diff options
Diffstat (limited to 'bsps/i386/pc386/start/bspgetworkarea.c')
-rw-r--r-- | bsps/i386/pc386/start/bspgetworkarea.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/bsps/i386/pc386/start/bspgetworkarea.c b/bsps/i386/pc386/start/bspgetworkarea.c new file mode 100644 index 0000000000..21cb472607 --- /dev/null +++ b/bsps/i386/pc386/start/bspgetworkarea.c @@ -0,0 +1,135 @@ +/* + * This routine is an implementation of the bsp_work_area_initialize() + * 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.org/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; + +static 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; +} + +void bsp_work_area_initialize(void) +{ + void *area_start; + uintptr_t area_size; + + /* + * We need to determine how much memory there is in the system. + */ + bsp_size_memory(); + + area_start = (void *) rtemsWorkAreaStart; + area_size = (uintptr_t) bsp_mem_size - (uintptr_t) rtemsWorkAreaStart; + bsp_work_area_initialize_default( area_start, area_size ); +} |