2 * arch/arm/common/mcpm_entry.c -- entry point for multi-cluster PM
4 * Created by: Nicolas Pitre, March 2012
5 * Copyright: (C) 2012-2013 Linaro Limited
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <linux/irqflags.h>
17 #include <asm/cacheflush.h>
18 #include <asm/idmap.h>
19 #include <asm/cputype.h>
21 extern unsigned long mcpm_entry_vectors[MAX_NR_CLUSTERS][MAX_CPUS_PER_CLUSTER];
23 void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr)
25 unsigned long val = ptr ? virt_to_phys(ptr) : 0;
26 mcpm_entry_vectors[cluster][cpu] = val;
27 sync_cache_w(&mcpm_entry_vectors[cluster][cpu]);
30 extern unsigned long mcpm_entry_early_pokes[MAX_NR_CLUSTERS][MAX_CPUS_PER_CLUSTER][2];
32 void mcpm_set_early_poke(unsigned cpu, unsigned cluster,
33 unsigned long poke_phys_addr, unsigned long poke_val)
35 unsigned long *poke = &mcpm_entry_early_pokes[cluster][cpu][0];
36 poke[0] = poke_phys_addr;
38 __cpuc_flush_dcache_area((void *)poke, 8);
39 outer_clean_range(__pa(poke), __pa(poke + 2));
42 static const struct mcpm_platform_ops *platform_ops;
44 int __init mcpm_platform_register(const struct mcpm_platform_ops *ops)
52 int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster)
55 return -EUNATCH; /* try not to shadow power_up errors */
57 return platform_ops->power_up(cpu, cluster);
60 typedef void (*phys_reset_t)(unsigned long);
62 void mcpm_cpu_power_down(void)
64 phys_reset_t phys_reset;
66 if (WARN_ON_ONCE(!platform_ops || !platform_ops->power_down))
68 BUG_ON(!irqs_disabled());
71 * Do this before calling into the power_down method,
72 * as it might not always be safe to do afterwards.
74 setup_mm_for_reboot();
76 platform_ops->power_down();
79 * It is possible for a power_up request to happen concurrently
80 * with a power_down request for the same CPU. In this case the
81 * power_down method might not be able to actually enter a
82 * powered down state with the WFI instruction if the power_up
83 * method has removed the required reset condition. The
84 * power_down method is then allowed to return. We must perform
85 * a re-entry in the kernel as if the power_up method just had
86 * deasserted reset on the CPU.
88 * To simplify race issues, the platform specific implementation
89 * must accommodate for the possibility of unordered calls to
90 * power_down and power_up with a usage count. Therefore, if a
91 * call to power_up is issued for a CPU that is not down, then
92 * the next call to power_down must not attempt a full shutdown
93 * but only do the minimum (normally disabling L1 cache and CPU
94 * coherency) and return just as if a concurrent power_up request
95 * had happened as described above.
98 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
99 phys_reset(virt_to_phys(mcpm_entry_point));
101 /* should never get here */
105 void mcpm_cpu_suspend(u64 expected_residency)
107 phys_reset_t phys_reset;
109 if (WARN_ON_ONCE(!platform_ops || !platform_ops->suspend))
111 BUG_ON(!irqs_disabled());
113 /* Very similar to mcpm_cpu_power_down() */
114 setup_mm_for_reboot();
115 platform_ops->suspend(expected_residency);
116 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
117 phys_reset(virt_to_phys(mcpm_entry_point));
121 int mcpm_cpu_powered_up(void)
125 if (platform_ops->powered_up)
126 platform_ops->powered_up();
130 struct sync_struct mcpm_sync;
133 * __mcpm_cpu_going_down: Indicates that the cpu is being torn down.
134 * This must be called at the point of committing to teardown of a CPU.
135 * The CPU cache (SCTRL.C bit) is expected to still be active.
137 void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster)
139 mcpm_sync.clusters[cluster].cpus[cpu].cpu = CPU_GOING_DOWN;
140 sync_cache_w(&mcpm_sync.clusters[cluster].cpus[cpu].cpu);
144 * __mcpm_cpu_down: Indicates that cpu teardown is complete and that the
145 * cluster can be torn down without disrupting this CPU.
146 * To avoid deadlocks, this must be called before a CPU is powered down.
147 * The CPU cache (SCTRL.C bit) is expected to be off.
148 * However L2 cache might or might not be active.
150 void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster)
153 mcpm_sync.clusters[cluster].cpus[cpu].cpu = CPU_DOWN;
154 sync_cache_w(&mcpm_sync.clusters[cluster].cpus[cpu].cpu);
159 * __mcpm_outbound_leave_critical: Leave the cluster teardown critical section.
160 * @state: the final state of the cluster:
161 * CLUSTER_UP: no destructive teardown was done and the cluster has been
162 * restored to the previous state (CPU cache still active); or
163 * CLUSTER_DOWN: the cluster has been torn-down, ready for power-off
164 * (CPU cache disabled, L2 cache either enabled or disabled).
166 void __mcpm_outbound_leave_critical(unsigned int cluster, int state)
169 mcpm_sync.clusters[cluster].cluster = state;
170 sync_cache_w(&mcpm_sync.clusters[cluster].cluster);
175 * __mcpm_outbound_enter_critical: Enter the cluster teardown critical section.
176 * This function should be called by the last man, after local CPU teardown
177 * is complete. CPU cache expected to be active.
180 * false: the critical section was not entered because an inbound CPU was
181 * observed, or the cluster is already being set up;
182 * true: the critical section was entered: it is now safe to tear down the
185 bool __mcpm_outbound_enter_critical(unsigned int cpu, unsigned int cluster)
188 struct mcpm_sync_struct *c = &mcpm_sync.clusters[cluster];
190 /* Warn inbound CPUs that the cluster is being torn down: */
191 c->cluster = CLUSTER_GOING_DOWN;
192 sync_cache_w(&c->cluster);
194 /* Back out if the inbound cluster is already in the critical region: */
195 sync_cache_r(&c->inbound);
196 if (c->inbound == INBOUND_COMING_UP)
200 * Wait for all CPUs to get out of the GOING_DOWN state, so that local
201 * teardown is complete on each CPU before tearing down the cluster.
203 * If any CPU has been woken up again from the DOWN state, then we
204 * shouldn't be taking the cluster down at all: abort in that case.
206 sync_cache_r(&c->cpus);
207 for (i = 0; i < MAX_CPUS_PER_CLUSTER; i++) {
214 cpustate = c->cpus[i].cpu;
215 if (cpustate != CPU_GOING_DOWN)
219 sync_cache_r(&c->cpus[i].cpu);
234 __mcpm_outbound_leave_critical(cluster, CLUSTER_UP);
238 int __mcpm_cluster_state(unsigned int cluster)
240 sync_cache_r(&mcpm_sync.clusters[cluster].cluster);
241 return mcpm_sync.clusters[cluster].cluster;
244 extern unsigned long mcpm_power_up_setup_phys;
246 int __init mcpm_sync_init(
247 void (*power_up_setup)(unsigned int affinity_level))
249 unsigned int i, j, mpidr, this_cluster;
251 BUILD_BUG_ON(MCPM_SYNC_CLUSTER_SIZE * MAX_NR_CLUSTERS != sizeof mcpm_sync);
252 BUG_ON((unsigned long)&mcpm_sync & (__CACHE_WRITEBACK_GRANULE - 1));
255 * Set initial CPU and cluster states.
256 * Only one cluster is assumed to be active at this point.
258 for (i = 0; i < MAX_NR_CLUSTERS; i++) {
259 mcpm_sync.clusters[i].cluster = CLUSTER_DOWN;
260 mcpm_sync.clusters[i].inbound = INBOUND_NOT_COMING_UP;
261 for (j = 0; j < MAX_CPUS_PER_CLUSTER; j++)
262 mcpm_sync.clusters[i].cpus[j].cpu = CPU_DOWN;
264 mpidr = read_cpuid_mpidr();
265 this_cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
266 for_each_online_cpu(i)
267 mcpm_sync.clusters[this_cluster].cpus[i].cpu = CPU_UP;
268 mcpm_sync.clusters[this_cluster].cluster = CLUSTER_UP;
269 sync_cache_w(&mcpm_sync);
271 if (power_up_setup) {
272 mcpm_power_up_setup_phys = virt_to_phys(power_up_setup);
273 sync_cache_w(&mcpm_power_up_setup_phys);