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/mm.h>
21 #include <linux/types.h>
22
23 #include <asm/cpu_ops.h>
24
25 struct parking_protocol_mailbox {
26 __le32 cpu_id;
27 __le32 reserved;
28 __le64 entry_point;
29 };
30
31 struct cpu_mailbox_entry {
32 struct parking_protocol_mailbox __iomem *mailbox;
33 phys_addr_t mailbox_addr;
34 u8 version;
35 u8 gic_cpu_id;
36 };
37
38 static struct cpu_mailbox_entry cpu_mailbox_entries[NR_CPUS];
39
acpi_set_mailbox_entry(int cpu,struct acpi_madt_generic_interrupt * p)40 void __init acpi_set_mailbox_entry(int cpu,
41 struct acpi_madt_generic_interrupt *p)
42 {
43 struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu];
44
45 cpu_entry->mailbox_addr = p->parked_address;
46 cpu_entry->version = p->parking_version;
47 cpu_entry->gic_cpu_id = p->cpu_interface_number;
48 }
49
acpi_parking_protocol_valid(int cpu)50 bool acpi_parking_protocol_valid(int cpu)
51 {
52 struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu];
53
54 return cpu_entry->mailbox_addr && cpu_entry->version;
55 }
56
acpi_parking_protocol_cpu_init(unsigned int cpu)57 static int acpi_parking_protocol_cpu_init(unsigned int cpu)
58 {
59 pr_debug("%s: ACPI parked addr=%llx\n", __func__,
60 cpu_mailbox_entries[cpu].mailbox_addr);
61
62 return 0;
63 }
64
acpi_parking_protocol_cpu_prepare(unsigned int cpu)65 static int acpi_parking_protocol_cpu_prepare(unsigned int cpu)
66 {
67 return 0;
68 }
69
acpi_parking_protocol_cpu_boot(unsigned int cpu)70 static int acpi_parking_protocol_cpu_boot(unsigned int cpu)
71 {
72 struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu];
73 struct parking_protocol_mailbox __iomem *mailbox;
74 u32 cpu_id;
75
76 /*
77 * Map mailbox memory with attribute device nGnRE (ie ioremap -
78 * this deviates from the parking protocol specifications since
79 * the mailboxes are required to be mapped nGnRnE; the attribute
80 * discrepancy is harmless insofar as the protocol specification
81 * is concerned).
82 * If the mailbox is mistakenly allocated in the linear mapping
83 * by FW ioremap will fail since the mapping will be prevented
84 * by the kernel (it clashes with the linear mapping attributes
85 * specifications).
86 */
87 mailbox = ioremap(cpu_entry->mailbox_addr, sizeof(*mailbox));
88 if (!mailbox)
89 return -EIO;
90
91 cpu_id = readl_relaxed(&mailbox->cpu_id);
92 /*
93 * Check if firmware has set-up the mailbox entry properly
94 * before kickstarting the respective cpu.
95 */
96 if (cpu_id != ~0U) {
97 iounmap(mailbox);
98 return -ENXIO;
99 }
100
101 /*
102 * stash the mailbox address mapping to use it for further FW
103 * checks in the postboot method
104 */
105 cpu_entry->mailbox = mailbox;
106
107 /*
108 * We write the entry point and cpu id as LE regardless of the
109 * native endianness of the kernel. Therefore, any boot-loaders
110 * that read this address need to convert this address to the
111 * Boot-Loader's endianness before jumping.
112 */
113 writeq_relaxed(__pa_symbol(secondary_entry), &mailbox->entry_point);
114 writel_relaxed(cpu_entry->gic_cpu_id, &mailbox->cpu_id);
115
116 arch_send_wakeup_ipi_mask(cpumask_of(cpu));
117
118 return 0;
119 }
120
acpi_parking_protocol_cpu_postboot(void)121 static void acpi_parking_protocol_cpu_postboot(void)
122 {
123 int cpu = smp_processor_id();
124 struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu];
125 struct parking_protocol_mailbox __iomem *mailbox = cpu_entry->mailbox;
126 u64 entry_point;
127
128 entry_point = readq_relaxed(&mailbox->entry_point);
129 /*
130 * Check if firmware has cleared the entry_point as expected
131 * by the protocol specification.
132 */
133 WARN_ON(entry_point);
134 }
135
136 const struct cpu_operations acpi_parking_protocol_ops = {
137 .name = "parking-protocol",
138 .cpu_init = acpi_parking_protocol_cpu_init,
139 .cpu_prepare = acpi_parking_protocol_cpu_prepare,
140 .cpu_boot = acpi_parking_protocol_cpu_boot,
141 .cpu_postboot = acpi_parking_protocol_cpu_postboot
142 };
143
