1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Copyright (C) 2002 ARM Ltd.
4  *  All Rights Reserved
5  */
6 #include <linux/init.h>
7 #include <linux/errno.h>
8 #include <linux/smp.h>
9 #include <linux/io.h>
10 #include <linux/of_address.h>
11 #include <linux/vexpress.h>
12 
13 #include <asm/mcpm.h>
14 #include <asm/smp_scu.h>
15 #include <asm/mach/map.h>
16 
17 #include "platsmp.h"
18 #include "vexpress.h"
19 
vexpress_smp_init_ops(void)20 bool __init vexpress_smp_init_ops(void)
21 {
22 #ifdef CONFIG_MCPM
23 	int cpu;
24 	struct device_node *cpu_node, *cci_node;
25 
26 	/*
27 	 * The best way to detect a multi-cluster configuration
28 	 * is to detect if the kernel can take over CCI ports
29 	 * control. Loop over possible CPUs and check if CCI
30 	 * port control is available.
31 	 * Override the default vexpress_smp_ops if so.
32 	 */
33 	for_each_possible_cpu(cpu) {
34 		bool available;
35 
36 		cpu_node = of_get_cpu_node(cpu, NULL);
37 		if (WARN(!cpu_node, "Missing cpu device node!"))
38 			return false;
39 
40 		cci_node = of_parse_phandle(cpu_node, "cci-control-port", 0);
41 		available = cci_node && of_device_is_available(cci_node);
42 		of_node_put(cci_node);
43 		of_node_put(cpu_node);
44 
45 		if (!available)
46 			return false;
47 	}
48 
49 	mcpm_smp_set_ops();
50 	return true;
51 #else
52 	return false;
53 #endif
54 }
55 
56 static const struct of_device_id vexpress_smp_dt_scu_match[] __initconst = {
57 	{ .compatible = "arm,cortex-a5-scu", },
58 	{ .compatible = "arm,cortex-a9-scu", },
59 	{}
60 };
61 
vexpress_smp_dt_prepare_cpus(unsigned int max_cpus)62 static void __init vexpress_smp_dt_prepare_cpus(unsigned int max_cpus)
63 {
64 	struct device_node *scu = of_find_matching_node(NULL,
65 			vexpress_smp_dt_scu_match);
66 
67 	if (scu)
68 		scu_enable(of_iomap(scu, 0));
69 
70 	/*
71 	 * Write the address of secondary startup into the
72 	 * system-wide flags register. The boot monitor waits
73 	 * until it receives a soft interrupt, and then the
74 	 * secondary CPU branches to this address.
75 	 */
76 	vexpress_flags_set(__pa_symbol(versatile_secondary_startup));
77 }
78 
79 #ifdef CONFIG_HOTPLUG_CPU
vexpress_cpu_die(unsigned int cpu)80 static void vexpress_cpu_die(unsigned int cpu)
81 {
82 	versatile_immitation_cpu_die(cpu, 0x40);
83 }
84 #endif
85 
86 const struct smp_operations vexpress_smp_dt_ops __initconst = {
87 	.smp_prepare_cpus	= vexpress_smp_dt_prepare_cpus,
88 	.smp_secondary_init	= versatile_secondary_init,
89 	.smp_boot_secondary	= versatile_boot_secondary,
90 #ifdef CONFIG_HOTPLUG_CPU
91 	.cpu_die		= vexpress_cpu_die,
92 #endif
93 };
94