1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
5 * RajeshwarR: Dec 11, 2007
6 * -- Added support for Inter Processor Interrupts
8 * Vineetg: Nov 1st, 2007
9 * -- Initial Write (Borrowed heavily from ARM)
12 #include <linux/spinlock.h>
13 #include <linux/sched/mm.h>
14 #include <linux/interrupt.h>
15 #include <linux/profile.h>
17 #include <linux/cpu.h>
18 #include <linux/irq.h>
19 #include <linux/atomic.h>
20 #include <linux/cpumask.h>
21 #include <linux/reboot.h>
22 #include <linux/irqdomain.h>
23 #include <linux/export.h>
24 #include <linux/of_fdt.h>
26 #include <asm/processor.h>
27 #include <asm/setup.h>
28 #include <asm/mach_desc.h>
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;
34 EXPORT_SYMBOL_GPL(smp_atomic_ops_lock);
35 EXPORT_SYMBOL_GPL(smp_bitops_lock);
38 struct plat_smp_ops __weak plat_smp_ops;
40 /* XXX: per cpu ? Only needed once in early seconday boot */
41 struct task_struct *secondary_idle_tsk;
43 /* Called from start_kernel */
44 void __init smp_prepare_boot_cpu(void)
48 static int __init arc_get_cpu_map(const char *name, struct cpumask *cpumask)
50 unsigned long dt_root = of_get_flat_dt_root();
53 buf = of_get_flat_dt_prop(dt_root, name, NULL);
57 if (cpulist_parse(buf, cpumask))
64 * Read from DeviceTree and setup cpu possible mask. If there is no
65 * "possible-cpus" property in DeviceTree pretend all [0..NR_CPUS-1] exist.
67 static void __init arc_init_cpu_possible(void)
69 struct cpumask cpumask;
71 if (arc_get_cpu_map("possible-cpus", &cpumask)) {
72 pr_warn("Failed to get possible-cpus from dtb, pretending all %u cpus exist\n",
75 cpumask_setall(&cpumask);
78 if (!cpumask_test_cpu(0, &cpumask))
79 panic("Master cpu (cpu[0]) is missed in cpu possible mask!");
81 init_cpu_possible(&cpumask);
85 * Called from setup_arch() before calling setup_processor()
87 * - Initialise the CPU possible map early - this describes the CPUs
88 * which may be present or become present in the system.
89 * - Call early smp init hook. This can initialize a specific multi-core
90 * IP which is say common to several platforms (hence not part of
91 * platform specific int_early() hook)
93 void __init smp_init_cpus(void)
95 arc_init_cpu_possible();
97 if (plat_smp_ops.init_early_smp)
98 plat_smp_ops.init_early_smp();
101 /* called from init ( ) => process 1 */
102 void __init smp_prepare_cpus(unsigned int max_cpus)
105 * if platform didn't set the present map already, do it now
106 * boot cpu is set to present already by init/main.c
108 if (num_present_cpus() <= 1)
109 init_cpu_present(cpu_possible_mask);
112 void __init smp_cpus_done(unsigned int max_cpus)
118 * Default smp boot helper for Run-on-reset case where all cores start off
119 * together. Non-masters need to wait for Master to start running.
120 * This is implemented using a flag in memory, which Non-masters spin-wait on.
121 * Master sets it to cpu-id of core to "ungate" it.
123 static volatile int wake_flag;
125 #ifdef CONFIG_ISA_ARCOMPACT
127 #define __boot_read(f) f
128 #define __boot_write(f, v) f = v
132 #define __boot_read(f) arc_read_uncached_32(&f)
133 #define __boot_write(f, v) arc_write_uncached_32(&f, v)
137 static void arc_default_smp_cpu_kick(int cpu, unsigned long pc)
141 __boot_write(wake_flag, cpu);
144 void arc_platform_smp_wait_to_boot(int cpu)
146 /* for halt-on-reset, we've waited already */
147 if (IS_ENABLED(CONFIG_ARC_SMP_HALT_ON_RESET))
150 while (__boot_read(wake_flag) != cpu)
153 __boot_write(wake_flag, 0);
156 const char *arc_platform_smp_cpuinfo(void)
158 return plat_smp_ops.info ? : "";
162 * The very first "C" code executed by secondary
163 * Called from asm stub in head.S
164 * "current"/R25 already setup by low level boot code
166 void start_kernel_secondary(void)
168 struct mm_struct *mm = &init_mm;
169 unsigned int cpu = smp_processor_id();
171 /* MMU, Caches, Vector Table, Interrupts etc */
176 current->active_mm = mm;
177 cpumask_set_cpu(cpu, mm_cpumask(mm));
179 /* Some SMP H/w setup - for each cpu */
180 if (plat_smp_ops.init_per_cpu)
181 plat_smp_ops.init_per_cpu(cpu);
183 if (machine_desc->init_per_cpu)
184 machine_desc->init_per_cpu(cpu);
186 notify_cpu_starting(cpu);
187 set_cpu_online(cpu, true);
189 pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu);
192 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
196 * Called from kernel_init( ) -> smp_init( ) - for each CPU
198 * At this point, Secondary Processor is "HALT"ed:
199 * -It booted, but was halted in head.S
200 * -It was configured to halt-on-reset
201 * So need to wake it up.
203 * Essential requirements being where to run from (PC) and stack (SP)
205 int __cpu_up(unsigned int cpu, struct task_struct *idle)
207 unsigned long wait_till;
209 secondary_idle_tsk = idle;
211 pr_info("Idle Task [%d] %p", cpu, idle);
212 pr_info("Trying to bring up CPU%u ...\n", cpu);
214 if (plat_smp_ops.cpu_kick)
215 plat_smp_ops.cpu_kick(cpu,
216 (unsigned long)first_lines_of_secondary);
218 arc_default_smp_cpu_kick(cpu, (unsigned long)NULL);
220 /* wait for 1 sec after kicking the secondary */
221 wait_till = jiffies + HZ;
222 while (time_before(jiffies, wait_till)) {
227 if (!cpu_online(cpu)) {
228 pr_info("Timeout: CPU%u FAILED to come up !!!\n", cpu);
232 secondary_idle_tsk = NULL;
240 int setup_profiling_timer(unsigned int multiplier)
245 /*****************************************************************************/
246 /* Inter Processor Interrupt Handling */
247 /*****************************************************************************/
257 * In arches with IRQ for each msg type (above), receiver can use IRQ-id to
258 * figure out what msg was sent. For those which don't (ARC has dedicated IPI
259 * IRQ), the msg-type needs to be conveyed via per-cpu data
262 static DEFINE_PER_CPU(unsigned long, ipi_data);
264 static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg)
266 unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu);
267 unsigned long old, new;
270 pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu);
272 local_irq_save(flags);
275 * Atomically write new msg bit (in case others are writing too),
276 * and read back old value
279 new = old = READ_ONCE(*ipi_data_ptr);
281 } while (cmpxchg(ipi_data_ptr, old, new) != old);
284 * Call the platform specific IPI kick function, but avoid if possible:
285 * Only do so if there's no pending msg from other concurrent sender(s).
286 * Otherwise, recevier will see this msg as well when it takes the
287 * IPI corresponding to that msg. This is true, even if it is already in
288 * IPI handler, because !@old means it has not yet dequeued the msg(s)
289 * so @new msg can be a free-loader
291 if (plat_smp_ops.ipi_send && !old)
292 plat_smp_ops.ipi_send(cpu);
294 local_irq_restore(flags);
297 static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
301 for_each_cpu(cpu, callmap)
302 ipi_send_msg_one(cpu, msg);
305 void smp_send_reschedule(int cpu)
307 ipi_send_msg_one(cpu, IPI_RESCHEDULE);
310 void smp_send_stop(void)
312 struct cpumask targets;
313 cpumask_copy(&targets, cpu_online_mask);
314 cpumask_clear_cpu(smp_processor_id(), &targets);
315 ipi_send_msg(&targets, IPI_CPU_STOP);
318 void arch_send_call_function_single_ipi(int cpu)
320 ipi_send_msg_one(cpu, IPI_CALL_FUNC);
323 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
325 ipi_send_msg(mask, IPI_CALL_FUNC);
329 * ipi_cpu_stop - handle IPI from smp_send_stop()
331 static void ipi_cpu_stop(void)
336 static inline int __do_IPI(unsigned long msg)
346 generic_smp_call_function_interrupt();
361 * arch-common ISR to handle for inter-processor interrupts
362 * Has hooks for platform specific IPI
364 irqreturn_t do_IPI(int irq, void *dev_id)
366 unsigned long pending;
367 unsigned long __maybe_unused copy;
369 pr_debug("IPI [%ld] received on cpu %d\n",
370 *this_cpu_ptr(&ipi_data), smp_processor_id());
372 if (plat_smp_ops.ipi_clear)
373 plat_smp_ops.ipi_clear(irq);
376 * "dequeue" the msg corresponding to this IPI (and possibly other
377 * piggybacked msg from elided IPIs: see ipi_send_msg_one() above)
379 copy = pending = xchg(this_cpu_ptr(&ipi_data), 0);
382 unsigned long msg = __ffs(pending);
387 pr_info("IPI with bogus msg %ld in %ld\n", msg, copy);
388 pending &= ~(1U << msg);
395 * API called by platform code to hookup arch-common ISR to their IPI IRQ
397 * Note: If IPI is provided by platform (vs. say ARC MCIP), their intc setup/map
398 * function needs to call call irq_set_percpu_devid() for IPI IRQ, otherwise
399 * request_percpu_irq() below will fail
401 static DEFINE_PER_CPU(int, ipi_dev);
403 int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq)
405 int *dev = per_cpu_ptr(&ipi_dev, cpu);
406 unsigned int virq = irq_find_mapping(NULL, hwirq);
409 panic("Cannot find virq for root domain and hwirq=%lu", hwirq);
411 /* Boot cpu calls request, all call enable */
415 rc = request_percpu_irq(virq, do_IPI, "IPI Interrupt", dev);
417 panic("Percpu IRQ request failed for %u\n", virq);
420 enable_percpu_irq(virq, 0);