1/*
2 * linux/arch/arm/mach-axxia/platsmp.c
3 *
4 * Copyright (C) 2012 LSI Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/init.h>
12#include <linux/io.h>
13#include <linux/smp.h>
14#include <linux/of.h>
15#include <linux/of_address.h>
16#include <asm/cacheflush.h>
17
18/* Syscon register offsets for releasing cores from reset */
19#define SC_CRIT_WRITE_KEY	0x1000
20#define SC_RST_CPU_HOLD		0x1010
21
22/*
23 * Write the kernel entry point for secondary CPUs to the specified address
24 */
25static void write_release_addr(u32 release_phys)
26{
27	u32 *virt = (u32 *) phys_to_virt(release_phys);
28	writel_relaxed(virt_to_phys(secondary_startup), virt);
29	/* Make sure this store is visible to other CPUs */
30	smp_wmb();
31	__cpuc_flush_dcache_area(virt, sizeof(u32));
32}
33
34static int axxia_boot_secondary(unsigned int cpu, struct task_struct *idle)
35{
36	struct device_node *syscon_np;
37	void __iomem *syscon;
38	u32 tmp;
39
40	syscon_np = of_find_compatible_node(NULL, NULL, "lsi,axxia-syscon");
41	if (!syscon_np)
42		return -ENOENT;
43
44	syscon = of_iomap(syscon_np, 0);
45	if (!syscon)
46		return -ENOMEM;
47
48	tmp = readl(syscon + SC_RST_CPU_HOLD);
49	writel(0xab, syscon + SC_CRIT_WRITE_KEY);
50	tmp &= ~(1 << cpu);
51	writel(tmp, syscon + SC_RST_CPU_HOLD);
52
53	return 0;
54}
55
56static void __init axxia_smp_prepare_cpus(unsigned int max_cpus)
57{
58	int cpu_count = 0;
59	int cpu;
60
61	/*
62	 * Initialise the present map, which describes the set of CPUs actually
63	 * populated at the present time.
64	 */
65	for_each_possible_cpu(cpu) {
66		struct device_node *np;
67		u32 release_phys;
68
69		np = of_get_cpu_node(cpu, NULL);
70		if (!np)
71			continue;
72		if (of_property_read_u32(np, "cpu-release-addr", &release_phys))
73			continue;
74
75		if (cpu_count < max_cpus) {
76			set_cpu_present(cpu, true);
77			cpu_count++;
78		}
79
80		if (release_phys != 0)
81			write_release_addr(release_phys);
82	}
83}
84
85static struct smp_operations axxia_smp_ops __initdata = {
86	.smp_prepare_cpus	= axxia_smp_prepare_cpus,
87	.smp_boot_secondary	= axxia_boot_secondary,
88};
89CPU_METHOD_OF_DECLARE(axxia_smp, "lsi,syscon-release", &axxia_smp_ops);
90