aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-exynos/platsmp.c
blob: 1c8d31e39520005f697974acb4b6cb021384a9b2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
/* linux/arch/arm/mach-exynos4/platsmp.c
 *
 * Copyright (c) 2010-2011 Samsung Electronics Co., Ltd.
 *		http://www.samsung.com
 *
 * Cloned from linux/arch/arm/mach-vexpress/platsmp.c
 *
 *  Copyright (C) 2002 ARM Ltd.
 *  All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
*/

#include <linux/init.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/jiffies.h>
#include <linux/smp.h>
#include <linux/io.h>
#include <linux/of_address.h>

#include <asm/cacheflush.h>
#include <asm/smp_plat.h>
#include <asm/smp_scu.h>
#include <asm/firmware.h>

#include "common.h"
#include "regs-pmu.h"

extern void exynos4_secondary_startup(void);

static inline void __iomem *cpu_boot_reg_base(void)
{
	if (soc_is_exynos4210() && samsung_rev() == EXYNOS4210_REV_1_1)
		return S5P_INFORM5;
	return sysram_base_addr;
}

static inline void __iomem *cpu_boot_reg(int cpu)
{
	void __iomem *boot_reg;

	boot_reg = cpu_boot_reg_base();
	if (!boot_reg)
		return ERR_PTR(-ENODEV);
	if (soc_is_exynos4412())
		boot_reg += 4*cpu;
	else if (soc_is_exynos5420() || soc_is_exynos5800())
		boot_reg += 4;
	return boot_reg;
}

/*
 * Write pen_release in a way that is guaranteed to be visible to all
 * observers, irrespective of whether they're taking part in coherency
 * or not.  This is necessary for the hotplug code to work reliably.
 */
static void write_pen_release(int val)
{
	pen_release = val;
	smp_wmb();
	sync_cache_w(&pen_release);
}

static void __iomem *scu_base_addr(void)
{
	return (void __iomem *)(S5P_VA_SCU);
}

static DEFINE_SPINLOCK(boot_lock);

static void exynos_secondary_init(unsigned int cpu)
{
	/*
	 * let the primary processor know we're out of the
	 * pen, then head off into the C entry point
	 */
	write_pen_release(-1);

	/*
	 * Synchronise with the boot thread.
	 */
	spin_lock(&boot_lock);
	spin_unlock(&boot_lock);
}

static int exynos_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
	unsigned long timeout;
	unsigned long phys_cpu = cpu_logical_map(cpu);
	int ret = -ENOSYS;

	/*
	 * Set synchronisation state between this boot processor
	 * and the secondary one
	 */
	spin_lock(&boot_lock);

	/*
	 * The secondary processor is waiting to be released from
	 * the holding pen - release it, then wait for it to flag
	 * that it has been released by resetting pen_release.
	 *
	 * Note that "pen_release" is the hardware CPU ID, whereas
	 * "cpu" is Linux's internal ID.
	 */
	write_pen_release(phys_cpu);

	if (!exynos_cpu_power_state(cpu)) {
		exynos_cpu_power_up(cpu);
		timeout = 10;

		/* wait max 10 ms until cpu1 is on */
		while (exynos_cpu_power_state(cpu) != S5P_CORE_LOCAL_PWR_EN) {
			if (timeout-- == 0)
				break;

			mdelay(1);
		}

		if (timeout == 0) {
			printk(KERN_ERR "cpu1 power enable failed");
			spin_unlock(&boot_lock);
			return -ETIMEDOUT;
		}
	}
	/*
	 * Send the secondary CPU a soft interrupt, thereby causing
	 * the boot monitor to read the system wide flags register,
	 * and branch to the address found there.
	 */

	timeout = jiffies + (1 * HZ);
	while (time_before(jiffies, timeout)) {
		unsigned long boot_addr;

		smp_rmb();

		boot_addr = virt_to_phys(exynos4_secondary_startup);

		/*
		 * Try to set boot address using firmware first
		 * and fall back to boot register if it fails.
		 */
		ret = call_firmware_op(set_cpu_boot_addr, phys_cpu, boot_addr);
		if (ret && ret != -ENOSYS)
			goto fail;
		if (ret == -ENOSYS) {
			void __iomem *boot_reg = cpu_boot_reg(phys_cpu);

			if (IS_ERR(boot_reg)) {
				ret = PTR_ERR(boot_reg);
				goto fail;
			}
			__raw_writel(boot_addr, cpu_boot_reg(phys_cpu));
		}

		call_firmware_op(cpu_boot, phys_cpu);

		arch_send_wakeup_ipi_mask(cpumask_of(cpu));

		if (pen_release == -1)
			break;

		udelay(10);
	}

	/*
	 * now the secondary core is starting up let it run its
	 * calibrations, then wait for it to finish
	 */
fail:
	spin_unlock(&boot_lock);

	return pen_release != -1 ? ret : 0;
}

/*
 * Initialise the CPU possible map early - this describes the CPUs
 * which may be present or become present in the system.
 */

static void __init exynos_smp_init_cpus(void)
{
	void __iomem *scu_base = scu_base_addr();
	unsigned int i, ncores;

	if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
		ncores = scu_base ? scu_get_core_count(scu_base) : 1;
	else
		/*
		 * CPU Nodes are passed thru DT and set_cpu_possible
		 * is set by "arm_dt_init_cpu_maps".
		 */
		return;

	/* sanity check */
	if (ncores > nr_cpu_ids) {
		pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
			ncores, nr_cpu_ids);
		ncores = nr_cpu_ids;
	}

	for (i = 0; i < ncores; i++)
		set_cpu_possible(i, true);
}

static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
{
	int i;

	exynos_sysram_init();

	if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
		scu_enable(scu_base_addr());

	/*
	 * Write the address of secondary startup into the
	 * system-wide flags register. The boot monitor waits
	 * until it receives a soft interrupt, and then the
	 * secondary CPU branches to this address.
	 *
	 * Try using firmware operation first and fall back to
	 * boot register if it fails.
	 */
	for (i = 1; i < max_cpus; ++i) {
		unsigned long phys_cpu;
		unsigned long boot_addr;
		int ret;

		phys_cpu = cpu_logical_map(i);
		boot_addr = virt_to_phys(exynos4_secondary_startup);

		ret = call_firmware_op(set_cpu_boot_addr, phys_cpu, boot_addr);
		if (ret && ret != -ENOSYS)
			break;
		if (ret == -ENOSYS) {
			void __iomem *boot_reg = cpu_boot_reg(phys_cpu);

			if (IS_ERR(boot_reg))
				break;
			__raw_writel(boot_addr, cpu_boot_reg(phys_cpu));
		}
	}
}

struct smp_operations exynos_smp_ops __initdata = {
	.smp_init_cpus		= exynos_smp_init_cpus,
	.smp_prepare_cpus	= exynos_smp_prepare_cpus,
	.smp_secondary_init	= exynos_secondary_init,
	.smp_boot_secondary	= exynos_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
	.cpu_die		= exynos_cpu_die,
#endif
};