xref: /openbmc/u-boot/arch/x86/cpu/lapic.c (revision 3ba98ed8)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * From coreboot file of same name
4  *
5  * Copyright (C) 2008-2009 coresystems GmbH
6  * Copyright (C) 2014 Google, Inc
7  */
8 
9 #include <common.h>
10 #include <asm/io.h>
11 #include <asm/lapic.h>
12 #include <asm/msr.h>
13 #include <asm/msr-index.h>
14 #include <asm/post.h>
15 
16 unsigned long lapic_read(unsigned long reg)
17 {
18 	return readl(LAPIC_DEFAULT_BASE + reg);
19 }
20 
21 #define xchg(ptr, v)	((__typeof__(*(ptr)))__xchg((unsigned long)(v), (ptr), \
22 						    sizeof(*(ptr))))
23 
24 struct __xchg_dummy	{ unsigned long a[100]; };
25 #define __xg(x)		((struct __xchg_dummy *)(x))
26 
27 /*
28  * Note: no "lock" prefix even on SMP. xchg always implies lock anyway.
29  *
30  * Note 2: xchg has side effect, so that attribute volatile is necessary,
31  *         but generally the primitive is invalid, *ptr is output argument.
32  */
33 static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
34 				   int size)
35 {
36 	switch (size) {
37 	case 1:
38 		__asm__ __volatile__("xchgb %b0,%1"
39 			: "=q" (x)
40 			: "m" (*__xg(ptr)), "0" (x)
41 			: "memory");
42 		break;
43 	case 2:
44 		__asm__ __volatile__("xchgw %w0,%1"
45 			: "=r" (x)
46 			: "m" (*__xg(ptr)), "0" (x)
47 			: "memory");
48 		break;
49 	case 4:
50 		__asm__ __volatile__("xchgl %0,%1"
51 			: "=r" (x)
52 			: "m" (*__xg(ptr)), "0" (x)
53 			: "memory");
54 		break;
55 	}
56 
57 	return x;
58 }
59 
60 void lapic_write(unsigned long reg, unsigned long v)
61 {
62 	(void)xchg((volatile unsigned long *)(LAPIC_DEFAULT_BASE + reg), v);
63 }
64 
65 void enable_lapic(void)
66 {
67 	if (!IS_ENABLED(CONFIG_INTEL_QUARK)) {
68 		msr_t msr;
69 
70 		msr = msr_read(MSR_IA32_APICBASE);
71 		msr.hi &= 0xffffff00;
72 		msr.lo |= MSR_IA32_APICBASE_ENABLE;
73 		msr.lo &= ~MSR_IA32_APICBASE_BASE;
74 		msr.lo |= LAPIC_DEFAULT_BASE;
75 		msr_write(MSR_IA32_APICBASE, msr);
76 	}
77 }
78 
79 void disable_lapic(void)
80 {
81 	if (!IS_ENABLED(CONFIG_INTEL_QUARK)) {
82 		msr_t msr;
83 
84 		msr = msr_read(MSR_IA32_APICBASE);
85 		msr.lo &= ~MSR_IA32_APICBASE_ENABLE;
86 		msr_write(MSR_IA32_APICBASE, msr);
87 	}
88 }
89 
90 unsigned long lapicid(void)
91 {
92 	return lapic_read(LAPIC_ID) >> 24;
93 }
94 
95 static void lapic_wait_icr_idle(void)
96 {
97 	do { } while (lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY);
98 }
99 
100 int lapic_remote_read(int apicid, int reg, unsigned long *pvalue)
101 {
102 	int timeout;
103 	unsigned long status;
104 	int result;
105 
106 	lapic_wait_icr_idle();
107 	lapic_write(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(apicid));
108 	lapic_write(LAPIC_ICR, LAPIC_DM_REMRD | (reg >> 4));
109 
110 	timeout = 0;
111 	do {
112 		status = lapic_read(LAPIC_ICR) & LAPIC_ICR_RR_MASK;
113 	} while (status == LAPIC_ICR_RR_INPROG && timeout++ < 1000);
114 
115 	result = -1;
116 	if (status == LAPIC_ICR_RR_VALID) {
117 		*pvalue = lapic_read(LAPIC_RRR);
118 		result = 0;
119 	}
120 
121 	return result;
122 }
123 
124 void lapic_setup(void)
125 {
126 	/* Only Pentium Pro and later have those MSR stuff */
127 	debug("Setting up local apic: ");
128 
129 	/* Enable the local apic */
130 	enable_lapic();
131 
132 	/* Set Task Priority to 'accept all' */
133 	lapic_write(LAPIC_TASKPRI,
134 		    lapic_read(LAPIC_TASKPRI) & ~LAPIC_TPRI_MASK);
135 
136 	/* Put the local apic in virtual wire mode */
137 	lapic_write(LAPIC_SPIV, (lapic_read(LAPIC_SPIV) &
138 		    ~(LAPIC_VECTOR_MASK)) | LAPIC_SPIV_ENABLE);
139 	lapic_write(LAPIC_LVT0, (lapic_read(LAPIC_LVT0) &
140 		    ~(LAPIC_LVT_MASKED | LAPIC_LVT_LEVEL_TRIGGER |
141 		    LAPIC_LVT_REMOTE_IRR | LAPIC_INPUT_POLARITY |
142 		    LAPIC_SEND_PENDING | LAPIC_LVT_RESERVED_1 |
143 		    LAPIC_DELIVERY_MODE_MASK)) |
144 		    (LAPIC_LVT_REMOTE_IRR | LAPIC_SEND_PENDING |
145 		    LAPIC_DELIVERY_MODE_EXTINT));
146 	lapic_write(LAPIC_LVT1, (lapic_read(LAPIC_LVT1) &
147 		    ~(LAPIC_LVT_MASKED | LAPIC_LVT_LEVEL_TRIGGER |
148 		    LAPIC_LVT_REMOTE_IRR | LAPIC_INPUT_POLARITY |
149 		    LAPIC_SEND_PENDING | LAPIC_LVT_RESERVED_1 |
150 		    LAPIC_DELIVERY_MODE_MASK)) |
151 		    (LAPIC_LVT_REMOTE_IRR | LAPIC_SEND_PENDING |
152 		    LAPIC_DELIVERY_MODE_NMI));
153 
154 	debug("apic_id: 0x%02lx, ", lapicid());
155 
156 	debug("done.\n");
157 	post_code(POST_LAPIC);
158 }
159