1 /*
2  * SMP support for SoCs with APMU
3  *
4  * Copyright (C) 2014  Renesas Electronics Corporation
5  * Copyright (C) 2013  Magnus Damm
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 #include <linux/cpu_pm.h>
12 #include <linux/delay.h>
13 #include <linux/init.h>
14 #include <linux/io.h>
15 #include <linux/ioport.h>
16 #include <linux/of_address.h>
17 #include <linux/smp.h>
18 #include <linux/suspend.h>
19 #include <linux/threads.h>
20 #include <asm/cacheflush.h>
21 #include <asm/cp15.h>
22 #include <asm/proc-fns.h>
23 #include <asm/smp_plat.h>
24 #include <asm/suspend.h>
25 #include "common.h"
26 #include "platsmp-apmu.h"
27 
28 static struct {
29 	void __iomem *iomem;
30 	int bit;
31 } apmu_cpus[NR_CPUS];
32 
33 #define WUPCR_OFFS 0x10
34 #define PSTR_OFFS 0x40
35 #define CPUNCR_OFFS(n) (0x100 + (0x10 * (n)))
36 
37 static int __maybe_unused apmu_power_on(void __iomem *p, int bit)
38 {
39 	/* request power on */
40 	writel_relaxed(BIT(bit), p + WUPCR_OFFS);
41 
42 	/* wait for APMU to finish */
43 	while (readl_relaxed(p + WUPCR_OFFS) != 0)
44 		;
45 
46 	return 0;
47 }
48 
49 static int apmu_power_off(void __iomem *p, int bit)
50 {
51 	/* request Core Standby for next WFI */
52 	writel_relaxed(3, p + CPUNCR_OFFS(bit));
53 	return 0;
54 }
55 
56 static int __maybe_unused apmu_power_off_poll(void __iomem *p, int bit)
57 {
58 	int k;
59 
60 	for (k = 0; k < 1000; k++) {
61 		if (((readl_relaxed(p + PSTR_OFFS) >> (bit * 4)) & 0x03) == 3)
62 			return 1;
63 
64 		mdelay(1);
65 	}
66 
67 	return 0;
68 }
69 
70 static int apmu_wrap(int cpu, int (*fn)(void __iomem *p, int cpu))
71 {
72 	void __iomem *p = apmu_cpus[cpu].iomem;
73 
74 	return p ? fn(p, apmu_cpus[cpu].bit) : -EINVAL;
75 }
76 
77 static void apmu_init_cpu(struct resource *res, int cpu, int bit)
78 {
79 	if ((cpu >= ARRAY_SIZE(apmu_cpus)) || apmu_cpus[cpu].iomem)
80 		return;
81 
82 	apmu_cpus[cpu].iomem = ioremap_nocache(res->start, resource_size(res));
83 	apmu_cpus[cpu].bit = bit;
84 
85 	pr_debug("apmu ioremap %d %d %pr\n", cpu, bit, res);
86 }
87 
88 static void apmu_parse_cfg(void (*fn)(struct resource *res, int cpu, int bit),
89 			   struct rcar_apmu_config *apmu_config, int num)
90 {
91 	u32 id;
92 	int k;
93 	int bit, index;
94 	bool is_allowed;
95 
96 	for (k = 0; k < num; k++) {
97 		/* only enable the cluster that includes the boot CPU */
98 		is_allowed = false;
99 		for (bit = 0; bit < ARRAY_SIZE(apmu_config[k].cpus); bit++) {
100 			id = apmu_config[k].cpus[bit];
101 			if (id >= 0) {
102 				if (id == cpu_logical_map(0))
103 					is_allowed = true;
104 			}
105 		}
106 		if (!is_allowed)
107 			continue;
108 
109 		for (bit = 0; bit < ARRAY_SIZE(apmu_config[k].cpus); bit++) {
110 			id = apmu_config[k].cpus[bit];
111 			if (id >= 0) {
112 				index = get_logical_index(id);
113 				if (index >= 0)
114 					fn(&apmu_config[k].iomem, index, bit);
115 			}
116 		}
117 	}
118 }
119 
120 void __init shmobile_smp_apmu_prepare_cpus(unsigned int max_cpus,
121 					   struct rcar_apmu_config *apmu_config,
122 					   int num)
123 {
124 	/* install boot code shared by all CPUs */
125 	shmobile_boot_fn = virt_to_phys(shmobile_smp_boot);
126 	shmobile_boot_arg = MPIDR_HWID_BITMASK;
127 
128 	/* perform per-cpu setup */
129 	apmu_parse_cfg(apmu_init_cpu, apmu_config, num);
130 }
131 
132 #ifdef CONFIG_SMP
133 int shmobile_smp_apmu_boot_secondary(unsigned int cpu, struct task_struct *idle)
134 {
135 	/* For this particular CPU register boot vector */
136 	shmobile_smp_hook(cpu, virt_to_phys(secondary_startup), 0);
137 
138 	return apmu_wrap(cpu, apmu_power_on);
139 }
140 #endif
141 
142 #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_SUSPEND)
143 /* nicked from arch/arm/mach-exynos/hotplug.c */
144 static inline void cpu_enter_lowpower_a15(void)
145 {
146 	unsigned int v;
147 
148 	asm volatile(
149 	"       mrc     p15, 0, %0, c1, c0, 0\n"
150 	"       bic     %0, %0, %1\n"
151 	"       mcr     p15, 0, %0, c1, c0, 0\n"
152 		: "=&r" (v)
153 		: "Ir" (CR_C)
154 		: "cc");
155 
156 	flush_cache_louis();
157 
158 	asm volatile(
159 	/*
160 	 * Turn off coherency
161 	 */
162 	"       mrc     p15, 0, %0, c1, c0, 1\n"
163 	"       bic     %0, %0, %1\n"
164 	"       mcr     p15, 0, %0, c1, c0, 1\n"
165 		: "=&r" (v)
166 		: "Ir" (0x40)
167 		: "cc");
168 
169 	isb();
170 	dsb();
171 }
172 
173 void shmobile_smp_apmu_cpu_shutdown(unsigned int cpu)
174 {
175 
176 	/* Select next sleep mode using the APMU */
177 	apmu_wrap(cpu, apmu_power_off);
178 
179 	/* Do ARM specific CPU shutdown */
180 	cpu_enter_lowpower_a15();
181 }
182 
183 static inline void cpu_leave_lowpower(void)
184 {
185 	unsigned int v;
186 
187 	asm volatile("mrc    p15, 0, %0, c1, c0, 0\n"
188 		     "       orr     %0, %0, %1\n"
189 		     "       mcr     p15, 0, %0, c1, c0, 0\n"
190 		     "       mrc     p15, 0, %0, c1, c0, 1\n"
191 		     "       orr     %0, %0, %2\n"
192 		     "       mcr     p15, 0, %0, c1, c0, 1\n"
193 		     : "=&r" (v)
194 		     : "Ir" (CR_C), "Ir" (0x40)
195 		     : "cc");
196 }
197 #endif
198 
199 #if defined(CONFIG_HOTPLUG_CPU)
200 void shmobile_smp_apmu_cpu_die(unsigned int cpu)
201 {
202 	/* For this particular CPU deregister boot vector */
203 	shmobile_smp_hook(cpu, 0, 0);
204 
205 	/* Shutdown CPU core */
206 	shmobile_smp_apmu_cpu_shutdown(cpu);
207 
208 	/* jump to shared mach-shmobile sleep / reset code */
209 	shmobile_smp_sleep();
210 }
211 
212 int shmobile_smp_apmu_cpu_kill(unsigned int cpu)
213 {
214 	return apmu_wrap(cpu, apmu_power_off_poll);
215 }
216 #endif
217 
218 #if defined(CONFIG_SUSPEND)
219 static int shmobile_smp_apmu_do_suspend(unsigned long cpu)
220 {
221 	shmobile_smp_hook(cpu, virt_to_phys(cpu_resume), 0);
222 	shmobile_smp_apmu_cpu_shutdown(cpu);
223 	cpu_do_idle(); /* WFI selects Core Standby */
224 	return 1;
225 }
226 
227 static int shmobile_smp_apmu_enter_suspend(suspend_state_t state)
228 {
229 	cpu_suspend(smp_processor_id(), shmobile_smp_apmu_do_suspend);
230 	cpu_leave_lowpower();
231 	return 0;
232 }
233 
234 void __init shmobile_smp_apmu_suspend_init(void)
235 {
236 	shmobile_suspend_ops.enter = shmobile_smp_apmu_enter_suspend;
237 }
238 #endif
239