[IA64] Add ACPI based P-state support
Patch to support P-state transitions on ia64. This driver is based on ACPI,
and uses the ACPI processor driver interface to find out the P-state support
information for the processor. This driver plugs into generic cpufreq
infrastructure.
Once this driver is loaded successfully, ondemand/userspace governor can be
used to change the CPU frequency dynamically based on load or on request from
userspace process.
Refer :
ACPI specification -
http://www.acpi.info
P-state related PAL calls -
http://developer.intel.com/design/itanium/downloads/24869909.pdf
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 8098813..3deced6 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -383,6 +383,12 @@
endif
+if PM
+
+source "arch/ia64/kernel/cpufreq/Kconfig"
+
+endif
+
endmenu
if !IA64_HP_SIM
diff --git a/arch/ia64/kernel/Makefile b/arch/ia64/kernel/Makefile
index e1fb68d..b242594 100644
--- a/arch/ia64/kernel/Makefile
+++ b/arch/ia64/kernel/Makefile
@@ -20,6 +20,7 @@
obj-$(CONFIG_NUMA) += numa.o
obj-$(CONFIG_PERFMON) += perfmon_default_smpl.o
obj-$(CONFIG_IA64_CYCLONE) += cyclone.o
+obj-$(CONFIG_CPU_FREQ) += cpufreq/
obj-$(CONFIG_IA64_MCA_RECOVERY) += mca_recovery.o
obj-$(CONFIG_KPROBES) += kprobes.o jprobes.o
obj-$(CONFIG_IA64_UNCACHED_ALLOCATOR) += uncached.o
diff --git a/arch/ia64/kernel/cpufreq/Kconfig b/arch/ia64/kernel/cpufreq/Kconfig
new file mode 100644
index 0000000..2d9d527
--- /dev/null
+++ b/arch/ia64/kernel/cpufreq/Kconfig
@@ -0,0 +1,29 @@
+
+#
+# CPU Frequency scaling
+#
+
+menu "CPU Frequency scaling"
+
+source "drivers/cpufreq/Kconfig"
+
+if CPU_FREQ
+
+comment "CPUFreq processor drivers"
+
+config IA64_ACPI_CPUFREQ
+ tristate "ACPI Processor P-States driver"
+ select CPU_FREQ_TABLE
+ depends on ACPI_PROCESSOR
+ help
+ This driver adds a CPUFreq driver which utilizes the ACPI
+ Processor Performance States.
+
+ For details, take a look at <file:Documentation/cpu-freq/>.
+
+ If in doubt, say N.
+
+endif # CPU_FREQ
+
+endmenu
+
diff --git a/arch/ia64/kernel/cpufreq/Makefile b/arch/ia64/kernel/cpufreq/Makefile
new file mode 100644
index 0000000..f748d34
--- /dev/null
+++ b/arch/ia64/kernel/cpufreq/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_IA64_ACPI_CPUFREQ) += acpi-cpufreq.o
diff --git a/arch/ia64/kernel/cpufreq/acpi-cpufreq.c b/arch/ia64/kernel/cpufreq/acpi-cpufreq.c
new file mode 100644
index 0000000..da4d5cf
--- /dev/null
+++ b/arch/ia64/kernel/cpufreq/acpi-cpufreq.c
@@ -0,0 +1,499 @@
+/*
+ * arch/ia64/kernel/cpufreq/acpi-cpufreq.c
+ * This file provides the ACPI based P-state support. This
+ * module works with generic cpufreq infrastructure. Most of
+ * the code is based on i386 version
+ * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)
+ *
+ * Copyright (C) 2005 Intel Corp
+ * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/pal.h>
+
+#include <linux/acpi.h>
+#include <acpi/processor.h>
+
+#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
+
+MODULE_AUTHOR("Venkatesh Pallipadi");
+MODULE_DESCRIPTION("ACPI Processor P-States Driver");
+MODULE_LICENSE("GPL");
+
+
+struct cpufreq_acpi_io {
+ struct acpi_processor_performance acpi_data;
+ struct cpufreq_frequency_table *freq_table;
+ unsigned int resume;
+};
+
+static struct cpufreq_acpi_io *acpi_io_data[NR_CPUS];
+
+static struct cpufreq_driver acpi_cpufreq_driver;
+
+
+static int
+processor_set_pstate (
+ u32 value)
+{
+ s64 retval;
+
+ dprintk("processor_set_pstate\n");
+
+ retval = ia64_pal_set_pstate((u64)value);
+
+ if (retval) {
+ dprintk("Failed to set freq to 0x%x, with error 0x%x\n",
+ value, retval);
+ return -ENODEV;
+ }
+ return (int)retval;
+}
+
+
+static int
+processor_get_pstate (
+ u32 *value)
+{
+ u64 pstate_index = 0;
+ s64 retval;
+
+ dprintk("processor_get_pstate\n");
+
+ retval = ia64_pal_get_pstate(&pstate_index);
+ *value = (u32) pstate_index;
+
+ if (retval)
+ dprintk("Failed to get current freq with "
+ "error 0x%x, idx 0x%x\n", retval, *value);
+
+ return (int)retval;
+}
+
+
+/* To be used only after data->acpi_data is initialized */
+static unsigned
+extract_clock (
+ struct cpufreq_acpi_io *data,
+ unsigned value,
+ unsigned int cpu)
+{
+ unsigned long i;
+
+ dprintk("extract_clock\n");
+
+ for (i = 0; i < data->acpi_data.state_count; i++) {
+ if (value >= data->acpi_data.states[i].control)
+ return data->acpi_data.states[i].core_frequency;
+ }
+ return data->acpi_data.states[i-1].core_frequency;
+}
+
+
+static unsigned int
+processor_get_freq (
+ struct cpufreq_acpi_io *data,
+ unsigned int cpu)
+{
+ int ret = 0;
+ u32 value = 0;
+ cpumask_t saved_mask;
+ unsigned long clock_freq;
+
+ dprintk("processor_get_freq\n");
+
+ saved_mask = current->cpus_allowed;
+ set_cpus_allowed(current, cpumask_of_cpu(cpu));
+ if (smp_processor_id() != cpu) {
+ ret = -EAGAIN;
+ goto migrate_end;
+ }
+
+ /*
+ * processor_get_pstate gets the average frequency since the
+ * last get. So, do two PAL_get_freq()...
+ */
+ ret = processor_get_pstate(&value);
+ ret = processor_get_pstate(&value);
+
+ if (ret) {
+ set_cpus_allowed(current, saved_mask);
+ printk(KERN_WARNING "get performance failed with error %d\n",
+ ret);
+ ret = -EAGAIN;
+ goto migrate_end;
+ }
+ clock_freq = extract_clock(data, value, cpu);
+ ret = (clock_freq*1000);
+
+migrate_end:
+ set_cpus_allowed(current, saved_mask);
+ return ret;
+}
+
+
+static int
+processor_set_freq (
+ struct cpufreq_acpi_io *data,
+ unsigned int cpu,
+ int state)
+{
+ int ret = 0;
+ u32 value = 0;
+ struct cpufreq_freqs cpufreq_freqs;
+ cpumask_t saved_mask;
+ int retval;
+
+ dprintk("processor_set_freq\n");
+
+ saved_mask = current->cpus_allowed;
+ set_cpus_allowed(current, cpumask_of_cpu(cpu));
+ if (smp_processor_id() != cpu) {
+ retval = -EAGAIN;
+ goto migrate_end;
+ }
+
+ if (state == data->acpi_data.state) {
+ if (unlikely(data->resume)) {
+ dprintk("Called after resume, resetting to P%d\n", state);
+ data->resume = 0;
+ } else {
+ dprintk("Already at target state (P%d)\n", state);
+ retval = 0;
+ goto migrate_end;
+ }
+ }
+
+ dprintk("Transitioning from P%d to P%d\n",
+ data->acpi_data.state, state);
+
+ /* cpufreq frequency struct */
+ cpufreq_freqs.cpu = cpu;
+ cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
+ cpufreq_freqs.new = data->freq_table[state].frequency;
+
+ /* notify cpufreq */
+ cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
+
+ /*
+ * First we write the target state's 'control' value to the
+ * control_register.
+ */
+
+ value = (u32) data->acpi_data.states[state].control;
+
+ dprintk("Transitioning to state: 0x%08x\n", value);
+
+ ret = processor_set_pstate(value);
+ if (ret) {
+ unsigned int tmp = cpufreq_freqs.new;
+ cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
+ cpufreq_freqs.new = cpufreq_freqs.old;
+ cpufreq_freqs.old = tmp;
+ cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
+ cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
+ printk(KERN_WARNING "Transition failed with error %d\n", ret);
+ retval = -ENODEV;
+ goto migrate_end;
+ }
+
+ cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
+
+ data->acpi_data.state = state;
+
+ retval = 0;
+
+migrate_end:
+ set_cpus_allowed(current, saved_mask);
+ return (retval);
+}
+
+
+static unsigned int
+acpi_cpufreq_get (
+ unsigned int cpu)
+{
+ struct cpufreq_acpi_io *data = acpi_io_data[cpu];
+
+ dprintk("acpi_cpufreq_get\n");
+
+ return processor_get_freq(data, cpu);
+}
+
+
+static int
+acpi_cpufreq_target (
+ struct cpufreq_policy *policy,
+ unsigned int target_freq,
+ unsigned int relation)
+{
+ struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
+ unsigned int next_state = 0;
+ unsigned int result = 0;
+
+ dprintk("acpi_cpufreq_setpolicy\n");
+
+ result = cpufreq_frequency_table_target(policy,
+ data->freq_table, target_freq, relation, &next_state);
+ if (result)
+ return (result);
+
+ result = processor_set_freq(data, policy->cpu, next_state);
+
+ return (result);
+}
+
+
+static int
+acpi_cpufreq_verify (
+ struct cpufreq_policy *policy)
+{
+ unsigned int result = 0;
+ struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
+
+ dprintk("acpi_cpufreq_verify\n");
+
+ result = cpufreq_frequency_table_verify(policy,
+ data->freq_table);
+
+ return (result);
+}
+
+
+/*
+ * processor_init_pdc - let BIOS know about the SMP capabilities
+ * of this driver
+ * @perf: processor-specific acpi_io_data struct
+ * @cpu: CPU being initialized
+ *
+ * To avoid issues with legacy OSes, some BIOSes require to be informed of
+ * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC
+ * accordingly. Actual call to _PDC is done in driver/acpi/processor.c
+ */
+static void
+processor_init_pdc (
+ struct acpi_processor_performance *perf,
+ unsigned int cpu,
+ struct acpi_object_list *obj_list
+ )
+{
+ union acpi_object *obj;
+ u32 *buf;
+
+ dprintk("processor_init_pdc\n");
+
+ perf->pdc = NULL;
+ /* Initialize pdc. It will be used later. */
+ if (!obj_list)
+ return;
+
+ if (!(obj_list->count && obj_list->pointer))
+ return;
+
+ obj = obj_list->pointer;
+ if ((obj->buffer.length == 12) && obj->buffer.pointer) {
+ buf = (u32 *)obj->buffer.pointer;
+ buf[0] = ACPI_PDC_REVISION_ID;
+ buf[1] = 1;
+ buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;
+ perf->pdc = obj_list;
+ }
+ return;
+}
+
+
+static int
+acpi_cpufreq_cpu_init (
+ struct cpufreq_policy *policy)
+{
+ unsigned int i;
+ unsigned int cpu = policy->cpu;
+ struct cpufreq_acpi_io *data;
+ unsigned int result = 0;
+
+ union acpi_object arg0 = {ACPI_TYPE_BUFFER};
+ u32 arg0_buf[3];
+ struct acpi_object_list arg_list = {1, &arg0};
+
+ dprintk("acpi_cpufreq_cpu_init\n");
+ /* setup arg_list for _PDC settings */
+ arg0.buffer.length = 12;
+ arg0.buffer.pointer = (u8 *) arg0_buf;
+
+ data = kmalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
+ if (!data)
+ return (-ENOMEM);
+
+ memset(data, 0, sizeof(struct cpufreq_acpi_io));
+
+ acpi_io_data[cpu] = data;
+
+ processor_init_pdc(&data->acpi_data, cpu, &arg_list);
+ result = acpi_processor_register_performance(&data->acpi_data, cpu);
+ data->acpi_data.pdc = NULL;
+
+ if (result)
+ goto err_free;
+
+ /* capability check */
+ if (data->acpi_data.state_count <= 1) {
+ dprintk("No P-States\n");
+ result = -ENODEV;
+ goto err_unreg;
+ }
+
+ if ((data->acpi_data.control_register.space_id !=
+ ACPI_ADR_SPACE_FIXED_HARDWARE) ||
+ (data->acpi_data.status_register.space_id !=
+ ACPI_ADR_SPACE_FIXED_HARDWARE)) {
+ dprintk("Unsupported address space [%d, %d]\n",
+ (u32) (data->acpi_data.control_register.space_id),
+ (u32) (data->acpi_data.status_register.space_id));
+ result = -ENODEV;
+ goto err_unreg;
+ }
+
+ /* alloc freq_table */
+ data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
+ (data->acpi_data.state_count + 1),
+ GFP_KERNEL);
+ if (!data->freq_table) {
+ result = -ENOMEM;
+ goto err_unreg;
+ }
+
+ /* detect transition latency */
+ policy->cpuinfo.transition_latency = 0;
+ for (i=0; i<data->acpi_data.state_count; i++) {
+ if ((data->acpi_data.states[i].transition_latency * 1000) >
+ policy->cpuinfo.transition_latency) {
+ policy->cpuinfo.transition_latency =
+ data->acpi_data.states[i].transition_latency * 1000;
+ }
+ }
+ policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+
+ policy->cur = processor_get_freq(data, policy->cpu);
+
+ /* table init */
+ for (i = 0; i <= data->acpi_data.state_count; i++)
+ {
+ data->freq_table[i].index = i;
+ if (i < data->acpi_data.state_count) {
+ data->freq_table[i].frequency =
+ data->acpi_data.states[i].core_frequency * 1000;
+ } else {
+ data->freq_table[i].frequency = CPUFREQ_TABLE_END;
+ }
+ }
+
+ result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
+ if (result) {
+ goto err_freqfree;
+ }
+
+ /* notify BIOS that we exist */
+ acpi_processor_notify_smm(THIS_MODULE);
+
+ printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "
+ "activated.\n", cpu);
+
+ for (i = 0; i < data->acpi_data.state_count; i++)
+ dprintk(" %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
+ (i == data->acpi_data.state?'*':' '), i,
+ (u32) data->acpi_data.states[i].core_frequency,
+ (u32) data->acpi_data.states[i].power,
+ (u32) data->acpi_data.states[i].transition_latency,
+ (u32) data->acpi_data.states[i].bus_master_latency,
+ (u32) data->acpi_data.states[i].status,
+ (u32) data->acpi_data.states[i].control);
+
+ cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
+
+ /* the first call to ->target() should result in us actually
+ * writing something to the appropriate registers. */
+ data->resume = 1;
+
+ return (result);
+
+ err_freqfree:
+ kfree(data->freq_table);
+ err_unreg:
+ acpi_processor_unregister_performance(&data->acpi_data, cpu);
+ err_free:
+ kfree(data);
+ acpi_io_data[cpu] = NULL;
+
+ return (result);
+}
+
+
+static int
+acpi_cpufreq_cpu_exit (
+ struct cpufreq_policy *policy)
+{
+ struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
+
+ dprintk("acpi_cpufreq_cpu_exit\n");
+
+ if (data) {
+ cpufreq_frequency_table_put_attr(policy->cpu);
+ acpi_io_data[policy->cpu] = NULL;
+ acpi_processor_unregister_performance(&data->acpi_data,
+ policy->cpu);
+ kfree(data);
+ }
+
+ return (0);
+}
+
+
+static struct freq_attr* acpi_cpufreq_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ NULL,
+};
+
+
+static struct cpufreq_driver acpi_cpufreq_driver = {
+ .verify = acpi_cpufreq_verify,
+ .target = acpi_cpufreq_target,
+ .get = acpi_cpufreq_get,
+ .init = acpi_cpufreq_cpu_init,
+ .exit = acpi_cpufreq_cpu_exit,
+ .name = "acpi-cpufreq",
+ .owner = THIS_MODULE,
+ .attr = acpi_cpufreq_attr,
+};
+
+
+static int __init
+acpi_cpufreq_init (void)
+{
+ dprintk("acpi_cpufreq_init\n");
+
+ return cpufreq_register_driver(&acpi_cpufreq_driver);
+}
+
+
+static void __exit
+acpi_cpufreq_exit (void)
+{
+ dprintk("acpi_cpufreq_exit\n");
+
+ cpufreq_unregister_driver(&acpi_cpufreq_driver);
+ return;
+}
+
+
+late_initcall(acpi_cpufreq_init);
+module_exit(acpi_cpufreq_exit);
+
diff --git a/include/asm-ia64/acpi.h b/include/asm-ia64/acpi.h
index 4c06d45..3a544ff 100644
--- a/include/asm-ia64/acpi.h
+++ b/include/asm-ia64/acpi.h
@@ -116,6 +116,11 @@
extern u16 ia64_acpiid_to_sapicid[];
+/*
+ * Refer Intel ACPI _PDC support document for bit definitions
+ */
+#define ACPI_PDC_EST_CAPABILITY_SMP 0x8
+
#endif /*__KERNEL__*/
#endif /*_ASM_ACPI_H*/
diff --git a/include/asm-ia64/pal.h b/include/asm-ia64/pal.h
index 2303a10..e828377 100644
--- a/include/asm-ia64/pal.h
+++ b/include/asm-ia64/pal.h
@@ -75,6 +75,8 @@
#define PAL_CACHE_READ 259 /* read tag & data of cacheline for diagnostic testing */
#define PAL_CACHE_WRITE 260 /* write tag & data of cacheline for diagnostic testing */
#define PAL_VM_TR_READ 261 /* read contents of translation register */
+#define PAL_GET_PSTATE 262 /* get the current P-state */
+#define PAL_SET_PSTATE 263 /* set the P-state */
#ifndef __ASSEMBLY__
@@ -1111,6 +1113,25 @@
return iprv.status;
}
+/* Get the current P-state information */
+static inline s64
+ia64_pal_get_pstate (u64 *pstate_index)
+{
+ struct ia64_pal_retval iprv;
+ PAL_CALL_STK(iprv, PAL_GET_PSTATE, 0, 0, 0);
+ *pstate_index = iprv.v0;
+ return iprv.status;
+}
+
+/* Set the P-state */
+static inline s64
+ia64_pal_set_pstate (u64 pstate_index)
+{
+ struct ia64_pal_retval iprv;
+ PAL_CALL_STK(iprv, PAL_SET_PSTATE, pstate_index, 0, 0);
+ return iprv.status;
+}
+
/* Cause the processor to enter LIGHT HALT state, where prefetching and execution are
* suspended, but cache and TLB coherency is maintained.
*/