setup-bus.c

linux 内核源代码

/* Sizing the IO windows of the PCI-PCI bridge is trivial,
   since these windows have 4K granularity and the IO ranges
   of non-bridge PCI devices are limited to 256 bytes.
   We must be careful with the ISA aliasing though. */
static void pbus_size_io(struct pci_bus *bus)
{
	struct pci_dev *dev;
	struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO);
	unsigned long size = 0, size1 = 0;

	if (!b_res)
 		return;

	list_for_each_entry(dev, &bus->devices, bus_list) {
		int i;

		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
			struct resource *r = &dev->resource[i];
			unsigned long r_size;

			if (r->parent || !(r->flags & IORESOURCE_IO))
				continue;
			r_size = r->end - r->start + 1;

			if (r_size < 0x400)
				/* Might be re-aligned for ISA */
				size += r_size;
			else
				size1 += r_size;
		}
	}
/* To be fixed in 2.5: we should have sort of HAVE_ISA
   flag in the struct pci_bus. */
#if defined(CONFIG_ISA) || defined(CONFIG_EISA)
	size = (size & 0xff) + ((size & ~0xffUL) << 2);
#endif
	size = ALIGN(size + size1, 4096);
	if (!size) {
		b_res->flags = 0;
		return;
	}
	/* Alignment of the IO window is always 4K */
	b_res->start = 4096;
	b_res->end = b_res->start + size - 1;
}

/* Calculate the size of the bus and minimal alignment which
   guarantees that all child resources fit in this size. */
static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, unsigned long type)
{
	struct pci_dev *dev;
	unsigned long min_align, align, size;
	unsigned long aligns[12];	/* Alignments from 1Mb to 2Gb */
	int order, max_order;
	struct resource *b_res = find_free_bus_resource(bus, type);

	if (!b_res)
		return 0;

	memset(aligns, 0, sizeof(aligns));
	max_order = 0;
	size = 0;

	list_for_each_entry(dev, &bus->devices, bus_list) {
		int i;
		
		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
			struct resource *r = &dev->resource[i];
			unsigned long r_size;

			if (r->parent || (r->flags & mask) != type)
				continue;
			r_size = r->end - r->start + 1;
			/* For bridges size != alignment */
			align = (i < PCI_BRIDGE_RESOURCES) ? r_size : r->start;
			order = __ffs(align) - 20;
			if (order > 11) {
				printk(KERN_WARNING "PCI: region %s/%d "
				       "too large: %llx-%llx\n",
					pci_name(dev), i,
					(unsigned long long)r->start,
					(unsigned long long)r->end);
				r->flags = 0;
				continue;
			}
			size += r_size;
			if (order < 0)
				order = 0;
			/* Exclude ranges with size > align from
			   calculation of the alignment. */
			if (r_size == align)
				aligns[order] += align;
			if (order > max_order)
				max_order = order;
		}
	}

	align = 0;
	min_align = 0;
	for (order = 0; order <= max_order; order++) {
		unsigned long align1 = 1UL << (order + 20);

		if (!align)
			min_align = align1;
		else if (ALIGN(align + min_align, min_align) < align1)
			min_align = align1 >> 1;
		align += aligns[order];
	}
	size = ALIGN(size, min_align);
	if (!size) {
		b_res->flags = 0;
		return 1;
	}
	b_res->start = min_align;
	b_res->end = size + min_align - 1;
	return 1;
}

static void __devinit
pci_bus_size_cardbus(struct pci_bus *bus)
{
	struct pci_dev *bridge = bus->self;
	struct resource *b_res = &bridge->resource[PCI_BRIDGE_RESOURCES];
	u16 ctrl;

	/*
	 * Reserve some resources for CardBus.  We reserve
	 * a fixed amount of bus space for CardBus bridges.
	 */
	b_res[0].start = pci_cardbus_io_size;
	b_res[0].end = b_res[0].start + pci_cardbus_io_size - 1;
	b_res[0].flags |= IORESOURCE_IO;

	b_res[1].start = pci_cardbus_io_size;
	b_res[1].end = b_res[1].start + pci_cardbus_io_size - 1;
	b_res[1].flags |= IORESOURCE_IO;

	/*
	 * Check whether prefetchable memory is supported
	 * by this bridge.
	 */
	pci_read_config_word(bridge, PCI_CB_BRIDGE_CONTROL, &ctrl);
	if (!(ctrl & PCI_CB_BRIDGE_CTL_PREFETCH_MEM0)) {
		ctrl |= PCI_CB_BRIDGE_CTL_PREFETCH_MEM0;
		pci_write_config_word(bridge, PCI_CB_BRIDGE_CONTROL, ctrl);
		pci_read_config_word(bridge, PCI_CB_BRIDGE_CONTROL, &ctrl);
	}

	/*
	 * If we have prefetchable memory support, allocate
	 * two regions.  Otherwise, allocate one region of
	 * twice the size.
	 */
	if (ctrl & PCI_CB_BRIDGE_CTL_PREFETCH_MEM0) {
		b_res[2].start = pci_cardbus_mem_size;
		b_res[2].end = b_res[2].start + pci_cardbus_mem_size - 1;
		b_res[2].flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH;

		b_res[3].start = pci_cardbus_mem_size;
		b_res[3].end = b_res[3].start + pci_cardbus_mem_size - 1;
		b_res[3].flags |= IORESOURCE_MEM;
	} else {
		b_res[3].start = pci_cardbus_mem_size * 2;
		b_res[3].end = b_res[3].start + pci_cardbus_mem_size * 2 - 1;
		b_res[3].flags |= IORESOURCE_MEM;
	}
}

void pci_bus_size_bridges(struct pci_bus *bus)
{
	struct pci_dev *dev;
	unsigned long mask, prefmask;

	list_for_each_entry(dev, &bus->devices, bus_list) {
		struct pci_bus *b = dev->subordinate;
		if (!b)
			continue;

		switch (dev->class >> 8) {
		case PCI_CLASS_BRIDGE_CARDBUS:
			pci_bus_size_cardbus(b);
			break;

		case PCI_CLASS_BRIDGE_PCI:
		default:
			pci_bus_size_bridges(b);
			break;
		}
	}

	/* The root bus? */
	if (!bus->self)
		return;

	switch (bus->self->class >> 8) {
	case PCI_CLASS_BRIDGE_CARDBUS:
		/* don't size cardbuses yet. */
		break;

	case PCI_CLASS_BRIDGE_PCI:
		/* don't size subtractive decoding (transparent)
		 * PCI-to-PCI bridges */
		if (bus->self->transparent)
			break;
		pci_bridge_check_ranges(bus);
		/* fall through */
	default:
		pbus_size_io(bus);
		/* If the bridge supports prefetchable range, size it
		   separately. If it doesn't, or its prefetchable window
		   has already been allocated by arch code, try
		   non-prefetchable range for both types of PCI memory
		   resources. */
		mask = IORESOURCE_MEM;
		prefmask = IORESOURCE_MEM | IORESOURCE_PREFETCH;
		if (pbus_size_mem(bus, prefmask, prefmask))
			mask = prefmask; /* Success, size non-prefetch only. */
		pbus_size_mem(bus, mask, IORESOURCE_MEM);
		break;
	}
}
EXPORT_SYMBOL(pci_bus_size_bridges);

void pci_bus_assign_resources(struct pci_bus *bus)
{
	struct pci_bus *b;
	struct pci_dev *dev;

	pbus_assign_resources_sorted(bus);

	list_for_each_entry(dev, &bus->devices, bus_list) {
		b = dev->subordinate;
		if (!b)
			continue;

		pci_bus_assign_resources(b);

		switch (dev->class >> 8) {
		case PCI_CLASS_BRIDGE_PCI:
			pci_setup_bridge(b);
			break;

		case PCI_CLASS_BRIDGE_CARDBUS:
			pci_setup_cardbus(b);
			break;

		default:
			printk(KERN_INFO "PCI: not setting up bridge %s "
			       "for bus %d\n", pci_name(dev), b->number);
			break;
		}
	}
}
EXPORT_SYMBOL(pci_bus_assign_resources);

void __init
pci_assign_unassigned_resources(void)
{
	struct pci_bus *bus;

	/* Depth first, calculate sizes and alignments of all
	   subordinate buses. */
	list_for_each_entry(bus, &pci_root_buses, node) {
		pci_bus_size_bridges(bus);
	}
	/* Depth last, allocate resources and update the hardware. */
	list_for_each_entry(bus, &pci_root_buses, node) {
		pci_bus_assign_resources(bus);
		pci_enable_bridges(bus);
	}
}