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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
Catalin Marinas356cb472008-02-04 17:34:58 +010034 ncores = __raw_readl(__io_address(REALVIEW_EB11MP_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 Marinas356cb472008-02-04 17:34:58 +010055 gic_cpu_init(0, __io_address(REALVIEW_EB11MP_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;
Catalin Marinas0e0ba762007-02-15 19:05:29 +010062 smp_wmb();
Russell King862184f2005-11-07 21:05:42 +000063
64 /*
65 * Synchronise with the boot thread.
66 */
67 spin_lock(&boot_lock);
68 spin_unlock(&boot_lock);
69}
70
71int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
72{
73 unsigned long timeout;
74
75 /*
76 * set synchronisation state between this boot processor
77 * and the secondary one
78 */
79 spin_lock(&boot_lock);
80
81 /*
82 * The secondary processor is waiting to be released from
83 * the holding pen - release it, then wait for it to flag
84 * that it has been released by resetting pen_release.
85 *
86 * Note that "pen_release" is the hardware CPU ID, whereas
87 * "cpu" is Linux's internal ID.
88 */
89 pen_release = cpu;
90 flush_cache_all();
91
92 /*
93 * XXX
94 *
95 * This is a later addition to the booting protocol: the
96 * bootMonitor now puts secondary cores into WFI, so
97 * poke_milo() no longer gets the cores moving; we need
98 * to send a soft interrupt to wake the secondary core.
99 * Use smp_cross_call() for this, since there's little
100 * point duplicating the code here
101 */
102 smp_cross_call(cpumask_of_cpu(cpu));
103
104 timeout = jiffies + (1 * HZ);
105 while (time_before(jiffies, timeout)) {
Catalin Marinas0e0ba762007-02-15 19:05:29 +0100106 smp_rmb();
Russell King862184f2005-11-07 21:05:42 +0000107 if (pen_release == -1)
108 break;
109
110 udelay(10);
111 }
112
113 /*
114 * now the secondary core is starting up let it run its
115 * calibrations, then wait for it to finish
116 */
117 spin_unlock(&boot_lock);
118
119 return pen_release != -1 ? -ENOSYS : 0;
120}
121
122static void __init poke_milo(void)
123{
124 extern void secondary_startup(void);
125
126 /* nobody is to be released from the pen yet */
127 pen_release = -1;
128
129 /*
130 * write the address of secondary startup into the system-wide
131 * flags register, then clear the bottom two bits, which is what
132 * BootMonitor is waiting for
133 */
134#if 1
135#define REALVIEW_SYS_FLAGSS_OFFSET 0x30
136 __raw_writel(virt_to_phys(realview_secondary_startup),
Russell King5d430452005-11-08 10:44:46 +0000137 __io_address(REALVIEW_SYS_BASE) +
138 REALVIEW_SYS_FLAGSS_OFFSET);
Russell King862184f2005-11-07 21:05:42 +0000139#define REALVIEW_SYS_FLAGSC_OFFSET 0x34
140 __raw_writel(3,
Russell King5d430452005-11-08 10:44:46 +0000141 __io_address(REALVIEW_SYS_BASE) +
142 REALVIEW_SYS_FLAGSC_OFFSET);
Russell King862184f2005-11-07 21:05:42 +0000143#endif
144
145 mb();
146}
147
Russell King7bbb7942006-02-16 11:08:09 +0000148/*
149 * Initialise the CPU possible map early - this describes the CPUs
150 * which may be present or become present in the system.
151 */
152void __init smp_init_cpus(void)
153{
154 unsigned int i, ncores = get_core_count();
155
156 for (i = 0; i < ncores; i++)
157 cpu_set(i, cpu_possible_map);
158}
159
Russell King862184f2005-11-07 21:05:42 +0000160void __init smp_prepare_cpus(unsigned int max_cpus)
161{
162 unsigned int ncores = get_core_count();
163 unsigned int cpu = smp_processor_id();
164 int i;
165
166 /* sanity check */
167 if (ncores == 0) {
168 printk(KERN_ERR
169 "Realview: strange CM count of 0? Default to 1\n");
170
171 ncores = 1;
172 }
173
174 if (ncores > NR_CPUS) {
175 printk(KERN_WARNING
176 "Realview: no. of cores (%d) greater than configured "
177 "maximum of %d - clipping\n",
178 ncores, NR_CPUS);
179 ncores = NR_CPUS;
180 }
181
182 smp_store_cpu_info(cpu);
183
184 /*
185 * are we trying to boot more cores than exist?
186 */
187 if (max_cpus > ncores)
188 max_cpus = ncores;
189
Catalin Marinasa8655e82008-02-04 17:30:57 +0100190#ifdef CONFIG_LOCAL_TIMERS
Russell King862184f2005-11-07 21:05:42 +0000191 /*
Catalin Marinasa8655e82008-02-04 17:30:57 +0100192 * Enable the local timer for primary CPU. If the device is
193 * dummy (!CONFIG_LOCAL_TIMERS), it was already registers in
194 * realview_timer_init
Russell King2a98beb2005-11-09 10:50:29 +0000195 */
196 local_timer_setup(cpu);
Catalin Marinasa8655e82008-02-04 17:30:57 +0100197#endif
Russell King2a98beb2005-11-09 10:50:29 +0000198
199 /*
Russell King7bbb7942006-02-16 11:08:09 +0000200 * Initialise the present map, which describes the set of CPUs
201 * actually populated at the present time.
Russell King862184f2005-11-07 21:05:42 +0000202 */
Russell King7bbb7942006-02-16 11:08:09 +0000203 for (i = 0; i < max_cpus; i++)
Russell King862184f2005-11-07 21:05:42 +0000204 cpu_set(i, cpu_present_map);
Russell King862184f2005-11-07 21:05:42 +0000205
206 /*
207 * Do we need any more CPUs? If so, then let them know where
208 * to start. Note that, on modern versions of MILO, the "poke"
209 * doesn't actually do anything until each individual core is
210 * sent a soft interrupt to get it out of WFI
211 */
212 if (max_cpus > 1)
213 poke_milo();
214}