xref: /openbmc/linux/arch/powerpc/include/asm/dbell.h (revision da1d9caf)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * Copyright 2009 Freescale Semiconductor, Inc.
4  *
5  * provides masks and opcode images for use by code generation, emulation
6  * and for instructions that older assemblers might not know about
7  */
8 #ifndef _ASM_POWERPC_DBELL_H
9 #define _ASM_POWERPC_DBELL_H
10 
11 #include <linux/smp.h>
12 #include <linux/threads.h>
13 
14 #include <asm/cputhreads.h>
15 #include <asm/ppc-opcode.h>
16 #include <asm/feature-fixups.h>
17 #include <asm/kvm_ppc.h>
18 
19 #define PPC_DBELL_MSG_BRDCAST	(0x04000000)
20 #define PPC_DBELL_TYPE(x)	(((x) & 0xf) << (63-36))
21 #define PPC_DBELL_TYPE_MASK	PPC_DBELL_TYPE(0xf)
22 #define PPC_DBELL_LPID(x)	((x) << (63 - 49))
23 #define PPC_DBELL_PIR_MASK	0x3fff
24 enum ppc_dbell {
25 	PPC_DBELL = 0,		/* doorbell */
26 	PPC_DBELL_CRIT = 1,	/* critical doorbell */
27 	PPC_G_DBELL = 2,	/* guest doorbell */
28 	PPC_G_DBELL_CRIT = 3,	/* guest critical doorbell */
29 	PPC_G_DBELL_MC = 4,	/* guest mcheck doorbell */
30 	PPC_DBELL_SERVER = 5,	/* doorbell on server */
31 };
32 
33 #ifdef CONFIG_PPC_BOOK3S
34 
35 #define PPC_DBELL_MSGTYPE		PPC_DBELL_SERVER
36 
37 static inline void _ppc_msgsnd(u32 msg)
38 {
39 	__asm__ __volatile__ (ASM_FTR_IFSET(PPC_MSGSND(%1), PPC_MSGSNDP(%1), %0)
40 				: : "i" (CPU_FTR_HVMODE), "r" (msg));
41 }
42 
43 /* sync before sending message */
44 static inline void ppc_msgsnd_sync(void)
45 {
46 	__asm__ __volatile__ ("sync" : : : "memory");
47 }
48 
49 /* sync after taking message interrupt */
50 static inline void ppc_msgsync(void)
51 {
52 	/* sync is not required when taking messages from the same core */
53 	__asm__ __volatile__ (ASM_FTR_IFSET(PPC_MSGSYNC " ; lwsync", "", %0)
54 				: : "i" (CPU_FTR_HVMODE|CPU_FTR_ARCH_300));
55 }
56 
57 static inline void _ppc_msgclr(u32 msg)
58 {
59 	__asm__ __volatile__ (ASM_FTR_IFSET(PPC_MSGCLR(%1), PPC_MSGCLRP(%1), %0)
60 				: : "i" (CPU_FTR_HVMODE), "r" (msg));
61 }
62 
63 static inline void ppc_msgclr(enum ppc_dbell type)
64 {
65 	u32 msg = PPC_DBELL_TYPE(type);
66 
67 	_ppc_msgclr(msg);
68 }
69 
70 #else /* CONFIG_PPC_BOOK3S */
71 
72 #define PPC_DBELL_MSGTYPE		PPC_DBELL
73 
74 static inline void _ppc_msgsnd(u32 msg)
75 {
76 	__asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
77 }
78 
79 /* sync before sending message */
80 static inline void ppc_msgsnd_sync(void)
81 {
82 	__asm__ __volatile__ ("sync" : : : "memory");
83 }
84 
85 /* sync after taking message interrupt */
86 static inline void ppc_msgsync(void)
87 {
88 }
89 
90 #endif /* CONFIG_PPC_BOOK3S */
91 
92 extern void doorbell_exception(struct pt_regs *regs);
93 
94 static inline void ppc_msgsnd(enum ppc_dbell type, u32 flags, u32 tag)
95 {
96 	u32 msg = PPC_DBELL_TYPE(type) | (flags & PPC_DBELL_MSG_BRDCAST) |
97 			(tag & 0x07ffffff);
98 
99 	_ppc_msgsnd(msg);
100 }
101 
102 #ifdef CONFIG_SMP
103 
104 /*
105  * Doorbells must only be used if CPU_FTR_DBELL is available.
106  * msgsnd is used in HV, and msgsndp is used in !HV.
107  *
108  * These should be used by platform code that is aware of restrictions.
109  * Other arch code should use ->cause_ipi.
110  *
111  * doorbell_global_ipi() sends a dbell to any target CPU.
112  * Must be used only by architectures that address msgsnd target
113  * by PIR/get_hard_smp_processor_id.
114  */
115 static inline void doorbell_global_ipi(int cpu)
116 {
117 	u32 tag = get_hard_smp_processor_id(cpu);
118 
119 	kvmppc_set_host_ipi(cpu);
120 	/* Order previous accesses vs. msgsnd, which is treated as a store */
121 	ppc_msgsnd_sync();
122 	ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag);
123 }
124 
125 /*
126  * doorbell_core_ipi() sends a dbell to a target CPU in the same core.
127  * Must be used only by architectures that address msgsnd target
128  * by TIR/cpu_thread_in_core.
129  */
130 static inline void doorbell_core_ipi(int cpu)
131 {
132 	u32 tag = cpu_thread_in_core(cpu);
133 
134 	kvmppc_set_host_ipi(cpu);
135 	/* Order previous accesses vs. msgsnd, which is treated as a store */
136 	ppc_msgsnd_sync();
137 	ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag);
138 }
139 
140 /*
141  * Attempt to cause a core doorbell if destination is on the same core.
142  * Returns 1 on success, 0 on failure.
143  */
144 static inline int doorbell_try_core_ipi(int cpu)
145 {
146 	int this_cpu = get_cpu();
147 	int ret = 0;
148 
149 	if (cpumask_test_cpu(cpu, cpu_sibling_mask(this_cpu))) {
150 		doorbell_core_ipi(cpu);
151 		ret = 1;
152 	}
153 
154 	put_cpu();
155 
156 	return ret;
157 }
158 
159 #endif /* CONFIG_SMP */
160 
161 #endif /* _ASM_POWERPC_DBELL_H */
162