1 /* 2 * Author: Kumar Gala <galak@kernel.crashing.org> 3 * 4 * Copyright 2009 Freescale Semiconductor Inc. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License as published by the 8 * Free Software Foundation; either version 2 of the License, or (at your 9 * option) any later version. 10 */ 11 12 #include <linux/stddef.h> 13 #include <linux/kernel.h> 14 #include <linux/smp.h> 15 #include <linux/threads.h> 16 #include <linux/percpu.h> 17 18 #include <asm/dbell.h> 19 #include <asm/irq_regs.h> 20 21 #ifdef CONFIG_SMP 22 struct doorbell_cpu_info { 23 unsigned long messages; /* current messages bits */ 24 unsigned int tag; /* tag value */ 25 }; 26 27 static DEFINE_PER_CPU(struct doorbell_cpu_info, doorbell_cpu_info); 28 29 void doorbell_setup_this_cpu(void) 30 { 31 struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info); 32 33 info->messages = 0; 34 info->tag = mfspr(SPRN_PIR) & 0x3fff; 35 } 36 37 void doorbell_message_pass(int target, int msg) 38 { 39 struct doorbell_cpu_info *info; 40 int i; 41 42 if (target < NR_CPUS) { 43 info = &per_cpu(doorbell_cpu_info, target); 44 set_bit(msg, &info->messages); 45 ppc_msgsnd(PPC_DBELL, 0, info->tag); 46 } 47 else if (target == MSG_ALL_BUT_SELF) { 48 for_each_online_cpu(i) { 49 if (i == smp_processor_id()) 50 continue; 51 info = &per_cpu(doorbell_cpu_info, i); 52 set_bit(msg, &info->messages); 53 ppc_msgsnd(PPC_DBELL, 0, info->tag); 54 } 55 } 56 else { /* target == MSG_ALL */ 57 for_each_online_cpu(i) { 58 info = &per_cpu(doorbell_cpu_info, i); 59 set_bit(msg, &info->messages); 60 } 61 ppc_msgsnd(PPC_DBELL, PPC_DBELL_MSG_BRDCAST, 0); 62 } 63 } 64 65 void doorbell_exception(struct pt_regs *regs) 66 { 67 struct pt_regs *old_regs = set_irq_regs(regs); 68 struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info); 69 int msg; 70 71 /* Warning: regs can be NULL when called from irq enable */ 72 73 if (!info->messages || (num_online_cpus() < 2)) 74 goto out; 75 76 for (msg = 0; msg < 4; msg++) 77 if (test_and_clear_bit(msg, &info->messages)) 78 smp_message_recv(msg); 79 80 out: 81 set_irq_regs(old_regs); 82 } 83 84 void doorbell_check_self(void) 85 { 86 struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info); 87 88 if (!info->messages) 89 return; 90 91 ppc_msgsnd(PPC_DBELL, 0, info->tag); 92 } 93 94 #else /* CONFIG_SMP */ 95 void doorbell_exception(struct pt_regs *regs) 96 { 97 printk(KERN_WARNING "Received doorbell on non-smp system\n"); 98 } 99 #endif /* CONFIG_SMP */ 100 101