1/*
2 * Symmetric Multi Processing (SMP) support for Armada XP
3 *
4 * Copyright (C) 2012 Marvell
5 *
6 * Lior Amsalem <alior@marvell.com>
7 * Yehuda Yitschak <yehuday@marvell.com>
8 * Gregory CLEMENT <gregory.clement@free-electrons.com>
9 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
10 *
11 * This file is licensed under the terms of the GNU General Public
12 * License version 2.  This program is licensed "as is" without any
13 * warranty of any kind, whether express or implied.
14 *
15 * The Armada XP SoC has 4 ARMv7 PJ4B CPUs running in full HW coherency
16 * This file implements the routines for preparing the SMP infrastructure
17 * and waking up the secondary CPUs
18 */
19
20#include <linux/init.h>
21#include <linux/smp.h>
22#include <linux/clk.h>
23#include <linux/of.h>
24#include <linux/of_address.h>
25#include <linux/mbus.h>
26#include <asm/cacheflush.h>
27#include <asm/smp_plat.h>
28#include "common.h"
29#include "armada-370-xp.h"
30#include "pmsu.h"
31#include "coherency.h"
32
33#define ARMADA_XP_MAX_CPUS 4
34
35#define AXP_BOOTROM_BASE 0xfff00000
36#define AXP_BOOTROM_SIZE 0x100000
37
38static struct clk *get_cpu_clk(int cpu)
39{
40	struct clk *cpu_clk;
41	struct device_node *np = of_get_cpu_node(cpu, NULL);
42
43	if (WARN(!np, "missing cpu node\n"))
44		return NULL;
45	cpu_clk = of_clk_get(np, 0);
46	if (WARN_ON(IS_ERR(cpu_clk)))
47		return NULL;
48	return cpu_clk;
49}
50
51static void set_secondary_cpu_clock(unsigned int cpu)
52{
53	int thiscpu;
54	unsigned long rate;
55	struct clk *cpu_clk;
56
57	thiscpu = get_cpu();
58
59	cpu_clk = get_cpu_clk(thiscpu);
60	if (!cpu_clk)
61		goto out;
62	clk_prepare_enable(cpu_clk);
63	rate = clk_get_rate(cpu_clk);
64
65	cpu_clk = get_cpu_clk(cpu);
66	if (!cpu_clk)
67		goto out;
68	clk_set_rate(cpu_clk, rate);
69	clk_prepare_enable(cpu_clk);
70
71out:
72	put_cpu();
73}
74
75static int armada_xp_boot_secondary(unsigned int cpu, struct task_struct *idle)
76{
77	int ret, hw_cpu;
78
79	pr_info("Booting CPU %d\n", cpu);
80
81	hw_cpu = cpu_logical_map(cpu);
82	set_secondary_cpu_clock(hw_cpu);
83	mvebu_pmsu_set_cpu_boot_addr(hw_cpu, armada_xp_secondary_startup);
84
85	/*
86	 * This is needed to wake up CPUs in the offline state after
87	 * using CPU hotplug.
88	 */
89	arch_send_wakeup_ipi_mask(cpumask_of(cpu));
90
91	/*
92	 * This is needed to take secondary CPUs out of reset on the
93	 * initial boot.
94	 */
95	ret = mvebu_cpu_reset_deassert(hw_cpu);
96	if (ret) {
97		pr_warn("unable to boot CPU: %d\n", ret);
98		return ret;
99	}
100
101	return 0;
102}
103
104/*
105 * When a CPU is brought back online, either through CPU hotplug, or
106 * because of the boot of a kexec'ed kernel, the PMSU configuration
107 * for this CPU might be in the deep idle state, preventing this CPU
108 * from receiving interrupts. Here, we therefore take out the current
109 * CPU from this state, which was entered by armada_xp_cpu_die()
110 * below.
111 */
112static void armada_xp_secondary_init(unsigned int cpu)
113{
114	mvebu_v7_pmsu_idle_exit();
115}
116
117static void __init armada_xp_smp_init_cpus(void)
118{
119	unsigned int ncores = num_possible_cpus();
120
121	if (ncores == 0 || ncores > ARMADA_XP_MAX_CPUS)
122		panic("Invalid number of CPUs in DT\n");
123}
124
125static void __init armada_xp_smp_prepare_cpus(unsigned int max_cpus)
126{
127	struct device_node *node;
128	struct resource res;
129	int err;
130
131	flush_cache_all();
132	set_cpu_coherent();
133
134	/*
135	 * In order to boot the secondary CPUs we need to ensure
136	 * the bootROM is mapped at the correct address.
137	 */
138	node = of_find_compatible_node(NULL, NULL, "marvell,bootrom");
139	if (!node)
140		panic("Cannot find 'marvell,bootrom' compatible node");
141
142	err = of_address_to_resource(node, 0, &res);
143	if (err < 0)
144		panic("Cannot get 'bootrom' node address");
145
146	if (res.start != AXP_BOOTROM_BASE ||
147	    resource_size(&res) != AXP_BOOTROM_SIZE)
148		panic("The address for the BootROM is incorrect");
149}
150
151#ifdef CONFIG_HOTPLUG_CPU
152static void armada_xp_cpu_die(unsigned int cpu)
153{
154	/*
155	 * CPU hotplug is implemented by putting offline CPUs into the
156	 * deep idle sleep state.
157	 */
158	armada_370_xp_pmsu_idle_enter(true);
159}
160
161/*
162 * We need a dummy function, so that platform_can_cpu_hotplug() knows
163 * we support CPU hotplug. However, the function does not need to do
164 * anything, because CPUs going offline can enter the deep idle state
165 * by themselves, without any help from a still alive CPU.
166 */
167static int armada_xp_cpu_kill(unsigned int cpu)
168{
169	return 1;
170}
171#endif
172
173struct smp_operations armada_xp_smp_ops __initdata = {
174	.smp_init_cpus		= armada_xp_smp_init_cpus,
175	.smp_prepare_cpus	= armada_xp_smp_prepare_cpus,
176	.smp_boot_secondary	= armada_xp_boot_secondary,
177	.smp_secondary_init     = armada_xp_secondary_init,
178#ifdef CONFIG_HOTPLUG_CPU
179	.cpu_die		= armada_xp_cpu_die,
180	.cpu_kill               = armada_xp_cpu_kill,
181#endif
182};
183
184CPU_METHOD_OF_DECLARE(armada_xp_smp, "marvell,armada-xp-smp",
185		      &armada_xp_smp_ops);
186