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Diffstat (limited to 'src/devices/device.c')
-rw-r--r--src/devices/device.c76
1 files changed, 52 insertions, 24 deletions
diff --git a/src/devices/device.c b/src/devices/device.c
index 033f41d2ca..87e627d52c 100644
--- a/src/devices/device.c
+++ b/src/devices/device.c
@@ -376,13 +376,14 @@ static void allocate_vga_resource(void)
struct bus *bus;
bus = 0;
vga = 0;
- for(dev = all_devices; dev; dev = dev->next) {
+ for (dev = all_devices; dev; dev = dev->next) {
if (((dev->class >> 16) == PCI_BASE_CLASS_DISPLAY) &&
- ((dev->class >> 8) != PCI_CLASS_DISPLAY_OTHER))
- {
+ ((dev->class >> 8) != PCI_CLASS_DISPLAY_OTHER)) {
if (!vga) {
printk_debug("Allocating VGA resource %s\n",
- dev_path(dev));
+ dev_path(dev));
+ printk_debug("parent of the vga device %s\n",
+ dev_path(dev->bus->dev));
vga = dev;
}
if (vga == dev) {
@@ -398,19 +399,28 @@ static void allocate_vga_resource(void)
bus = vga->bus;
}
/* Now walk up the bridges setting the VGA enable */
- while(bus) {
+ while (bus) {
+ printk_info("Enabling VGA forward on bus connect to %s\n",
+ dev_path(bus->dev));
bus->bridge_ctrl |= PCI_BRIDGE_CTL_VGA;
bus = (bus == bus->dev->bus)? 0 : bus->dev->bus;
}
}
-/** Assign the computed resources to the bridges and devices on the bus.
- * Recurse to any bridges found on this bus first. Then do the devices
- * on this bus.
- *
+/**
+ * @brief Assign the computed resources to the devices on the bus.
+ *
* @param bus Pointer to the structure for this bus
- */
+ *
+ * Use the device specific set_resources method to store the computed
+ * resources to hardware. For bridge devices, the set_resources() method
+ * has to recurse into every down stream buses.
+ *
+ * Mutual recursion:
+ * assign_resources() -> device_operation::set_resources()
+ * device_operation::set_resources() -> assign_resources()
+ */
void assign_resources(struct bus *bus)
{
struct device *curdev;
@@ -418,7 +428,7 @@ void assign_resources(struct bus *bus)
printk_spew("%s assign_resources, bus %d link: %d\n",
dev_path(bus->dev), bus->secondary, bus->link);
- for(curdev = bus->children; curdev; curdev = curdev->sibling) {
+ for (curdev = bus->children; curdev; curdev = curdev->sibling) {
if (!curdev->enabled || !curdev->resources) {
continue;
}
@@ -443,10 +453,13 @@ void assign_resources(struct bus *bus)
*
* The parent's resources should be enabled first to avoid having enabling
* order problem. This is done by calling the parent's enable_resources()
- * method and let that method to call it's children's enable_resoruces() via
- * enable_childrens_resources().
+ * method and let that method to call it's children's enable_resoruces()
+ * method via the (global) enable_childrens_resources().
*
* Indirect mutual recursion:
+ * enable_resources() -> device_operations::enable_resource()
+ * device_operations::enable_resource() -> enable_children_resources()
+ * enable_children_resources() -> enable_resources()
*/
void enable_resources(struct device *dev)
{
@@ -461,16 +474,25 @@ void enable_resources(struct device *dev)
}
/**
- * @brief Determine the existence of dynamic devices and construct dynamic
+ * @brief Determine the existence of devices and extend the device tree.
+ *
+ * Most of the devices in the system are listed in the mainboard Config.lb
+ * file. The device structures for these devices are generated at compile
+ * time by the config tool and are organized into the device tree. This
+ * function determines if the devices created at compile time actually exist
+ * in the physical system.
+ *
+ * For devices in the physical system but not listed in the Config.lb file,
+ * the device structures have to be created at run time and attached to the
* device tree.
*
- * Start from the root device 'dev_root', scan the buses in the system
- * recursively, build the dynamic device tree according to the result
- * of the probe.
+ * This function starts from the root device 'dev_root', scan the buses in
+ * the system recursively, modify the device tree according to the result of
+ * the probe.
*
* This function has no idea how to scan and probe buses and devices at all.
* It depends on the bus/device specific scan_bus() method to do it. The
- * scan_bus() function also has to create the device structure and attach
+ * scan_bus() method also has to create the device structure and attach
* it to the device tree.
*/
void dev_enumerate(void)
@@ -490,12 +512,13 @@ void dev_enumerate(void)
printk_info("done\n");
}
-
/**
* @brief Configure devices on the devices tree.
*
- * Starting at the root of the dynamic device tree, travel recursively,
- * and compute resources needed by each device and allocate them.
+ * Starting at the root of the device tree, travel it recursively in two
+ * passes. In the first pass, we compute and allocate resources (ranges)
+ * requried by each device. In the second pass, the resources ranges are
+ * relocated to their final position and stored to the hardware.
*
* I/O resources start at DEVICE_IO_START and grow upward. MEM resources start
* at DEVICE_MEM_START and grow downward.
@@ -519,7 +542,10 @@ void dev_configure(void)
printk_err("dev_root missing set_resources\n");
return;
}
+
+ printk_info("Reading resources...\n");
root->ops->read_resources(root);
+ printk_info("Done\n");
/* Get the resources */
io = &root->resource[0];
@@ -539,8 +565,9 @@ void dev_configure(void)
allocate_vga_resource();
/* Store the computed resource allocations into device registers ... */
+ printk_info("Setting resources...\n");
root->ops->set_resources(root);
-
+ printk_info("Done\n");
#if 0
mem->flags |= IORESOURCE_STORED;
report_resource_stored(root, mem, "");
@@ -569,14 +596,15 @@ void dev_enable(void)
* @brief Initialize all devices in the global device list.
*
* Starting at the first device on the global device link list,
- * walk the list and call a driver to do device specific setup.
+ * walk the list and call the device's init() method to do deivce
+ * specific setup.
*/
void dev_initialize(void)
{
struct device *dev;
printk_info("Initializing devices...\n");
- for(dev = all_devices; dev; dev = dev->next) {
+ for (dev = all_devices; dev; dev = dev->next) {
if (dev->enabled && !dev->initialized &&
dev->ops && dev->ops->init)
{