From: Scott Moser <smoser@redhat.com>
Date: Tue, 20 Nov 2007 17:29:37 -0500
Subject: [ppc64] cbe_cpufreq: fixes from 2.6.23-rc7
Message-id: 11955977803420-do-send-email-smoser@redhat.com
O-Subject: [PATCH RHEL5u2] bz279171 Cell/B.E. Power and Thermal Management [2/4]
Bugzilla: 279171

Backport from 74889e41d9a1f80928130a02af9b010673bc5ba7,
5050063c0464663a0b0c3dc9fc5bc822aa74a1dd,
36ca4ba4b9728f3c420a589a3322c2fbd7ec88b7 and fixes to those.

Subject: cbe_cpufreq: backport cbe_cpufreq driver to rhel-5-2

From: krafft@linux.vnet.ibm.com
This patch ports the cbe_cpufreq driver to the rhel-5-2 kernel.
It includes all fixes that made it into 2.6.23-rc7.

Signed-off-by: Christian Krafft <krafft@de.ibm.com>
--
 arch/powerpc/configs/cell_defconfig                 |   16 +
 arch/powerpc/kernel/prom.c                          |    1
 arch/powerpc/kernel/smp.c                           |    1
 arch/powerpc/platforms/cell/Kconfig                 |   19 +
 arch/powerpc/platforms/cell/Makefile                |    4
 arch/powerpc/platforms/cell/cbe_cpufreq.c           |  209 ++++++++++++++
 arch/powerpc/platforms/cell/cbe_cpufreq.h           |   23 +
 arch/powerpc/platforms/cell/cbe_cpufreq_pervasive.c |  118 +++++++
 arch/powerpc/platforms/cell/cbe_cpufreq_pmi.c       |  146 +++++++++
 9 files changed, 536 insertions(+), 1 deletion(-)

Acked-by: David Howells <dhowells@redhat.com>

diff --git a/arch/powerpc/configs/cell_defconfig b/arch/powerpc/configs/cell_defconfig
index 6fd9e7a..327c2d2 100644
--- a/arch/powerpc/configs/cell_defconfig
+++ b/arch/powerpc/configs/cell_defconfig
@@ -133,7 +133,19 @@ CONFIG_RTAS_FLASH=y
 CONFIG_MMIO_NVRAM=y
 # CONFIG_PPC_MPC106 is not set
 # CONFIG_PPC_970_NAP is not set
-# CONFIG_CPU_FREQ is not set
+CONFIG_CPU_FREQ=y
+CONFIG_CPU_FREQ_TABLE=y
+# CONFIG_CPU_FREQ_DEBUG is not set
+CONFIG_CPU_FREQ_STAT=y
+# CONFIG_CPU_FREQ_STAT_DETAILS is not set
+CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y
+# CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE is not set
+CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
+CONFIG_CPU_FREQ_GOV_POWERSAVE=m
+CONFIG_CPU_FREQ_GOV_USERSPACE=m
+CONFIG_CPU_FREQ_GOV_ONDEMAND=m
+# CONFIG_CPU_FREQ_GOV_CONSERVATIVE is not set
+
 # CONFIG_WANT_EARLY_SERIAL is not set
 # CONFIG_MPIC is not set
 
@@ -144,6 +156,8 @@ CONFIG_SPU_FS=m
 CONFIG_SPU_BASE=y
 CONFIG_SPUFS_MMAP=y
 CONFIG_CBE_RAS=y
+CONFIG_CBE_CPUFREQ=m
+CONFIG_CBE_CPUFREQ_PMI=m
 
 #
 # Kernel options
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 5d1d1dd..4bb5798 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -1729,6 +1729,7 @@ struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
 	}
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(of_get_cpu_node);
 
 #ifdef DEBUG
 static struct debugfs_blob_wrapper flat_dt_blob;
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 6a9bc9c..464f9b1 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -65,6 +65,7 @@ cpumask_t cpu_sibling_map[NR_CPUS] = { [0 ... NR_CPUS-1] = CPU_MASK_NONE };
 
 EXPORT_SYMBOL(cpu_online_map);
 EXPORT_SYMBOL(cpu_possible_map);
+EXPORT_SYMBOL(cpu_sibling_map);
 
 /* SMP operations for this machine */
 struct smp_ops_t *smp_ops;
diff --git a/arch/powerpc/platforms/cell/Kconfig b/arch/powerpc/platforms/cell/Kconfig
index ec27d03..e5d2e8c 100644
--- a/arch/powerpc/platforms/cell/Kconfig
+++ b/arch/powerpc/platforms/cell/Kconfig
@@ -25,6 +25,25 @@ config CBE_RAS
 	bool "RAS features for bare metal Cell BE"
 	default y
 
+config CBE_CPUFREQ
+        tristate "CBE frequency scaling"
+        depends on CBE_RAS && CPU_FREQ
+        default m
+        help
+          This adds the cpufreq driver for Cell BE processors.
+          For details, take a look at <file:Documentation/cpu-freq/>.
+          If you don't have such processor, say N
+
+config CBE_CPUFREQ_PMI
+        tristate "CBE frequency scaling using PMI interface"
+        depends on CBE_CPUFREQ && PPC_PMI && EXPERIMENTAL
+        default n
+        help
+          Select this, if you want to use the PMI interface
+          to switch frequencies. Using PMI, the
+          processor will not only be able to run at lower speed,
+          but also at lower core voltage.
+
 config CBE_AXON_UTL
 	bool "CBE/Axon PCIe Upper Transaction layer error handling"
 	default n
diff --git a/arch/powerpc/platforms/cell/Makefile b/arch/powerpc/platforms/cell/Makefile
index b5a968c..9f671e4 100644
--- a/arch/powerpc/platforms/cell/Makefile
+++ b/arch/powerpc/platforms/cell/Makefile
@@ -3,6 +3,10 @@ obj-$(CONFIG_PPC_CELL_NATIVE)		+= interrupt.o iommu.o setup.o \
 					   io-workarounds.o
 obj-$(CONFIG_CBE_RAS)			+= ras.o
 
+obj-$(CONFIG_CBE_CPUFREQ_PMI)           += cbe_cpufreq_pmi.o
+obj-$(CONFIG_CBE_CPUFREQ)               += cbe-cpufreq.o
+cbe-cpufreq-y                           += cbe_cpufreq_pervasive.o cbe_cpufreq.o
+
 obj-$(CONFIG_CBE_AXON_UTL)		+= axon_utl.o
 obj-$(CONFIG_CBE_AXON_PCI)		+= axon_pci-error.o
 
diff --git a/arch/powerpc/platforms/cell/cbe_cpufreq.c b/arch/powerpc/platforms/cell/cbe_cpufreq.c
new file mode 100644
index 0000000..4673ff6
--- /dev/null
+++ b/arch/powerpc/platforms/cell/cbe_cpufreq.c
@@ -0,0 +1,209 @@
+/*
+ * cpufreq driver for the cell processor
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
+ *
+ * Author: Christian Krafft <krafft@de.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/cpufreq.h>
+#include <asm/machdep.h>
+#include <asm/prom.h>
+#include <asm/smp.h>
+#include "cbe_regs.h"
+#include "cbe_cpufreq.h"
+
+static DEFINE_MUTEX(cbe_switch_mutex);
+
+
+/* the CBE supports an 8 step frequency scaling */
+static struct cpufreq_frequency_table cbe_freqs[] = {
+	{1,	0},
+	{2,	0},
+	{3,	0},
+	{4,	0},
+	{5,	0},
+	{6,	0},
+	{8,	0},
+	{10,	0},
+	{0,	CPUFREQ_TABLE_END},
+};
+
+/*
+ * hardware specific functions
+ */
+
+static int set_pmode(unsigned int cpu, unsigned int slow_mode)
+{
+	int rc;
+
+	if (cbe_cpufreq_has_pmi)
+		rc = cbe_cpufreq_set_pmode_pmi(cpu, slow_mode);
+	else
+		rc = cbe_cpufreq_set_pmode(cpu, slow_mode);
+
+	pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu));
+
+	return rc;
+}
+
+/*
+ * cpufreq functions
+ */
+
+static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+	const u32 *max_freqp;
+	u32 max_freq;
+	int i, cur_pmode;
+	struct device_node *cpu;
+
+	cpu = of_get_cpu_node(policy->cpu, NULL);
+
+	if (!cpu)
+		return -ENODEV;
+
+	pr_debug("init cpufreq on CPU %d\n", policy->cpu);
+
+	/*
+	 * Let's check we can actually get to the CELL regs
+	 */
+	if (!cbe_get_cpu_pmd_regs(policy->cpu) ||
+	    !cbe_get_cpu_mic_tm_regs(policy->cpu)) {
+		pr_info("invalid CBE regs pointers for cpufreq\n");
+		return -EINVAL;
+	}
+
+	max_freqp = get_property(cpu, "clock-frequency", NULL);
+
+	of_node_put(cpu);
+
+	if (!max_freqp)
+		return -EINVAL;
+
+	/* we need the freq in kHz */
+	max_freq = *max_freqp / 1000;
+
+	pr_debug("max clock-frequency is at %u kHz\n", max_freq);
+	pr_debug("initializing frequency table\n");
+
+	/* initialize frequency table */
+	for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
+		cbe_freqs[i].frequency = max_freq / cbe_freqs[i].index;
+		pr_debug("%d: %d\n", i, cbe_freqs[i].frequency);
+	}
+
+	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+
+	/* if DEBUG is enabled set_pmode() measures the latency
+	 * of a transition */
+	policy->cpuinfo.transition_latency = 25000;
+
+	cur_pmode = cbe_cpufreq_get_pmode(policy->cpu);
+	pr_debug("current pmode is at %d\n",cur_pmode);
+
+	policy->cur = cbe_freqs[cur_pmode].frequency;
+
+#ifdef CONFIG_SMP
+	policy->cpus = cpu_sibling_map[policy->cpu];
+#endif
+
+	cpufreq_frequency_table_get_attr(cbe_freqs, policy->cpu);
+
+	/* this ensures that policy->cpuinfo_min
+	 * and policy->cpuinfo_max are set correctly */
+	return cpufreq_frequency_table_cpuinfo(policy, cbe_freqs);
+}
+
+static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
+{
+	cpufreq_frequency_table_put_attr(policy->cpu);
+	return 0;
+}
+
+static int cbe_cpufreq_verify(struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy, cbe_freqs);
+}
+
+static int cbe_cpufreq_target(struct cpufreq_policy *policy,
+			      unsigned int target_freq,
+			      unsigned int relation)
+{
+	int rc;
+	struct cpufreq_freqs freqs;
+	unsigned int cbe_pmode_new;
+
+	cpufreq_frequency_table_target(policy,
+				       cbe_freqs,
+				       target_freq,
+				       relation,
+				       &cbe_pmode_new);
+
+	freqs.old = policy->cur;
+	freqs.new = cbe_freqs[cbe_pmode_new].frequency;
+	freqs.cpu = policy->cpu;
+
+	mutex_lock(&cbe_switch_mutex);
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	pr_debug("setting frequency for cpu %d to %d kHz, " \
+		 "1/%d of max frequency\n",
+		 policy->cpu,
+		 cbe_freqs[cbe_pmode_new].frequency,
+		 cbe_freqs[cbe_pmode_new].index);
+
+	rc = set_pmode(policy->cpu, cbe_pmode_new);
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+	mutex_unlock(&cbe_switch_mutex);
+
+	return rc;
+}
+
+static struct cpufreq_driver cbe_cpufreq_driver = {
+	.verify		= cbe_cpufreq_verify,
+	.target		= cbe_cpufreq_target,
+	.init		= cbe_cpufreq_cpu_init,
+	.exit		= cbe_cpufreq_cpu_exit,
+	.name		= "cbe-cpufreq",
+	.owner		= THIS_MODULE,
+	.flags		= CPUFREQ_CONST_LOOPS,
+};
+
+/*
+ * module init and destoy
+ */
+
+static int __init cbe_cpufreq_init(void)
+{
+	if (!machine_is(cell))
+		return -ENODEV;
+
+	return cpufreq_register_driver(&cbe_cpufreq_driver);
+}
+
+static void __exit cbe_cpufreq_exit(void)
+{
+	cpufreq_unregister_driver(&cbe_cpufreq_driver);
+}
+
+module_init(cbe_cpufreq_init);
+module_exit(cbe_cpufreq_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
diff --git a/arch/powerpc/platforms/cell/cbe_cpufreq.h b/arch/powerpc/platforms/cell/cbe_cpufreq.h
new file mode 100644
index 0000000..4166558
--- /dev/null
+++ b/arch/powerpc/platforms/cell/cbe_cpufreq.h
@@ -0,0 +1,23 @@
+/*
+ * cbe_cpufreq.h
+ *
+ * This file contains the definitions used by the cbe_cpufreq driver.
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
+ *
+ * Author: Christian Krafft <krafft@de.ibm.com>
+ *
+ */
+
+#include <linux/cpufreq.h>
+
+int cbe_cpufreq_set_pmode(int cpu, unsigned int pmode);
+int cbe_cpufreq_get_pmode(int cpu);
+
+int cbe_cpufreq_set_pmode_pmi(int cpu, unsigned int pmode);
+
+#if defined(CONFIG_CBE_CPUFREQ_PMI) || defined(CONFIG_CBE_CPUFREQ_PMI_MODULE)
+extern int cbe_cpufreq_has_pmi;
+#else
+#define cbe_cpufreq_has_pmi (0)
+#endif
diff --git a/arch/powerpc/platforms/cell/cbe_cpufreq_pervasive.c b/arch/powerpc/platforms/cell/cbe_cpufreq_pervasive.c
new file mode 100644
index 0000000..e9d87b4
--- /dev/null
+++ b/arch/powerpc/platforms/cell/cbe_cpufreq_pervasive.c
@@ -0,0 +1,118 @@
+/*
+ * pervasive backend for the cbe_cpufreq driver
+ *
+ * This driver makes use of the pervasive unit to
+ * engage the desired frequency.
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
+ *
+ * Author: Christian Krafft <krafft@de.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/kernel.h>
+#include <asm/machdep.h>
+#include <asm/hw_irq.h>
+#include <asm/io.h>
+
+#ifdef DEBUG
+#include <asm/time.h>
+#endif
+
+#include "cbe_regs.h"
+#include "cbe_cpufreq.h"
+
+/* to write to MIC register */
+static u64 MIC_Slow_Fast_Timer_table[] = {
+	[0 ... 7] = 0x007fc00000000000ull,
+};
+
+/* more values for the MIC */
+static u64 MIC_Slow_Next_Timer_table[] = {
+	0x0000240000000000ull,
+	0x0000268000000000ull,
+	0x000029C000000000ull,
+	0x00002D0000000000ull,
+	0x0000300000000000ull,
+	0x0000334000000000ull,
+	0x000039C000000000ull,
+	0x00003FC000000000ull,
+};
+
+
+int cbe_cpufreq_set_pmode(int cpu, unsigned int pmode)
+{
+	struct cbe_pmd_regs __iomem *pmd_regs;
+	struct cbe_mic_tm_regs __iomem *mic_tm_regs;
+	u64 flags;
+	u64 value;
+#ifdef DEBUG
+	long time;
+#endif
+
+	local_irq_save(flags);
+
+	mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
+	pmd_regs = cbe_get_cpu_pmd_regs(cpu);
+
+#ifdef DEBUG
+	time = jiffies;
+#endif
+
+	out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
+	out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);
+
+	out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
+	out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);
+
+	value = in_be64(&pmd_regs->pmcr);
+	/* set bits to zero */
+	value &= 0xFFFFFFFFFFFFFFF8ull;
+	/* set bits to next pmode */
+	value |= pmode;
+
+	out_be64(&pmd_regs->pmcr, value);
+
+#ifdef DEBUG
+	/* wait until new pmode appears in status register */
+	value = in_be64(&pmd_regs->pmsr) & 0x07;
+	while(value != pmode) {
+		cpu_relax();
+		value = in_be64(&pmd_regs->pmsr) & 0x07;
+	}
+
+	time = jiffies  - time;
+	time = jiffies_to_msecs(time);
+	pr_debug("had to wait %lu ms for a transition using " \
+		 "pervasive unit\n", time);
+#endif
+	local_irq_restore(flags);
+
+	return 0;
+}
+
+
+int cbe_cpufreq_get_pmode(int cpu)
+{
+	int ret;
+	struct cbe_pmd_regs __iomem *pmd_regs;
+
+	pmd_regs = cbe_get_cpu_pmd_regs(cpu);
+	ret = in_be64(&pmd_regs->pmsr) & 0x07;
+
+	return ret;
+}
+
diff --git a/arch/powerpc/platforms/cell/cbe_cpufreq_pmi.c b/arch/powerpc/platforms/cell/cbe_cpufreq_pmi.c
new file mode 100644
index 0000000..0f3cdd2
--- /dev/null
+++ b/arch/powerpc/platforms/cell/cbe_cpufreq_pmi.c
@@ -0,0 +1,146 @@
+/*
+ * pmi backend for the cbe_cpufreq driver
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
+ *
+ * Author: Christian Krafft <krafft@de.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <asm/processor.h>
+#include <asm/prom.h>
+#include <asm/pmi.h>
+
+#ifdef DEBUG
+#include <asm/time.h>
+#endif
+
+#include "cbe_regs.h"
+#include "cbe_cpufreq.h"
+
+static u8 pmi_slow_mode_limit[MAX_CBE];
+
+int cbe_cpufreq_has_pmi = 0;
+EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);
+
+/*
+ * hardware specific functions
+ */
+
+int cbe_cpufreq_set_pmode_pmi(int cpu, unsigned int pmode)
+{
+	int ret;
+	pmi_message_t pmi_msg;
+#ifdef DEBUG
+	long time;
+#endif
+	pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
+	pmi_msg.data1 =	cbe_cpu_to_node(cpu);
+	pmi_msg.data2 = pmode;
+
+#ifdef DEBUG
+	time = jiffies;
+#endif
+	pmi_send_message(pmi_msg);
+
+#ifdef DEBUG
+	time = jiffies  - time;
+	time = jiffies_to_msecs(time);
+	pr_debug("had to wait %lu ms for a transition using " \
+		 "PMI\n", time);
+#endif
+	ret = pmi_msg.data2;
+	pr_debug("PMI returned slow mode %d\n", ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);
+
+
+static void cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg)
+{
+	u8 node, slow_mode;
+
+	BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
+
+	node = pmi_msg.data1;
+	slow_mode = pmi_msg.data2;
+
+	pmi_slow_mode_limit[node] = slow_mode;
+
+	pr_debug("cbe_handle_pmi: node: %d max_freq: %d\n", node, slow_mode);
+}
+
+static int pmi_notifier(struct notifier_block *nb,
+				       unsigned long event, void *data)
+{
+	struct cpufreq_policy *policy = data;
+	struct cpufreq_frequency_table *cbe_freqs;
+	u8 node;
+
+	cbe_freqs = cpufreq_frequency_get_table(policy->cpu);
+	node = cbe_cpu_to_node(policy->cpu);
+
+	pr_debug("got notified, event=%lu, node=%u\n", event, node);
+
+	if (pmi_slow_mode_limit[node] != 0) {
+		pr_debug("limiting node %d to slow mode %d\n",
+			 node, pmi_slow_mode_limit[node]);
+
+		cpufreq_verify_within_limits(policy, 0,
+
+			cbe_freqs[pmi_slow_mode_limit[node]].frequency);
+	}
+
+	return 0;
+}
+
+static struct notifier_block pmi_notifier_block = {
+	.notifier_call = pmi_notifier,
+};
+
+static struct pmi_handler cbe_pmi_handler = {
+	.type			= PMI_TYPE_FREQ_CHANGE,
+	.handle_pmi_message	= cbe_cpufreq_handle_pmi,
+};
+
+
+
+static int __init cbe_cpufreq_pmi_init(void)
+{
+	cbe_cpufreq_has_pmi = pmi_register_handler(&cbe_pmi_handler) == 0;
+
+	if (!cbe_cpufreq_has_pmi)
+		return -ENODEV;
+
+	cpufreq_register_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
+
+	return 0;
+}
+
+static void __exit cbe_cpufreq_pmi_exit(void)
+{
+	cpufreq_unregister_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
+	pmi_unregister_handler(&cbe_pmi_handler);
+}
+
+module_init(cbe_cpufreq_pmi_init);
+module_exit(cbe_cpufreq_pmi_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");