arch/mips/paravirt/paravirt-smp.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2013 Cavium, Inc.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/cpumask.h>
  11 #include <linux/kernel.h>
  12 #include <linux/sched.h>
  13
  14 #include <asm/mipsregs.h>
  15 #include <asm/setup.h>
  16 #include <asm/time.h>
  17 #include <asm/smp.h>
  18
  19 /*
  20  * Writing the sp releases the CPU, so writes must be ordered, gp
  21  * first, then sp.
  22  */
  23 unsigned long paravirt_smp_sp[NR_CPUS];
  24 unsigned long paravirt_smp_gp[NR_CPUS];
  25
  26 static int numcpus = 1;
  27
  28 static int __init set_numcpus(char *str)
  29 {
  30         int newval;
  31
  32         if (get_option(&str, &newval)) {
  33                 if (newval < 1 || newval >= NR_CPUS)
  34                         goto bad;
  35                 numcpus = newval;
  36                 return 0;
  37         }
  38 bad:
  39         return -EINVAL;
  40 }
  41 early_param("numcpus", set_numcpus);
  42
  43
  44 static void paravirt_smp_setup(void)
  45 {
  46         int id;
  47         unsigned int cpunum = get_ebase_cpunum();
  48
  49         if (WARN_ON(cpunum >= NR_CPUS))
  50                 return;
  51
  52         /* The present CPUs are initially just the boot cpu (CPU 0). */
  53         for (id = 0; id < NR_CPUS; id++) {
  54                 set_cpu_possible(id, id == 0);
  55                 set_cpu_present(id, id == 0);
  56         }
  57         __cpu_number_map[cpunum] = 0;
  58         __cpu_logical_map[0] = cpunum;
  59
  60         for (id = 0; id < numcpus; id++) {
  61                 set_cpu_possible(id, true);
  62                 set_cpu_present(id, true);
  63                 __cpu_number_map[id] = id;
  64                 __cpu_logical_map[id] = id;
  65         }
  66 }
  67
  68 void irq_mbox_ipi(int cpu, unsigned int actions);
  69 static void paravirt_send_ipi_single(int cpu, unsigned int action)
  70 {
  71         irq_mbox_ipi(cpu, action);
  72 }
  73
  74 static void paravirt_send_ipi_mask(const struct cpumask *mask, unsigned int action)
  75 {
  76         unsigned int cpu;
  77
  78         for_each_cpu(cpu, mask)
  79                 paravirt_send_ipi_single(cpu, action);
  80 }
  81
  82 static void paravirt_init_secondary(void)
  83 {
  84         unsigned int sr;
  85
  86         sr = set_c0_status(ST0_BEV);
  87         write_c0_ebase((u32)ebase);
  88
  89         sr |= STATUSF_IP2; /* Interrupt controller on IP2 */
  90         write_c0_status(sr);
  91
  92         irq_cpu_online();
  93 }
  94
  95 static void paravirt_smp_finish(void)
  96 {
  97         /* to generate the first CPU timer interrupt */
  98         write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ);
  99         local_irq_enable();
 100 }
 101
 102 static void paravirt_boot_secondary(int cpu, struct task_struct *idle)
 103 {
 104         paravirt_smp_gp[cpu] = (unsigned long)task_thread_info(idle);
 105         smp_wmb();
 106         paravirt_smp_sp[cpu] = __KSTK_TOS(idle);
 107 }
 108
 109 static irqreturn_t paravirt_reched_interrupt(int irq, void *dev_id)
 110 {
 111         scheduler_ipi();
 112         return IRQ_HANDLED;
 113 }
 114
 115 static irqreturn_t paravirt_function_interrupt(int irq, void *dev_id)
 116 {
 117         generic_smp_call_function_interrupt();
 118         return IRQ_HANDLED;
 119 }
 120
 121 static void paravirt_prepare_cpus(unsigned int max_cpus)
 122 {
 123         if (request_irq(MIPS_IRQ_MBOX0, paravirt_reched_interrupt,
 124                         IRQF_PERCPU | IRQF_NO_THREAD, "Scheduler",
 125                         paravirt_reched_interrupt)) {
 126                 panic("Cannot request_irq for SchedulerIPI");
 127         }
 128         if (request_irq(MIPS_IRQ_MBOX1, paravirt_function_interrupt,
 129                         IRQF_PERCPU | IRQF_NO_THREAD, "SMP-Call",
 130                         paravirt_function_interrupt)) {
 131                 panic("Cannot request_irq for SMP-Call");
 132         }
 133 }
 134
 135 struct plat_smp_ops paravirt_smp_ops = {
 136         .send_ipi_single        = paravirt_send_ipi_single,
 137         .send_ipi_mask          = paravirt_send_ipi_mask,
 138         .init_secondary         = paravirt_init_secondary,
 139         .smp_finish             = paravirt_smp_finish,
 140         .boot_secondary         = paravirt_boot_secondary,
 141         .smp_setup              = paravirt_smp_setup,
 142         .prepare_cpus           = paravirt_prepare_cpus,
 143 };