init.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

			    IO_FIELD(R_MMU_KBASE_HI, base_b, 0xb ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_a, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_9, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_8, 0x0 ) );
	
	*R_MMU_KBASE_LO = ( IO_FIELD(R_MMU_KBASE_LO, base_7, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_6, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_5, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_4, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_3, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_2, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_1, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_0, 0x0 ) );
#else
	/* Etrax-100 LX version 1 has a bug so that we cannot map anything
	 * across the 0x80000000 boundary, so we need to shrink the user-virtual
	 * area to 0x50000000 instead of 0xb0000000 and map things slightly
	 * different. The unused areas are marked as paged so that we can catch
	 * freak kernel accesses there.
	 *
	 * The ARTPEC chip is mapped at 0xa so we pass that segment straight
	 * through. We cannot vremap it because the vmalloc area is below 0x8
	 * and Juliette needs an uncached area above 0x8.
	 *
	 * Same thing with 0xc and 0x9, which is memory-mapped I/O on some boards.
	 * We map them straight over in LOW_MAP, but use vremap in LX version 2.
	 */

	*R_MMU_KSEG = ( IO_STATE(R_MMU_KSEG, seg_f, page ) | 
			IO_STATE(R_MMU_KSEG, seg_e, page ) |
			IO_STATE(R_MMU_KSEG, seg_d, page ) | 
			IO_STATE(R_MMU_KSEG, seg_c, page ) |   
			IO_STATE(R_MMU_KSEG, seg_b, seg  ) |  /* kernel reg area */
#ifdef CONFIG_JULIETTE
			IO_STATE(R_MMU_KSEG, seg_a, seg  ) |  /* ARTPEC etc. */
#else
			IO_STATE(R_MMU_KSEG, seg_a, page ) |
#endif
			IO_STATE(R_MMU_KSEG, seg_9, seg  ) |  /* LED's on some boards */
			IO_STATE(R_MMU_KSEG, seg_8, seg  ) |  /* CSE0/1, flash and I/O */
			IO_STATE(R_MMU_KSEG, seg_7, page ) |  /* kernel vmalloc area */
			IO_STATE(R_MMU_KSEG, seg_6, seg  ) |  /* kernel DRAM area */
			IO_STATE(R_MMU_KSEG, seg_5, seg  ) |  /* cached flash */
			IO_STATE(R_MMU_KSEG, seg_4, page ) |  /* user area */
			IO_STATE(R_MMU_KSEG, seg_3, page ) |  /* user area */
			IO_STATE(R_MMU_KSEG, seg_2, page ) |  /* user area */
			IO_STATE(R_MMU_KSEG, seg_1, page ) |  /* user area */
			IO_STATE(R_MMU_KSEG, seg_0, page ) ); /* user area */

	*R_MMU_KBASE_HI = ( IO_FIELD(R_MMU_KBASE_HI, base_f, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_e, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_d, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_c, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_b, 0xb ) |
#ifdef CONFIG_JULIETTE
			    IO_FIELD(R_MMU_KBASE_HI, base_a, 0xa ) |
#else
			    IO_FIELD(R_MMU_KBASE_HI, base_a, 0x0 ) |
#endif
			    IO_FIELD(R_MMU_KBASE_HI, base_9, 0x9 ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_8, 0x8 ) );
	
	*R_MMU_KBASE_LO = ( IO_FIELD(R_MMU_KBASE_LO, base_7, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_6, 0x4 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_5, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_4, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_3, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_2, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_1, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_LO, base_0, 0x0 ) );
#endif

	*R_MMU_CONTEXT = ( IO_FIELD(R_MMU_CONTEXT, page_id, 0 ) );
	
	/* The MMU has been enabled ever since head.S but just to make
	 * it totally obvious we do it here as well.
	 */

	*R_MMU_CTRL = ( IO_STATE(R_MMU_CTRL, inv_excp, enable ) |
			IO_STATE(R_MMU_CTRL, acc_excp, enable ) |
			IO_STATE(R_MMU_CTRL, we_excp,  enable ) );
	
	*R_MMU_ENABLE = IO_STATE(R_MMU_ENABLE, mmu_enable, enable);

	/*
	 * initialize the bad page table and bad page to point
	 * to a couple of allocated pages
	 */

	empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
	memset((void *)empty_zero_page, 0, PAGE_SIZE);

	/* All pages are DMA'able in Etrax, so put all in the DMA'able zone */

	zones_size[0] = ((unsigned long)high_memory - PAGE_OFFSET) >> PAGE_SHIFT;

	for (i = 1; i < MAX_NR_ZONES; i++)
		zones_size[i] = 0;

	/* Use free_area_init_node instead of free_area_init, because the former
	 * is designed for systems where the DRAM starts at an address substantially
	 * higher than 0, like us (we start at PAGE_OFFSET). This saves space in the
	 * mem_map page array.
	 */

	free_area_init_node(0, 0, 0, zones_size, PAGE_OFFSET, 0);

}

extern unsigned long loops_per_jiffy; /* init/main.c */
unsigned long loops_per_usec;

extern char _stext, _edata, _etext;
extern char __init_begin, __init_end;

void __init
mem_init(void)
{
	int codesize, reservedpages, datasize, initsize;
	unsigned long tmp;

	if(!mem_map)
		BUG();

	/* max/min_low_pfn was set by setup.c
	 * now we just copy it to some other necessary places...
	 *
	 * high_memory was also set in setup.c
	 */

	max_mapnr = num_physpages = max_low_pfn - min_low_pfn;
 
	/* this will put all memory onto the freelists */
        totalram_pages = free_all_bootmem();

	reservedpages = 0;
	for (tmp = 0; tmp < max_mapnr; tmp++) {
		/*
                 * Only count reserved RAM pages
                 */
		if (PageReserved(mem_map + tmp))
			reservedpages++;
	}

	codesize =  (unsigned long) &_etext - (unsigned long) &_stext;
        datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
        initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
	
        printk("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, "
	       "%dk init)\n" ,
	       (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
	       max_mapnr << (PAGE_SHIFT-10),
	       codesize >> 10,
	       reservedpages << (PAGE_SHIFT-10),
	       datasize >> 10,
	       initsize >> 10
               );

	/* HACK alert - calculate a loops_per_usec for asm/delay.h here
	 * since this is called just after calibrate_delay in init/main.c
	 * but before places which use udelay. cannot be in time.c since
	 * that is called _before_ calibrate_delay
	 */

	loops_per_usec = (loops_per_jiffy * HZ) / 1000000;

	return;
}

/* Initialize remaps of some I/O-ports. This is designed to be callable
 * multiple times from the drivers init-sections, because we don't know
 * beforehand which driver will get initialized first.
 */

void 
init_ioremap(void)
{
  
	/* Give the external I/O-port addresses their values */

        static int initialized = 0;
  
        if( !initialized ) {
                initialized++;
            
#ifdef CONFIG_CRIS_LOW_MAP
               /* Simply a linear map (see the KSEG map above in paging_init) */
               port_cse1_addr = (volatile unsigned long *)(MEM_CSE1_START | 
                                                           MEM_NON_CACHEABLE);
               port_csp0_addr = (volatile unsigned long *)(MEM_CSP0_START |
                                                           MEM_NON_CACHEABLE);
               port_csp4_addr = (volatile unsigned long *)(MEM_CSP4_START |
                                                           MEM_NON_CACHEABLE);
#else
               /* Note that nothing blows up just because we do this remapping 
                * it's ok even if the ports are not used or connected 
                * to anything (or connected to a non-I/O thing) */        
               port_cse1_addr = (volatile unsigned long *)
                 ioremap((unsigned long)(MEM_CSE1_START | 
                                         MEM_NON_CACHEABLE), 16);
               port_csp0_addr = (volatile unsigned long *)
                 ioremap((unsigned long)(MEM_CSP0_START |
                                         MEM_NON_CACHEABLE), 16);
               port_csp4_addr = (volatile unsigned long *)
                 ioremap((unsigned long)(MEM_CSP4_START |
                                         MEM_NON_CACHEABLE), 16);
#endif	
        }
}


/* free the pages occupied by initialization code */

void 
free_initmem(void)
{
        unsigned long addr;

        addr = (unsigned long)(&__init_begin);
        for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
                ClearPageReserved(virt_to_page(addr));
                set_page_count(virt_to_page(addr), 1);
                free_page(addr);
                totalram_pages++;
        }
        printk ("Freeing unused kernel memory: %luk freed\n", 
		(&__init_end - &__init_begin) >> 10);
}

void 
si_meminfo(struct sysinfo *val)
{
        val->totalram = totalram_pages;
        val->sharedram = 0;
        val->freeram = nr_free_pages();
        val->bufferram = atomic_read(&buffermem_pages);
        val->totalhigh = 0;
        val->freehigh = 0;
        val->mem_unit = PAGE_SIZE;
}