[rtems commit] score: Add _SMP_Before_multitasking_action()
Sebastian Huber
sebh at rtems.org
Fri Mar 4 13:52:25 UTC 2016
Module: rtems
Branch: master
Commit: 5b0d2c1965e1dab2915231866aaa5623ced66330
Changeset: http://git.rtems.org/rtems/commit/?id=5b0d2c1965e1dab2915231866aaa5623ced66330
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date: Thu Mar 3 13:37:14 2016 +0100
score: Add _SMP_Before_multitasking_action()
The use case for this is the Cortex-A9 MPCore which has per-processor
registers (only accessible by a particular processor) for the global
timer used by the clock driver. This might be useful for other drivers
as well.
Update #2554.
---
cpukit/score/include/rtems/score/percpu.h | 8 +++
cpukit/score/include/rtems/score/smpimpl.h | 48 +++++++++++++++-
cpukit/score/src/percpu.c | 92 +++++++++++++++++++++++++++---
cpukit/score/src/smp.c | 23 ++++++++
cpukit/score/src/smpmulticastaction.c | 4 +-
5 files changed, 164 insertions(+), 11 deletions(-)
diff --git a/cpukit/score/include/rtems/score/percpu.h b/cpukit/score/include/rtems/score/percpu.h
index 19f46d2..39be1e3 100644
--- a/cpukit/score/include/rtems/score/percpu.h
+++ b/cpukit/score/include/rtems/score/percpu.h
@@ -361,6 +361,14 @@ typedef struct Per_CPU_Control {
Per_CPU_State state;
/**
+ * @brief Action to be executed by this processor in the
+ * SYSTEM_STATE_BEFORE_MULTITASKING state on behalf of the boot processor.
+ *
+ * @see _SMP_Before_multitasking_action().
+ */
+ Atomic_Uintptr before_multitasking_action;
+
+ /**
* @brief Indicates if the processor has been successfully started via
* _CPU_SMP_Start_processor().
*/
diff --git a/cpukit/score/include/rtems/score/smpimpl.h b/cpukit/score/include/rtems/score/smpimpl.h
index 386216f..59a99ec 100644
--- a/cpukit/score/include/rtems/score/smpimpl.h
+++ b/cpukit/score/include/rtems/score/smpimpl.h
@@ -235,7 +235,7 @@ void _SMP_Send_message_multicast(
unsigned long message
);
-typedef void ( *SMP_Multicast_action_handler )( void *arg );
+typedef void ( *SMP_Action_handler )( void *arg );
/**
* @brief Initiates a SMP multicast action to a set of processors.
@@ -250,10 +250,54 @@ typedef void ( *SMP_Multicast_action_handler )( void *arg );
void _SMP_Multicast_action(
const size_t setsize,
const cpu_set_t *cpus,
- SMP_Multicast_action_handler handler,
+ SMP_Action_handler handler,
void *arg
);
+/**
+ * @brief Executes a handler with argument on the specified processor on behalf
+ * of the boot processor.
+ *
+ * The calling processor must be the boot processor. In case the specified
+ * processor is not online or not in the
+ * PER_CPU_STATE_READY_TO_START_MULTITASKING state, then no action is
+ * performed.
+ *
+ * @param cpu The processor to execute the action.
+ * @param handler The handler of the action.
+ * @param arg The argument of the action.
+ *
+ * @retval true The handler executed on the specified processor.
+ * @retval false Otherwise.
+ *
+ * @see _SMP_Before_multitasking_action_broadcast().
+ */
+bool _SMP_Before_multitasking_action(
+ Per_CPU_Control *cpu,
+ SMP_Action_handler handler,
+ void *arg
+);
+
+/**
+ * @brief Executes a handler with argument on all online processors except the
+ * boot processor on behalf of the boot processor.
+ *
+ * The calling processor must be the boot processor.
+ *
+ * @param handler The handler of the action.
+ * @param arg The argument of the action.
+ *
+ * @retval true The handler executed on all online processors except the boot
+ * processor.
+ * @retval false Otherwise.
+ *
+ * @see _SMP_Before_multitasking_action().
+ */
+bool _SMP_Before_multitasking_action_broadcast(
+ SMP_Action_handler handler,
+ void *arg
+);
+
#endif /* defined( RTEMS_SMP ) */
/**
diff --git a/cpukit/score/src/percpu.c b/cpukit/score/src/percpu.c
index 730528a..0e4c067 100644
--- a/cpukit/score/src/percpu.c
+++ b/cpukit/score/src/percpu.c
@@ -20,6 +20,7 @@
#include <rtems/score/percpu.h>
#include <rtems/score/assert.h>
+#include <rtems/score/isrlock.h>
#include <rtems/score/smpimpl.h>
#include <rtems/config.h>
@@ -35,11 +36,48 @@ RTEMS_STATIC_ASSERT(
#if defined(RTEMS_SMP)
-static SMP_lock_Control _Per_CPU_State_lock =
- SMP_LOCK_INITIALIZER("per-CPU state");
+typedef struct {
+ SMP_Action_handler handler;
+ void *arg;
+} SMP_Before_multicast_action;
+
+ISR_LOCK_DEFINE( static, _Per_CPU_State_lock, "Per-CPU State" )
+
+static void _Per_CPU_State_acquire( ISR_lock_Context *lock_context )
+{
+ _ISR_lock_ISR_disable_and_acquire( &_Per_CPU_State_lock, lock_context );
+}
+
+static void _Per_CPU_State_release( ISR_lock_Context *lock_context )
+{
+ _ISR_lock_Release_and_ISR_enable( &_Per_CPU_State_lock, lock_context );
+}
+
+static void _Per_CPU_State_before_multitasking_action( Per_CPU_Control *cpu )
+{
+ uintptr_t action_value;
+
+ action_value = _Atomic_Load_uintptr(
+ &cpu->before_multitasking_action,
+ ATOMIC_ORDER_ACQUIRE
+ );
+
+ if ( action_value != 0 ) {
+ SMP_Before_multicast_action *action =
+ (SMP_Before_multicast_action *) action_value;
+
+ ( *action->handler )( action->arg );
+
+ _Atomic_Store_uintptr(
+ &cpu->before_multitasking_action,
+ 0,
+ ATOMIC_ORDER_RELEASE
+ );
+ }
+}
static void _Per_CPU_State_busy_wait(
- const Per_CPU_Control *cpu,
+ Per_CPU_Control *cpu,
Per_CPU_State new_state
)
{
@@ -60,6 +98,7 @@ static void _Per_CPU_State_busy_wait(
state != PER_CPU_STATE_REQUEST_START_MULTITASKING
&& state != PER_CPU_STATE_SHUTDOWN
) {
+ _Per_CPU_State_before_multitasking_action( cpu );
_CPU_SMP_Processor_event_receive();
state = cpu->state;
}
@@ -122,13 +161,12 @@ void _Per_CPU_State_change(
Per_CPU_State new_state
)
{
- SMP_lock_Control *lock = &_Per_CPU_State_lock;
- SMP_lock_Context lock_context;
+ ISR_lock_Context lock_context;
Per_CPU_State next_state;
_Per_CPU_State_busy_wait( cpu, new_state );
- _SMP_lock_ISR_disable_and_acquire( lock, &lock_context );
+ _Per_CPU_State_acquire( &lock_context );
next_state = _Per_CPU_State_get_next( cpu->state, new_state );
cpu->state = next_state;
@@ -157,7 +195,7 @@ void _Per_CPU_State_change(
_CPU_SMP_Processor_event_broadcast();
- _SMP_lock_Release_and_ISR_enable( lock, &lock_context );
+ _Per_CPU_State_release( &lock_context );
if (
next_state == PER_CPU_STATE_SHUTDOWN
@@ -167,6 +205,46 @@ void _Per_CPU_State_change(
}
}
+bool _SMP_Before_multitasking_action(
+ Per_CPU_Control *cpu,
+ SMP_Action_handler handler,
+ void *arg
+)
+{
+ bool done;
+
+ _Assert( _Per_CPU_Is_boot_processor( _Per_CPU_Get() ) );
+
+ if ( _Per_CPU_Is_processor_online( cpu ) ) {
+ SMP_Before_multicast_action action = {
+ .handler = handler,
+ .arg = arg
+ };
+ Per_CPU_State expected_state = PER_CPU_STATE_READY_TO_START_MULTITASKING;
+
+ _Atomic_Store_uintptr(
+ &cpu->before_multitasking_action,
+ (uintptr_t) &action,
+ ATOMIC_ORDER_RELEASE
+ );
+
+ _CPU_SMP_Processor_event_broadcast();
+
+ _Per_CPU_State_busy_wait( cpu, expected_state );
+
+ do {
+ done = _Atomic_Load_uintptr(
+ &cpu->before_multitasking_action,
+ ATOMIC_ORDER_ACQUIRE
+ ) == 0;
+ } while ( !done && cpu->state == expected_state );
+ } else {
+ done = false;
+ }
+
+ return done;
+}
+
#else
/*
* On single core systems, we can efficiently directly access a single
diff --git a/cpukit/score/src/smp.c b/cpukit/score/src/smp.c
index 8049643..4dacd4e 100644
--- a/cpukit/score/src/smp.c
+++ b/cpukit/score/src/smp.c
@@ -211,4 +211,27 @@ void _SMP_Send_message_multicast(
}
}
+bool _SMP_Before_multitasking_action_broadcast(
+ SMP_Action_handler handler,
+ void *arg
+)
+{
+ bool done = true;
+ uint32_t cpu_count = _SMP_Get_processor_count();
+ uint32_t cpu_index;
+
+ for ( cpu_index = 0 ; done && cpu_index < cpu_count ; ++cpu_index ) {
+ Per_CPU_Control *cpu = _Per_CPU_Get_by_index( cpu_index );
+
+ if (
+ !_Per_CPU_Is_boot_processor( cpu )
+ && _Per_CPU_Is_processor_online( cpu )
+ ) {
+ done = _SMP_Before_multitasking_action( cpu, handler, arg );
+ }
+ }
+
+ return done;
+}
+
SMP_Test_message_handler _SMP_Test_message_handler;
diff --git a/cpukit/score/src/smpmulticastaction.c b/cpukit/score/src/smpmulticastaction.c
index 2e59262..d5d0064 100644
--- a/cpukit/score/src/smpmulticastaction.c
+++ b/cpukit/score/src/smpmulticastaction.c
@@ -17,7 +17,7 @@
typedef struct {
Chain_Node Node;
- SMP_Multicast_action_handler handler;
+ SMP_Action_handler handler;
void *arg;
cpu_set_t *recipients;
size_t setsize;
@@ -94,7 +94,7 @@ _SMP_Multicast_actions_try_process( void )
void _SMP_Multicast_action(
const size_t setsize,
const cpu_set_t *cpus,
- SMP_Multicast_action_handler handler,
+ SMP_Action_handler handler,
void *arg
)
{
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