1/*
2 * NOOP APIC driver.
3 *
4 * Does almost nothing and should be substituted by a real apic driver via
5 * probe routine.
6 *
7 * Though in case if apic is disabled (for some reason) we try
8 * to not uglify the caller's code and allow to call (some) apic routines
9 * like self-ipi, etc...
10 */
11
12#include <linux/threads.h>
13#include <linux/cpumask.h>
14#include <linux/module.h>
15#include <linux/string.h>
16#include <linux/kernel.h>
17#include <linux/ctype.h>
18#include <linux/errno.h>
19#include <asm/fixmap.h>
20#include <asm/mpspec.h>
21#include <asm/apicdef.h>
22#include <asm/apic.h>
23#include <asm/setup.h>
24
25#include <linux/smp.h>
26#include <asm/ipi.h>
27
28#include <linux/interrupt.h>
29#include <asm/acpi.h>
30#include <asm/e820.h>
31
32static void noop_init_apic_ldr(void) { }
33static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
34static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
35static void noop_send_IPI_allbutself(int vector) { }
36static void noop_send_IPI_all(int vector) { }
37static void noop_send_IPI_self(int vector) { }
38static void noop_apic_wait_icr_idle(void) { }
39static void noop_apic_icr_write(u32 low, u32 id) { }
40
41static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
42{
43	return -1;
44}
45
46static u32 noop_safe_apic_wait_icr_idle(void)
47{
48	return 0;
49}
50
51static u64 noop_apic_icr_read(void)
52{
53	return 0;
54}
55
56static int noop_phys_pkg_id(int cpuid_apic, int index_msb)
57{
58	return 0;
59}
60
61static unsigned int noop_get_apic_id(unsigned long x)
62{
63	return 0;
64}
65
66static int noop_probe(void)
67{
68	/*
69	 * NOOP apic should not ever be
70	 * enabled via probe routine
71	 */
72	return 0;
73}
74
75static int noop_apic_id_registered(void)
76{
77	/*
78	 * if we would be really "pedantic"
79	 * we should pass read_apic_id() here
80	 * but since NOOP suppose APIC ID = 0
81	 * lets save a few cycles
82	 */
83	return physid_isset(0, phys_cpu_present_map);
84}
85
86static const struct cpumask *noop_target_cpus(void)
87{
88	/* only BSP here */
89	return cpumask_of(0);
90}
91
92static void noop_vector_allocation_domain(int cpu, struct cpumask *retmask,
93					  const struct cpumask *mask)
94{
95	if (cpu != 0)
96		pr_warning("APIC: Vector allocated for non-BSP cpu\n");
97	cpumask_copy(retmask, cpumask_of(cpu));
98}
99
100static u32 noop_apic_read(u32 reg)
101{
102	WARN_ON_ONCE((cpu_has_apic && !disable_apic));
103	return 0;
104}
105
106static void noop_apic_write(u32 reg, u32 v)
107{
108	WARN_ON_ONCE(cpu_has_apic && !disable_apic);
109}
110
111struct apic apic_noop = {
112	.name				= "noop",
113	.probe				= noop_probe,
114	.acpi_madt_oem_check		= NULL,
115
116	.apic_id_valid			= default_apic_id_valid,
117	.apic_id_registered		= noop_apic_id_registered,
118
119	.irq_delivery_mode		= dest_LowestPrio,
120	/* logical delivery broadcast to all CPUs: */
121	.irq_dest_mode			= 1,
122
123	.target_cpus			= noop_target_cpus,
124	.disable_esr			= 0,
125	.dest_logical			= APIC_DEST_LOGICAL,
126	.check_apicid_used		= default_check_apicid_used,
127
128	.vector_allocation_domain	= noop_vector_allocation_domain,
129	.init_apic_ldr			= noop_init_apic_ldr,
130
131	.ioapic_phys_id_map		= default_ioapic_phys_id_map,
132	.setup_apic_routing		= NULL,
133
134	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
135	.apicid_to_cpu_present		= physid_set_mask_of_physid,
136
137	.check_phys_apicid_present	= default_check_phys_apicid_present,
138
139	.phys_pkg_id			= noop_phys_pkg_id,
140
141	.get_apic_id			= noop_get_apic_id,
142	.set_apic_id			= NULL,
143	.apic_id_mask			= 0x0F << 24,
144
145	.cpu_mask_to_apicid_and		= flat_cpu_mask_to_apicid_and,
146
147	.send_IPI_mask			= noop_send_IPI_mask,
148	.send_IPI_mask_allbutself	= noop_send_IPI_mask_allbutself,
149	.send_IPI_allbutself		= noop_send_IPI_allbutself,
150	.send_IPI_all			= noop_send_IPI_all,
151	.send_IPI_self			= noop_send_IPI_self,
152
153	.wakeup_secondary_cpu		= noop_wakeup_secondary_cpu,
154
155	.inquire_remote_apic		= NULL,
156
157	.read				= noop_apic_read,
158	.write				= noop_apic_write,
159	.eoi_write			= noop_apic_write,
160	.icr_read			= noop_apic_icr_read,
161	.icr_write			= noop_apic_icr_write,
162	.wait_icr_idle			= noop_apic_wait_icr_idle,
163	.safe_wait_icr_idle		= noop_safe_apic_wait_icr_idle,
164
165#ifdef CONFIG_X86_32
166	.x86_32_early_logical_apicid	= noop_x86_32_early_logical_apicid,
167#endif
168};
169