Here is the core patch for the PowerOp concept. It adds the powerop
struct
for opertaing point support to linux/pm.h and adds support to transition
to supported operating points by
setting their name into /sys/power/state.
The supported operating points are shown in a readonly sysfs file,
/sys/power/supported_states.
Signed-Off-by: David Singleton <dsingleton at mvista.com>
Documentation/power/powerop.txt | 168 +++++++++++++++++++++++++++++++++++
include/linux/pm.h | 26 +++++
kernel/power/main.c | 190
+++++++++++++++++++++++++++++++---------
kernel/power/power.h | 2
4 files changed, 342 insertions(+), 44 deletions(-)
Index: linux-2.6.17/kernel/power/main.c
===================================================================
--- linux-2.6.17.orig/kernel/power/main.c
+++ linux-2.6.17/kernel/power/main.c
@@ -49,7 +49,7 @@ void pm_set_ops(struct pm_ops * ops)
* the platform can enter the requested state.
*/
-static int suspend_prepare(suspend_state_t state)
+static int suspend_prepare(struct powerop * state)
{
int error = 0;
unsigned int free_pages;
@@ -82,7 +82,7 @@ static int suspend_prepare(suspend_state
}
if (pm_ops->prepare) {
- if ((error = pm_ops->prepare(state)))
+ if ((error = pm_ops->prepare(state->type)))
goto Thaw;
}
@@ -94,7 +94,7 @@ static int suspend_prepare(suspend_state
return 0;
Finish:
if (pm_ops->finish)
- pm_ops->finish(state);
+ pm_ops->finish(state->type);
Thaw:
thaw_processes();
Enable_cpu:
@@ -104,7 +104,7 @@ static int suspend_prepare(suspend_state
}
-int suspend_enter(suspend_state_t state)
+int suspend_enter(struct powerop * state)
{
int error = 0;
unsigned long flags;
@@ -115,7 +115,7 @@ int suspend_enter(suspend_state_t state)
printk(KERN_ERR "Some devices failed to power down\n");
goto Done;
}
- error = pm_ops->enter(state);
+ error = pm_ops->enter(state->type);
device_power_up();
Done:
local_irq_restore(flags);
@@ -131,36 +131,95 @@ int suspend_enter(suspend_state_t state)
* console that we've allocated. This is not called for
suspend-to-disk.
*/
-static void suspend_finish(suspend_state_t state)
+static void suspend_finish(struct powerop * state)
{
device_resume();
resume_console();
thaw_processes();
enable_nonboot_cpus();
if (pm_ops && pm_ops->finish)
- pm_ops->finish(state);
+ pm_ops->finish(state->type);
pm_restore_console();
}
+struct powerop *current_state;
+struct powerop pm_states = {
+ .name = "default",
+ .type = PM_SUSPEND_ON,
+};
+EXPORT_SYMBOL(pm_states);
-
-static const char * const pm_states[PM_SUSPEND_MAX] = {
- [PM_SUSPEND_STANDBY] = "standby",
- [PM_SUSPEND_MEM] = "mem",
+static struct powerop standby = {
+ .name = "standby",
+ .description = "Power-On Suspend ACPI State: S1",
+ .type = PM_SUSPEND_STANDBY,
+};
+static struct powerop mem = {
+ .name = "mem ",
+ .description = "Suspend-to-RAM ACPI State: S3",
+ .type = PM_SUSPEND_MEM,
+};
#ifdef CONFIG_SOFTWARE_SUSPEND
- [PM_SUSPEND_DISK] = "disk",
-#endif
+static struct powerop disk = {
+ .name = "disk ",
+ .description = "Suspend-to-disk ACPI State: S4",
+ .type = PM_SUSPEND_DISK,
};
+#endif
-static inline int valid_state(suspend_state_t state)
+/*
+ *
+ */
+static int pm_change_state(struct powerop *state)
+{
+ int error = -EINVAL;
+ int len = strlen(state->name);
+ struct powerop *this, *next;
+ struct list_head *head = &pm_states.list;
+
+ /*
+ * list_find new operating point.
+ * compare to current operating point.
+ * if different change to new operating point.
+ */
+ list_for_each_entry_safe(this, next, head, list) {
+ if (strncmp(state->name, this->name, len) == 0) {
+ if ((strcmp(current_state->name, this->name)) ==
0) {
+ return 0;
+ }
+
+ if (this->prepare_transition(current_state,
this)) {
+ break;
+ }
+
+ if (this->transition(current_state, this)) {
+ break;
+ }
+
+ /*
+ * now lets wait for the transition latency
+ */
+ udelay(this->latency);
+
+ error = this->finish_transition(current_state,
this);
+
+ if (error == 0)
+ current_state = this;
+ break;
+ }
+ }
+ return error;
+}
+
+static inline int valid_state(struct powerop * state)
{
/* Suspend-to-disk does not really need low-level support.
* It can work with reboot if needed. */
- if (state == PM_SUSPEND_DISK)
+ if (state->type == PM_SUSPEND_DISK)
return 1;
- if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
+ if (pm_ops && pm_ops->valid && !pm_ops->valid(state->type))
return 0;
return 1;
}
@@ -168,7 +227,7 @@ static inline int valid_state(suspend_st
/**
* enter_state - Do common work of entering low-power state.
- * @state: pm_state structure for state we're entering.
+ * @state: powerop structure for state we're entering.
*
* Make sure we're the only ones trying to enter a sleep state. Fail
* if someone has beat us to it, since we don't want anything weird to
@@ -177,7 +236,7 @@ static inline int valid_state(suspend_st
* we've woken up).
*/
-static int enter_state(suspend_state_t state)
+static int enter_state(struct powerop *state)
{
int error;
@@ -186,16 +245,21 @@ static int enter_state(suspend_state_t s
if (down_trylock(&pm_sem))
return -EBUSY;
- if (state == PM_SUSPEND_DISK) {
+ if (state->type == PM_SUSPEND_DISK) {
error = pm_suspend_disk();
goto Unlock;
}
- pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
+ if (state->type == PM_FREQ_CHANGE) {
+ error = pm_change_state(state);
+ goto Unlock;
+ }
+
+ pr_debug("PM: Preparing system for %s sleep\n", state->name);
if ((error = suspend_prepare(state)))
goto Unlock;
- pr_debug("PM: Entering %s sleep\n", pm_states[state]);
+ pr_debug("PM: Entering %s sleep\n", state->name);
error = suspend_enter(state);
pr_debug("PM: Finishing wakeup.\n");
@@ -211,7 +275,15 @@ static int enter_state(suspend_state_t s
*/
int software_suspend(void)
{
- return enter_state(PM_SUSPEND_DISK);
+ struct powerop *this, *next;
+ struct list_head *head = &pm_states.list;
+ int error = 0;
+
+ list_for_each_entry_safe(this, next, head, list) {
+ if (this->type == PM_SUSPEND_DISK)
+ error= enter_state(this);
+ }
+ return error;
}
@@ -223,16 +295,48 @@ int software_suspend(void)
* structure, and enter (above).
*/
-int pm_suspend(suspend_state_t state)
+int pm_suspend(struct powerop * state)
{
- if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
+ if (state->type > PM_SUSPEND_ON && state->type <= PM_SUSPEND_MAX)
return enter_state(state);
return -EINVAL;
}
+decl_subsys(power,NULL,NULL);
+/**
+ * supported_states - control system power state.
+ *
+ * show() returns what states are supported, which are no longer
+ * hard-coded to just 'standby' (Power-On Suspend), 'mem'
(Suspend-to-RAM),
+ * and *'disk' (Suspend-to-Disk), but show all the power states.
+ *
+ * store() unwritable
+ */
-decl_subsys(power,NULL,NULL);
+static ssize_t supported_states_show(struct subsystem * subsys, char *
buf)
+{
+ struct powerop *this, *next;
+ struct list_head *head = &pm_states.list;
+ const char *header = "< Name > <Frequency> <Voltage>
<Transition Latency> < Description >\n";
+ char * s = buf;
+
+ s += sprintf(s, "%s", header);
+ list_for_each_entry_safe(this, next, head, list) {
+ s += sprintf(s,"%s %dKHz %dmV %dus %s\n", this->name,
+ this->frequency, this->voltage, this->latency,
+ this->description);
+ }
+
+ return (s - buf);
+}
+
+static ssize_t supported_states_store(struct subsystem * subsys, const
char *buf, size_t n)
+{
+ return -EINVAL;
+}
+
+power_attr(supported_states);
/**
@@ -248,36 +352,28 @@ decl_subsys(power,NULL,NULL);
static ssize_t state_show(struct subsystem * subsys, char * buf)
{
- int i;
char * s = buf;
- for (i = 0; i < PM_SUSPEND_MAX; i++) {
- if (pm_states[i] && valid_state(i))
- s += sprintf(s,"%s ", pm_states[i]);
- }
- s += sprintf(s,"\n");
+ s += sprintf(s,"%s\n", current_state->name);
return (s - buf);
}
static ssize_t state_store(struct subsystem * subsys, const char * buf,
size_t n)
{
- suspend_state_t state = PM_SUSPEND_STANDBY;
- const char * const *s;
+ struct powerop *this, *next;
+ struct list_head *head = &pm_states.list;
char *p;
- int error;
+ int error = -EINVAL;
int len;
p = memchr(buf, '\n', n);
len = p ? p - buf : n;
-
- for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
- if (*s && !strncmp(buf, *s, len))
+ list_for_each_entry_safe(this, next, head, list) {
+ if (!strncmp(buf, this->name, len)) {
+ error = enter_state(this);
break;
+ }
}
- if (state < PM_SUSPEND_MAX && *s)
- error = enter_state(state);
- else
- error = -EINVAL;
return error ? error : n;
}
@@ -285,6 +381,7 @@ power_attr(state);
static struct attribute * g[] = {
&state_attr.attr,
+ &supported_states_attr.attr,
NULL,
};
@@ -295,9 +392,20 @@ static struct attribute_group attr_group
static int __init pm_init(void)
{
+
int error = subsystem_register(&power_subsys);
if (!error)
error =
sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
+
+ INIT_LIST_HEAD(&pm_states.list);
+
+#ifdef CONFIG_SOFTWARE_SUSPEND
+ list_add(&disk.list, &pm_states.list);
+#endif
+ list_add(&mem.list, &pm_states.list);
+ list_add(&standby.list, &pm_states.list);
+ current_state = &pm_states;
+
return error;
}
Index: linux-2.6.17/include/linux/pm.h
===================================================================
--- linux-2.6.17.orig/include/linux/pm.h
+++ linux-2.6.17/include/linux/pm.h
@@ -108,7 +108,29 @@ typedef int __bitwise suspend_state_t;
#define PM_SUSPEND_STANDBY ((__force suspend_state_t) 1)
#define PM_SUSPEND_MEM ((__force suspend_state_t) 3)
#define PM_SUSPEND_DISK ((__force suspend_state_t) 4)
-#define PM_SUSPEND_MAX ((__force suspend_state_t) 5)
+#define PM_FREQ_CHANGE ((__force suspend_state_t) 5)
+#define PM_VOLT_CHANGE ((__force suspend_state_t) 6)
+#define PM_SUSPEND_MAX ((__force suspend_state_t) 7)
+
+#define PM_NAME_SIZE 16
+#define PM_DESCRIPTION_SIZE 48
+
+struct powerop {
+ struct list_head list;
+ suspend_state_t type;
+ char name[PM_NAME_SIZE];
+ char description[PM_DESCRIPTION_SIZE];
+ unsigned int frequency; /* in KHz */
+ unsigned int voltage; /* mV */
+ unsigned int latency; /* transition latency in us */
+ int (*prepare_transition)(struct powerop *cur, struct
powerop *new);
+ int (*transition)(struct powerop *cur, struct powerop *new);
+ int (*finish_transition)(struct powerop *cur, struct powerop
*new);
+
+ void *md_data; /* arch dependent data (dpm_opt) */
+};
+extern struct powerop pm_states;
+extern struct powerop *current_state;
typedef int __bitwise suspend_disk_method_t;
@@ -128,7 +150,7 @@ struct pm_ops {
extern void pm_set_ops(struct pm_ops *);
extern struct pm_ops *pm_ops;
-extern int pm_suspend(suspend_state_t state);
+extern int pm_suspend(struct powerop *state);
/*
Index: linux-2.6.17/kernel/power/power.h
===================================================================
--- linux-2.6.17.orig/kernel/power/power.h
+++ linux-2.6.17/kernel/power/power.h
@@ -113,4 +113,4 @@ extern int swsusp_resume(void);
extern int swsusp_read(void);
extern int swsusp_write(void);
extern void swsusp_close(void);
-extern int suspend_enter(suspend_state_t state);
+extern int suspend_enter(struct powerop * state);
Index: linux-2.6.17/Documentation/power/powerop.txt
===================================================================
--- /dev/null
+++ linux-2.6.17/Documentation/power/powerop.txt
@@ -0,0 +1,168 @@
+
+The PowerOp Power Management infrastructure.
+
+David Singleton <dsingleton at mvista.com>
+
+25 July 2006
+
+Copyright (c) 2006 MontaVista Software Inc.
+
+0. Introduction
+
+The goal of PowerOp power management is to provide a framework that
unifies
+and simplifies the various power management infrastructures in Linux. The
+three infrastructures Power Op is concerned with are:
+
+ 1) basic suspend/resume power management (CONFIG_PM)
+
+ 2) basic processor frequency management (CONFIG_CPUFREQ)
+
+ 3) SourceForge's Dynamic Power Management (CONFIG_DPM)
+
+All three power management infrastructures are concerned with controlling
+power states of the system, and interestingly enough they all perform the
+same basic operational steps to control changes in power state.
+
+PowerOp uses the existing power management sysfs infrastructure and
extends it
+to perform cpufreq and dynamic power management operations. The
traditional
+suspend to memory or disk (or swap) infrastructure has the correct
operational
+structure that supports all types of power state change.
+
+The CPUFREQ table based frequency control makes controlling cpu frequency
+simple and straight forward. The user doesn't get to set the cpu to
+any speed, but only to supported speeds that have been provided by
+the hardware vendor and validated.
+
+Dynamic Power Management treats all types of power states as operating
points,
+wether it's a suspend operating point, a particular frequency, or a
specific
+voltage.
+
+By combining the best of all of these power management infrastructures
+PowerOp uses the operational structure of tradition CONFIG_PM power
+management and converts all power states, frequency, voltage, idle or
+suspend to the CPUFREQ concept of only supported and validated operating
+points.
+
+PowerOp then becomes a simplified power management infrastructure in that
+only operating points that are supported and validated are available
+to the user. Control of all operating points are done by the operating
+point name. The user cannot supply invalid, or malicious,
+parameters that would hang or crash the system.
+
+1) PowerOp interface.
+
+To simplify power management all operations take place through two sysfs
+files, /sys/power/state and /sys/power/supported_states. The 'state' file
+shows the current operating point of the system. The readonly
+'supported_states' file shows the operating points the system supports.
+
+Supported operating points are displayed in tuple format of:
+
+<name, frequency, voltage, transition latency, description>
+
+The supported_states file contains rows of tuples with each
+tuple describing a supported operating point of the system.
+The supported_states file looks like a merge between the old
+/sys/power/state file and a cpufreq table.
+
+The system can transition to any of the supported states by simply
+storing the operating point name in the /sys/power/state file.
+
+To allow user space notification of events, like low battery, lid of
+the notebook being closed, etc. PowerOp notifies the user through
+the hotplug interface.
+
+
+2) PowerOP Operating Points.
+
+An operating point is represented by the powerop struct which contains:
+
+struct powerop {
+ struct list_head list;
+ suspend_state_t type;
+ char name[PM_NAME_SIZE];
+ char description[PM_DESCRIPTION_SIZE];
+ unsigned int frequency; /* in KHz */
+ unsigned int voltage; /* mV */
+ unsigned int latency; /* transition latency in us */
+ int (*prepare_transition)(struct powerop *cur, struct
powerop *new);
+ int (*transition)(struct powerop *cur, struct powerop *new);
+ int (*finish_transition)(struct powerop *cur, struct
powerop *new);
+
+ void *md_data; /* arch dependent data */
+};
+
+Each operating point has its own functions for preparing to transition,
+transitioning and finishing transition. Cpu frequency operating points
+will probably share their op vectors, idle and suspend operating points
my have
+different op vectors.
+
+
+3) Traditional Operation of Power Management Code.
+
+All three power management infrastructures have the same operational
model.
+All three follow the PM model of preparing to suspend, suspending,
+and finish the state change. It was easiest to follow the model
+enforced by the traditional power management and use the three step
process of:
+
+ 1) get ready to change state
+ 2) change state
+ 3) finish changes
+
+Cpufreq infrastructure makes three calls to change the frequency of the
+processor:
+
+ 1) cpufreq_notify_transition(&freq, CPUFREQ_PRECHANGE);
+
+ 2) acpi_processor_set_performance (data, j, next_state);
+
+ 3) cpufreq_notify_transition(&freq, CPUFREQ_POSTCHANGE);
+
+DPM uses these three calls to change frequency and/or voltage:
+
+ 1) dpm_driver_scale(SCALE_PRECHANGE, new);
+
+ 2) clk_set_rate(prcm_set, new->md_opt.prcm_clock);
+
+ 3) dpm_driver_scale(SCALE_POStCHANGE, new);
+
+PM uses these three calls to suspend:
+
+ 1) suspend_prepare(state);
+
+ 2) suspend_enter(state->type);
+
+ 3) suspend_finish(state);
+
+
+4) PowerOP Operation.
+
+PowerOP uses the following three calls to transition to a new operating
+point.
+
+ prepare_to_transition(cur_state, new_state);
+
+ transition(cur_state, new_state);
+
+ finish_transistion(cur_state, new_state);
+
+The parameters are pointers to operating point structures, struct powerop.
+
+Power OP is a simplified version of all three of these infrastructures in
+that it only deals with operating points, and more specifically with
+supported operating points. Power Op presents a set of supported
operating
+points to the user. This is similar to the cpufreq table concept in that
+only supported and validated frequencies are avaliable.
+
+The definition of the operating point is done in a manner similar to
cpufreqs
+in that the supported operating frequency, voltage and transition latency,
+are predefined (by the hardware vendor) and validated.
+
+The user maninuplates the operting points of the system by the
+name of the operating points. This simplifies both the code and the
+control of the system's operating points in the PowerOp daemon.
+
+All supported operating points are defined at compile time and
+the user sets the system to different operating points by
+the operating point name.
+
