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/*
* This routine is an implementation of the bsp_get_work_area()
* that can be used by all m68k BSPs following linkcmds conventions
* regarding heap, stack, and workspace allocation.
*
* COPYRIGHT (c) 1989-2008.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
/* #define BSP_GET_WORK_AREA_DEBUG */
#include <bsp.h>
#include <bsp/bootcard.h>
#ifdef BSP_GET_WORK_AREA_DEBUG
#include <rtems/bspIo.h>
#endif
/*
* These are provided by the linkcmds.
*/
extern char WorkAreaBase[];
extern char HeapSize[];
extern char RamSize[];
/* rudimentary multiboot info */
struct multiboot_info {
uint32_t flags; /* start.S only raises flags for items actually */
/* saved; this allows us to check for the size */
/* of the data structure. */
uint32_t mem_lower; /* avail kB in lower memory */
uint32_t mem_upper; /* avail kB in lower memory */
/* ... (unimplemented) */
};
extern struct multiboot_info _boot_multiboot_info;
/*
* This is the first address of the memory we can use for the RTEMS
* Work Area.
*/
static uintptr_t rtemsWorkAreaStart;
/*
* Board's memory size easily be overridden by application.
*/
uint32_t bsp_mem_size = 0;
/* Size of stack used during initialization. Defined in 'start.s'. */
extern uint32_t _stack_size;
void bsp_size_memory(void)
{
uintptr_t topAddr;
/* Set the value of start of free memory. */
rtemsWorkAreaStart = (uint32_t)WorkAreaBase + _stack_size;
/* Align the RTEMS Work Area at beginning of free memory. */
if (rtemsWorkAreaStart & (CPU_ALIGNMENT - 1)) /* not aligned => align it */
rtemsWorkAreaStart = (rtemsWorkAreaStart+CPU_ALIGNMENT) & ~(CPU_ALIGNMENT-1);
/* The memory detection algorithm is very crude; try
* to use multiboot info, if possible (set from start.S)
*/
if ( ((uintptr_t)RamSize == (uintptr_t) 0xFFFFFFFF) &&
(_boot_multiboot_info.flags & 1) &&
_boot_multiboot_info.mem_upper ) {
topAddr = _boot_multiboot_info.mem_upper * 1024;
#ifdef BSP_GET_WORK_AREA_DEBUG
printk( "Multiboot info says we have 0x%08x\n", topAddr );
#endif
} else if ( (uintptr_t) RamSize == (uintptr_t) 0xFFFFFFFF ) {
uintptr_t lowest;
uint32_t val;
int i;
/*
* We have to dynamically size memory. Memory size can be anything
* between no less than 2M and 2048M. If we can write a value to
* an address and read the same value back, then the memory is there.
*
* WARNING: This can detect memory which should be reserved for
* graphics controllers which share the CPU's RAM.
*/
/* find the lowest 1M boundary to probe */
lowest = ((rtemsWorkAreaStart + (1<<20)) >> 20) + 1;
if ( lowest < 2 )
lowest = 2;
for (i=2048; i>=lowest; i--) {
topAddr = i*1024*1024 - 4;
*(volatile uint32_t*)topAddr = topAddr;
}
for(i=lowest; i<=2048; i++) {
topAddr = i*1024*1024 - 4;
val = *(volatile uint32_t*)topAddr;
if (val != topAddr) {
break;
}
}
topAddr = (i-1)*1024*1024;
#ifdef BSP_GET_WORK_AREA_DEBUG
printk( "Dynamically sized to 0x%08x\n", topAddr );
#endif
} else {
topAddr = (uintptr_t) RamSize;
#ifdef BSP_GET_WORK_AREA_DEBUG
printk( "hardcoded to 0x%08x\n", topAddr );
#endif
}
bsp_mem_size = topAddr;
}
/*
* This method returns the base address and size of the area which
* is to be allocated between the RTEMS Workspace and the C Program
* Heap.
*/
void bsp_get_work_area(
void **work_area_start,
uintptr_t *work_area_size,
void **heap_start,
uintptr_t *heap_size
)
{
*work_area_start = (void *) rtemsWorkAreaStart;
*work_area_size = (uintptr_t) bsp_mem_size - (uintptr_t) rtemsWorkAreaStart;
*heap_start = BSP_BOOTCARD_HEAP_USES_WORK_AREA;
*heap_size = (uintptr_t) HeapSize;
#ifdef BSP_GET_WORK_AREA_DEBUG
printk( "bsp_mem_size = 0x%08x\n", bsp_mem_size );
printk( "rtemsWorkAreaStart = 0x%08x\n", rtemsWorkAreaStart );
printk( "WorkArea Base = %p\n", *work_area_start );
printk( "WorkArea Size = 0x%08x\n", *work_area_size );
printk( "C Program Heap Base = %p\n", *heap_start );
printk( "C Program Heap Size = 0x%08x\n", *heap_size );
printk( "End of WorkArea = %p\n", *work_area_start + *work_area_size );
#endif
}
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