prom_init.c

h内核

	s = os = (char *)RELOC(dt_string_start);
	s += 4;
	while (s <  (char *)RELOC(dt_string_end)) {
		if (strcmp(s, str) == 0)
			return s - os;
		s += strlen(s) + 1;
	}
	return 0;
}

static void __init scan_dt_build_strings(phandle node, unsigned long *mem_start,
					 unsigned long *mem_end)
{
	unsigned long offset = reloc_offset();
	char *prev_name, *namep, *sstart;
	unsigned long soff;
	phandle child;

	sstart =  (char *)RELOC(dt_string_start);

	/* get and store all property names */
	prev_name = RELOC("");
	for (;;) {
		
		/* 32 is max len of name including nul. */
		namep = make_room(mem_start, mem_end, 32, 1);
		if (call_prom("nextprop", 3, 1, node, prev_name, namep) <= 0) {
			/* No more nodes: unwind alloc */
			*mem_start = (unsigned long)namep;
			break;
		}
		soff = dt_find_string(namep);
		if (soff != 0) {
			*mem_start = (unsigned long)namep;
			namep = sstart + soff;
		} else {
			/* Trim off some if we can */
			*mem_start = (unsigned long)namep + strlen(namep) + 1;
			RELOC(dt_string_end) = *mem_start;
		}
		prev_name = namep;
	}

	/* do all our children */
	child = call_prom("child", 1, 1, node);
	while (child != (phandle)0) {
		scan_dt_build_strings(child, mem_start, mem_end);
		child = call_prom("peer", 1, 1, child);
	}
}

static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
					unsigned long *mem_end)
{
	int l, align;
	phandle child;
	char *namep, *prev_name, *sstart;
	unsigned long soff;
	unsigned char *valp;
	unsigned long offset = reloc_offset();
	char pname[32];
	char *path;

	path = RELOC(prom_scratch);

	dt_push_token(OF_DT_BEGIN_NODE, mem_start, mem_end);

	/* get the node's full name */
	namep = (char *)*mem_start;
	l = call_prom("package-to-path", 3, 1, node,
		      namep, *mem_end - *mem_start);
	if (l >= 0) {
		/* Didn't fit?  Get more room. */
		if (l+1 > *mem_end - *mem_start) {
			namep = make_room(mem_start, mem_end, l+1, 1);
			call_prom("package-to-path", 3, 1, node, namep, l);
		}
		namep[l] = '\0';
		*mem_start = _ALIGN(((unsigned long) namep) + strlen(namep) + 1, 4);
	}

	/* get it again for debugging */
	memset(path, 0, PROM_SCRATCH_SIZE);
	call_prom("package-to-path", 3, 1, node, path, PROM_SCRATCH_SIZE-1);

	/* get and store all properties */
	prev_name = RELOC("");
	sstart = (char *)RELOC(dt_string_start);
	for (;;) {
		if (call_prom("nextprop", 3, 1, node, prev_name, pname) <= 0)
			break;

		/* find string offset */
		soff = dt_find_string(pname);
		if (soff == 0) {
			prom_printf("WARNING: Can't find string index for <%s>, node %s\n",
				    pname, path);
			break;
		}
		prev_name = sstart + soff;

		/* get length */
		l = call_prom("getproplen", 2, 1, node, pname);

		/* sanity checks */
		if (l < 0)
			continue;
		if (l > MAX_PROPERTY_LENGTH) {
			prom_printf("WARNING: ignoring large property ");
			/* It seems OF doesn't null-terminate the path :-( */
			prom_printf("[%s] ", path);
			prom_printf("%s length 0x%x\n", pname, l);
			continue;
		}

		/* push property head */
		dt_push_token(OF_DT_PROP, mem_start, mem_end);
		dt_push_token(l, mem_start, mem_end);
		dt_push_token(soff, mem_start, mem_end);

		/* push property content */
		align = (l >= 8) ? 8 : 4;
		valp = make_room(mem_start, mem_end, l, align);
		call_prom("getprop", 4, 1, node, pname, valp, l);
		*mem_start = _ALIGN(*mem_start, 4);
	}

	/* Add a "linux,phandle" property. */
	soff = dt_find_string(RELOC("linux,phandle"));
	if (soff == 0)
		prom_printf("WARNING: Can't find string index for <linux-phandle>"
			    " node %s\n", path);
	else {
		dt_push_token(OF_DT_PROP, mem_start, mem_end);
		dt_push_token(4, mem_start, mem_end);
		dt_push_token(soff, mem_start, mem_end);
		valp = make_room(mem_start, mem_end, 4, 4);
		*(u32 *)valp = node;
	}

	/* do all our children */
	child = call_prom("child", 1, 1, node);
	while (child != (phandle)0) {
		scan_dt_build_struct(child, mem_start, mem_end);
		child = call_prom("peer", 1, 1, child);
	}

	dt_push_token(OF_DT_END_NODE, mem_start, mem_end);
}

static void __init flatten_device_tree(void)
{
	phandle root;
	unsigned long offset = reloc_offset();
	unsigned long mem_start, mem_end, room;
	struct boot_param_header *hdr;
	char *namep;
	u64 *rsvmap;

	/*
	 * Check how much room we have between alloc top & bottom (+/- a
	 * few pages), crop to 4Mb, as this is our "chuck" size
	 */
	room = RELOC(alloc_top) - RELOC(alloc_bottom) - 0x4000;
	if (room > DEVTREE_CHUNK_SIZE)
		room = DEVTREE_CHUNK_SIZE;
	prom_debug("starting device tree allocs at %x\n", RELOC(alloc_bottom));

	/* Now try to claim that */
	mem_start = (unsigned long)alloc_up(room, PAGE_SIZE);
	if (mem_start == 0)
		prom_panic("Can't allocate initial device-tree chunk\n");
	mem_end = RELOC(alloc_top);

	/* Get root of tree */
	root = call_prom("peer", 1, 1, (phandle)0);
	if (root == (phandle)0)
		prom_panic ("couldn't get device tree root\n");

	/* Build header and make room for mem rsv map */ 
	mem_start = _ALIGN(mem_start, 4);
	hdr = make_room(&mem_start, &mem_end, sizeof(struct boot_param_header), 4);
	RELOC(dt_header_start) = (unsigned long)hdr;
	rsvmap = make_room(&mem_start, &mem_end, sizeof(mem_reserve_map), 8);

	/* Start of strings */
	mem_start = PAGE_ALIGN(mem_start);
	RELOC(dt_string_start) = mem_start;
	mem_start += 4; /* hole */

	/* Add "linux,phandle" in there, we'll need it */
	namep = make_room(&mem_start, &mem_end, 16, 1);
	strcpy(namep, RELOC("linux,phandle"));
	mem_start = (unsigned long)namep + strlen(namep) + 1;
	RELOC(dt_string_end) = mem_start;

	/* Build string array */
	prom_printf("Building dt strings...\n"); 
	scan_dt_build_strings(root, &mem_start, &mem_end);

	/* Build structure */
	mem_start = PAGE_ALIGN(mem_start);
	RELOC(dt_struct_start) = mem_start;
	prom_printf("Building dt structure...\n"); 
	scan_dt_build_struct(root, &mem_start, &mem_end);
	dt_push_token(OF_DT_END, &mem_start, &mem_end);
	RELOC(dt_struct_end) = PAGE_ALIGN(mem_start);

	/* Finish header */
	hdr->magic = OF_DT_HEADER;
	hdr->totalsize = RELOC(dt_struct_end) - RELOC(dt_header_start);
	hdr->off_dt_struct = RELOC(dt_struct_start) - RELOC(dt_header_start);
	hdr->off_dt_strings = RELOC(dt_string_start) - RELOC(dt_header_start);
	hdr->off_mem_rsvmap = ((unsigned long)rsvmap) - RELOC(dt_header_start);
	hdr->version = OF_DT_VERSION;
	hdr->last_comp_version = 1;

	/* Reserve the whole thing and copy the reserve map in, we
	 * also bump mem_reserve_cnt to cause further reservations to
	 * fail since it's too late.
	 */
	reserve_mem(RELOC(dt_header_start), hdr->totalsize);
	memcpy(rsvmap, RELOC(mem_reserve_map), sizeof(mem_reserve_map));

#ifdef DEBUG_PROM
	{
		int i;
		prom_printf("reserved memory map:\n");
		for (i = 0; i < RELOC(mem_reserve_cnt); i++)
			prom_printf("  %x - %x\n", RELOC(mem_reserve_map)[i].base,
				    RELOC(mem_reserve_map)[i].size);
	}
#endif
	RELOC(mem_reserve_cnt) = MEM_RESERVE_MAP_SIZE;

	prom_printf("Device tree strings 0x%x -> 0x%x\n",
		    RELOC(dt_string_start), RELOC(dt_string_end)); 
	prom_printf("Device tree struct  0x%x -> 0x%x\n",
		    RELOC(dt_struct_start), RELOC(dt_struct_end));

 }

static void __init prom_find_boot_cpu(void)
{
	unsigned long offset = reloc_offset();
       	struct prom_t *_prom = PTRRELOC(&prom);
	u32 getprop_rval;
	ihandle prom_cpu;
	phandle cpu_pkg;

	if (prom_getprop(_prom->chosen, "cpu", &prom_cpu, sizeof(prom_cpu)) <= 0)
		prom_panic("cannot find boot cpu");

	cpu_pkg = call_prom("instance-to-package", 1, 1, prom_cpu);

	prom_setprop(cpu_pkg, "linux,boot-cpu", NULL, 0);
	prom_getprop(cpu_pkg, "reg", &getprop_rval, sizeof(getprop_rval));
	_prom->cpu = getprop_rval;

	prom_debug("Booting CPU hw index = 0x%x\n", _prom->cpu);
}

static void __init prom_check_initrd(unsigned long r3, unsigned long r4)
{
#ifdef CONFIG_BLK_DEV_INITRD
	unsigned long offset = reloc_offset();
       	struct prom_t *_prom = PTRRELOC(&prom);

	if ( r3 && r4 && r4 != 0xdeadbeef) {
		u64 val;

		RELOC(prom_initrd_start) = (r3 >= KERNELBASE) ? __pa(r3) : r3;
		RELOC(prom_initrd_end) = RELOC(prom_initrd_start) + r4;

		val = (u64)RELOC(prom_initrd_start);
		prom_setprop(_prom->chosen, "linux,initrd-start", &val, sizeof(val));
		val = (u64)RELOC(prom_initrd_end);
		prom_setprop(_prom->chosen, "linux,initrd-end", &val, sizeof(val));

		reserve_mem(RELOC(prom_initrd_start),
			    RELOC(prom_initrd_end) - RELOC(prom_initrd_start));

		prom_debug("initrd_start=0x%x\n", RELOC(prom_initrd_start));
		prom_debug("initrd_end=0x%x\n", RELOC(prom_initrd_end));
	}
#endif /* CONFIG_BLK_DEV_INITRD */
}

/*
 * We enter here early on, when the Open Firmware prom is still
 * handling exceptions and the MMU hash table for us.
 */

unsigned long __init prom_init(unsigned long r3, unsigned long r4, unsigned long pp,
			       unsigned long r6, unsigned long r7)
{	
	unsigned long offset = reloc_offset();
       	struct prom_t *_prom = PTRRELOC(&prom);
	unsigned long phys = KERNELBASE - offset;
	u32 getprop_rval;
	
	/*
	 * First zero the BSS
	 */
	memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start);

	/*
	 * Init interface to Open Firmware, get some node references,
	 * like /chosen
	 */
	prom_init_client_services(pp);

	/*
	 * Init prom stdout device
	 */
	prom_init_stdout();
	prom_debug("klimit=0x%x\n", RELOC(klimit));
	prom_debug("offset=0x%x\n", offset);

	/*
	 * Check for an initrd
	 */
	prom_check_initrd(r3, r4);

	/*
	 * Get default machine type. At this point, we do not differenciate
	 * between pSeries SMP and pSeries LPAR
	 */
	RELOC(of_platform) = prom_find_machine_type();
	getprop_rval = RELOC(of_platform);
	prom_setprop(_prom->chosen, "linux,platform",
		     &getprop_rval, sizeof(getprop_rval));

	/*
	 * On pSeries, copy the CPU hold code
	 */
       	if (RELOC(of_platform) & PLATFORM_PSERIES)
       		copy_and_flush(0, KERNELBASE - offset, 0x100, 0);

	/*
	 * Get memory cells format
	 */
	getprop_rval = 1;
	prom_getprop(_prom->root, "#size-cells",
		     &getprop_rval, sizeof(getprop_rval));
	_prom->root_size_cells = getprop_rval;
	getprop_rval = 2;
	prom_getprop(_prom->root, "#address-cells",
		     &getprop_rval, sizeof(getprop_rval));
	_prom->root_addr_cells = getprop_rval;

	/*
	 * Do early parsing of command line
	 */
	early_cmdline_parse();

	/*
	 * Initialize memory management within prom_init
	 */
	prom_init_mem();

	/*
	 * Determine which cpu is actually running right _now_
	 */
	prom_find_boot_cpu();

	/* 
	 * Initialize display devices
	 */
	prom_check_displays();

	/*
	 * Initialize IOMMU (TCE tables) on pSeries. Do that before anything else
	 * that uses the allocator, we need to make sure we get the top of memory
	 * available for us here...
	 */
	if (RELOC(of_platform) == PLATFORM_PSERIES)
		prom_initialize_tce_table();

	/*
	 * On non-powermacs, try to instantiate RTAS and puts all CPUs
	 * in spin-loops. PowerMacs don't have a working RTAS and use
	 * a different way to spin CPUs
	 */
	if (RELOC(of_platform) != PLATFORM_POWERMAC) {
		prom_instantiate_rtas();
		prom_hold_cpus();
	}

	/*
	 * Fill in some infos for use by the kernel later on
	 */
	if (RELOC(ppc64_iommu_off))
		prom_setprop(_prom->chosen, "linux,iommu-off", NULL, 0);
	if (RELOC(iommu_force_on))
		prom_setprop(_prom->chosen, "linux,iommu-force-on", NULL, 0);

	/*
	 * Now finally create the flattened device-tree
	 */
       	prom_printf("copying OF device tree ...\n");
       	flatten_device_tree();

	/* in case stdin is USB and still active on IBM machines... */
	prom_close_stdin();

	/*
	 * Call OF "quiesce" method to shut down pending DMA's from
	 * devices etc...
	 */
	prom_printf("Calling quiesce ...\n");
	call_prom("quiesce", 0, 0);

	/*
	 * And finally, call the kernel passing it the flattened device
	 * tree and NULL as r5, thus triggering the new entry point which
	 * is common to us and kexec
	 */
	prom_printf("returning from prom_init\n");
	prom_debug("->dt_header_start=0x%x\n", RELOC(dt_header_start));
	prom_debug("->phys=0x%x\n", phys);

	__start(RELOC(dt_header_start), phys, 0);

	return 0;
}