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/hardirq.h> 17 18 #include <asm/dbell.h> 19 #include <asm/irq_regs.h> 20 #include <asm/kvm_ppc.h> 21 22 #ifdef CONFIG_SMP 23 24 /* 25 * Doorbells must only be used if CPU_FTR_DBELL is available. 26 * msgsnd is used in HV, and msgsndp is used in !HV. 27 * 28 * These should be used by platform code that is aware of restrictions. 29 * Other arch code should use ->cause_ipi. 30 * 31 * doorbell_global_ipi() sends a dbell to any target CPU. 32 * Must be used only by architectures that address msgsnd target 33 * by PIR/get_hard_smp_processor_id. 34 */ 35 void doorbell_global_ipi(int cpu) 36 { 37 u32 tag = get_hard_smp_processor_id(cpu); 38 39 kvmppc_set_host_ipi(cpu, 1); 40 /* Order previous accesses vs. msgsnd, which is treated as a store */ 41 ppc_msgsnd_sync(); 42 ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag); 43 } 44 45 /* 46 * doorbell_core_ipi() sends a dbell to a target CPU in the same core. 47 * Must be used only by architectures that address msgsnd target 48 * by TIR/cpu_thread_in_core. 49 */ 50 void doorbell_core_ipi(int cpu) 51 { 52 u32 tag = cpu_thread_in_core(cpu); 53 54 kvmppc_set_host_ipi(cpu, 1); 55 /* Order previous accesses vs. msgsnd, which is treated as a store */ 56 ppc_msgsnd_sync(); 57 ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag); 58 } 59 60 /* 61 * Attempt to cause a core doorbell if destination is on the same core. 62 * Returns 1 on success, 0 on failure. 63 */ 64 int doorbell_try_core_ipi(int cpu) 65 { 66 int this_cpu = get_cpu(); 67 int ret = 0; 68 69 if (cpumask_test_cpu(cpu, cpu_sibling_mask(this_cpu))) { 70 doorbell_core_ipi(cpu); 71 ret = 1; 72 } 73 74 put_cpu(); 75 76 return ret; 77 } 78 79 void doorbell_exception(struct pt_regs *regs) 80 { 81 struct pt_regs *old_regs = set_irq_regs(regs); 82 83 irq_enter(); 84 85 ppc_msgsync(); 86 87 may_hard_irq_enable(); 88 89 kvmppc_set_host_ipi(smp_processor_id(), 0); 90 __this_cpu_inc(irq_stat.doorbell_irqs); 91 92 smp_ipi_demux_relaxed(); /* already performed the barrier */ 93 94 irq_exit(); 95 set_irq_regs(old_regs); 96 } 97 #else /* CONFIG_SMP */ 98 void doorbell_exception(struct pt_regs *regs) 99 { 100 printk(KERN_WARNING "Received doorbell on non-smp system\n"); 101 } 102 #endif /* CONFIG_SMP */ 103 104