blob: 990250965f2cfb4e4e3a984678fcf62eedbcdb8d [file] [log] [blame]
Nicolas Pitree8db2882012-04-12 02:45:22 -04001/*
2 * arch/arm/common/mcpm_entry.c -- entry point for multi-cluster PM
3 *
4 * Created by: Nicolas Pitre, March 2012
5 * Copyright: (C) 2012-2013 Linaro Limited
6 *
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.
10 */
11
Nicolas Pitre7c2b8602012-09-20 16:05:37 -040012#include <linux/kernel.h>
13#include <linux/init.h>
14#include <linux/irqflags.h>
15
Nicolas Pitree8db2882012-04-12 02:45:22 -040016#include <asm/mcpm.h>
17#include <asm/cacheflush.h>
Nicolas Pitre7c2b8602012-09-20 16:05:37 -040018#include <asm/idmap.h>
Dave Martin7fe31d22012-07-17 14:25:42 +010019#include <asm/cputype.h>
Nicolas Pitree8db2882012-04-12 02:45:22 -040020
21extern unsigned long mcpm_entry_vectors[MAX_NR_CLUSTERS][MAX_CPUS_PER_CLUSTER];
22
23void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr)
24{
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]);
28}
Nicolas Pitre7c2b8602012-09-20 16:05:37 -040029
30static const struct mcpm_platform_ops *platform_ops;
31
32int __init mcpm_platform_register(const struct mcpm_platform_ops *ops)
33{
34 if (platform_ops)
35 return -EBUSY;
36 platform_ops = ops;
37 return 0;
38}
39
40int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster)
41{
42 if (!platform_ops)
43 return -EUNATCH; /* try not to shadow power_up errors */
44 might_sleep();
45 return platform_ops->power_up(cpu, cluster);
46}
47
48typedef void (*phys_reset_t)(unsigned long);
49
50void mcpm_cpu_power_down(void)
51{
52 phys_reset_t phys_reset;
53
Nicolas Pitred0cdef62013-09-25 23:26:24 +010054 if (WARN_ON_ONCE(!platform_ops || !platform_ops->power_down))
55 return;
Nicolas Pitre7c2b8602012-09-20 16:05:37 -040056 BUG_ON(!irqs_disabled());
57
58 /*
59 * Do this before calling into the power_down method,
60 * as it might not always be safe to do afterwards.
61 */
62 setup_mm_for_reboot();
63
64 platform_ops->power_down();
65
66 /*
67 * It is possible for a power_up request to happen concurrently
68 * with a power_down request for the same CPU. In this case the
69 * power_down method might not be able to actually enter a
70 * powered down state with the WFI instruction if the power_up
71 * method has removed the required reset condition. The
72 * power_down method is then allowed to return. We must perform
73 * a re-entry in the kernel as if the power_up method just had
74 * deasserted reset on the CPU.
75 *
76 * To simplify race issues, the platform specific implementation
77 * must accommodate for the possibility of unordered calls to
78 * power_down and power_up with a usage count. Therefore, if a
79 * call to power_up is issued for a CPU that is not down, then
80 * the next call to power_down must not attempt a full shutdown
81 * but only do the minimum (normally disabling L1 cache and CPU
82 * coherency) and return just as if a concurrent power_up request
83 * had happened as described above.
84 */
85
86 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
87 phys_reset(virt_to_phys(mcpm_entry_point));
88
89 /* should never get here */
90 BUG();
91}
92
93void mcpm_cpu_suspend(u64 expected_residency)
94{
95 phys_reset_t phys_reset;
96
Nicolas Pitred0cdef62013-09-25 23:26:24 +010097 if (WARN_ON_ONCE(!platform_ops || !platform_ops->suspend))
98 return;
Nicolas Pitre7c2b8602012-09-20 16:05:37 -040099 BUG_ON(!irqs_disabled());
100
101 /* Very similar to mcpm_cpu_power_down() */
102 setup_mm_for_reboot();
103 platform_ops->suspend(expected_residency);
104 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
105 phys_reset(virt_to_phys(mcpm_entry_point));
106 BUG();
107}
108
109int mcpm_cpu_powered_up(void)
110{
111 if (!platform_ops)
112 return -EUNATCH;
113 if (platform_ops->powered_up)
114 platform_ops->powered_up();
115 return 0;
116}
Dave Martin7fe31d22012-07-17 14:25:42 +0100117
118struct sync_struct mcpm_sync;
119
120/*
121 * __mcpm_cpu_going_down: Indicates that the cpu is being torn down.
122 * This must be called at the point of committing to teardown of a CPU.
123 * The CPU cache (SCTRL.C bit) is expected to still be active.
124 */
125void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster)
126{
127 mcpm_sync.clusters[cluster].cpus[cpu].cpu = CPU_GOING_DOWN;
128 sync_cache_w(&mcpm_sync.clusters[cluster].cpus[cpu].cpu);
129}
130
131/*
132 * __mcpm_cpu_down: Indicates that cpu teardown is complete and that the
133 * cluster can be torn down without disrupting this CPU.
134 * To avoid deadlocks, this must be called before a CPU is powered down.
135 * The CPU cache (SCTRL.C bit) is expected to be off.
136 * However L2 cache might or might not be active.
137 */
138void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster)
139{
140 dmb();
141 mcpm_sync.clusters[cluster].cpus[cpu].cpu = CPU_DOWN;
142 sync_cache_w(&mcpm_sync.clusters[cluster].cpus[cpu].cpu);
143 dsb_sev();
144}
145
146/*
147 * __mcpm_outbound_leave_critical: Leave the cluster teardown critical section.
148 * @state: the final state of the cluster:
149 * CLUSTER_UP: no destructive teardown was done and the cluster has been
150 * restored to the previous state (CPU cache still active); or
151 * CLUSTER_DOWN: the cluster has been torn-down, ready for power-off
152 * (CPU cache disabled, L2 cache either enabled or disabled).
153 */
154void __mcpm_outbound_leave_critical(unsigned int cluster, int state)
155{
156 dmb();
157 mcpm_sync.clusters[cluster].cluster = state;
158 sync_cache_w(&mcpm_sync.clusters[cluster].cluster);
159 dsb_sev();
160}
161
162/*
163 * __mcpm_outbound_enter_critical: Enter the cluster teardown critical section.
164 * This function should be called by the last man, after local CPU teardown
165 * is complete. CPU cache expected to be active.
166 *
167 * Returns:
168 * false: the critical section was not entered because an inbound CPU was
169 * observed, or the cluster is already being set up;
170 * true: the critical section was entered: it is now safe to tear down the
171 * cluster.
172 */
173bool __mcpm_outbound_enter_critical(unsigned int cpu, unsigned int cluster)
174{
175 unsigned int i;
176 struct mcpm_sync_struct *c = &mcpm_sync.clusters[cluster];
177
178 /* Warn inbound CPUs that the cluster is being torn down: */
179 c->cluster = CLUSTER_GOING_DOWN;
180 sync_cache_w(&c->cluster);
181
182 /* Back out if the inbound cluster is already in the critical region: */
183 sync_cache_r(&c->inbound);
184 if (c->inbound == INBOUND_COMING_UP)
185 goto abort;
186
187 /*
188 * Wait for all CPUs to get out of the GOING_DOWN state, so that local
189 * teardown is complete on each CPU before tearing down the cluster.
190 *
191 * If any CPU has been woken up again from the DOWN state, then we
192 * shouldn't be taking the cluster down at all: abort in that case.
193 */
194 sync_cache_r(&c->cpus);
195 for (i = 0; i < MAX_CPUS_PER_CLUSTER; i++) {
196 int cpustate;
197
198 if (i == cpu)
199 continue;
200
201 while (1) {
202 cpustate = c->cpus[i].cpu;
203 if (cpustate != CPU_GOING_DOWN)
204 break;
205
206 wfe();
207 sync_cache_r(&c->cpus[i].cpu);
208 }
209
210 switch (cpustate) {
211 case CPU_DOWN:
212 continue;
213
214 default:
215 goto abort;
216 }
217 }
218
219 return true;
220
221abort:
222 __mcpm_outbound_leave_critical(cluster, CLUSTER_UP);
223 return false;
224}
225
226int __mcpm_cluster_state(unsigned int cluster)
227{
228 sync_cache_r(&mcpm_sync.clusters[cluster].cluster);
229 return mcpm_sync.clusters[cluster].cluster;
230}
231
232extern unsigned long mcpm_power_up_setup_phys;
233
234int __init mcpm_sync_init(
235 void (*power_up_setup)(unsigned int affinity_level))
236{
237 unsigned int i, j, mpidr, this_cluster;
238
239 BUILD_BUG_ON(MCPM_SYNC_CLUSTER_SIZE * MAX_NR_CLUSTERS != sizeof mcpm_sync);
240 BUG_ON((unsigned long)&mcpm_sync & (__CACHE_WRITEBACK_GRANULE - 1));
241
242 /*
243 * Set initial CPU and cluster states.
244 * Only one cluster is assumed to be active at this point.
245 */
246 for (i = 0; i < MAX_NR_CLUSTERS; i++) {
247 mcpm_sync.clusters[i].cluster = CLUSTER_DOWN;
248 mcpm_sync.clusters[i].inbound = INBOUND_NOT_COMING_UP;
249 for (j = 0; j < MAX_CPUS_PER_CLUSTER; j++)
250 mcpm_sync.clusters[i].cpus[j].cpu = CPU_DOWN;
251 }
252 mpidr = read_cpuid_mpidr();
253 this_cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
254 for_each_online_cpu(i)
255 mcpm_sync.clusters[this_cluster].cpus[i].cpu = CPU_UP;
256 mcpm_sync.clusters[this_cluster].cluster = CLUSTER_UP;
257 sync_cache_w(&mcpm_sync);
258
259 if (power_up_setup) {
260 mcpm_power_up_setup_phys = virt_to_phys(power_up_setup);
261 sync_cache_w(&mcpm_power_up_setup_phys);
262 }
263
264 return 0;
265}