Generic Timer is an optional extension to an ARM v7A or v7R processor
implementation. Generic Timer provides a system counter that measures
the passing of time in real-time. This system counter is in a always-on
power domain. The system counter is guaranteed to be atleast 56-bits
wide. The timer increments at a frequency typically in the range 1-50MHz.
On OMAP5, the Generic Timers increment at a frequency of 6.144 MHz.
This timer is guaranteed to have a roll-over time of no less than
40 years.
This module supports non-secure PL1 physical counter and virtual counter
operating as 64-bit upcounters. The timer triggers when the appropriate
counter reaches the programmed threshold value.
Timer Triggered = ((Counter[63:0] - Threshold[63:0]) >= 0)
For more information please refer the Generic Timer section on pg. B8-1929
of ARM Architecture TRM for v7-AR.
const Timer_ANY |
|
Const used to specify any timer
#define Timer_ANY (UInt)~0
const Timer_MAX_PERIOD |
|
Max value of Timer period for PeriodType_COUNTS
#define Timer_MAX_PERIOD (UInt64)0x00FFFFFFFFFFFFFF
DETAILS
The architecture guarantees the system counter is atleast
56-bits wide. Therefore, this module limits the maximum
count to the largest 56 bit number.
const Timer_NUM_TIMER_DEVICES |
|
Number of timer peripherals on chip
#define Timer_NUM_TIMER_DEVICES (Int)2
enum Timer_PeriodType |
|
Timer period units
typedef enum Timer_PeriodType {
Timer_PeriodType_MICROSECS,
// period in microsecs
Timer_PeriodType_COUNTS
// period in counts
} Timer_PeriodType;
VALUES
PeriodType_MICROSECS
Period value is in microseconds.
PeriodType_COUNTS
Period value is in counts.
enum Timer_RunMode |
|
Timer Run Modes
typedef enum Timer_RunMode {
Timer_RunMode_CONTINUOUS,
// periodic and continuous
Timer_RunMode_ONESHOT,
// one-shot
Timer_RunMode_DYNAMIC
// dynamically reprogrammed (available on subset of devices)
} Timer_RunMode;
VALUES
RunMode_CONTINUOUS
Timer is periodic and runs continuously.
RunMode_ONESHOT
Timer runs for a single period value and stops.
RunMode_DYNAMIC
Timer is dynamically reprogrammed for the next required tick. This mode
is intended only for use by the Clock module when it is operating in
TickMode_DYNAMIC; it is not applicable for user-created Timer instances.
enum Timer_StartMode |
|
Timer Start Modes
typedef enum Timer_StartMode {
Timer_StartMode_AUTO,
// timer starts automatically
Timer_StartMode_USER
// timer will be started by user
} Timer_StartMode;
VALUES
StartMode_AUTO
Statically created/constructed Timers will be started in BIOS_start().
Dynamically created Timers will start at create() time. This includes
timers created before BIOS_start().
StartMode_USER
Timer will be started by the user using start().
enum Timer_Status |
|
Timer Status
typedef enum Timer_Status {
Timer_Status_INUSE,
// timer in use
Timer_Status_FREE
// timer is free
} Timer_Status;
VALUES
Status_INUSE
Timer is in use. A timer is marked in use from the time it gets
created to the time it gets deleted.
Status_FREE
Timer is free and can be acquired using create.
typedef Timer_FuncPtr |
|
Timer tick function prototype
typedef Void (*Timer_FuncPtr)(UArg);
config Timer_E_cannotSupport // module-wide |
|
Error raised when period requested is not supported
extern const Error_Id Timer_E_cannotSupport;
config Timer_E_invalidHwiMask // module-wide |
|
Error raised when Hwi Params has mask where self is turned on
extern const Error_Id Timer_E_invalidHwiMask;
DETAILS
This is not allowed because the timers on this platform do not
support one-shot mode and a stub is used to stop it.
Another timer interrupt cannot go off when the ISR is running.
config Timer_E_invalidTimer // module-wide |
|
Error raised when timer id specified is not supported
extern const Error_Id Timer_E_invalidTimer;
config Timer_E_notAvailable // module-wide |
|
Error raised when timer requested is in use
extern const Error_Id Timer_E_notAvailable;
config Timer_anyMask // module-wide |
|
Available mask to be used when select = Timer_ANY
extern const UInt Timer_anyMask;
config Timer_availMask // module-wide |
|
Available mask tracks the available/free timer peripherals
extern const UInt Timer_availMask;
config Timer_intFreq // module-wide |
|
Default internal timer input clock frequency
NOTE
On OMAP5x, DRA7x and ADAS devices, the Generic Timer
operates at a fixed frequency of 6144000 Hz.
On Keystone 2 devices, the Genric Timer operates at
Main PLL frequency /6. The default internal timer
input frequency for Keystone 2 devices is 20480000 Hz
which is derived from the Main PLL bypass clock fequency
of 122.88 MHz. If the Main PLL is initialized to a different
frequency then this config param should be updated accordigly.
For instance, if Main PLL frequency is configured to be 614.4 MHz,
the Timer operates at 102.4 MHz and Timer.intFreq should be set to
this value.
var Timer = xdc.useModule('ti.sysbios.family.arm.systimer.Timer');
Timer.intFreq.lo = 102400000; // = (Main PLL freq / 6)
Timer.intFreq.hi = 0;
config Timer_intNumDef // module-wide |
|
A15 Generic Timer interrupt numbers
extern const UInt Timer_intNumDef[2];
DETAILS
Generic Timer Interrupts are forwarded to GIC's private peripheral
interrupts and have a architecture defined fixed mapping that should
be same across all A15 variants.
Non-secure physical timer -> PPI2 or Interrupt #30
Virtual timer -> PPI4 or Interrupt #27
Timer_getNumTimers() // module-wide |
|
Returns number of timer peripherals on the platform
UInt Timer_getNumTimers();
RETURNS
Number of timer peripherals.
Timer_getStatus() // module-wide |
|
Returns timer status (free or in use)
RETURNS
timer status
Module-Wide Built-Ins |
|
// Get this module's unique id
Bool Timer_Module_startupDone();
// Test if this module has completed startup
// The heap from which this module allocates memory
Bool Timer_Module_hasMask();
// Test whether this module has a diagnostics mask
Bits16 Timer_Module_getMask();
// Returns the diagnostics mask for this module
Void Timer_Module_setMask(Bits16 mask);
// Set the diagnostics mask for this module
Instance Object Types |
|
typedef struct Timer_Object Timer_Object;
// Opaque internal representation of an instance object
// Client reference to an instance object
typedef struct Timer_Struct Timer_Struct;
// Opaque client structure large enough to hold an instance object
// Convert this instance structure pointer into an instance handle
// Convert this instance handle into an instance structure pointer
Instance Config Parameters |
|
typedef struct Timer_Params {
// Instance config-params structure
// Common per-instance configs
UArg arg;
// Argument for tick function
// Timer frequency
// Hwi Params for Hwi Object. Default is null
UInt32 period;
// Period of a tick
UInt64 period64;
// Period of a tick
// Period type
// Timer run mode
// Timer start mode
} Timer_Params;
// Initialize this config-params structure with supplier-specified defaults before instance creation
config Timer_Params.arg // instance |
|
Argument for tick function
DETAILS
Default is null.
config Timer_Params.extFreq // instance |
|
Timer frequency
DETAILS
This parameter is meaningfull only on platforms where the timer's
input clock can be changed. If value is left at zero, then input clock
to the timer clock is assumed.
This value is used to convert timer ticks to real time units; seconds,
milliseconds, etc.
config Timer_Params.hwiParams // instance |
|
Hwi Params for Hwi Object. Default is null
config Timer_Params.period // instance |
|
Period of a tick
DETAILS
The period can be specified in timer counts or microseconds
and its default value is 0.
The implementation of ITimer will support a period of UInt32
timer counts and use pre-scalars if necessary.
config Timer_Params.period64 // instance |
|
Period of a tick
DETAILS
The period can be specified in timer counts or microseconds and its
default value is 0.
This timer implementation supports a max period of UInt64 timer
counts.
config Timer_Params.periodType // instance |
|
Period type
DETAILS
Default is PeriodType_MICROSECS
config Timer_Params.runMode // instance |
|
Timer run mode
DETAILS
config Timer_Params.startMode // instance |
|
Timer start mode
DETAILS
Runtime Instance Creation |
|
// Allocate and initialize a new instance object and return its handle
// Initialize a new instance object inside the provided structure
ARGUMENTS
id
Timer id ranging from 0 to a platform specific value,
or ANY
tickFxn
function that runs upon timer expiry.
params
per-instance config params, or NULL to select default values (target-domain only)
eb
active error-handling block, or NULL to select default policy (target-domain only)
DETAILS
Create could fail if timer peripheral is unavailable. To
request any available timer use
ANY as the id.
TimerId's are logical ids. The family-specific implementations
map the ids to physical peripherals.
Instance Deletion |
|
// Finalize and free this previously allocated instance object, setting the referenced handle to NULL
// Finalize the instance object inside the provided structure
Timer_getCount() // instance |
|
Read timer counter register
ARGUMENTS
handle
handle of a previously-created Timer instance object
RETURNS
timer counter value
Timer_getCount64() // instance |
|
Read timer counter register
ARGUMENTS
handle
handle of a previously-created Timer instance object
RETURNS
64 bit timer counter value
Timer_getFreq() // instance |
|
Return timer frequency in Hz
ARGUMENTS
handle
handle of a previously-created Timer instance object
freq
frequency in Hz
DETAILS
This is the effective frequency of the clock incrementing the timer
counter register after all scaling factors are taken into account.
(including pre-scalars).
Timer_getFunc() // instance |
|
Get Timer function and arg
ARGUMENTS
handle
handle of a previously-created Timer instance object
arg
pointer for returning Timer's function argument
RETURNS
Timer's function
Timer_getPeriod() // instance |
|
Get timer period in timer counts
ARGUMENTS
handle
handle of a previously-created Timer instance object
RETURNS
period in timer counts
Timer_getPeriod64() // instance |
|
Get timer period in timer counts
ARGUMENTS
handle
handle of a previously-created Timer instance object
RETURNS
64 bit period in timer counts
Timer_reconfig() // instance |
|
Used to modify static timer instances at runtime
ARGUMENTS
handle
handle of a previously-created Timer instance object
timerParams
timer Params
tickFxn
functions that runs when timer expires.
Timer_setFunc() // instance |
|
Overwrite Timer function and arg
ARGUMENTS
handle
handle of a previously-created Timer instance object
fxn
pointer to function
arg
argument to function
DETAILS
Replaces a Timer object's tickFxn function originally
provided in
create.
Timer_setPeriod() // instance |
|
Set timer period specified in timer counts
ARGUMENTS
handle
handle of a previously-created Timer instance object
period
period in timer counts
DETAILS
Timer_setPeriod() invokes Timer_stop() prior to setting the period
and leaves the timer in the stopped state.
To dynamically change the period of a timer you must
protect against re-entrancy by disabling interrupts.
Use the following call sequence to guarantee proper results:
// disable interrupts if an interrupt could lead to
// another call to Timer_start().
key = Hwi_disable();
Timer_setPeriod(period);
Timer_start();
Hwi_restore(key);
ITimer implementation must support UInt32 and use pre-scalars whenever
necessary
SIDE EFFECTS
Calls Timer_stop(), and disables the timer's interrupt.
Timer_setPeriod64() // instance |
|
Set timer period specified in timer counts
ARGUMENTS
handle
handle of a previously-created Timer instance object
period
64 bit period in timer counts
DETAILS
Timer_setPeriod64() invokes Timer_stop() prior to setting the period
and leaves the timer in the stopped state.
A15 architecture guarantees a minimum timer counter width of 56 bits.
Therefore, the period should be limited to a value no greater than
0xFFFFFFFFFFFFFF.
To dynamically change the period of a timer you must
protect against re-entrancy by disabling interrupts.
Use the following call sequence to guarantee proper results:
// disable interrupts if an interrupt could lead to
// another call to Timer_start().
key = Hwi_disable();
Timer_setPeriod64(period);
Timer_start();
Hwi_restore(key);
SIDE EFFECTS
Calls Timer_stop(), and disables the timer's interrupt.
Timer_setPeriodMicroSecs() // instance |
|
Set timer period specified in microseconds
Bool Timer_setPeriodMicroSecs(
Timer_Handle handle,
UInt32 microsecs);
ARGUMENTS
handle
handle of a previously-created Timer instance object
period
period in microseconds
DETAILS
A best-effort method will be used to set the period register.
There might be a slight rounding error based on resolution of timer
period register. If the timer frequency cannot support the requested
period, i.e. the timer period register cannot support the requested
period, then this function returns false.
Timer_setPeriodMicroSecs() invokes Timer_stop() prior to setting
the period and leaves the timer in the stopped state.
To dynamically change the period of a timer you must
protect against re-entrancy by disabling interrupts.
Use the following call sequence to guarantee proper results:
// disable interrupts if an interrupt could lead to
// another call to Timer_start().
key = Hwi_disable();
Timer_setPeriodMicroSecs(period);
Timer_start();
Hwi_restore(key);
Timer_setPeriodMicroSecs64() // instance |
|
Set timer period specified in microseconds
Bool Timer_setPeriodMicroSecs64(
Timer_Handle handle,
UInt64 microsecs);
ARGUMENTS
handle
handle of a previously-created Timer instance object
period
period in microseconds
DETAILS
A best-effort method will be used to set the period register.
There might be a slight rounding error based on resolution of timer
period register. If the timer frequency cannot support the requested
period, i.e. the timer period register cannot support the requested
period, then this function returns false.
Timer_setPeriodMicroSecs() invokes Timer_stop() prior to setting
the period and leaves the timer in the stopped state.
To dynamically change the period of a timer you must
protect against re-entrancy by disabling interrupts.
Use the following call sequence to guarantee proper results:
// disable interrupts if an interrupt could lead to
// another call to Timer_start().
key = Hwi_disable();
Timer_setPeriodMicroSecs(period);
Timer_start();
Hwi_restore(key);
Timer_start() // instance |
|
Reload and start the timer
ARGUMENTS
handle
handle of a previously-created Timer instance object
DETAILS
Thread safety must be observed when using the
start
and
stop APIs to avoid possible miss-
configuration of the timers and unintended behaviors.
To protect against re-entrancy, surround the start/stop invocations
with
Hwi_disable() and
Hwi_restore() calls:
// disable interrupts if an interrupt could lead to
// another call to Timer_start().
key = Hwi_disable();
Timer_stop();
...
Timer_start();
Hwi_restore(key);
SIDE EFFECTS
Enables the timer's interrupt.
Timer_stop() // instance |
|
Stop the timer
ARGUMENTS
handle
handle of a previously-created Timer instance object
DETAILS
Thread safety must be observed when using the
start
and
stop APIs to avoid possible miss-
configuration of the timers and unintended behaviors.
To protect against re-entrancy, surround the start/stop invocations
with
Hwi_disable() and
Hwi_restore() calls:
// disable interrupts if an interrupt could lead to
// another call to Timer_start().
key = Hwi_disable();
Timer_stop();
...
Timer_start();
Hwi_restore(key);
SIDE EFFECTS
Disables the timer's interrupt.
Instance Convertors |
|
// unconditionally move one level up the inheritance hierarchy
// conditionally move one level down the inheritance hierarchy; NULL upon failure
Instance Built-Ins |
|
Int Timer_Object_count();
// The number of statically-created instance objects
// The handle of the i-th statically-created instance object (array == NULL)
// The handle of the first dynamically-created instance object, or NULL
// The handle of the next dynamically-created instance object, or NULL
// The heap used to allocate dynamically-created instance objects
// The label associated with this instance object
// The name of this instance object
const Timer.ANY |
|
Const used to specify any timer
C SYNOPSIS
const Timer.MAX_PERIOD |
|
Max value of Timer period for PeriodType_COUNTS
const Timer.MAX_PERIOD = 0x00FFFFFFFFFFFFFF;
DETAILS
The architecture guarantees the system counter is atleast
56-bits wide. Therefore, this module limits the maximum
count to the largest 56 bit number.
C SYNOPSIS
const Timer.NUM_TIMER_DEVICES |
|
Number of timer peripherals on chip
const Timer.NUM_TIMER_DEVICES = 2;
C SYNOPSIS
enum Timer.PeriodType |
|
Timer period units
values of type Timer.PeriodType
const Timer.PeriodType_MICROSECS;
// period in microsecs
const Timer.PeriodType_COUNTS;
// period in counts
VALUES
PeriodType_MICROSECS
Period value is in microseconds.
PeriodType_COUNTS
Period value is in counts.
C SYNOPSIS
enum Timer.RunMode |
|
Timer Run Modes
values of type Timer.RunMode
const Timer.RunMode_CONTINUOUS;
// periodic and continuous
const Timer.RunMode_ONESHOT;
// one-shot
const Timer.RunMode_DYNAMIC;
// dynamically reprogrammed (available on subset of devices)
VALUES
RunMode_CONTINUOUS
Timer is periodic and runs continuously.
RunMode_ONESHOT
Timer runs for a single period value and stops.
RunMode_DYNAMIC
Timer is dynamically reprogrammed for the next required tick. This mode
is intended only for use by the Clock module when it is operating in
TickMode_DYNAMIC; it is not applicable for user-created Timer instances.
C SYNOPSIS
enum Timer.StartMode |
|
Timer Start Modes
values of type Timer.StartMode
const Timer.StartMode_AUTO;
// timer starts automatically
const Timer.StartMode_USER;
// timer will be started by user
VALUES
StartMode_AUTO
Statically created/constructed Timers will be started in BIOS_start().
Dynamically created Timers will start at create() time. This includes
timers created before BIOS_start().
StartMode_USER
Timer will be started by the user using start().
C SYNOPSIS
enum Timer.Status |
|
Timer Status
values of type Timer.Status
const Timer.Status_INUSE;
// timer in use
const Timer.Status_FREE;
// timer is free
VALUES
Status_INUSE
Timer is in use. A timer is marked in use from the time it gets
created to the time it gets deleted.
Status_FREE
Timer is free and can be acquired using create.
C SYNOPSIS
config Timer.E_cannotSupport // module-wide |
|
Error raised when period requested is not supported
msg: "E_cannotSupport: Timer cannot support requested period %d"
};
C SYNOPSIS
config Timer.E_invalidHwiMask // module-wide |
|
Error raised when Hwi Params has mask where self is turned on
msg: "E_InvalidMask: Mask in hwiParams cannot enable self"
};
DETAILS
This is not allowed because the timers on this platform do not
support one-shot mode and a stub is used to stop it.
Another timer interrupt cannot go off when the ISR is running.
C SYNOPSIS
config Timer.E_invalidTimer // module-wide |
|
Error raised when timer id specified is not supported
msg: "E_invalidTimer: Invalid Timer Id %d"
};
C SYNOPSIS
config Timer.E_notAvailable // module-wide |
|
Error raised when timer requested is in use
msg: "E_notAvailable: Timer not available %d"
};
C SYNOPSIS
config Timer.anyMask // module-wide |
|
Available mask to be used when select = Timer_ANY
Timer.anyMask = UInt 0x3;
C SYNOPSIS
config Timer.availMask // module-wide |
|
Available mask tracks the available/free timer peripherals
Timer.availMask = UInt 0x3;
C SYNOPSIS
config Timer.intFreq // module-wide |
|
Default internal timer input clock frequency
NOTE
On OMAP5x, DRA7x and ADAS devices, the Generic Timer
operates at a fixed frequency of 6144000 Hz.
On Keystone 2 devices, the Genric Timer operates at
Main PLL frequency /6. The default internal timer
input frequency for Keystone 2 devices is 20480000 Hz
which is derived from the Main PLL bypass clock fequency
of 122.88 MHz. If the Main PLL is initialized to a different
frequency then this config param should be updated accordigly.
For instance, if Main PLL frequency is configured to be 614.4 MHz,
the Timer operates at 102.4 MHz and Timer.intFreq should be set to
this value.
var Timer = xdc.useModule('ti.sysbios.family.arm.systimer.Timer');
Timer.intFreq.lo = 102400000; // = (Main PLL freq / 6)
Timer.intFreq.hi = 0;
C SYNOPSIS
config Timer.intNumDef // module-wide |
|
A15 Generic Timer interrupt numbers
Timer.intNumDef = UInt[2] undefined;
DETAILS
Generic Timer Interrupts are forwarded to GIC's private peripheral
interrupts and have a architecture defined fixed mapping that should
be same across all A15 variants.
Non-secure physical timer -> PPI2 or Interrupt #30
Virtual timer -> PPI4 or Interrupt #27
C SYNOPSIS
metaonly config Timer.common$ // module-wide |
|
Common module configuration parameters
DETAILS
All modules have this configuration parameter. Its name
contains the '$' character to ensure it does not conflict with
configuration parameters declared by the module. This allows
new configuration parameters to be added in the future without
any chance of breaking existing modules.
Instance Config Parameters |
|
var params = new Timer.Params;
// Instance config-params object
params.arg = UArg null;
// Argument for tick function
// Timer frequency
lo: 0,
hi: 0
};
// Hwi Params for Hwi Object. Default is null
params.period = UInt32 0;
// Period of a tick
params.period64 = UInt64 0;
// Period of a tick
// Period type
// Timer run mode
// Timer start mode
config Timer.Params.arg // instance |
|
Argument for tick function
var params = new Timer.Params;
...
params.arg = UArg null;
DETAILS
Default is null.
C SYNOPSIS
config Timer.Params.extFreq // instance |
|
Timer frequency
var params = new Timer.Params;
...
lo: 0,
hi: 0
};
DETAILS
This parameter is meaningfull only on platforms where the timer's
input clock can be changed. If value is left at zero, then input clock
to the timer clock is assumed.
This value is used to convert timer ticks to real time units; seconds,
milliseconds, etc.
C SYNOPSIS
config Timer.Params.hwiParams // instance |
|
Hwi Params for Hwi Object. Default is null
var params = new Timer.Params;
...
C SYNOPSIS
config Timer.Params.period // instance |
|
Period of a tick
var params = new Timer.Params;
...
params.period = UInt32 0;
DETAILS
The period can be specified in timer counts or microseconds
and its default value is 0.
The implementation of ITimer will support a period of UInt32
timer counts and use pre-scalars if necessary.
C SYNOPSIS
config Timer.Params.period64 // instance |
|
Period of a tick
var params = new Timer.Params;
...
params.period64 = UInt64 0;
DETAILS
The period can be specified in timer counts or microseconds and its
default value is 0.
This timer implementation supports a max period of UInt64 timer
counts.
C SYNOPSIS
config Timer.Params.periodType // instance |
|
Period type
var params = new Timer.Params;
...
DETAILS
Default is PeriodType_MICROSECS
C SYNOPSIS
config Timer.Params.runMode // instance |
|
Timer run mode
var params = new Timer.Params;
...
DETAILS
C SYNOPSIS
config Timer.Params.startMode // instance |
|
Timer start mode
var params = new Timer.Params;
...
DETAILS
C SYNOPSIS
Static Instance Creation |
|
var params =
new Timer.
Params;
// Allocate instance config-params
params.config = ...
// Assign individual configs
var inst = Timer.create(Int id, Void(*)(UArg) tickFxn, params);
// Create an instance-object
ARGUMENTS
id
Timer id ranging from 0 to a platform specific value,
or ANY
tickFxn
function that runs upon timer expiry.
params
per-instance config params, or NULL to select default values (target-domain only)
eb
active error-handling block, or NULL to select default policy (target-domain only)
DETAILS
Create could fail if timer peripheral is unavailable. To
request any available timer use
ANY as the id.
TimerId's are logical ids. The family-specific implementations
map the ids to physical peripherals.