Kukjin Kim | 7d30e8b | 2011-02-14 16:33:10 +0900 | [diff] [blame^] | 1 | /* linux/arch/arm/mach-exynos4/platsmp.c |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 2 | * |
Kukjin Kim | 7d30e8b | 2011-02-14 16:33:10 +0900 | [diff] [blame^] | 3 | * Copyright (c) 2010-2011 Samsung Electronics Co., Ltd. |
| 4 | * http://www.samsung.com |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 5 | * |
| 6 | * Cloned from linux/arch/arm/mach-vexpress/platsmp.c |
| 7 | * |
| 8 | * Copyright (C) 2002 ARM Ltd. |
| 9 | * All Rights Reserved |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or modify |
| 12 | * it under the terms of the GNU General Public License version 2 as |
| 13 | * published by the Free Software Foundation. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/errno.h> |
| 18 | #include <linux/delay.h> |
| 19 | #include <linux/device.h> |
| 20 | #include <linux/jiffies.h> |
| 21 | #include <linux/smp.h> |
| 22 | #include <linux/io.h> |
| 23 | |
| 24 | #include <asm/cacheflush.h> |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 25 | #include <asm/smp_scu.h> |
| 26 | #include <asm/unified.h> |
| 27 | |
| 28 | #include <mach/hardware.h> |
| 29 | #include <mach/regs-clock.h> |
| 30 | |
Kukjin Kim | 7d30e8b | 2011-02-14 16:33:10 +0900 | [diff] [blame^] | 31 | extern void exynos4_secondary_startup(void); |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 32 | |
| 33 | /* |
| 34 | * control for which core is the next to come out of the secondary |
| 35 | * boot "holding pen" |
| 36 | */ |
| 37 | |
| 38 | volatile int __cpuinitdata pen_release = -1; |
| 39 | |
Russell King | 3705ff6 | 2010-12-18 10:53:12 +0000 | [diff] [blame] | 40 | /* |
| 41 | * Write pen_release in a way that is guaranteed to be visible to all |
| 42 | * observers, irrespective of whether they're taking part in coherency |
| 43 | * or not. This is necessary for the hotplug code to work reliably. |
| 44 | */ |
| 45 | static void write_pen_release(int val) |
| 46 | { |
| 47 | pen_release = val; |
| 48 | smp_wmb(); |
| 49 | __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); |
| 50 | outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1)); |
| 51 | } |
| 52 | |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 53 | static void __iomem *scu_base_addr(void) |
| 54 | { |
| 55 | return (void __iomem *)(S5P_VA_SCU); |
| 56 | } |
| 57 | |
| 58 | static DEFINE_SPINLOCK(boot_lock); |
| 59 | |
| 60 | void __cpuinit platform_secondary_init(unsigned int cpu) |
| 61 | { |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 62 | /* |
| 63 | * if any interrupts are already enabled for the primary |
| 64 | * core (e.g. timer irq), then they will not have been enabled |
| 65 | * for us: do so |
| 66 | */ |
Russell King | 3848953 | 2010-12-04 16:01:03 +0000 | [diff] [blame] | 67 | gic_secondary_init(0); |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 68 | |
| 69 | /* |
| 70 | * let the primary processor know we're out of the |
| 71 | * pen, then head off into the C entry point |
| 72 | */ |
Russell King | 3705ff6 | 2010-12-18 10:53:12 +0000 | [diff] [blame] | 73 | write_pen_release(-1); |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 74 | |
| 75 | /* |
| 76 | * Synchronise with the boot thread. |
| 77 | */ |
| 78 | spin_lock(&boot_lock); |
| 79 | spin_unlock(&boot_lock); |
| 80 | } |
| 81 | |
| 82 | int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) |
| 83 | { |
| 84 | unsigned long timeout; |
| 85 | |
| 86 | /* |
| 87 | * Set synchronisation state between this boot processor |
| 88 | * and the secondary one |
| 89 | */ |
| 90 | spin_lock(&boot_lock); |
| 91 | |
| 92 | /* |
| 93 | * The secondary processor is waiting to be released from |
| 94 | * the holding pen - release it, then wait for it to flag |
| 95 | * that it has been released by resetting pen_release. |
| 96 | * |
| 97 | * Note that "pen_release" is the hardware CPU ID, whereas |
| 98 | * "cpu" is Linux's internal ID. |
| 99 | */ |
Russell King | 3705ff6 | 2010-12-18 10:53:12 +0000 | [diff] [blame] | 100 | write_pen_release(cpu); |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 101 | |
| 102 | /* |
| 103 | * Send the secondary CPU a soft interrupt, thereby causing |
| 104 | * the boot monitor to read the system wide flags register, |
| 105 | * and branch to the address found there. |
| 106 | */ |
Russell King | ad3b6993 | 2010-11-15 09:42:08 +0000 | [diff] [blame] | 107 | smp_cross_call(cpumask_of(cpu), 1); |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 108 | |
| 109 | timeout = jiffies + (1 * HZ); |
| 110 | while (time_before(jiffies, timeout)) { |
| 111 | smp_rmb(); |
| 112 | if (pen_release == -1) |
| 113 | break; |
| 114 | |
| 115 | udelay(10); |
| 116 | } |
| 117 | |
| 118 | /* |
| 119 | * now the secondary core is starting up let it run its |
| 120 | * calibrations, then wait for it to finish |
| 121 | */ |
| 122 | spin_unlock(&boot_lock); |
| 123 | |
| 124 | return pen_release != -1 ? -ENOSYS : 0; |
| 125 | } |
| 126 | |
| 127 | /* |
| 128 | * Initialise the CPU possible map early - this describes the CPUs |
| 129 | * which may be present or become present in the system. |
| 130 | */ |
| 131 | |
| 132 | void __init smp_init_cpus(void) |
| 133 | { |
| 134 | void __iomem *scu_base = scu_base_addr(); |
| 135 | unsigned int i, ncores; |
| 136 | |
| 137 | ncores = scu_base ? scu_get_core_count(scu_base) : 1; |
| 138 | |
| 139 | /* sanity check */ |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 140 | if (ncores > NR_CPUS) { |
| 141 | printk(KERN_WARNING |
Kukjin Kim | 7d30e8b | 2011-02-14 16:33:10 +0900 | [diff] [blame^] | 142 | "EXYNOS4: no. of cores (%d) greater than configured " |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 143 | "maximum of %d - clipping\n", |
| 144 | ncores, NR_CPUS); |
| 145 | ncores = NR_CPUS; |
| 146 | } |
| 147 | |
| 148 | for (i = 0; i < ncores; i++) |
| 149 | set_cpu_possible(i, true); |
| 150 | } |
| 151 | |
Russell King | 05c74a6 | 2010-12-03 11:09:48 +0000 | [diff] [blame] | 152 | void __init platform_smp_prepare_cpus(unsigned int max_cpus) |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 153 | { |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 154 | int i; |
| 155 | |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 156 | /* |
| 157 | * Initialise the present map, which describes the set of CPUs |
| 158 | * actually populated at the present time. |
| 159 | */ |
| 160 | for (i = 0; i < max_cpus; i++) |
| 161 | set_cpu_present(i, true); |
| 162 | |
Russell King | 05c74a6 | 2010-12-03 11:09:48 +0000 | [diff] [blame] | 163 | scu_enable(scu_base_addr()); |
| 164 | |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 165 | /* |
Russell King | 05c74a6 | 2010-12-03 11:09:48 +0000 | [diff] [blame] | 166 | * Write the address of secondary startup into the |
| 167 | * system-wide flags register. The boot monitor waits |
| 168 | * until it receives a soft interrupt, and then the |
| 169 | * secondary CPU branches to this address. |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 170 | */ |
Kukjin Kim | 7d30e8b | 2011-02-14 16:33:10 +0900 | [diff] [blame^] | 171 | __raw_writel(BSYM(virt_to_phys(exynos4_secondary_startup)), S5P_VA_SYSRAM); |
Changhwan Youn | 2b12b5c | 2010-07-26 21:08:52 +0900 | [diff] [blame] | 172 | } |