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smp-emev2.c
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1 /*
2  * SMP support for Emma Mobile EV2
3  *
4  * Copyright (C) 2012 Renesas Solutions Corp.
5  * Copyright (C) 2012 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 as published by
9  * the Free Software Foundation; version 2 of the License.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 #include <linux/kernel.h>
21 #include <linux/init.h>
22 #include <linux/smp.h>
23 #include <linux/spinlock.h>
24 #include <linux/io.h>
25 #include <linux/delay.h>
26 #include <mach/common.h>
27 #include <mach/emev2.h>
28 #include <asm/smp_plat.h>
29 #include <asm/smp_scu.h>
30 #include <asm/hardware/gic.h>
31 #include <asm/cacheflush.h>
32 
33 #define EMEV2_SCU_BASE 0x1e000000
34 
35 static DEFINE_SPINLOCK(scu_lock);
36 static void __iomem *scu_base;
37 
38 static void modify_scu_cpu_psr(unsigned long set, unsigned long clr)
39 {
40  unsigned long tmp;
41 
42  /* we assume this code is running on a different cpu
43  * than the one that is changing coherency setting */
44  spin_lock(&scu_lock);
45  tmp = readl(scu_base + 8);
46  tmp &= ~clr;
47  tmp |= set;
48  writel(tmp, scu_base + 8);
49  spin_unlock(&scu_lock);
50 
51 }
52 
53 static unsigned int __init emev2_get_core_count(void)
54 {
55  if (!scu_base) {
56  scu_base = ioremap(EMEV2_SCU_BASE, PAGE_SIZE);
57  emev2_clock_init(); /* need ioremapped SMU */
58  }
59 
60  WARN_ON_ONCE(!scu_base);
61 
62  return scu_base ? scu_get_core_count(scu_base) : 1;
63 }
64 
65 static int emev2_platform_cpu_kill(unsigned int cpu)
66 {
67  return 0; /* not supported yet */
68 }
69 
70 static int __maybe_unused emev2_cpu_kill(unsigned int cpu)
71 {
72  int k;
73 
74  /* this function is running on another CPU than the offline target,
75  * here we need wait for shutdown code in platform_cpu_die() to
76  * finish before asking SoC-specific code to power off the CPU core.
77  */
78  for (k = 0; k < 1000; k++) {
79  if (shmobile_cpu_is_dead(cpu))
80  return emev2_platform_cpu_kill(cpu);
81  mdelay(1);
82  }
83 
84  return 0;
85 }
86 
87 
88 static void __cpuinit emev2_secondary_init(unsigned int cpu)
89 {
91 }
92 
93 static int __cpuinit emev2_boot_secondary(unsigned int cpu, struct task_struct *idle)
94 {
95  cpu = cpu_logical_map(cpu);
96 
97  /* enable cache coherency */
98  modify_scu_cpu_psr(0, 3 << (cpu * 8));
99 
100  /* Tell ROM loader about our vector (in headsmp.S) */
102 
103  gic_raise_softirq(cpumask_of(cpu), 0);
104  return 0;
105 }
106 
107 static void __init emev2_smp_prepare_cpus(unsigned int max_cpus)
108 {
109  int cpu = cpu_logical_map(0);
110 
111  scu_enable(scu_base);
112 
113  /* enable cache coherency on CPU0 */
114  modify_scu_cpu_psr(0, 3 << (cpu * 8));
115 }
116 
117 static void __init emev2_smp_init_cpus(void)
118 {
119  unsigned int ncores = emev2_get_core_count();
120 
121  shmobile_smp_init_cpus(ncores);
122 }
123 
125  .smp_init_cpus = emev2_smp_init_cpus,
126  .smp_prepare_cpus = emev2_smp_prepare_cpus,
127  .smp_secondary_init = emev2_secondary_init,
128  .smp_boot_secondary = emev2_boot_secondary,
129 #ifdef CONFIG_HOTPLUG_CPU
130  .cpu_kill = emev2_cpu_kill,
131  .cpu_die = shmobile_cpu_die,
132  .cpu_disable = shmobile_cpu_disable,
133 #endif
134 };