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authorJon Medhurst <tixy@linaro.org>2013-05-09 14:07:09 +0100
committerJon Medhurst <tixy@linaro.org>2013-05-09 14:07:09 +0100
commit4b460cf013ef6b158d870f5d5dff7989535f5aac (patch)
tree566f5774f5b5795338481b69bacfcfa097245cf8 /arch/arm/mach-vexpress/tc2_pm_psci.c
parentc5b970dd2f809ce3675902f672a1d676aed43c7a (diff)
parent42ef096d399170367f55a37c126c67eb846c381b (diff)
downloadvexpress-lsk-4b460cf013ef6b158d870f5d5dff7989535f5aac.tar.gz
Merge branch 'tracking-armlt-tc2-psci' into lsk-3.9-vexpress
Diffstat (limited to 'arch/arm/mach-vexpress/tc2_pm_psci.c')
-rw-r--r--arch/arm/mach-vexpress/tc2_pm_psci.c168
1 files changed, 168 insertions, 0 deletions
diff --git a/arch/arm/mach-vexpress/tc2_pm_psci.c b/arch/arm/mach-vexpress/tc2_pm_psci.c
new file mode 100644
index 00000000000..5a5e4f56849
--- /dev/null
+++ b/arch/arm/mach-vexpress/tc2_pm_psci.c
@@ -0,0 +1,168 @@
+/*
+ * arch/arm/mach-vexpress/tc2_pm_psci.c - TC2 PSCI support
+ *
+ * Created by: Achin Gupta, December 2012
+ * Copyright: (C) 2012 ARM Limited
+ *
+ * Some portions of this file were originally written by Nicolas Pitre
+ * Copyright: (C) 2012 Linaro Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/errno.h>
+
+#include <asm/mcpm.h>
+#include <asm/proc-fns.h>
+#include <asm/cacheflush.h>
+#include <asm/psci.h>
+#include <asm/atomic.h>
+#include <asm/cputype.h>
+#include <asm/cp15.h>
+
+#include <mach/motherboard.h>
+#include <mach/tc2.h>
+
+#include <linux/vexpress.h>
+
+/*
+ * Platform specific state id understood by the firmware and used to
+ * program the power controller
+ */
+#define PSCI_POWER_STATE_ID 0
+
+static atomic_t tc2_pm_use_count[TC2_MAX_CPUS][TC2_MAX_CLUSTERS];
+
+static int tc2_pm_psci_power_up(unsigned int cpu, unsigned int cluster)
+{
+ unsigned int mpidr = (cluster << 8) | cpu;
+ int ret = 0;
+
+ BUG_ON(!psci_ops.cpu_on);
+
+ switch (atomic_inc_return(&tc2_pm_use_count[cpu][cluster])) {
+ case 1:
+ /*
+ * This is a request to power up a cpu that linux thinks has
+ * been powered down. Retries are needed if the firmware has
+ * seen the power down request as yet.
+ */
+ do
+ ret = psci_ops.cpu_on(mpidr,
+ virt_to_phys(mcpm_entry_point));
+ while (ret == -EAGAIN);
+
+ return ret;
+ case 2:
+ /* This power up request has overtaken a power down request */
+ return ret;
+ default:
+ /* Any other value is a bug */
+ BUG();
+ }
+}
+
+static void tc2_pm_psci_power_down(void)
+{
+ struct psci_power_state power_state;
+ unsigned int mpidr, cpu, cluster;
+
+ mpidr = read_cpuid_mpidr();
+ cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+ cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+
+ BUG_ON(!psci_ops.cpu_off);
+
+ switch (atomic_dec_return(&tc2_pm_use_count[cpu][cluster])) {
+ case 1:
+ /*
+ * Overtaken by a power up. Flush caches, exit coherency,
+ * return & fake a reset
+ */
+ set_cr(get_cr() & ~CR_C);
+
+ flush_cache_louis();
+
+ asm volatile ("clrex");
+ set_auxcr(get_auxcr() & ~(1 << 6));
+
+ return;
+ case 0:
+ /* A normal request to possibly power down the cluster */
+ power_state.id = PSCI_POWER_STATE_ID;
+ power_state.type = PSCI_POWER_STATE_TYPE_POWER_DOWN;
+ power_state.affinity_level = PSCI_POWER_STATE_AFFINITY_LEVEL1;
+
+ psci_ops.cpu_off(power_state);
+
+ /* On success this function never returns */
+ default:
+ /* Any other value is a bug */
+ BUG();
+ }
+}
+
+static void tc2_pm_psci_suspend(u64 unused)
+{
+ struct psci_power_state power_state;
+
+ BUG_ON(!psci_ops.cpu_suspend);
+
+ /* On TC2 always attempt to power down the cluster */
+ power_state.id = PSCI_POWER_STATE_ID;
+ power_state.type = PSCI_POWER_STATE_TYPE_POWER_DOWN;
+ power_state.affinity_level = PSCI_POWER_STATE_AFFINITY_LEVEL1;
+
+ psci_ops.cpu_suspend(power_state, virt_to_phys(mcpm_entry_point));
+
+ /* On success this function never returns */
+ BUG();
+}
+
+static const struct mcpm_platform_ops tc2_pm_power_ops = {
+ .power_up = tc2_pm_psci_power_up,
+ .power_down = tc2_pm_psci_power_down,
+ .suspend = tc2_pm_psci_suspend,
+};
+
+static void __init tc2_pm_usage_count_init(void)
+{
+ unsigned int mpidr, cpu, cluster;
+
+ mpidr = read_cpuid_mpidr();
+ cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+ cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+
+ pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+ BUG_ON(cluster >= TC2_MAX_CLUSTERS ||
+ cpu >= vexpress_spc_get_nb_cpus(cluster));
+
+ atomic_set(&tc2_pm_use_count[cpu][cluster], 1);
+}
+
+static int __init tc2_pm_psci_init(void)
+{
+ int ret;
+
+ ret = psci_probe();
+ if (ret) {
+ pr_debug("psci not found. Aborting psci init\n");
+ return -ENODEV;
+ }
+
+ tc2_pm_usage_count_init();
+
+ ret = mcpm_platform_register(&tc2_pm_power_ops);
+ if (!ret)
+ ret = mcpm_sync_init(NULL);
+ if (!ret)
+ pr_info("TC2 power management initialized\n");
+ return ret;
+}
+
+early_initcall(tc2_pm_psci_init);