xref: /openbmc/linux/arch/arm/mach-actions/platsmp.c (revision 612a462a)
1 /*
2  * Actions Semi Leopard
3  *
4  * This file is based on arm realview smp platform.
5  *
6  * Copyright 2012 Actions Semi Inc.
7  * Author: Actions Semi, Inc.
8  *
9  * Copyright (c) 2017 Andreas Färber
10  *
11  * This program is free software; you can redistribute it and/or modify it
12  * under the terms of the GNU General Public License as published by the
13  * Free Software Foundation; either version 2 of the License, or (at your
14  * option) any later version.
15  */
16 
17 #include <linux/delay.h>
18 #include <linux/io.h>
19 #include <linux/of.h>
20 #include <linux/of_address.h>
21 #include <linux/smp.h>
22 #include <linux/soc/actions/owl-sps.h>
23 #include <asm/cacheflush.h>
24 #include <asm/smp_plat.h>
25 #include <asm/smp_scu.h>
26 
27 #define OWL_CPU1_ADDR	0x50
28 #define OWL_CPU1_FLAG	0x5c
29 
30 #define OWL_CPUx_FLAG_BOOT	0x55aa
31 
32 #define OWL_SPS_PG_CTL_PWR_CPU2	BIT(5)
33 #define OWL_SPS_PG_CTL_PWR_CPU3	BIT(6)
34 #define OWL_SPS_PG_CTL_ACK_CPU2	BIT(21)
35 #define OWL_SPS_PG_CTL_ACK_CPU3	BIT(22)
36 
37 static void __iomem *scu_base_addr;
38 static void __iomem *sps_base_addr;
39 static void __iomem *timer_base_addr;
40 static int ncores;
41 
42 static DEFINE_SPINLOCK(boot_lock);
43 
44 void owl_secondary_startup(void);
45 
46 static int s500_wakeup_secondary(unsigned int cpu)
47 {
48 	int ret;
49 
50 	if (cpu > 3)
51 		return -EINVAL;
52 
53 	/* The generic PM domain driver is not available this early. */
54 	switch (cpu) {
55 	case 2:
56 		ret = owl_sps_set_pg(sps_base_addr,
57 		                     OWL_SPS_PG_CTL_PWR_CPU2,
58 				     OWL_SPS_PG_CTL_ACK_CPU2, true);
59 		if (ret)
60 			return ret;
61 		break;
62 	case 3:
63 		ret = owl_sps_set_pg(sps_base_addr,
64 		                     OWL_SPS_PG_CTL_PWR_CPU3,
65 				     OWL_SPS_PG_CTL_ACK_CPU3, true);
66 		if (ret)
67 			return ret;
68 		break;
69 	}
70 
71 	/* wait for CPUx to run to WFE instruction */
72 	udelay(200);
73 
74 	writel(virt_to_phys(owl_secondary_startup),
75 	       timer_base_addr + OWL_CPU1_ADDR + (cpu - 1) * 4);
76 	writel(OWL_CPUx_FLAG_BOOT,
77 	       timer_base_addr + OWL_CPU1_FLAG + (cpu - 1) * 4);
78 
79 	dsb_sev();
80 	mb();
81 
82 	return 0;
83 }
84 
85 static int s500_smp_boot_secondary(unsigned int cpu, struct task_struct *idle)
86 {
87 	unsigned long timeout;
88 	int ret;
89 
90 	ret = s500_wakeup_secondary(cpu);
91 	if (ret)
92 		return ret;
93 
94 	udelay(10);
95 
96 	spin_lock(&boot_lock);
97 
98 	smp_send_reschedule(cpu);
99 
100 	timeout = jiffies + (1 * HZ);
101 	while (time_before(jiffies, timeout)) {
102 		if (pen_release == -1)
103 			break;
104 	}
105 
106 	writel(0, timer_base_addr + OWL_CPU1_ADDR + (cpu - 1) * 4);
107 	writel(0, timer_base_addr + OWL_CPU1_FLAG + (cpu - 1) * 4);
108 
109 	spin_unlock(&boot_lock);
110 
111 	return 0;
112 }
113 
114 static void __init s500_smp_prepare_cpus(unsigned int max_cpus)
115 {
116 	struct device_node *node;
117 
118 	node = of_find_compatible_node(NULL, NULL, "actions,s500-timer");
119 	if (!node) {
120 		pr_err("%s: missing timer\n", __func__);
121 		return;
122 	}
123 
124 	timer_base_addr = of_iomap(node, 0);
125 	if (!timer_base_addr) {
126 		pr_err("%s: could not map timer registers\n", __func__);
127 		return;
128 	}
129 
130 	node = of_find_compatible_node(NULL, NULL, "actions,s500-sps");
131 	if (!node) {
132 		pr_err("%s: missing sps\n", __func__);
133 		return;
134 	}
135 
136 	sps_base_addr = of_iomap(node, 0);
137 	if (!sps_base_addr) {
138 		pr_err("%s: could not map sps registers\n", __func__);
139 		return;
140 	}
141 
142 	if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9) {
143 		node = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
144 		if (!node) {
145 			pr_err("%s: missing scu\n", __func__);
146 			return;
147 		}
148 
149 		scu_base_addr = of_iomap(node, 0);
150 		if (!scu_base_addr) {
151 			pr_err("%s: could not map scu registers\n", __func__);
152 			return;
153 		}
154 
155 		/*
156 		 * While the number of cpus is gathered from dt, also get the
157 		 * number of cores from the scu to verify this value when
158 		 * booting the cores.
159 		 */
160 		ncores = scu_get_core_count(scu_base_addr);
161 		pr_debug("%s: ncores %d\n", __func__, ncores);
162 
163 		scu_enable(scu_base_addr);
164 	}
165 }
166 
167 static const struct smp_operations s500_smp_ops __initconst = {
168 	.smp_prepare_cpus = s500_smp_prepare_cpus,
169 	.smp_boot_secondary = s500_smp_boot_secondary,
170 };
171 CPU_METHOD_OF_DECLARE(s500_smp, "actions,s500-smp", &s500_smp_ops);
172