source: rtems/bsps/i386/pc386/start/bspgetworkarea.c @ eea21eac

5
Last change on this file since eea21eac was eea21eac, checked in by Sebastian Huber <sebastian.huber@…>, on Dec 13, 2019 at 5:18:36 AM

bsps: Rework work area initialization

The work area initialization was done by the BSP through
bsp_work_area_initialize(). This approach predated the system
initialization through the system initialization linker set. The
workspace and C program heap were unconditionally initialized. The aim
is to support RTEMS application configurations which do not need the
workspace and C program heap. In these configurations, the workspace
and C prgram heap should not get initialized.

Change all bsp_work_area_initialize() to implement _Memory_Get()
instead. Move the dirty memory, sbrk(), per-CPU data, workspace, and
malloc() heap initialization into separate system initialization steps.
This makes it also easier to test the individual initialization steps.

This change adds a dependency to _Heap_Extend() to all BSPs. This
dependency will be removed in a follow up change.

Update #3838.

  • Property mode set to 100644
File size: 3.8 KB
Line 
1/*
2 *  COPYRIGHT (c) 1989-2008.
3 *  On-Line Applications Research Corporation (OAR).
4 *
5 *  The license and distribution terms for this file may be
6 *  found in the file LICENSE in this distribution or at
7 *  http://www.rtems.org/license/LICENSE.
8 */
9
10/* #define BSP_GET_WORK_AREA_DEBUG */
11#include <bsp.h>
12#include <bsp/bootcard.h>
13
14#include <rtems/sysinit.h>
15
16#ifdef BSP_GET_WORK_AREA_DEBUG
17  #include <rtems/bspIo.h>
18#endif
19
20/*
21 *  These are provided by the linkcmds.
22 */
23extern char   WorkAreaBase[];
24extern char   HeapSize[];
25extern char   RamSize[];
26
27/* rudimentary multiboot info */
28struct multiboot_info {
29  uint32_t  flags;       /* start.S only raises flags for items actually */
30                         /* saved; this allows us to check for the size  */
31                         /* of the data structure.                       */
32  uint32_t  mem_lower;  /* avail kB in lower memory */
33  uint32_t  mem_upper;  /* avail kB in lower memory */
34  /* ... (unimplemented) */
35};
36
37extern struct multiboot_info _boot_multiboot_info;
38
39/*
40 *  This is the first address of the memory we can use for the RTEMS
41 *  Work Area.
42 */ 
43static uintptr_t rtemsWorkAreaStart;
44
45/*
46 * Board's memory size easily be overridden by application.
47 */
48uint32_t bsp_mem_size = 0;
49
50static void bsp_size_memory(void)
51{
52  uintptr_t topAddr;
53
54  /* Set the value of start of free memory. */
55  rtemsWorkAreaStart = (uint32_t)WorkAreaBase;
56
57  /* Align the RTEMS Work Area at beginning of free memory. */
58  if (rtemsWorkAreaStart & (CPU_ALIGNMENT - 1))  /* not aligned => align it */
59    rtemsWorkAreaStart = (rtemsWorkAreaStart+CPU_ALIGNMENT) & ~(CPU_ALIGNMENT-1);
60
61  /* The memory detection algorithm is very crude; try
62   * to use multiboot info, if possible (set from start.S)
63   */
64  if ( ((uintptr_t)RamSize == (uintptr_t) 0xFFFFFFFF)  &&
65       (_boot_multiboot_info.flags & 1) &&
66       _boot_multiboot_info.mem_upper ) {
67    topAddr = _boot_multiboot_info.mem_upper * 1024;
68    #ifdef BSP_GET_WORK_AREA_DEBUG
69      printk( "Multiboot info says we have 0x%08x\n", topAddr );
70    #endif
71  } else if ( (uintptr_t) RamSize == (uintptr_t) 0xFFFFFFFF ) {
72    uintptr_t lowest;
73    uint32_t  val;
74    int       i;
75
76    /*
77     * We have to dynamically size memory. Memory size can be anything
78     * between no less than 2M and 2048M.  If we can write a value to
79     * an address and read the same value back, then the memory is there.
80     *
81     * WARNING: This can detect memory which should be reserved for
82     *          graphics controllers which share the CPU's RAM.
83     */
84
85    /* find the lowest 1M boundary to probe */
86    lowest = ((rtemsWorkAreaStart + (1<<20)) >> 20) + 1;
87    if ( lowest  < 2 )
88      lowest = 2;
89
90    for (i=2048; i>=lowest; i--) {
91      topAddr = i*1024*1024 - 4;
92      *(volatile uint32_t*)topAddr = topAddr;
93    }
94
95    for(i=lowest; i<=2048; i++) {
96      topAddr = i*1024*1024 - 4;
97      val =  *(volatile uint32_t*)topAddr;
98      if (val != topAddr) {
99        break;
100      }
101    }
102
103    topAddr = (i-1)*1024*1024;
104    #ifdef BSP_GET_WORK_AREA_DEBUG
105      printk( "Dynamically sized to 0x%08x\n", topAddr );
106    #endif
107  } else {
108    topAddr = (uintptr_t) RamSize;
109    #ifdef BSP_GET_WORK_AREA_DEBUG
110      printk( "hardcoded to 0x%08x\n", topAddr );
111    #endif
112  }
113
114  bsp_mem_size = topAddr;
115}
116
117static Memory_Area _Memory_Areas[ 1 ];
118
119static void bsp_memory_initialize( void )
120{
121  /*
122   *  We need to determine how much memory there is in the system.
123   */
124  bsp_size_memory();
125
126  _Memory_Initialize_by_size(
127    &_Memory_Areas[0],
128    (void *) rtemsWorkAreaStart,
129    (uintptr_t) bsp_mem_size - (uintptr_t) rtemsWorkAreaStart
130  );
131}
132
133RTEMS_SYSINIT_ITEM(
134  bsp_memory_initialize,
135  RTEMS_SYSINIT_MEMORY,
136  RTEMS_SYSINIT_ORDER_MIDDLE
137);
138
139static const Memory_Information _Memory_Information =
140  MEMORY_INFORMATION_INITIALIZER( _Memory_Areas );
141
142const Memory_Information *_Memory_Get( void )
143{
144  return &_Memory_Information;
145}
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