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 278