(CONCATENATE(PICK_ARG, n), args) 111 #define PICK_ARG1(args...) FIRST_ARG(args) 112 #define PICK_ARG2(args...) PICK_ARG1(DROP_FIRST_ARG(args)) 113 #define PICK_ARG3(args...) PICK_ARG2(DROP_FIRST_ARG(args)) 114 #define PICK_ARG4(args...) PICK_ARG3(DROP_FIRST_ARG(args)) 115 #define PICK_ARG5(args...) PICK_ARG4(DROP_FIRST_ARG(args)) 116 #define PICK_ARG6(args...) PICK_ARG5(DROP_FIRST_ARG(args)) 117 #define PICK_ARG7(args...) PICK_ARG6(DROP_FIRST_ARG(args)) 118 #define PICK_ARG8(args...) PICK_ARG7(DROP_FIRST_ARG(args)) 119 #define PICK_ARG9(args...) PICK_ARG8(DROP_FIRST_ARG(args)) 120 #define PICK_ARG10(args...) PICK_ARG9(DROP_FIRST_ARG(args)) 121 #define PICK_ARG11(args...) PICK_ARG10(DROP_FIRST_ARG(args)) 122 #define PICK_ARG12(args...) PICK_ARG11(DROP_FIRST_ARG(args)) 123 124 /** 125 * ARGS_SEP_COMMA - Definition of a comma character. 126 * 127 * This definition can be used in cases where any intermediate macro expects 128 * fixed number of arguments, but we want to pass more arguments which can 129 * be properly evaluated only by the next level macro. 130 * 131 * Example: 132 * 133 * #define foo(f) f(X) f(Y) f(Z) f(Q) 134 * #define bar DROP_FIRST_ARG(foo(ARGS_SEP_COMMA __stringify)) 135 * #define buz CALL_ARGS(COUNT_ARGS, DROP_FIRST_ARG(foo(ARGS_SEP_COMMA))) 136 * 137 * With above definitions bar expands to 138 * "X", "Y", "Z", "Q" 139 * and buz expands to 4. 140 */ 141 #define ARGS_SEP_COMMA , 142 143 #endif 144