1 /* 2 * Smp support for CHRP machines. 3 * 4 * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great 5 * deal of code from the sparc and intel versions. 6 * 7 * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu> 8 * 9 */ 10 11 #include <linux/config.h> 12 #include <linux/kernel.h> 13 #include <linux/sched.h> 14 #include <linux/smp.h> 15 #include <linux/smp_lock.h> 16 #include <linux/interrupt.h> 17 #include <linux/kernel_stat.h> 18 #include <linux/delay.h> 19 #include <linux/init.h> 20 #include <linux/spinlock.h> 21 22 #include <asm/ptrace.h> 23 #include <asm/atomic.h> 24 #include <asm/irq.h> 25 #include <asm/page.h> 26 #include <asm/pgtable.h> 27 #include <asm/sections.h> 28 #include <asm/io.h> 29 #include <asm/prom.h> 30 #include <asm/smp.h> 31 #include <asm/residual.h> 32 #include <asm/time.h> 33 #include <asm/open_pic.h> 34 #include <asm/machdep.h> 35 #include <asm/smp.h> 36 #include <asm/mpic.h> 37 38 extern unsigned long smp_chrp_cpu_nr; 39 40 static int __init smp_chrp_probe(void) 41 { 42 struct device_node *cpus = NULL; 43 unsigned int *reg; 44 int reglen; 45 int ncpus = 0; 46 int cpuid; 47 unsigned int phys; 48 49 /* Count CPUs in the device-tree */ 50 cpuid = 1; /* the boot cpu is logical cpu 0 */ 51 while ((cpus = of_find_node_by_type(cpus, "cpu")) != NULL) { 52 phys = ncpus; 53 reg = (unsigned int *) get_property(cpus, "reg", ®len); 54 if (reg && reglen >= sizeof(unsigned int)) 55 /* hmmm, not having a reg property would be bad */ 56 phys = *reg; 57 if (phys != boot_cpuid_phys) { 58 set_hard_smp_processor_id(cpuid, phys); 59 ++cpuid; 60 } 61 ++ncpus; 62 } 63 64 printk(KERN_INFO "CHRP SMP probe found %d cpus\n", ncpus); 65 66 /* Nothing more to do if less than 2 of them */ 67 if (ncpus <= 1) 68 return 1; 69 70 mpic_request_ipis(); 71 72 return ncpus; 73 } 74 75 static void __devinit smp_chrp_kick_cpu(int nr) 76 { 77 *(unsigned long *)KERNELBASE = nr; 78 asm volatile("dcbf 0,%0"::"r"(KERNELBASE):"memory"); 79 } 80 81 static void __devinit smp_chrp_setup_cpu(int cpu_nr) 82 { 83 mpic_setup_this_cpu(); 84 } 85 86 static DEFINE_SPINLOCK(timebase_lock); 87 static unsigned int timebase_upper = 0, timebase_lower = 0; 88 89 void __devinit smp_chrp_give_timebase(void) 90 { 91 spin_lock(&timebase_lock); 92 rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL); 93 timebase_upper = get_tbu(); 94 timebase_lower = get_tbl(); 95 spin_unlock(&timebase_lock); 96 97 while (timebase_upper || timebase_lower) 98 barrier(); 99 rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL); 100 } 101 102 void __devinit smp_chrp_take_timebase(void) 103 { 104 while (!(timebase_upper || timebase_lower)) 105 barrier(); 106 spin_lock(&timebase_lock); 107 set_tb(timebase_upper, timebase_lower); 108 timebase_upper = 0; 109 timebase_lower = 0; 110 spin_unlock(&timebase_lock); 111 printk("CPU %i taken timebase\n", smp_processor_id()); 112 } 113 114 /* CHRP with openpic */ 115 struct smp_ops_t chrp_smp_ops = { 116 .message_pass = smp_mpic_message_pass, 117 .probe = smp_chrp_probe, 118 .kick_cpu = smp_chrp_kick_cpu, 119 .setup_cpu = smp_chrp_setup_cpu, 120 .give_timebase = smp_chrp_give_timebase, 121 .take_timebase = smp_chrp_take_timebase, 122 }; 123