1 /*
2 * Symmetric Multi Processing (SMP) support for Marvell EBU Cortex-A9
3 * based SOCs (Armada 375/38x).
4 *
5 * Copyright (C) 2014 Marvell
6 *
7 * Gregory CLEMENT <gregory.clement@free-electrons.com>
8 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
9 *
10 * This file is licensed under the terms of the GNU General Public
11 * License version 2. This program is licensed "as is" without any
12 * warranty of any kind, whether express or implied.
13 */
14
15 #include <linux/init.h>
16 #include <linux/io.h>
17 #include <linux/of.h>
18 #include <linux/smp.h>
19 #include <linux/mbus.h>
20 #include <asm/smp_scu.h>
21 #include <asm/smp_plat.h>
22 #include "common.h"
23 #include "pmsu.h"
24
25 extern void mvebu_cortex_a9_secondary_startup(void);
26
mvebu_cortex_a9_boot_secondary(unsigned int cpu,struct task_struct * idle)27 static int mvebu_cortex_a9_boot_secondary(unsigned int cpu,
28 struct task_struct *idle)
29 {
30 int ret, hw_cpu;
31
32 pr_info("Booting CPU %d\n", cpu);
33
34 /*
35 * Write the address of secondary startup into the system-wide
36 * flags register. The boot monitor waits until it receives a
37 * soft interrupt, and then the secondary CPU branches to this
38 * address.
39 */
40 hw_cpu = cpu_logical_map(cpu);
41 if (of_machine_is_compatible("marvell,armada375"))
42 mvebu_system_controller_set_cpu_boot_addr(mvebu_cortex_a9_secondary_startup);
43 else
44 mvebu_pmsu_set_cpu_boot_addr(hw_cpu, mvebu_cortex_a9_secondary_startup);
45 smp_wmb();
46
47 /*
48 * Doing this before deasserting the CPUs is needed to wake up CPUs
49 * in the offline state after using CPU hotplug.
50 */
51 arch_send_wakeup_ipi_mask(cpumask_of(cpu));
52
53 ret = mvebu_cpu_reset_deassert(hw_cpu);
54 if (ret) {
55 pr_err("Could not start the secondary CPU: %d\n", ret);
56 return ret;
57 }
58
59 return 0;
60 }
61 /*
62 * When a CPU is brought back online, either through CPU hotplug, or
63 * because of the boot of a kexec'ed kernel, the PMSU configuration
64 * for this CPU might be in the deep idle state, preventing this CPU
65 * from receiving interrupts. Here, we therefore take out the current
66 * CPU from this state, which was entered by armada_38x_cpu_die()
67 * below.
68 */
armada_38x_secondary_init(unsigned int cpu)69 static void armada_38x_secondary_init(unsigned int cpu)
70 {
71 mvebu_v7_pmsu_idle_exit();
72 }
73
74 #ifdef CONFIG_HOTPLUG_CPU
armada_38x_cpu_die(unsigned int cpu)75 static void armada_38x_cpu_die(unsigned int cpu)
76 {
77 /*
78 * CPU hotplug is implemented by putting offline CPUs into the
79 * deep idle sleep state.
80 */
81 armada_38x_do_cpu_suspend(true);
82 }
83
84 /*
85 * We need a dummy function, so that platform_can_cpu_hotplug() knows
86 * we support CPU hotplug. However, the function does not need to do
87 * anything, because CPUs going offline can enter the deep idle state
88 * by themselves, without any help from a still alive CPU.
89 */
armada_38x_cpu_kill(unsigned int cpu)90 static int armada_38x_cpu_kill(unsigned int cpu)
91 {
92 return 1;
93 }
94 #endif
95
96 static const struct smp_operations mvebu_cortex_a9_smp_ops __initconst = {
97 .smp_boot_secondary = mvebu_cortex_a9_boot_secondary,
98 };
99
100 static const struct smp_operations armada_38x_smp_ops __initconst = {
101 .smp_boot_secondary = mvebu_cortex_a9_boot_secondary,
102 .smp_secondary_init = armada_38x_secondary_init,
103 #ifdef CONFIG_HOTPLUG_CPU
104 .cpu_die = armada_38x_cpu_die,
105 .cpu_kill = armada_38x_cpu_kill,
106 #endif
107 };
108
109 CPU_METHOD_OF_DECLARE(mvebu_armada_375_smp, "marvell,armada-375-smp",
110 &mvebu_cortex_a9_smp_ops);
111 CPU_METHOD_OF_DECLARE(mvebu_armada_380_smp, "marvell,armada-380-smp",
112 &armada_38x_smp_ops);
113 CPU_METHOD_OF_DECLARE(mvebu_armada_390_smp, "marvell,armada-390-smp",
114 &armada_38x_smp_ops);
115