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5e89c55e LP |
1 | /* |
2 | * ARM64 ACPI Parking Protocol implementation | |
3 | * | |
4 | * Authors: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | |
5 | * Mark Salter <msalter@redhat.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | #include <linux/acpi.h> | |
20 | #include <linux/types.h> | |
21 | ||
22 | #include <asm/cpu_ops.h> | |
23 | ||
c1e4659b LP |
24 | struct parking_protocol_mailbox { |
25 | __le32 cpu_id; | |
26 | __le32 reserved; | |
27 | __le64 entry_point; | |
28 | }; | |
29 | ||
5e89c55e | 30 | struct cpu_mailbox_entry { |
c1e4659b | 31 | struct parking_protocol_mailbox __iomem *mailbox; |
5e89c55e LP |
32 | phys_addr_t mailbox_addr; |
33 | u8 version; | |
34 | u8 gic_cpu_id; | |
35 | }; | |
36 | ||
37 | static struct cpu_mailbox_entry cpu_mailbox_entries[NR_CPUS]; | |
38 | ||
39 | void __init acpi_set_mailbox_entry(int cpu, | |
40 | struct acpi_madt_generic_interrupt *p) | |
41 | { | |
42 | struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu]; | |
43 | ||
44 | cpu_entry->mailbox_addr = p->parked_address; | |
45 | cpu_entry->version = p->parking_version; | |
46 | cpu_entry->gic_cpu_id = p->cpu_interface_number; | |
47 | } | |
48 | ||
49 | bool acpi_parking_protocol_valid(int cpu) | |
50 | { | |
51 | struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu]; | |
52 | ||
53 | return cpu_entry->mailbox_addr && cpu_entry->version; | |
54 | } | |
55 | ||
56 | static int acpi_parking_protocol_cpu_init(unsigned int cpu) | |
57 | { | |
58 | pr_debug("%s: ACPI parked addr=%llx\n", __func__, | |
59 | cpu_mailbox_entries[cpu].mailbox_addr); | |
60 | ||
61 | return 0; | |
62 | } | |
63 | ||
64 | static int acpi_parking_protocol_cpu_prepare(unsigned int cpu) | |
65 | { | |
66 | return 0; | |
67 | } | |
68 | ||
5e89c55e LP |
69 | static int acpi_parking_protocol_cpu_boot(unsigned int cpu) |
70 | { | |
71 | struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu]; | |
72 | struct parking_protocol_mailbox __iomem *mailbox; | |
73 | __le32 cpu_id; | |
74 | ||
75 | /* | |
76 | * Map mailbox memory with attribute device nGnRE (ie ioremap - | |
77 | * this deviates from the parking protocol specifications since | |
78 | * the mailboxes are required to be mapped nGnRnE; the attribute | |
79 | * discrepancy is harmless insofar as the protocol specification | |
80 | * is concerned). | |
81 | * If the mailbox is mistakenly allocated in the linear mapping | |
82 | * by FW ioremap will fail since the mapping will be prevented | |
83 | * by the kernel (it clashes with the linear mapping attributes | |
84 | * specifications). | |
85 | */ | |
86 | mailbox = ioremap(cpu_entry->mailbox_addr, sizeof(*mailbox)); | |
87 | if (!mailbox) | |
88 | return -EIO; | |
89 | ||
90 | cpu_id = readl_relaxed(&mailbox->cpu_id); | |
91 | /* | |
92 | * Check if firmware has set-up the mailbox entry properly | |
93 | * before kickstarting the respective cpu. | |
94 | */ | |
95 | if (cpu_id != ~0U) { | |
96 | iounmap(mailbox); | |
97 | return -ENXIO; | |
98 | } | |
99 | ||
c1e4659b LP |
100 | /* |
101 | * stash the mailbox address mapping to use it for further FW | |
102 | * checks in the postboot method | |
103 | */ | |
104 | cpu_entry->mailbox = mailbox; | |
105 | ||
5e89c55e LP |
106 | /* |
107 | * We write the entry point and cpu id as LE regardless of the | |
108 | * native endianness of the kernel. Therefore, any boot-loaders | |
109 | * that read this address need to convert this address to the | |
110 | * Boot-Loader's endianness before jumping. | |
111 | */ | |
112 | writeq_relaxed(__pa(secondary_entry), &mailbox->entry_point); | |
113 | writel_relaxed(cpu_entry->gic_cpu_id, &mailbox->cpu_id); | |
114 | ||
115 | arch_send_wakeup_ipi_mask(cpumask_of(cpu)); | |
116 | ||
5e89c55e LP |
117 | return 0; |
118 | } | |
119 | ||
120 | static void acpi_parking_protocol_cpu_postboot(void) | |
121 | { | |
122 | int cpu = smp_processor_id(); | |
123 | struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu]; | |
c1e4659b | 124 | struct parking_protocol_mailbox __iomem *mailbox = cpu_entry->mailbox; |
5e89c55e LP |
125 | __le64 entry_point; |
126 | ||
5e89c55e LP |
127 | entry_point = readl_relaxed(&mailbox->entry_point); |
128 | /* | |
129 | * Check if firmware has cleared the entry_point as expected | |
130 | * by the protocol specification. | |
131 | */ | |
132 | WARN_ON(entry_point); | |
5e89c55e LP |
133 | } |
134 | ||
135 | const struct cpu_operations acpi_parking_protocol_ops = { | |
136 | .name = "parking-protocol", | |
137 | .cpu_init = acpi_parking_protocol_cpu_init, | |
138 | .cpu_prepare = acpi_parking_protocol_cpu_prepare, | |
139 | .cpu_boot = acpi_parking_protocol_cpu_boot, | |
140 | .cpu_postboot = acpi_parking_protocol_cpu_postboot | |
141 | }; |