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Russell King862184f2005-11-07 21:05:42 +00001/*
2 * linux/arch/arm/mach-realview/platsmp.c
3 *
4 * Copyright (C) 2002 ARM Ltd.
5 * All Rights Reserved
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/init.h>
12#include <linux/errno.h>
13#include <linux/delay.h>
14#include <linux/device.h>
15#include <linux/smp.h>
16
17#include <asm/cacheflush.h>
18#include <asm/hardware/arm_scu.h>
19#include <asm/hardware.h>
Russell Kingce07d902005-11-16 14:38:19 +000020#include <asm/io.h>
Russell King862184f2005-11-07 21:05:42 +000021
22extern void realview_secondary_startup(void);
23
24/*
25 * control for which core is the next to come out of the secondary
26 * boot "holding pen"
27 */
28volatile int __cpuinitdata pen_release = -1;
29
30static unsigned int __init get_core_count(void)
31{
32 unsigned int ncores;
33
Russell King5d430452005-11-08 10:44:46 +000034 ncores = __raw_readl(__io_address(REALVIEW_MPCORE_SCU_BASE) + SCU_CONFIG);
Russell King862184f2005-11-07 21:05:42 +000035
36 return (ncores & 0x03) + 1;
37}
38
39static DEFINE_SPINLOCK(boot_lock);
40
41void __cpuinit platform_secondary_init(unsigned int cpu)
42{
43 /*
44 * the primary core may have used a "cross call" soft interrupt
45 * to get this processor out of WFI in the BootMonitor - make
46 * sure that we are no longer being sent this soft interrupt
47 */
48 smp_cross_call_done(cpumask_of_cpu(cpu));
49
50 /*
51 * if any interrupts are already enabled for the primary
52 * core (e.g. timer irq), then they will not have been enabled
53 * for us: do so
54 */
Catalin Marinasb3a1bde2007-02-14 19:14:56 +010055 gic_cpu_init(0, __io_address(REALVIEW_GIC_CPU_BASE));
Russell King862184f2005-11-07 21:05:42 +000056
57 /*
58 * let the primary processor know we're out of the
59 * pen, then head off into the C entry point
60 */
61 pen_release = -1;
62
63 /*
64 * Synchronise with the boot thread.
65 */
66 spin_lock(&boot_lock);
67 spin_unlock(&boot_lock);
68}
69
70int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
71{
72 unsigned long timeout;
73
74 /*
75 * set synchronisation state between this boot processor
76 * and the secondary one
77 */
78 spin_lock(&boot_lock);
79
80 /*
81 * The secondary processor is waiting to be released from
82 * the holding pen - release it, then wait for it to flag
83 * that it has been released by resetting pen_release.
84 *
85 * Note that "pen_release" is the hardware CPU ID, whereas
86 * "cpu" is Linux's internal ID.
87 */
88 pen_release = cpu;
89 flush_cache_all();
90
91 /*
92 * XXX
93 *
94 * This is a later addition to the booting protocol: the
95 * bootMonitor now puts secondary cores into WFI, so
96 * poke_milo() no longer gets the cores moving; we need
97 * to send a soft interrupt to wake the secondary core.
98 * Use smp_cross_call() for this, since there's little
99 * point duplicating the code here
100 */
101 smp_cross_call(cpumask_of_cpu(cpu));
102
103 timeout = jiffies + (1 * HZ);
104 while (time_before(jiffies, timeout)) {
105 if (pen_release == -1)
106 break;
107
108 udelay(10);
109 }
110
111 /*
112 * now the secondary core is starting up let it run its
113 * calibrations, then wait for it to finish
114 */
115 spin_unlock(&boot_lock);
116
117 return pen_release != -1 ? -ENOSYS : 0;
118}
119
120static void __init poke_milo(void)
121{
122 extern void secondary_startup(void);
123
124 /* nobody is to be released from the pen yet */
125 pen_release = -1;
126
127 /*
128 * write the address of secondary startup into the system-wide
129 * flags register, then clear the bottom two bits, which is what
130 * BootMonitor is waiting for
131 */
132#if 1
133#define REALVIEW_SYS_FLAGSS_OFFSET 0x30
134 __raw_writel(virt_to_phys(realview_secondary_startup),
Russell King5d430452005-11-08 10:44:46 +0000135 __io_address(REALVIEW_SYS_BASE) +
136 REALVIEW_SYS_FLAGSS_OFFSET);
Russell King862184f2005-11-07 21:05:42 +0000137#define REALVIEW_SYS_FLAGSC_OFFSET 0x34
138 __raw_writel(3,
Russell King5d430452005-11-08 10:44:46 +0000139 __io_address(REALVIEW_SYS_BASE) +
140 REALVIEW_SYS_FLAGSC_OFFSET);
Russell King862184f2005-11-07 21:05:42 +0000141#endif
142
143 mb();
144}
145
Russell King7bbb7942006-02-16 11:08:09 +0000146/*
147 * Initialise the CPU possible map early - this describes the CPUs
148 * which may be present or become present in the system.
149 */
150void __init smp_init_cpus(void)
151{
152 unsigned int i, ncores = get_core_count();
153
154 for (i = 0; i < ncores; i++)
155 cpu_set(i, cpu_possible_map);
156}
157
Russell King862184f2005-11-07 21:05:42 +0000158void __init smp_prepare_cpus(unsigned int max_cpus)
159{
160 unsigned int ncores = get_core_count();
161 unsigned int cpu = smp_processor_id();
162 int i;
163
164 /* sanity check */
165 if (ncores == 0) {
166 printk(KERN_ERR
167 "Realview: strange CM count of 0? Default to 1\n");
168
169 ncores = 1;
170 }
171
172 if (ncores > NR_CPUS) {
173 printk(KERN_WARNING
174 "Realview: no. of cores (%d) greater than configured "
175 "maximum of %d - clipping\n",
176 ncores, NR_CPUS);
177 ncores = NR_CPUS;
178 }
179
180 smp_store_cpu_info(cpu);
181
182 /*
183 * are we trying to boot more cores than exist?
184 */
185 if (max_cpus > ncores)
186 max_cpus = ncores;
187
188 /*
Russell King2a98beb2005-11-09 10:50:29 +0000189 * Enable the local timer for primary CPU
190 */
191 local_timer_setup(cpu);
192
193 /*
Russell King7bbb7942006-02-16 11:08:09 +0000194 * Initialise the present map, which describes the set of CPUs
195 * actually populated at the present time.
Russell King862184f2005-11-07 21:05:42 +0000196 */
Russell King7bbb7942006-02-16 11:08:09 +0000197 for (i = 0; i < max_cpus; i++)
Russell King862184f2005-11-07 21:05:42 +0000198 cpu_set(i, cpu_present_map);
Russell King862184f2005-11-07 21:05:42 +0000199
200 /*
201 * Do we need any more CPUs? If so, then let them know where
202 * to start. Note that, on modern versions of MILO, the "poke"
203 * doesn't actually do anything until each individual core is
204 * sent a soft interrupt to get it out of WFI
205 */
206 if (max_cpus > 1)
207 poke_milo();
208}