source: rtems/cpukit/score/include/rtems/bspsmp.h @ 2f6108f9

4.115
Last change on this file since 2f6108f9 was 2f6108f9, checked in by Sebastian Huber <sebastian.huber@…>, on May 28, 2013 at 8:58:19 AM

smp: Simplify SMP initialization sequence

Delete bsp_smp_wait_for(). Other parts of the system work without
timeout, e.g. the spinlocks. Using a timeout here does not make the
system more robust.

Delete bsp_smp_cpu_state and replace it with Per_CPU_State. The
Per_CPU_State follows the Score naming conventions. Add
_Per_CPU_Change_state() and _Per_CPU_Wait_for_state() functions to
change and observe states.

Use Per_CPU_State in Per_CPU_Control instead of the anonymous integer.

Add _CPU_Processor_event_broadcast() and _CPU_Processor_event_receive()
functions provided by the CPU port. Use these functions in
_Per_CPU_Change_state() and _Per_CPU_Wait_for_state().

Add prototype for _SMP_Send_message().

Delete RTEMS_BSP_SMP_FIRST_TASK message. The first context switch is
now performed in rtems_smp_secondary_cpu_initialize(). Issuing the
first context switch in the context of the inter-processor interrupt is
not possible on systems with a modern interrupt controller. Such an
interrupt controler usually requires a handshake protocol with interrupt
acknowledge and end of interrupt signals. A direct context switch in an
interrupt handler circumvents the interrupt processing epilogue and may
leave the system in an inconsistent state.

Release lock in rtems_smp_process_interrupt() even if no message was
delivered. This prevents deadlock of the system.

Simplify and format _SMP_Send_message(),
_SMP_Request_other_cores_to_perform_first_context_switch(),
_SMP_Request_other_cores_to_dispatch() and
_SMP_Request_other_cores_to_shutdown().

  • Property mode set to 100644
File size: 4.6 KB
Line 
1/**
2 *  @file  rtems/bspsmp.h
3 *
4 *  @brief Interface Between RTEMS and an SMP Aware BSP
5 *
6 *  This include file defines the interface between RTEMS and an
7 *  SMP aware BSP.  These methods will only be used when RTEMS
8 *  is configured with SMP support enabled.
9 */
10
11/*
12 *  COPYRIGHT (c) 1989-2011.
13 *  On-Line Applications Research Corporation (OAR).
14 *
15 *  The license and distribution terms for this file may be
16 *  found in the file LICENSE in this distribution or at
17 *  http://www.rtems.com/license/LICENSE.
18 */
19
20#ifndef _RTEMS_BSPSMP_H
21#define _RTEMS_BSPSMP_H
22
23#include <rtems/score/cpuopts.h>
24
25#if defined (RTEMS_SMP)
26#include <rtems/score/percpu.h>
27
28/**
29 *  @defgroup RTEMS BSP SMP Interface
30 *
31 *  @ingroup Score
32 *
33 *  This defines the interface between RTEMS and the BSP for
34 *  SMP support.  The interface uses the term primary
35 *  to refer to the "boot" processor and secondary to refer
36 *  to the "application" processors.  Different architectures
37 *  use different terminology.
38 *
39 *  It is assumed that when the processor is reset and thus
40 *  when RTEMS is initialized, that the primary processor is
41 *  the only one executing.  The others are assumed to be in
42 *  a quiescent or reset state awaiting a command to come online.
43 */
44
45/**@{*/
46
47#ifdef __cplusplus
48extern "C" {
49#endif
50
51
52#ifndef ASM
53
54/**
55 * @brief Performs BSP specific SMP initialization in the context of the main
56 * processor.
57 *
58 * This function is invoked on the main processor by RTEMS during
59 * initialization.  All interrupt stacks are allocated at this point in case
60 * the CPU port allocates the interrupt stacks.
61 *
62 * The BSP may start secondary processors now.
63 *
64 * @param[in] configured_cpu_count The count of processors requested by the
65 * application configuration.
66 *
67 * @return The count of processors available for the application in the system.
68 * This value is less than or equal to the configured count of processors.
69 */
70uint32_t bsp_smp_initialize( uint32_t configured_cpu_count );
71
72/**
73 *  @brief Obtain current CPU index.
74 *
75 *  This method is invoked by RTEMS when it needs to know the index
76 *  of the CPU it is executing on.
77 *
78 *  @retval This method returns the current CPU index.
79 */
80int bsp_smp_processor_id(void) RTEMS_COMPILER_PURE_ATTRIBUTE;
81
82/**
83 *  @brief Generate an interprocessor broadcast interrupt.
84 *
85 *  This method is invoked when RTEMS wants to let all of the other
86 *  CPUs know that it has sent them message.  CPUs not including
87 *  the originating CPU should receive the interrupt.
88
89 *
90 *  @note On CPUs without the capability to generate a broadcast
91 *        to all other CPUs interrupt, this can be implemented by
92 *        a loop of sending interrupts to specific CPUs.
93 */
94void bsp_smp_broadcast_interrupt(void);
95
96/**
97 *  @brief Generate a interprocessor interrupt.
98 *
99 *  This method is invoked by RTEMS to let @a cpu know that it
100 *  has sent it a message.
101 *
102 *  @param [in] cpu is the recipient CPU
103 */
104void bsp_smp_interrupt_cpu(
105  int cpu
106);
107
108/**
109 *  @brief Obtain CPU core number.
110 *
111 *  This method is invoked by RTEMS when it needs to know which core
112 *  number it is executing on.  This is used when it needs to perform
113 *  some action or bookkeeping and needs to distinguish itself from
114 *  the other cores.  For example, it may need to realize it needs to
115 *  preempt a thread on another node.
116 *
117 *  @retval This method returns the Id of the current CPU core.
118 */
119int   bsp_smp_processor_id( void );
120
121/**
122 * @brief Performs high-level initialization of a secondary CPU and runs the
123 * application threads.
124 *
125 * The low-level initialization code must call this function to hand over the
126 * control of this processor to RTEMS.  Interrupts must be disabled.  It must
127 * be possible to send inter-processor interrupts to this processor.  Since
128 * interrupts are disabled the inter-processor interrupt delivery is postponed
129 * until interrupts are enabled the first time.  This is usually a side-effect
130 * of the context switch to the first thread.
131 *
132 * The pre-requisites for the call to this function are
133 * - disabled interrupts,
134 * - reception of inter-processor interrupts is possible,
135 * - a valid stack pointer and enough stack space,
136 * - a valid code memory, and
137 * - a valid BSS section.
138 *
139 * This function must not be called by the main processor.
140 */
141void rtems_smp_secondary_cpu_initialize( void );
142
143/**
144 *  @brief Process the incoming interprocessor request.
145 *
146 *  This is the method called by the BSP's interrupt handler
147 *  to process the incoming interprocessor request.
148 */
149void rtems_smp_process_interrupt(void);
150
151#endif
152
153#ifdef __cplusplus
154}
155#endif
156
157#else
158  #define bsp_smp_processor_id()  0
159#endif
160
161/**@}*/
162#endif
163
164/* end of include file */
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