setup.c

底层驱动开发

		 */
		if (c == ' ' && strncmp(from, "mem=", 4) == 0) {
			memory_end = simple_strtoul(from+4, &from, 0);
			if ( *from == 'K' || *from == 'k' ) {
				memory_end = memory_end << 10;
				from++;
			} else if ( *from == 'M' || *from == 'm' ) {
				memory_end = memory_end << 20;
				from++;
			}
		}
		/*
		 * "ipldelay=XXX[sm]" sets ipl delay in seconds or minutes
		 */
		if (c == ' ' && strncmp(from, "ipldelay=", 9) == 0) {
			delay = simple_strtoul(from+9, &from, 0);
			if (*from == 's' || *from == 'S') {
				delay = delay*1000000;
				from++;
			} else if (*from == 'm' || *from == 'M') {
				delay = delay*60*1000000;
				from++;
			}
			/* now wait for the requested amount of time */
			udelay(delay);
		}
		cn = *(from++);
		if (!cn)
			break;
		if (cn == '\n')
			cn = ' ';  /* replace newlines with space */
		if (cn == 0x0d)
			cn = ' ';  /* replace 0x0d with space */
		if (cn == ' ' && c == ' ')
			continue;  /* remove additional spaces */
		c = cn;
		if (to - command_line >= COMMAND_LINE_SIZE)
			break;
		*(to++) = c;
	}
	if (c == ' ' && to > command_line) to--;
	*to = '\0';
	*cmdline_p = command_line;
}

static void __init
setup_lowcore(void)
{
	struct _lowcore *lc;
	int lc_pages;

	/*
	 * Setup lowcore for boot cpu
	 */
	lc_pages = sizeof(void *) == 8 ? 2 : 1;
	lc = (struct _lowcore *)
		__alloc_bootmem(lc_pages * PAGE_SIZE, lc_pages * PAGE_SIZE, 0);
	memset(lc, 0, lc_pages * PAGE_SIZE);
	lc->restart_psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
	lc->restart_psw.addr =
		PSW_ADDR_AMODE | (unsigned long) restart_int_handler;
	lc->external_new_psw.mask = PSW_KERNEL_BITS;
	lc->external_new_psw.addr =
		PSW_ADDR_AMODE | (unsigned long) ext_int_handler;
	lc->svc_new_psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT;
	lc->svc_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) system_call;
	lc->program_new_psw.mask = PSW_KERNEL_BITS;
	lc->program_new_psw.addr =
		PSW_ADDR_AMODE | (unsigned long)pgm_check_handler;
	lc->mcck_new_psw.mask =
		PSW_KERNEL_BITS & ~PSW_MASK_MCHECK & ~PSW_MASK_DAT;
	lc->mcck_new_psw.addr =
		PSW_ADDR_AMODE | (unsigned long) mcck_int_handler;
	lc->io_new_psw.mask = PSW_KERNEL_BITS;
	lc->io_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) io_int_handler;
	lc->ipl_device = S390_lowcore.ipl_device;
	lc->jiffy_timer = -1LL;
	lc->kernel_stack = ((unsigned long) &init_thread_union) + THREAD_SIZE;
	lc->async_stack = (unsigned long)
		__alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0) + ASYNC_SIZE;
	lc->panic_stack = (unsigned long)
		__alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0) + PAGE_SIZE;
	lc->current_task = (unsigned long) init_thread_union.thread_info.task;
	lc->thread_info = (unsigned long) &init_thread_union;
#ifndef CONFIG_ARCH_S390X
	if (MACHINE_HAS_IEEE) {
		lc->extended_save_area_addr = (__u32)
			__alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0);
		/* enable extended save area */
		ctl_set_bit(14, 29);
	}
#endif
	set_prefix((u32)(unsigned long) lc);
}

static void __init
setup_resources(void)
{
	struct resource *res;
	int i;

	for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
		res = alloc_bootmem_low(sizeof(struct resource));
		res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
		switch (memory_chunk[i].type) {
		case CHUNK_READ_WRITE:
			res->name = "System RAM";
			break;
		case CHUNK_READ_ONLY:
			res->name = "System ROM";
			res->flags |= IORESOURCE_READONLY;
			break;
		default:
			res->name = "reserved";
		}
		res->start = memory_chunk[i].addr;
		res->end = memory_chunk[i].addr +  memory_chunk[i].size - 1;
		request_resource(&iomem_resource, res);
		request_resource(res, &code_resource);
		request_resource(res, &data_resource);
	}
}

static void __init
setup_memory(void)
{
        unsigned long bootmap_size;
	unsigned long start_pfn, end_pfn, init_pfn;
	unsigned long last_rw_end;
	int i;

	/*
	 * partially used pages are not usable - thus
	 * we are rounding upwards:
	 */
	start_pfn = (__pa(&_end) + PAGE_SIZE - 1) >> PAGE_SHIFT;
	end_pfn = max_pfn = memory_end >> PAGE_SHIFT;

	/* Initialize storage key for kernel pages */
	for (init_pfn = 0 ; init_pfn < start_pfn; init_pfn++)
		page_set_storage_key(init_pfn << PAGE_SHIFT, PAGE_DEFAULT_KEY);

	/*
	 * Initialize the boot-time allocator (with low memory only):
	 */
	bootmap_size = init_bootmem(start_pfn, end_pfn);

	/*
	 * Register RAM areas with the bootmem allocator.
	 */
	last_rw_end = start_pfn;

	for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
		unsigned long start_chunk, end_chunk;

		if (memory_chunk[i].type != CHUNK_READ_WRITE)
			continue;
		start_chunk = (memory_chunk[i].addr + PAGE_SIZE - 1);
		start_chunk >>= PAGE_SHIFT;
		end_chunk = (memory_chunk[i].addr + memory_chunk[i].size);
		end_chunk >>= PAGE_SHIFT;
		if (start_chunk < start_pfn)
			start_chunk = start_pfn;
		if (end_chunk > end_pfn)
			end_chunk = end_pfn;
		if (start_chunk < end_chunk) {
			/* Initialize storage key for RAM pages */
			for (init_pfn = start_chunk ; init_pfn < end_chunk;
			     init_pfn++)
				page_set_storage_key(init_pfn << PAGE_SHIFT,
						     PAGE_DEFAULT_KEY);
			free_bootmem(start_chunk << PAGE_SHIFT,
				     (end_chunk - start_chunk) << PAGE_SHIFT);
			if (last_rw_end < start_chunk)
				add_memory_hole(last_rw_end, start_chunk - 1);
			last_rw_end = end_chunk;
		}
	}

	psw_set_key(PAGE_DEFAULT_KEY);

	if (last_rw_end < end_pfn - 1)
		add_memory_hole(last_rw_end, end_pfn - 1);

	/*
	 * Reserve the bootmem bitmap itself as well. We do this in two
	 * steps (first step was init_bootmem()) because this catches
	 * the (very unlikely) case of us accidentally initializing the
	 * bootmem allocator with an invalid RAM area.
	 */
	reserve_bootmem(start_pfn << PAGE_SHIFT, bootmap_size);

#ifdef CONFIG_BLK_DEV_INITRD
	if (INITRD_START) {
		if (INITRD_START + INITRD_SIZE <= memory_end) {
			reserve_bootmem(INITRD_START, INITRD_SIZE);
			initrd_start = INITRD_START;
			initrd_end = initrd_start + INITRD_SIZE;
		} else {
			printk("initrd extends beyond end of memory "
			       "(0x%08lx > 0x%08lx)\ndisabling initrd\n",
			       initrd_start + INITRD_SIZE, memory_end);
			initrd_start = initrd_end = 0;
		}
	}
#endif
}

/*
 * Setup function called from init/main.c just after the banner
 * was printed.
 */

void __init
setup_arch(char **cmdline_p)
{
        /*
         * print what head.S has found out about the machine
         */
#ifndef CONFIG_ARCH_S390X
	printk((MACHINE_IS_VM) ?
	       "We are running under VM (31 bit mode)\n" :
	       "We are running native (31 bit mode)\n");
	printk((MACHINE_HAS_IEEE) ?
	       "This machine has an IEEE fpu\n" :
	       "This machine has no IEEE fpu\n");
#else /* CONFIG_ARCH_S390X */
	printk((MACHINE_IS_VM) ?
	       "We are running under VM (64 bit mode)\n" :
	       "We are running native (64 bit mode)\n");
#endif /* CONFIG_ARCH_S390X */

        ROOT_DEV = Root_RAM0;
#ifndef CONFIG_ARCH_S390X
	memory_end = memory_size & ~0x400000UL;  /* align memory end to 4MB */
        /*
         * We need some free virtual space to be able to do vmalloc.
         * On a machine with 2GB memory we make sure that we have at
         * least 128 MB free space for vmalloc.
         */
        if (memory_end > 1920*1024*1024)
                memory_end = 1920*1024*1024;
#else /* CONFIG_ARCH_S390X */
	memory_end = memory_size & ~0x200000UL;  /* detected in head.s */
#endif /* CONFIG_ARCH_S390X */

	init_mm.start_code = PAGE_OFFSET;
	init_mm.end_code = (unsigned long) &_etext;
	init_mm.end_data = (unsigned long) &_edata;
	init_mm.brk = (unsigned long) &_end;

	parse_cmdline_early(cmdline_p);

	setup_memory();
	setup_resources();
	setup_lowcore();

        cpu_init();
        __cpu_logical_map[0] = S390_lowcore.cpu_data.cpu_addr;

	/*
	 * Create kernel page tables and switch to virtual addressing.
	 */
        paging_init();

        /* Setup default console */
	conmode_default();
}

void print_cpu_info(struct cpuinfo_S390 *cpuinfo)
{
   printk("cpu %d "
#ifdef CONFIG_SMP
           "phys_idx=%d "
#endif
           "vers=%02X ident=%06X machine=%04X unused=%04X\n",
           cpuinfo->cpu_nr,
#ifdef CONFIG_SMP
           cpuinfo->cpu_addr,
#endif
           cpuinfo->cpu_id.version,
           cpuinfo->cpu_id.ident,
           cpuinfo->cpu_id.machine,
           cpuinfo->cpu_id.unused);
}

/*
 * show_cpuinfo - Get information on one CPU for use by procfs.
 */

static int show_cpuinfo(struct seq_file *m, void *v)
{
        struct cpuinfo_S390 *cpuinfo;
	unsigned long n = (unsigned long) v - 1;

	preempt_disable();
	if (!n) {
		seq_printf(m, "vendor_id       : IBM/S390\n"
			       "# processors    : %i\n"
			       "bogomips per cpu: %lu.%02lu\n",
			       num_online_cpus(), loops_per_jiffy/(500000/HZ),
			       (loops_per_jiffy/(5000/HZ))%100);
	}
	if (cpu_online(n)) {
#ifdef CONFIG_SMP
		if (smp_processor_id() == n)
			cpuinfo = &S390_lowcore.cpu_data;
		else
			cpuinfo = &lowcore_ptr[n]->cpu_data;
#else
		cpuinfo = &S390_lowcore.cpu_data;
#endif
		seq_printf(m, "processor %li: "
			       "version = %02X,  "
			       "identification = %06X,  "
			       "machine = %04X\n",
			       n, cpuinfo->cpu_id.version,
			       cpuinfo->cpu_id.ident,
			       cpuinfo->cpu_id.machine);
	}
	preempt_enable();
        return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
	return *pos < NR_CPUS ? (void *)((unsigned long) *pos + 1) : NULL;
}
static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
	++*pos;
	return c_start(m, pos);
}
static void c_stop(struct seq_file *m, void *v)
{
}
struct seq_operations cpuinfo_op = {
	.start	= c_start,
	.next	= c_next,
	.stop	= c_stop,
	.show	= show_cpuinfo,
};