arch/csky/kernel/smp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/module.h>
   4 #include <linux/init.h>
   5 #include <linux/kernel.h>
   6 #include <linux/mm.h>
   7 #include <linux/sched.h>
   8 #include <linux/kernel_stat.h>
   9 #include <linux/notifier.h>
  10 #include <linux/cpu.h>
  11 #include <linux/percpu.h>
  12 #include <linux/delay.h>
  13 #include <linux/err.h>
  14 #include <linux/irq.h>
  15 #include <linux/irqdomain.h>
  16 #include <linux/of.h>
  17 #include <linux/sched/task_stack.h>
  18 #include <linux/sched/mm.h>
  19 #include <linux/sched/hotplug.h>
  20 #include <asm/irq.h>
  21 #include <asm/traps.h>
  22 #include <asm/sections.h>
  23 #include <asm/mmu_context.h>
  24 #include <asm/pgalloc.h>
  25
  26 struct ipi_data_struct {
  27         unsigned long bits ____cacheline_aligned;
  28 };
  29 static DEFINE_PER_CPU(struct ipi_data_struct, ipi_data);
  30
  31 enum ipi_message_type {
  32         IPI_EMPTY,
  33         IPI_RESCHEDULE,
  34         IPI_CALL_FUNC,
  35         IPI_MAX
  36 };
  37
  38 static irqreturn_t handle_ipi(int irq, void *dev)
  39 {
  40         while (true) {
  41                 unsigned long ops;
  42
  43                 ops = xchg(&this_cpu_ptr(&ipi_data)->bits, 0);
  44                 if (ops == 0)
  45                         return IRQ_HANDLED;
  46
  47                 if (ops & (1 << IPI_RESCHEDULE))
  48                         scheduler_ipi();
  49
  50                 if (ops & (1 << IPI_CALL_FUNC))
  51                         generic_smp_call_function_interrupt();
  52
  53                 BUG_ON((ops >> IPI_MAX) != 0);
  54         }
  55
  56         return IRQ_HANDLED;
  57 }
  58
  59 static void (*send_arch_ipi)(const struct cpumask *mask);
  60
  61 static int ipi_irq;
  62 void __init set_send_ipi(void (*func)(const struct cpumask *mask), int irq)
  63 {
  64         if (send_arch_ipi)
  65                 return;
  66
  67         send_arch_ipi = func;
  68         ipi_irq = irq;
  69 }
  70
  71 static void
  72 send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation)
  73 {
  74         int i;
  75
  76         for_each_cpu(i, to_whom)
  77                 set_bit(operation, &per_cpu_ptr(&ipi_data, i)->bits);
  78
  79         smp_mb();
  80         send_arch_ipi(to_whom);
  81 }
  82
  83 void arch_send_call_function_ipi_mask(struct cpumask *mask)
  84 {
  85         send_ipi_message(mask, IPI_CALL_FUNC);
  86 }
  87
  88 void arch_send_call_function_single_ipi(int cpu)
  89 {
  90         send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
  91 }
  92
  93 static void ipi_stop(void *unused)
  94 {
  95         while (1);
  96 }
  97
  98 void smp_send_stop(void)
  99 {
 100         on_each_cpu(ipi_stop, NULL, 1);
 101 }
 102
 103 void smp_send_reschedule(int cpu)
 104 {
 105         send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 106 }
 107
 108 void __init smp_prepare_boot_cpu(void)
 109 {
 110 }
 111
 112 void __init smp_prepare_cpus(unsigned int max_cpus)
 113 {
 114 }
 115
 116 static int ipi_dummy_dev;
 117
 118 void __init setup_smp_ipi(void)
 119 {
 120         int rc;
 121
 122         if (ipi_irq == 0)
 123                 return;
 124
 125         rc = request_percpu_irq(ipi_irq, handle_ipi, "IPI Interrupt",
 126                                 &ipi_dummy_dev);
 127         if (rc)
 128                 panic("%s IRQ request failed\n", __func__);
 129
 130         enable_percpu_irq(ipi_irq, 0);
 131 }
 132
 133 void __init setup_smp(void)
 134 {
 135         struct device_node *node = NULL;
 136         int cpu;
 137
 138         for_each_of_cpu_node(node) {
 139                 if (!of_device_is_available(node))
 140                         continue;
 141
 142                 if (of_property_read_u32(node, "reg", &cpu))
 143                         continue;
 144
 145                 if (cpu >= NR_CPUS)
 146                         continue;
 147
 148                 set_cpu_possible(cpu, true);
 149                 set_cpu_present(cpu, true);
 150         }
 151 }
 152
 153 extern void _start_smp_secondary(void);
 154
 155 volatile unsigned int secondary_hint;
 156 volatile unsigned int secondary_ccr;
 157 volatile unsigned int secondary_stack;
 158
 159 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 160 {
 161         unsigned long mask = 1 << cpu;
 162
 163         secondary_stack =
 164                 (unsigned int) task_stack_page(tidle) + THREAD_SIZE - 8;
 165         secondary_hint = mfcr("cr31");
 166         secondary_ccr  = mfcr("cr18");
 167
 168         /*
 169          * Because other CPUs are in reset status, we must flush data
 170          * from cache to out and secondary CPUs use them in
 171          * csky_start_secondary(void)
 172          */
 173         mtcr("cr17", 0x22);
 174
 175         if (mask & mfcr("cr<29, 0>")) {
 176                 send_arch_ipi(cpumask_of(cpu));
 177         } else {
 178                 /* Enable cpu in SMP reset ctrl reg */
 179                 mask |= mfcr("cr<29, 0>");
 180                 mtcr("cr<29, 0>", mask);
 181         }
 182
 183         /* Wait for the cpu online */
 184         while (!cpu_online(cpu));
 185
 186         secondary_stack = 0;
 187
 188         return 0;
 189 }
 190
 191 void __init smp_cpus_done(unsigned int max_cpus)
 192 {
 193 }
 194
 195 int setup_profiling_timer(unsigned int multiplier)
 196 {
 197         return -EINVAL;
 198 }
 199
 200 void csky_start_secondary(void)
 201 {
 202         struct mm_struct *mm = &init_mm;
 203         unsigned int cpu = smp_processor_id();
 204
 205         mtcr("cr31", secondary_hint);
 206         mtcr("cr18", secondary_ccr);
 207
 208         mtcr("vbr", vec_base);
 209
 210         flush_tlb_all();
 211         write_mmu_pagemask(0);
 212         TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir);
 213         TLBMISS_HANDLER_SETUP_PGD_KERNEL(swapper_pg_dir);
 214
 215 #ifdef CONFIG_CPU_HAS_FPU
 216         init_fpu();
 217 #endif
 218
 219         enable_percpu_irq(ipi_irq, 0);
 220
 221         mmget(mm);
 222         mmgrab(mm);
 223         current->active_mm = mm;
 224         cpumask_set_cpu(cpu, mm_cpumask(mm));
 225
 226         notify_cpu_starting(cpu);
 227         set_cpu_online(cpu, true);
 228
 229         pr_info("CPU%u Online: %s...\n", cpu, __func__);
 230
 231         local_irq_enable();
 232         preempt_disable();
 233         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 234 }
 235
 236 #ifdef CONFIG_HOTPLUG_CPU
 237 int __cpu_disable(void)
 238 {
 239         unsigned int cpu = smp_processor_id();
 240
 241         set_cpu_online(cpu, false);
 242
 243         irq_migrate_all_off_this_cpu();
 244
 245         clear_tasks_mm_cpumask(cpu);
 246
 247         return 0;
 248 }
 249
 250 void __cpu_die(unsigned int cpu)
 251 {
 252         if (!cpu_wait_death(cpu, 5)) {
 253                 pr_crit("CPU%u: shutdown failed\n", cpu);
 254                 return;
 255         }
 256         pr_notice("CPU%u: shutdown\n", cpu);
 257 }
 258
 259 void arch_cpu_idle_dead(void)
 260 {
 261         idle_task_exit();
 262
 263         cpu_report_death();
 264
 265         while (!secondary_stack)
 266                 arch_cpu_idle();
 267
 268         local_irq_disable();
 269
 270         asm volatile(
 271                 "mov    sp, %0\n"
 272                 "mov    r8, %0\n"
 273                 "jmpi   csky_start_secondary"
 274                 :
 275                 : "r" (secondary_stack));
 276 }
 277 #endif