1 /* 2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * RajeshwarR: Dec 11, 2007 9 * -- Added support for Inter Processor Interrupts 10 * 11 * Vineetg: Nov 1st, 2007 12 * -- Initial Write (Borrowed heavily from ARM) 13 */ 14 15 #include <linux/spinlock.h> 16 #include <linux/sched.h> 17 #include <linux/interrupt.h> 18 #include <linux/profile.h> 19 #include <linux/mm.h> 20 #include <linux/cpu.h> 21 #include <linux/irq.h> 22 #include <linux/atomic.h> 23 #include <linux/cpumask.h> 24 #include <linux/reboot.h> 25 #include <linux/irqdomain.h> 26 #include <asm/processor.h> 27 #include <asm/setup.h> 28 #include <asm/mach_desc.h> 29 30 #ifndef CONFIG_ARC_HAS_LLSC 31 arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED; 32 arch_spinlock_t smp_bitops_lock = __ARCH_SPIN_LOCK_UNLOCKED; 33 #endif 34 35 struct plat_smp_ops __weak plat_smp_ops; 36 37 /* XXX: per cpu ? Only needed once in early seconday boot */ 38 struct task_struct *secondary_idle_tsk; 39 40 /* Called from start_kernel */ 41 void __init smp_prepare_boot_cpu(void) 42 { 43 } 44 45 /* 46 * Called from setup_arch() before calling setup_processor() 47 * 48 * - Initialise the CPU possible map early - this describes the CPUs 49 * which may be present or become present in the system. 50 * - Call early smp init hook. This can initialize a specific multi-core 51 * IP which is say common to several platforms (hence not part of 52 * platform specific int_early() hook) 53 */ 54 void __init smp_init_cpus(void) 55 { 56 unsigned int i; 57 58 for (i = 0; i < NR_CPUS; i++) 59 set_cpu_possible(i, true); 60 61 if (plat_smp_ops.init_early_smp) 62 plat_smp_ops.init_early_smp(); 63 } 64 65 /* called from init ( ) => process 1 */ 66 void __init smp_prepare_cpus(unsigned int max_cpus) 67 { 68 int i; 69 70 /* 71 * if platform didn't set the present map already, do it now 72 * boot cpu is set to present already by init/main.c 73 */ 74 if (num_present_cpus() <= 1) { 75 for (i = 0; i < max_cpus; i++) 76 set_cpu_present(i, true); 77 } 78 } 79 80 void __init smp_cpus_done(unsigned int max_cpus) 81 { 82 83 } 84 85 /* 86 * Default smp boot helper for Run-on-reset case where all cores start off 87 * together. Non-masters need to wait for Master to start running. 88 * This is implemented using a flag in memory, which Non-masters spin-wait on. 89 * Master sets it to cpu-id of core to "ungate" it. 90 */ 91 static volatile int wake_flag; 92 93 static void arc_default_smp_cpu_kick(int cpu, unsigned long pc) 94 { 95 BUG_ON(cpu == 0); 96 wake_flag = cpu; 97 } 98 99 void arc_platform_smp_wait_to_boot(int cpu) 100 { 101 while (wake_flag != cpu) 102 ; 103 104 wake_flag = 0; 105 __asm__ __volatile__("j @first_lines_of_secondary \n"); 106 } 107 108 109 const char *arc_platform_smp_cpuinfo(void) 110 { 111 return plat_smp_ops.info ? : ""; 112 } 113 114 /* 115 * The very first "C" code executed by secondary 116 * Called from asm stub in head.S 117 * "current"/R25 already setup by low level boot code 118 */ 119 void start_kernel_secondary(void) 120 { 121 struct mm_struct *mm = &init_mm; 122 unsigned int cpu = smp_processor_id(); 123 124 /* MMU, Caches, Vector Table, Interrupts etc */ 125 setup_processor(); 126 127 atomic_inc(&mm->mm_users); 128 atomic_inc(&mm->mm_count); 129 current->active_mm = mm; 130 cpumask_set_cpu(cpu, mm_cpumask(mm)); 131 132 /* Some SMP H/w setup - for each cpu */ 133 if (plat_smp_ops.init_per_cpu) 134 plat_smp_ops.init_per_cpu(cpu); 135 136 if (machine_desc->init_per_cpu) 137 machine_desc->init_per_cpu(cpu); 138 139 notify_cpu_starting(cpu); 140 set_cpu_online(cpu, true); 141 142 pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu); 143 144 local_irq_enable(); 145 preempt_disable(); 146 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 147 } 148 149 /* 150 * Called from kernel_init( ) -> smp_init( ) - for each CPU 151 * 152 * At this point, Secondary Processor is "HALT"ed: 153 * -It booted, but was halted in head.S 154 * -It was configured to halt-on-reset 155 * So need to wake it up. 156 * 157 * Essential requirements being where to run from (PC) and stack (SP) 158 */ 159 int __cpu_up(unsigned int cpu, struct task_struct *idle) 160 { 161 unsigned long wait_till; 162 163 secondary_idle_tsk = idle; 164 165 pr_info("Idle Task [%d] %p", cpu, idle); 166 pr_info("Trying to bring up CPU%u ...\n", cpu); 167 168 if (plat_smp_ops.cpu_kick) 169 plat_smp_ops.cpu_kick(cpu, 170 (unsigned long)first_lines_of_secondary); 171 else 172 arc_default_smp_cpu_kick(cpu, (unsigned long)NULL); 173 174 /* wait for 1 sec after kicking the secondary */ 175 wait_till = jiffies + HZ; 176 while (time_before(jiffies, wait_till)) { 177 if (cpu_online(cpu)) 178 break; 179 } 180 181 if (!cpu_online(cpu)) { 182 pr_info("Timeout: CPU%u FAILED to comeup !!!\n", cpu); 183 return -1; 184 } 185 186 secondary_idle_tsk = NULL; 187 188 return 0; 189 } 190 191 /* 192 * not supported here 193 */ 194 int setup_profiling_timer(unsigned int multiplier) 195 { 196 return -EINVAL; 197 } 198 199 /*****************************************************************************/ 200 /* Inter Processor Interrupt Handling */ 201 /*****************************************************************************/ 202 203 enum ipi_msg_type { 204 IPI_EMPTY = 0, 205 IPI_RESCHEDULE = 1, 206 IPI_CALL_FUNC, 207 IPI_CPU_STOP, 208 }; 209 210 /* 211 * In arches with IRQ for each msg type (above), receiver can use IRQ-id to 212 * figure out what msg was sent. For those which don't (ARC has dedicated IPI 213 * IRQ), the msg-type needs to be conveyed via per-cpu data 214 */ 215 216 static DEFINE_PER_CPU(unsigned long, ipi_data); 217 218 static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg) 219 { 220 unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu); 221 unsigned long old, new; 222 unsigned long flags; 223 224 pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu); 225 226 local_irq_save(flags); 227 228 /* 229 * Atomically write new msg bit (in case others are writing too), 230 * and read back old value 231 */ 232 do { 233 new = old = ACCESS_ONCE(*ipi_data_ptr); 234 new |= 1U << msg; 235 } while (cmpxchg(ipi_data_ptr, old, new) != old); 236 237 /* 238 * Call the platform specific IPI kick function, but avoid if possible: 239 * Only do so if there's no pending msg from other concurrent sender(s). 240 * Otherwise, recevier will see this msg as well when it takes the 241 * IPI corresponding to that msg. This is true, even if it is already in 242 * IPI handler, because !@old means it has not yet dequeued the msg(s) 243 * so @new msg can be a free-loader 244 */ 245 if (plat_smp_ops.ipi_send && !old) 246 plat_smp_ops.ipi_send(cpu); 247 248 local_irq_restore(flags); 249 } 250 251 static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg) 252 { 253 unsigned int cpu; 254 255 for_each_cpu(cpu, callmap) 256 ipi_send_msg_one(cpu, msg); 257 } 258 259 void smp_send_reschedule(int cpu) 260 { 261 ipi_send_msg_one(cpu, IPI_RESCHEDULE); 262 } 263 264 void smp_send_stop(void) 265 { 266 struct cpumask targets; 267 cpumask_copy(&targets, cpu_online_mask); 268 cpumask_clear_cpu(smp_processor_id(), &targets); 269 ipi_send_msg(&targets, IPI_CPU_STOP); 270 } 271 272 void arch_send_call_function_single_ipi(int cpu) 273 { 274 ipi_send_msg_one(cpu, IPI_CALL_FUNC); 275 } 276 277 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 278 { 279 ipi_send_msg(mask, IPI_CALL_FUNC); 280 } 281 282 /* 283 * ipi_cpu_stop - handle IPI from smp_send_stop() 284 */ 285 static void ipi_cpu_stop(void) 286 { 287 machine_halt(); 288 } 289 290 static inline int __do_IPI(unsigned long msg) 291 { 292 int rc = 0; 293 294 switch (msg) { 295 case IPI_RESCHEDULE: 296 scheduler_ipi(); 297 break; 298 299 case IPI_CALL_FUNC: 300 generic_smp_call_function_interrupt(); 301 break; 302 303 case IPI_CPU_STOP: 304 ipi_cpu_stop(); 305 break; 306 307 default: 308 rc = 1; 309 } 310 311 return rc; 312 } 313 314 /* 315 * arch-common ISR to handle for inter-processor interrupts 316 * Has hooks for platform specific IPI 317 */ 318 irqreturn_t do_IPI(int irq, void *dev_id) 319 { 320 unsigned long pending; 321 unsigned long __maybe_unused copy; 322 323 pr_debug("IPI [%ld] received on cpu %d\n", 324 *this_cpu_ptr(&ipi_data), smp_processor_id()); 325 326 if (plat_smp_ops.ipi_clear) 327 plat_smp_ops.ipi_clear(irq); 328 329 /* 330 * "dequeue" the msg corresponding to this IPI (and possibly other 331 * piggybacked msg from elided IPIs: see ipi_send_msg_one() above) 332 */ 333 copy = pending = xchg(this_cpu_ptr(&ipi_data), 0); 334 335 do { 336 unsigned long msg = __ffs(pending); 337 int rc; 338 339 rc = __do_IPI(msg); 340 if (rc) 341 pr_info("IPI with bogus msg %ld in %ld\n", msg, copy); 342 pending &= ~(1U << msg); 343 } while (pending); 344 345 return IRQ_HANDLED; 346 } 347 348 /* 349 * API called by platform code to hookup arch-common ISR to their IPI IRQ 350 * 351 * Note: If IPI is provided by platform (vs. say ARC MCIP), their intc setup/map 352 * function needs to call call irq_set_percpu_devid() for IPI IRQ, otherwise 353 * request_percpu_irq() below will fail 354 */ 355 static DEFINE_PER_CPU(int, ipi_dev); 356 357 int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq) 358 { 359 int *dev = per_cpu_ptr(&ipi_dev, cpu); 360 unsigned int virq = irq_find_mapping(NULL, hwirq); 361 362 if (!virq) 363 panic("Cannot find virq for root domain and hwirq=%lu", hwirq); 364 365 /* Boot cpu calls request, all call enable */ 366 if (!cpu) { 367 int rc; 368 369 rc = request_percpu_irq(virq, do_IPI, "IPI Interrupt", dev); 370 if (rc) 371 panic("Percpu IRQ request failed for %u\n", virq); 372 } 373 374 enable_percpu_irq(virq, 0); 375 376 return 0; 377 } 378