src/devices/root_device.c

#include <console/console.h>
#include <device/device.h>
#include <device/pci.h>

/** 
 * Read the resources for the root device,
 * that encompase the resources for the entire system.
 * @param root Pointer to the device structure for the system root device
 */
void root_dev_read_resources(device_t root)
{
	int res = 0;

	printk_spew("%s . Root is %p\n", __FUNCTION__, root);
	/* Initialize the system wide io space constraints */
	root->resource[res].base  = 0x400;
	root->resource[res].size  = 0;
	root->resource[res].align = 0;
	root->resource[res].gran  = 0;
	root->resource[res].limit = 0xffffUL;
	root->resource[res].flags = IORESOURCE_IO;
	root->resource[res].index = 0;
	printk_spew("%s . link %p, resource %p\n", __FUNCTION__, 
					&root->link[0], &root->resource[res]);
	compute_allocate_resource(&root->link[0], &root->resource[res], 
		IORESOURCE_IO, IORESOURCE_IO);
	res++;

	/* Initialize the system wide memory resources constraints */
	root->resource[res].base  = 0;
	root->resource[res].size  = 0;
	root->resource[res].align = 0;
	root->resource[res].gran  = 0;
	root->resource[res].limit = 0xffffffffUL;
	root->resource[res].flags = IORESOURCE_MEM;
	root->resource[res].index = 1;
	printk_spew("%s . link %p, resource %p\n", __FUNCTION__, 
				&root->link[0], &root->resource[res]);
	compute_allocate_resource(&root->link[0], &root->resource[res], 
		IORESOURCE_MEM, IORESOURCE_MEM);
	res++;

	root->resources = res;
	printk_spew("%s DONE\n", __FUNCTION__);
}

/**
 * Write the resources for the root device,
 * and every device under it which are all of the devices.
 * @param root Pointer to the device structure for the system root device
 */
void root_dev_set_resources(device_t root)
{
	struct bus *bus;
	bus = &root->link[0];
	compute_allocate_resource(bus,
		&root->resource[0], IORESOURCE_IO, IORESOURCE_IO);
	compute_allocate_resource(bus, 
		&root->resource[1], IORESOURCE_MEM, IORESOURCE_MEM);
	assign_resources(bus);
}

/**
 * Walk through devices on the motherboard and scan for devices behind
 * them.
 * @param root Pointer to the device structure for the system root device
 * @param max  Maximum bus number allowed in the system.
 * @return Largest bus number used.
 */
unsigned int walk_static_devices(device_t bus, unsigned int max)
{
	device_t child;
	unsigned link;
	for(link = 0; link < bus->links; link++) {
		for(child = bus->link[link].children; child; child = child->sibling) {
			if (child->ops && child->ops->enable) {
				child->ops->enable(child);
			}
			printk_debug("%s %s\n",
				dev_path(child),
				child->enable?"enabled": "disabled");
		}
	}
	for(link = 0; link < bus->links; link++) {
		for(child = bus->link[link].children; child; child = child->sibling) {
			if (!child->ops || !child->ops->scan_bus)
				continue;
			printk_debug("%s scanning...\n", dev_path(child));
			max = child->ops->scan_bus(child, max);
		}
	}
	return max;
}

void enable_childrens_resources(device_t dev)
{
	unsigned link;
	for(link = 0; link < dev->links; link++) {
		device_t child;
		for(child = dev->link[link].children; child; child = child->sibling) {
			enable_resources(child);
		}
	}
}

unsigned int root_dev_scan_pci_bus(device_t root, unsigned int max)
{
	return pci_scan_bus(&root->link[0], 0, 0xff, max);
}

struct device_operations default_dev_ops_root = {
	.read_resources   = root_dev_read_resources,
	.set_resources    = root_dev_set_resources,
	.enable_resources = enable_childrens_resources,
	.init             = 0,
	.scan_bus         = root_dev_scan_pci_bus,
};

/**
 * This is the root of the device tree. A PCI tree always has 
 * one bus, bus 0. Bus 0 contains devices and bridges. 
 */
struct device dev_root = {
	.ops = &default_dev_ops_root,
	.bus = &dev_root.link[0],
	.links = 1,
	.link = {
		[0] = {
			.dev = &dev_root,
			.link = 0,
		},
	},
};