prom_init.c

底层驱动开发

		u32	type;
		char	name[8];	/* "PowerPC" */
		struct chrpdesc {
			u32	real_mode;
			u32	real_base;
			u32	real_size;
			u32	virt_base;
			u32	virt_size;
			u32	load_base;
		} chrpdesc;
	} chrpnote;
	struct rpanote {
		u32	namesz;
		u32	descsz;
		u32	type;
		char	name[24];	/* "IBM,RPA-Client-Config" */
		struct rpadesc {
			u32	lpar_affinity;
			u32	min_rmo_size;
			u32	min_rmo_percent;
			u32	max_pft_size;
			u32	splpar;
			u32	min_load;
			u32	new_mem_def;
			u32	ignore_me;
		} rpadesc;
	} rpanote;
} fake_elf = {
	.elfhdr = {
		.e_ident = { 0x7f, 'E', 'L', 'F',
			     ELFCLASS32, ELFDATA2MSB, EV_CURRENT },
		.e_type = ET_EXEC,	/* yeah right */
		.e_machine = EM_PPC,
		.e_version = EV_CURRENT,
		.e_phoff = offsetof(struct fake_elf, phdr),
		.e_phentsize = sizeof(Elf32_Phdr),
		.e_phnum = 2
	},
	.phdr = {
		[0] = {
			.p_type = PT_NOTE,
			.p_offset = offsetof(struct fake_elf, chrpnote),
			.p_filesz = sizeof(struct chrpnote)
		}, [1] = {
			.p_type = PT_NOTE,
			.p_offset = offsetof(struct fake_elf, rpanote),
			.p_filesz = sizeof(struct rpanote)
		}
	},
	.chrpnote = {
		.namesz = sizeof("PowerPC"),
		.descsz = sizeof(struct chrpdesc),
		.type = 0x1275,
		.name = "PowerPC",
		.chrpdesc = {
			.real_mode = ~0U,	/* ~0 means "don't care" */
			.real_base = ~0U,
			.real_size = ~0U,
			.virt_base = ~0U,
			.virt_size = ~0U,
			.load_base = ~0U
		},
	},
	.rpanote = {
		.namesz = sizeof("IBM,RPA-Client-Config"),
		.descsz = sizeof(struct rpadesc),
		.type = 0x12759999,
		.name = "IBM,RPA-Client-Config",
		.rpadesc = {
			.lpar_affinity = 0,
			.min_rmo_size = 64,	/* in megabytes */
			.min_rmo_percent = 0,
			.max_pft_size = 48,	/* 2^48 bytes max PFT size */
			.splpar = 1,
			.min_load = ~0U,
			.new_mem_def = 0
		}
	}
};

static void __init prom_send_capabilities(void)
{
	unsigned long offset = reloc_offset();
	ihandle elfloader;

	elfloader = call_prom("open", 1, 1, ADDR("/packages/elf-loader"));
	if (elfloader == 0) {
		prom_printf("couldn't open /packages/elf-loader\n");
		return;
	}
	call_prom("call-method", 3, 1, ADDR("process-elf-header"),
			elfloader, ADDR(&fake_elf));
	call_prom("close", 1, 0, elfloader);
}

/*
 * Memory allocation strategy... our layout is normally:
 *
 *  at 14Mb or more we vmlinux, then a gap and initrd. In some rare cases, initrd
 *  might end up beeing before the kernel though. We assume this won't override
 *  the final kernel at 0, we have no provision to handle that in this version,
 *  but it should hopefully never happen.
 *
 *  alloc_top is set to the top of RMO, eventually shrink down if the TCEs overlap
 *  alloc_bottom is set to the top of kernel/initrd
 *
 *  from there, allocations are done that way : rtas is allocated topmost, and
 *  the device-tree is allocated from the bottom. We try to grow the device-tree
 *  allocation as we progress. If we can't, then we fail, we don't currently have
 *  a facility to restart elsewhere, but that shouldn't be necessary neither
 *
 *  Note that calls to reserve_mem have to be done explicitely, memory allocated
 *  with either alloc_up or alloc_down isn't automatically reserved.
 */


/*
 * Allocates memory in the RMO upward from the kernel/initrd
 *
 * When align is 0, this is a special case, it means to allocate in place
 * at the current location of alloc_bottom or fail (that is basically
 * extending the previous allocation). Used for the device-tree flattening
 */
static unsigned long __init alloc_up(unsigned long size, unsigned long align)
{
	unsigned long offset = reloc_offset();
	unsigned long base = _ALIGN_UP(RELOC(alloc_bottom), align);
	unsigned long addr = 0;

	prom_debug("alloc_up(%x, %x)\n", size, align);
	if (RELOC(ram_top) == 0)
		prom_panic("alloc_up() called with mem not initialized\n");

	if (align)
		base = _ALIGN_UP(RELOC(alloc_bottom), align);
	else
		base = RELOC(alloc_bottom);

	for(; (base + size) <= RELOC(alloc_top); 
	    base = _ALIGN_UP(base + 0x100000, align)) {
		prom_debug("    trying: 0x%x\n\r", base);
		addr = (unsigned long)prom_claim(base, size, 0);
		if (addr != PROM_ERROR)
			break;
		addr = 0;
		if (align == 0)
			break;
	}
	if (addr == 0)
		return 0;
	RELOC(alloc_bottom) = addr;

	prom_debug(" -> %x\n", addr);
	prom_debug("  alloc_bottom : %x\n", RELOC(alloc_bottom));
	prom_debug("  alloc_top    : %x\n", RELOC(alloc_top));
	prom_debug("  alloc_top_hi : %x\n", RELOC(alloc_top_high));
	prom_debug("  rmo_top      : %x\n", RELOC(rmo_top));
	prom_debug("  ram_top      : %x\n", RELOC(ram_top));

	return addr;
}

/*
 * Allocates memory downard, either from top of RMO, or if highmem
 * is set, from the top of RAM. Note that this one doesn't handle
 * failures. In does claim memory if highmem is not set.
 */
static unsigned long __init alloc_down(unsigned long size, unsigned long align,
				       int highmem)
{
	unsigned long offset = reloc_offset();
	unsigned long base, addr = 0;

	prom_debug("alloc_down(%x, %x, %s)\n", size, align,
		   highmem ? RELOC("(high)") : RELOC("(low)"));
	if (RELOC(ram_top) == 0)
		prom_panic("alloc_down() called with mem not initialized\n");

	if (highmem) {
		/* Carve out storage for the TCE table. */
		addr = _ALIGN_DOWN(RELOC(alloc_top_high) - size, align);
		if (addr <= RELOC(alloc_bottom))
			return 0;
		else {
			/* Will we bump into the RMO ? If yes, check out that we
			 * didn't overlap existing allocations there, if we did,
			 * we are dead, we must be the first in town !
			 */
			if (addr < RELOC(rmo_top)) {
				/* Good, we are first */
				if (RELOC(alloc_top) == RELOC(rmo_top))
					RELOC(alloc_top) = RELOC(rmo_top) = addr;
				else
					return 0;
			}
			RELOC(alloc_top_high) = addr;
		}
		goto bail;
	}

	base = _ALIGN_DOWN(RELOC(alloc_top) - size, align);
	for(; base > RELOC(alloc_bottom); base = _ALIGN_DOWN(base - 0x100000, align))  {
		prom_debug("    trying: 0x%x\n\r", base);
		addr = (unsigned long)prom_claim(base, size, 0);
		if (addr != PROM_ERROR)
			break;
		addr = 0;
	}
	if (addr == 0)
		return 0;
	RELOC(alloc_top) = addr;

 bail:
	prom_debug(" -> %x\n", addr);
	prom_debug("  alloc_bottom : %x\n", RELOC(alloc_bottom));
	prom_debug("  alloc_top    : %x\n", RELOC(alloc_top));
	prom_debug("  alloc_top_hi : %x\n", RELOC(alloc_top_high));
	prom_debug("  rmo_top      : %x\n", RELOC(rmo_top));
	prom_debug("  ram_top      : %x\n", RELOC(ram_top));

	return addr;
}

/*
 * Parse a "reg" cell
 */
static unsigned long __init prom_next_cell(int s, cell_t **cellp)
{
	cell_t *p = *cellp;
	unsigned long r = 0;

	/* Ignore more than 2 cells */
	while (s > 2) {
		p++;
		s--;
	}
	while (s) {
		r <<= 32;
		r |= *(p++);
		s--;
	}

	*cellp = p;
	return r;
}

/*
 * Very dumb function for adding to the memory reserve list, but
 * we don't need anything smarter at this point
 *
 * XXX Eventually check for collisions. They should NEVER happen
 * if problems seem to show up, it would be a good start to track
 * them down.
 */
static void reserve_mem(unsigned long base, unsigned long size)
{
	unsigned long offset = reloc_offset();
	unsigned long top = base + size;
	unsigned long cnt = RELOC(mem_reserve_cnt);

	if (size == 0)
		return;

	/* We need to always keep one empty entry so that we
	 * have our terminator with "size" set to 0 since we are
	 * dumb and just copy this entire array to the boot params
	 */
	base = _ALIGN_DOWN(base, PAGE_SIZE);
	top = _ALIGN_UP(top, PAGE_SIZE);
	size = top - base;

	if (cnt >= (MEM_RESERVE_MAP_SIZE - 1))
		prom_panic("Memory reserve map exhausted !\n");
	RELOC(mem_reserve_map)[cnt].base = base;
	RELOC(mem_reserve_map)[cnt].size = size;
	RELOC(mem_reserve_cnt) = cnt + 1;
}

/*
 * Initialize memory allocation mecanism, parse "memory" nodes and
 * obtain that way the top of memory and RMO to setup out local allocator
 */
static void __init prom_init_mem(void)
{
	phandle node;
	char *path, type[64];
	unsigned int plen;
	cell_t *p, *endp;
	unsigned long offset = reloc_offset();
	struct prom_t *_prom = PTRRELOC(&prom);

	/*
	 * We iterate the memory nodes to find
	 * 1) top of RMO (first node)
	 * 2) top of memory
	 */
	prom_debug("root_addr_cells: %x\n", (long)_prom->root_addr_cells);
	prom_debug("root_size_cells: %x\n", (long)_prom->root_size_cells);

	prom_debug("scanning memory:\n");
	path = RELOC(prom_scratch);

	for (node = 0; prom_next_node(&node); ) {
		type[0] = 0;
		prom_getprop(node, "device_type", type, sizeof(type));

		if (strcmp(type, RELOC("memory")))
			continue;
	
		plen = prom_getprop(node, "reg", RELOC(regbuf), sizeof(regbuf));
		if (plen > sizeof(regbuf)) {
			prom_printf("memory node too large for buffer !\n");
			plen = sizeof(regbuf);
		}
		p = RELOC(regbuf);
		endp = p + (plen / sizeof(cell_t));

#ifdef DEBUG_PROM
		memset(path, 0, PROM_SCRATCH_SIZE);
		call_prom("package-to-path", 3, 1, node, path, PROM_SCRATCH_SIZE-1);
		prom_debug("  node %s :\n", path);
#endif /* DEBUG_PROM */

		while ((endp - p) >= (_prom->root_addr_cells + _prom->root_size_cells)) {
			unsigned long base, size;

			base = prom_next_cell(_prom->root_addr_cells, &p);
			size = prom_next_cell(_prom->root_size_cells, &p);

			if (size == 0)
				continue;
			prom_debug("    %x %x\n", base, size);
			if (base == 0)
				RELOC(rmo_top) = size;
			if ((base + size) > RELOC(ram_top))
				RELOC(ram_top) = base + size;
		}
	}

	RELOC(alloc_bottom) = PAGE_ALIGN(RELOC(klimit) - offset + 0x4000);

	/* Check if we have an initrd after the kernel, if we do move our bottom
	 * point to after it
	 */
	if (RELOC(prom_initrd_start)) {
		if (RELOC(prom_initrd_end) > RELOC(alloc_bottom))
			RELOC(alloc_bottom) = PAGE_ALIGN(RELOC(prom_initrd_end));
	}

	/*
	 * If prom_memory_limit is set we reduce the upper limits *except* for
	 * alloc_top_high. This must be the real top of RAM so we can put
	 * TCE's up there.
	 */

	RELOC(alloc_top_high) = RELOC(ram_top);

	if (RELOC(prom_memory_limit)) {
		if (RELOC(prom_memory_limit) <= RELOC(alloc_bottom)) {
			prom_printf("Ignoring mem=%x <= alloc_bottom.\n",
				RELOC(prom_memory_limit));
			RELOC(prom_memory_limit) = 0;
		} else if (RELOC(prom_memory_limit) >= RELOC(ram_top)) {
			prom_printf("Ignoring mem=%x >= ram_top.\n",
				RELOC(prom_memory_limit));
			RELOC(prom_memory_limit) = 0;
		} else {
			RELOC(ram_top) = RELOC(prom_memory_limit);
			RELOC(rmo_top) = min(RELOC(rmo_top), RELOC(prom_memory_limit));
		}
	}

	/*
	 * Setup our top alloc point, that is top of RMO or top of
	 * segment 0 when running non-LPAR.
	 */
	if ( RELOC(of_platform) == PLATFORM_PSERIES_LPAR )
		RELOC(alloc_top) = RELOC(rmo_top);
	else
		/* Some RS64 machines have buggy firmware where claims up at 1GB
		 * fails. Cap at 768MB as a workaround. Still plenty of room.
		 */
		RELOC(alloc_top) = RELOC(rmo_top) = min(0x30000000ul, RELOC(ram_top));

	prom_printf("memory layout at init:\n");
	prom_printf("  memory_limit : %x (16 MB aligned)\n", RELOC(prom_memory_limit));
	prom_printf("  alloc_bottom : %x\n", RELOC(alloc_bottom));
	prom_printf("  alloc_top    : %x\n", RELOC(alloc_top));
	prom_printf("  alloc_top_hi : %x\n", RELOC(alloc_top_high));
	prom_printf("  rmo_top      : %x\n", RELOC(rmo_top));
	prom_printf("  ram_top      : %x\n", RELOC(ram_top));
}


/*
 * Allocate room for and instanciate RTAS
 */
static void __init prom_instantiate_rtas(void)
{
	unsigned long offset = reloc_offset();
	struct prom_t *_prom = PTRRELOC(&prom);
	phandle rtas_node;
	ihandle rtas_inst;
	u32 base, entry = 0;
	u32 size = 0;

	prom_debug("prom_instantiate_rtas: start...\n");

	rtas_node = call_prom("finddevice", 1, 1, ADDR("/rtas"));
	prom_debug("rtas_node: %x\n", rtas_node);
	if (!PHANDLE_VALID(rtas_node))
		return;

	prom_getprop(rtas_node, "rtas-size", &size, sizeof(size));
	if (size == 0)
		return;

	base = alloc_down(size, PAGE_SIZE, 0);
	if (base == 0) {
		prom_printf("RTAS allocation failed !\n");
		return;
	}

	rtas_inst = call_prom("open", 1, 1, ADDR("/rtas"));
	if (!IHANDLE_VALID(rtas_inst)) {
		prom_printf("opening rtas package failed");
		return;
	}

	prom_printf("instantiating rtas at 0x%x ...", base);

	if (call_prom("call-method", 3, 2,
		      ADDR("instantiate-rtas"),
		      rtas_inst, base) != PROM_ERROR) {
		entry = (long)_prom->args.rets[1];
	}
	if (entry == 0) {
		prom_printf(" failed\n");
		return;
	}
	prom_printf(" done\n");

	reserve_mem(base, size);

	prom_setprop(rtas_node, "linux,rtas-base", &base, sizeof(base));
	prom_setprop(rtas_node, "linux,rtas-entry", &entry, sizeof(entry));

	prom_debug("rtas base     = 0x%x\n", base);
	prom_debug("rtas entry    = 0x%x\n", entry);
	prom_debug("rtas size     = 0x%x\n", (long)size);

	prom_debug("prom_instantiate_rtas: end...\n");
}


/*
 * Allocate room for and initialize TCE tables
 */
static void __init prom_initialize_tce_table(void)
{
	phandle node;
	ihandle phb_node;
	unsigned long offset = reloc_offset();
	char compatible[64], type[64], model[64];
	char *path = RELOC(prom_scratch);
	u64 base, align;
	u32 minalign, minsize;
	u64 tce_entry, *tce_entryp;
	u64 local_alloc_top, local_alloc_bottom;
	u64 i;

	if (RELOC(ppc64_iommu_off))
		return;

	prom_debug("starting prom_initialize_tce_table\n");

	/* Cache current top of allocs so we reserve a single block */
	local_alloc_top = RELOC(alloc_top_high);
	local_alloc_bottom = local_alloc_top;

	/* Search all nodes looking for PHBs. */
	for (node = 0; prom_next_node(&node); ) {
		compatible[0] = 0;
		type[0] = 0;
		model[0] = 0;
		prom_getprop(node, "compatible",
			     compatible, sizeof(compatible));
		prom_getprop(node, "device_type", type, sizeof(type));
		prom_getprop(node, "model", model, sizeof(model));

		if ((type[0] == 0) || (strstr(type, RELOC("pci")) == NULL))
			continue;

		/* Keep the old logic in tack to avoid regression. */
		if (compatible[0] != 0) {
			if ((strstr(compatible, RELOC("python")) == NULL) &&
			    (strstr(compatible, RELOC("Speedwagon")) == NULL) &&
			    (strstr(compatible, RELOC("Winnipeg")) == NULL))
				continue;
		} else if (model[0] != 0) {
			if ((strstr(model, RELOC("ython")) == NULL) &&
			    (strstr(model, RELOC("peedwagon")) == NULL) &&
			    (strstr(model, RELOC("innipeg")) == NULL))
				continue;
		}

		if (prom_getprop(node, "tce-table-minalign", &minalign,
				 sizeof(minalign)) == PROM_ERROR)
			minalign = 0;
		if (prom_getprop(node, "tce-table-minsize", &minsize,
				 sizeof(minsize)) == PROM_ERROR)
			minsize = 4UL << 20;

		/*