setup.c

嵌入式系统设计与实验教材二源码linux内核移植与编译

	prom_init(argc, argv, envp, prom_vec);

#ifdef CONFIG_SGI_IP22
	sgi_sysinit();
#endif

	/*
	 * Determine the mmu/cache attached to this machine,
	 * then flush the tlb and caches.  On the r4xx0
	 * variants this also sets CP0_WIRED to zero.
	 */
	loadmmu();

	/* Disable coprocessors and set FPU for 16 FPRs */
	s = read_32bit_cp0_register(CP0_STATUS);
	s &= ~(ST0_CU1|ST0_CU2|ST0_CU3|ST0_KX|ST0_SX|ST0_FR);
	s |= ST0_CU0;
	write_32bit_cp0_register(CP0_STATUS, s);

	start_kernel();
}

void __init add_memory_region(unsigned long start, unsigned long size,
			      long type)
{
	int x = boot_mem_map.nr_map;

	if (x == BOOT_MEM_MAP_MAX) {
		printk("Ooops! Too many entries in the memory map!\n");
		return;
	}

	boot_mem_map.map[x].addr = start;
	boot_mem_map.map[x].size = size;
	boot_mem_map.map[x].type = type;
	boot_mem_map.nr_map++;
}

static void __init print_memory_map(void)
{
	int i;

	for (i = 0; i < boot_mem_map.nr_map; i++) {
		printk(" memory: %08lx @ %08lx ",
			boot_mem_map.map[i].size, boot_mem_map.map[i].addr);
		switch (boot_mem_map.map[i].type) {
		case BOOT_MEM_RAM:
			printk("(usable)\n");
			break;
		case BOOT_MEM_ROM_DATA:
			printk("(ROM data)\n");
			break;
		case BOOT_MEM_RESERVED:
			printk("(reserved)\n");
			break;
		default:
			printk("type %lu\n", boot_mem_map.map[i].type);
			break;
		}
	}
}

static inline void parse_mem_cmdline(void)
{
	char c = ' ', *to = command_line, *from = saved_command_line;
	unsigned long start_at, mem_size;
	int len = 0;
	int usermem = 0;

	printk("Determined physical RAM map:\n");
	print_memory_map();

	for (;;) {
		/*
		 * "mem=XXX[kKmM]" defines a memory region from
		 * 0 to <XXX>, overriding the determined size.
		 * "mem=XXX[KkmM]@YYY[KkmM]" defines a memory region from
		 * <YYY> to <YYY>+<XXX>, overriding the determined size.
		 */
		if (c == ' ' && !memcmp(from, "mem=", 4)) {
			if (to != command_line)
				to--;
			/*
			 * If a user specifies memory size, we
			 * blow away any automatically generated
			 * size.
			 */
			if (usermem == 0) {
				boot_mem_map.nr_map = 0;
				usermem = 1;
			}
			mem_size = memparse(from + 4, &from);
			if (*from == '@')
				start_at = memparse(from + 1, &from);
			else
				start_at = 0;
			add_memory_region(start_at, mem_size, BOOT_MEM_RAM);
		}
		c = *(from++);
		if (!c)
			break;
		if (COMMAND_LINE_SIZE <= ++len)
			break;
		*(to++) = c;
	}
	*to = '\0';

	if (usermem) {
		printk("User-defined physical RAM map:\n");
		print_memory_map();
	}
}

void __init setup_arch(char **cmdline_p)
{
	void atlas_setup(void);
	void baget_setup(void);
	void ddb_setup(void);
	void decstation_setup(void);
	void deskstation_setup(void);
	void jazz_setup(void);
	void sni_rm200_pci_setup(void);
	void sgi_setup(void);
        void ev96100_setup(void);
	void malta_setup(void);
	void momenco_ocelot_setup(void);
	void nino_setup(void);

	unsigned long bootmap_size;
	unsigned long start_pfn, max_pfn, first_usable_pfn;

	int i;

#ifdef CONFIG_BLK_DEV_FD
	fd_ops = &no_fd_ops;
#endif

#ifdef CONFIG_BLK_DEV_IDE
	ide_ops = &no_ide_ops;
#endif

#ifdef CONFIG_PC_KEYB
	kbd_ops = &no_kbd_ops;
#endif
	
	rtc_ops = &no_rtc_ops;

	switch(mips_machgroup)
	{
#ifdef CONFIG_BAGET_MIPS
	case MACH_GROUP_BAGET: 
		baget_setup();
		break;
#endif
#ifdef CONFIG_DECSTATION
	case MACH_GROUP_DEC:
		decstation_setup();
		break;
#endif
#ifdef CONFIG_MIPS_ATLAS
	case MACH_GROUP_UNKNOWN:
		atlas_setup();
		break;
#endif
#ifdef CONFIG_MIPS_JAZZ
	case MACH_GROUP_JAZZ:
		jazz_setup();
		break;
#endif
#ifdef CONFIG_MIPS_MALTA
	case MACH_GROUP_UNKNOWN:
		malta_setup();
		break;
#endif
#ifdef CONFIG_MOMENCO_OCELOT
	case MACH_GROUP_MOMENCO:
		momenco_ocelot_setup();
		break;
#endif
#ifdef CONFIG_SGI_IP22
	/* As of now this is only IP22.  */
	case MACH_GROUP_SGI:
		sgi_setup();
		break;
#endif
#ifdef CONFIG_SNI_RM200_PCI
	case MACH_GROUP_SNI_RM:
		sni_rm200_pci_setup();
		break;
#endif
#ifdef CONFIG_DDB5074
	case MACH_GROUP_NEC_DDB:
		ddb_setup();
		break;
#endif
#ifdef CONFIG_DDB5476
       case MACH_GROUP_NEC_DDB:
               ddb_setup();
               break;
#endif
#ifdef CONFIG_DDB5477
       case MACH_GROUP_NEC_DDB:
               ddb_setup();
               break;
#endif
#ifdef CONFIG_MIPS_EV96100
	case MACH_GROUP_GALILEO:
		ev96100_setup();
		break;
#endif
#ifdef CONFIG_MIPS_EV64120
	case MACH_GROUP_GALILEO:
		ev64120_setup();
		break;
#endif
#if defined(CONFIG_MIPS_IVR) || defined(CONFIG_MIPS_ITE8172)
	case  MACH_GROUP_ITE:
	case  MACH_GROUP_GLOBESPAN:
		it8172_setup();
		break;
#endif  
#ifdef CONFIG_NINO
	case MACH_GROUP_PHILIPS:
		nino_setup();
		break;
#endif
#ifdef CONFIG_MIPS_PB1000
	case MACH_GROUP_ALCHEMY:
		au1000_setup();
		break;
#endif
	default:
		panic("Unsupported architecture");
	}

	strncpy(command_line, arcs_cmdline, sizeof command_line);
	command_line[sizeof command_line - 1] = 0;
	strcpy(saved_command_line, command_line);
	*cmdline_p = command_line;

	parse_mem_cmdline();

#define PFN_UP(x)	(((x) + PAGE_SIZE - 1) >> PAGE_SHIFT)
#define PFN_DOWN(x)	((x) >> PAGE_SHIFT)
#define PFN_PHYS(x)	((x) << PAGE_SHIFT)

	/*
	 * Partially used pages are not usable - thus
	 * we are rounding upwards.
	 */
	start_pfn = PFN_UP(__pa(&_end));

	/* Find the highest page frame number we have available.  */
	max_pfn = 0;
	first_usable_pfn = -1UL;
	for (i = 0; i < boot_mem_map.nr_map; i++) {
		unsigned long start, end;

		if (boot_mem_map.map[i].type != BOOT_MEM_RAM)
			continue;

		start = PFN_UP(boot_mem_map.map[i].addr);
		end = PFN_DOWN(boot_mem_map.map[i].addr
		      + boot_mem_map.map[i].size);

		if (start >= end)
			continue;
		if (end > max_pfn)
			max_pfn = end;
		if (start < first_usable_pfn) {
			if (start > start_pfn) {
				first_usable_pfn = start;
			} else if (end > start_pfn) {
				first_usable_pfn = start_pfn;
			}
		}
	}
	
	/* Initialize the boot-time allocator.  */
	bootmap_size = init_bootmem(first_usable_pfn, max_pfn);

	/*
	 * Register fully available low RAM pages with the bootmem allocator.
	 */
	for (i = 0; i < boot_mem_map.nr_map; i++) {
		unsigned long curr_pfn, last_pfn, size;

		/*
		 * Reserve usable memory.
		 */
		if (boot_mem_map.map[i].type != BOOT_MEM_RAM)
			continue;

		/*
		 * We are rounding up the start address of usable memory:
		 */
		curr_pfn = PFN_UP(boot_mem_map.map[i].addr);
		if (curr_pfn >= max_pfn)
			continue;
		if (curr_pfn < start_pfn)
			curr_pfn = start_pfn;

		/*
		 * ... and at the end of the usable range downwards:
		 */
		last_pfn = PFN_DOWN(boot_mem_map.map[i].addr
				    + boot_mem_map.map[i].size);

		if (last_pfn > max_pfn)
			last_pfn = max_pfn;

		/*
		 * ... finally, did all the rounding and playing
		 * around just make the area go away?
		 */
		if (last_pfn <= curr_pfn)
			continue;

		size = last_pfn - curr_pfn;
		free_bootmem(PFN_PHYS(curr_pfn), PFN_PHYS(size));
	}

	/* Reserve the bootmap memory.  */
	reserve_bootmem(PFN_PHYS(first_usable_pfn), bootmap_size);

#ifdef CONFIG_BLK_DEV_INITRD
	/* Board specific code should have set up initrd_start and initrd_end */
	ROOT_DEV = MKDEV(RAMDISK_MAJOR, 0);
	if( __rd_start != __rd_end ) {
		initrd_start = (unsigned long)&__rd_start;
		initrd_end = (unsigned long)&__rd_end;
	}
	initrd_below_start_ok = 1;
	if (initrd_start) {
		unsigned long initrd_size = ((unsigned char *)initrd_end) - ((unsigned char *)initrd_start); 
		printk("Initial ramdisk at: 0x%p (%lu bytes)\n",
		       (void *)initrd_start, 
		       initrd_size);
		if ((void *)initrd_end > phys_to_virt(PFN_PHYS(max_low_pfn))) {
			printk("initrd extends beyond end of memory "
			       "(0x%lx > 0x%p)\ndisabling initrd\n",
			       initrd_end,
			       phys_to_virt(PFN_PHYS(max_low_pfn)));
			initrd_start = initrd_end = 0;
		} 
	}
#endif /* CONFIG_BLK_DEV_INITRD  */

	paging_init();

	code_resource.start = virt_to_bus(&_ftext);
	code_resource.end = virt_to_bus(&_etext) - 1;
	data_resource.start = virt_to_bus(&_fdata);
	data_resource.end = virt_to_bus(&_edata) - 1;

	/*
	 * Request address space for all standard RAM.
	 */
	for (i = 0; i < boot_mem_map.nr_map; i++) {
		struct resource *res;

		res = alloc_bootmem(sizeof(struct resource));
		switch (boot_mem_map.map[i].type) {
		case BOOT_MEM_RAM:
		case BOOT_MEM_ROM_DATA:
			res->name = "System RAM";
			break;
		case BOOT_MEM_RESERVED:
		default:
			res->name = "reserved";
		}
		res->start = boot_mem_map.map[i].addr;
		res->end = res->start + boot_mem_map.map[i].size - 1;
		res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
		request_resource(&iomem_resource, res);

		/*
		 *  We dont't know which RAM region contains kernel data,
		 *  so we try it repeatedly and let the resource manager
		 *  test it.
		 */
		request_resource(res, &code_resource);
		request_resource(res, &data_resource);
	}
}

void r3081_wait(void) 
{
	unsigned long cfg = read_32bit_cp0_register(CP0_CONF);
	write_32bit_cp0_register(CP0_CONF, cfg|CONF_HALT);
}

void r4k_wait(void)
{
	__asm__(".set\tmips3\n\t"
		"wait\n\t"
		".set\tmips0");
}