coreboot/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 encompass 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)
{
	struct resource *resource;

	/* Initialize the system wide io space constraints */
	resource = new_resource(root, 0);
	resource->base  = 0x400;
	resource->size  = 0;
	resource->align = 0;
	resource->gran  = 0;
	resource->limit = 0xffffUL;
	resource->flags = IORESOURCE_IO;
	compute_allocate_resource(&root->link[0], resource, 
		IORESOURCE_IO, IORESOURCE_IO);

	/* Initialize the system wide memory resources constraints */
	resource = new_resource(root, 1);
	resource->base  = 0;
	resource->size  = 0;
	resource->align = 0;
	resource->gran  = 0;
	resource->limit = 0xffffffffUL;
	resource->flags = IORESOURCE_MEM;
	compute_allocate_resource(&root->link[0], resource,
		IORESOURCE_MEM, IORESOURCE_MEM);
}

/**
 * @brief 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);
}

/**
 * @brief Scan devices on static buses.
 *
 * The enumeration of certain buses is purely static. The existence of
 * devices on those buses can be completely determined at compile time
 * and is specified in the config file. Typical exapmles are the 'PNP'
 * devices on a legacy ISA/LPC bus. There is no need of probing of any
 * kind, the only thing we have to do is to walk through the bus and
 * enable or disable devices as indicated in the config file.
 *
 * On the other hand, some devices are virtual and their existence is
 * artificial. They can not be probed at run time. One example is the
 * debug device. Those virtual devices have to be listed in the config
 * file under some static bus in order to be enumerated at run time.
 *
 * This function is the default scan_bus() method for the root device and
 * LPC bridges.
 *
 * @param root Pointer to the root device which the static buses are attached
 * @param max  Maximum bus number currently used before scanning.
 * @return Largest bus number used after scanning.
 */
unsigned int scan_static_bus(device_t root, unsigned int max)
{
	device_t child;
	unsigned link;

	printk_spew("%s for %s\n", __func__, dev_path(root));

	for (link = 0; link < root->links; link++) {
		for (child = root->link[link].children; child; child = child->sibling) {
			if (child->chip_ops && child->chip_ops->enable_dev) {
				child->chip_ops->enable_dev(child);
			}
			if (child->ops && child->ops->enable) {
				child->ops->enable(child);
			}
			printk_debug("%s %s\n",
				dev_path(child),
				child->enabled?"enabled": "disabled");
		}
	}
	for (link = 0; link < root->links; link++) {
		for (child = root->link[link].children; child; child = child->sibling) {
			if (!child->ops || !child->ops->scan_bus)
				continue;
			printk_spew("%s scanning...\n", dev_path(child));
			max = child->ops->scan_bus(child, max);
		}
	}

	printk_spew("%s for  %s done\n", __func__, dev_path(root));

	return max;
}

/**
 * @brief Enable resources for children devices
 *
 * @param dev the device whos children's resources are to be enabled
 *
 * This function is call by the global enable_resources() indirectly via the
 * device_operation::enable_resources() method of devices.
 *
 * Indirect mutual recursion:
 *	enable_childrens_resources() -> enable_resources()
 *	enable_resources() -> device_operation::enable_resources()
 *	device_operation::enable_resources() -> enable_children_resources()
 */
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);
		}
	}
}

void root_dev_enable_resources(device_t dev)
{
	enable_childrens_resources(dev);
}

/**
 * @brief Scan root bus for generic systems
 *
 * @param root The root device structure
 * @param max The current bus number scanned so far, usually 0x00
 *
 * This function is the default scan_bus() method of the root device.
 */
unsigned int root_dev_scan_bus(device_t root, unsigned int max)
{
	return scan_static_bus(root, max);
}

void root_dev_init(device_t root)
{
}

/**
 * @brief Default device operation for root device
 *
 * This is the default device operation for root devices. These operations
 * should be fully usable as is.  However the chip_operations::enable_dev()
 * of a motherboard can override this if you want non-default behavior.
 */
struct device_operations default_dev_ops_root = {
	.read_resources   = root_dev_read_resources,
	.set_resources    = root_dev_set_resources,
	.enable_resources = root_dev_enable_resources,
	.init             = root_dev_init,
	.scan_bus         = root_dev_scan_bus,
};

/**
 * @brief The root of device tree.
 *
 * This is the root of the device tree. The device tree is defined in the
 * static.c file and is generated by config tool during compile time.
 */
extern struct device dev_root;