Doxidization, reformat

git-svn-id: svn://svn.coreboot.org/coreboot/trunk@1469 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

5 files changed, 397 insertions, 220 deletions

diff --git a/src/devices/chip.c b/src/devices/chip.c
index d8a59e3062..33f3976eb8 100644
--- a/src/devices/chip.c
+++ b/src/devices/chip.c
@@ -9,8 +9,22 @@
 #include <device/chip.h>
 #include <device/pci.h>
 
-void
-chip_configure(struct chip *root, enum chip_pass pass)
+/**
+ * @brief Configure static devices
+ *
+ * Starting from the static device 'root', walk the tree and configure each
+ * device by calling the device specific chip_control::enable().
+ *
+ * This function is only an iterator, the exact definition of 'configure'
+ * depends on the device specific implementation of chip_control::enable(). 
+ *
+ * @param root root of the static device tree to be configured.
+ * @param pass pass of the configuration operation to be perfromed.
+ *
+ * @see chip_pass
+ * @see chip_control::enable
+ */  
+void chip_configure(struct chip *root, enum chip_pass pass)
 {
 	struct chip *c;
 
@@ -25,24 +39,37 @@ chip_configure(struct chip *root, enum chip_pass pass)
 	}
 }
 
-/** Convert a static struct chip structure to a set of dynamic device structures.
- * @param chip Static chip structure to start with.
+/**
+ * @brief Convert static device structures to dynamic structures.
+ *
+ * A static device may contain one or more dynamic devices. Dynamic device
+ * structures of these devices have to be generated before the enumeration
+ * of dynamic devices. This function converts a static chip structure to a
+ * set of dynamic device structures.
+ *
+ * This function is the generic method called by enumerate_static_device_chain()
+ * for static devices. Devices extend this default behavior by defining their
+ * own chip_controll::enumerate(). Generally, device specific
+ * chip_control::enumerate() method calls this function as its last operation.
+ *
+ * @param chip static chip structure to be converted.
+ *
  */
-
 void chip_enumerate(struct chip *chip)
 {
 	struct chip *child;
 	device_t dev;
 	int link;
 	int i;
+
 	dev = 0;
 	link = 0;
-#if 1
+
 	if (chip->control && chip->control->name) {
 		printk_debug("Enumerating: %s\n", chip->control->name);
 	}
-#endif
-	for(i = 0; i < MAX_CHIP_PATHS; i++) {
+
+	for (i = 0; i < MAX_CHIP_PATHS; i++) {
 		int identical_paths;
 		identical_paths = 
 			(i > 0) &&
@@ -55,6 +82,7 @@ void chip_enumerate(struct chip *chip)
 			parent = chip->bus;
 			switch(chip->path[i].path.type) {
 			case DEVICE_PATH_NONE:
+				/* no dynamic device associated */
 				break;
 			case DEVICE_PATH_PCI:
 				bus = chip->path[i].path.u.pci.bus;
@@ -62,7 +90,7 @@ void chip_enumerate(struct chip *chip)
 					device_t dev;
 					int i = 1;
 					dev = chip->dev;
-					while(dev && (i != bus)) {
+					while (dev && (i != bus)) {
 						dev = dev->next;
 						i++;
 					}
@@ -75,18 +103,21 @@ void chip_enumerate(struct chip *chip)
 				dev = alloc_dev(parent, &chip->path[i].path);
 				break;
 			}
-		}
-		else {
+		} else {
 			link += 1;
 		}
+
 		if (dev) {
 			struct chip_resource *res, *res_limit;
-			printk_spew("path (%p) %s %s", dev, dev_path(dev), identical_paths?"identical":"");
-			printk_spew(" parent: (%p) %s\n",dev->bus->dev,  dev_path(dev->bus->dev));
+			printk_spew("path (%p) %s %s",
+				    dev, dev_path(dev),
+				    identical_paths?"identical":"");
+			printk_spew(" parent: (%p) %s\n",
+				    dev->bus->dev,  dev_path(dev->bus->dev));
 			dev->chip = chip;
 			dev->enable = chip->path[i].enable;
 			dev->links = link + 1;
-			for(child = chip->children; child; child = child->next) {
+			for (child = chip->children; child; child = child->next) {
 				if (!child->bus && child->link == i) {
 					child->bus = &dev->link[link];
 				}
@@ -102,21 +133,42 @@ void chip_enumerate(struct chip *chip)
 				}
 			}
 		}
+
 		if (dev && !chip->dev) {
 			chip->dev = dev;
 		}
 	}
-	for(child = chip->children; child; child = child->next) {
+
+	for (child = chip->children; child; child = child->next) {
 		if (!child->bus) {
 			child->bus = &chip->dev->link[0];
 		}
 	}
 }
 
+/**
+ * @brief Enumerate a static device tree.
+ *
+ * A static device chain is a linked list of static device structures which are
+ * on the same branch of the static device tree. This function does not only
+ * enumerate the devices on a single chain, as its name suggest, it also walks
+ * into the subordinary chains. It calls the device specific
+ * chip_control::enumerate() of the device if one exists or calls the generic
+ * chip_enumerate(). 
+ *
+ * This function is only an iterator, the exact definition of 'enumerate'
+ * depends on the implementation of the generic chip_enumerate() and/or device
+ * specific chip_control::enumerate(). 
+ *
+ * @param root static chip structure to start with.
+ *
+ * @see chip_control::enumerate()
+ */
 static void enumerate_static_device_chain(struct chip *root)
 {
 	struct chip *chip;
-	for(chip = root; chip; chip = chip->next) {
+
+	for (chip = root; chip; chip = chip->next) {
 		void (*enumerate)(struct chip *chip);
 		enumerate = chip_enumerate;
 		if (chip->control && chip->control->enumerate) {
@@ -125,13 +177,30 @@ static void enumerate_static_device_chain(struct chip *root)
 		enumerate(chip);
 	}
 
-	for(chip = root; chip; chip = chip->next) {
+	for (chip = root; chip; chip = chip->next) {
 		if (chip->children) {
 			enumerate_static_device_chain(chip->children);
 		}
 	}
 }
 
+/**
+ * @brief Enumerate static devices in the system.
+ *
+ * \note The definition of 'enumerate' is not clear in this context. Does it mean
+ * probe ?
+ *
+ * \note How do we determine the existence of the static devices ? Static
+ * devices are listed in the config file and generated at compile time by config
+ * tool. This function is called at certain point in the early stage of
+ * LinuxBIOS. It uses the chip_enumerate() function to convert the static
+ * structures into dynamic ones. What if the static devices listed in the config
+ * file does actually not exist in the system ? Is there any side effect of
+ * these 'phantom' device structures
+ *
+ * The static device does not necesarry conform to the dynamic device tree in
+ * the system.
+ */
 void enumerate_static_devices(void)
 {
 	enumerate_static_device_chain(&static_root);
diff --git a/src/devices/device.c b/src/devices/device.c
index b54e770294..0186aa977a 100644
--- a/src/devices/device.c
+++ b/src/devices/device.c
@@ -22,24 +22,41 @@
 #include <stdlib.h>
 #include <string.h>
 
-/* Linked list of ALL devices */
+/** Linked list of ALL devices */
 struct device *all_devices = &dev_root;
-/* pointer to the last device */
+/** Pointer to the last device */
 static struct device **last_dev_p = &dev_root.next;
 
-#define DEVICE_MEM_HIGH  0xFEC00000UL /* Reserve 20M for the system */
+/** The upper limit of MEM resource of the devices.
+ * Reserve 20M for the system */
+#define DEVICE_MEM_HIGH 0xFEC00000UL
+/** The lower limit of IO resource of the devices.
+ * Reserve 4k for ISA/Legacy devices */
 #define DEVICE_IO_START 0x1000
 
-/** Allocate a new device structure
+/**
+ * @brief Allocate a new device structure.
+ * 
+ * Allocte a new device structure and attached it to the device tree as a child
+ * of the parent bus.
+ *
+ * @param parent parent bus the newly created device attached to.
+ * @param path path to the device to be created.
+ *
+ * @return pointer to the newly created device structure.
+ *
+ * @see device_path
  */
 device_t alloc_dev(struct bus *parent, struct device_path *path)
 {
 	device_t dev, child;
 	int link;
+
 	/* Find the last child of our parent */
-	for(child = parent->children; child && child->sibling; ) {
+	for (child = parent->children; child && child->sibling; ) {
 		child = child->sibling;
 	}
+
 	dev = malloc(sizeof(*dev));
 	if (dev == 0) {
 		die("DEV: out of memory.\n");
@@ -47,14 +64,14 @@ device_t alloc_dev(struct bus *parent, struct device_path *path)
 	memset(dev, 0, sizeof(*dev));
 	memcpy(&dev->path, path, sizeof(*path));
 
-	/* Append a new device to the global device chain.
-	 * The chain is used to find devices once everything is set up.
+	/* Append a new device to the global device list.
+	 * The list is used to find devices once everything is set up.
 	 */
 	*last_dev_p = dev;
 	last_dev_p = &dev->next;
 
 	/* Initialize the back pointers in the link fields */
-	for(link = 0; link < MAX_LINKS; link++) {
+	for (link = 0; link < MAX_LINKS; link++) {
 		dev->link[link].dev  = dev;
 		dev->link[link].link = link;
 	}
@@ -66,12 +83,15 @@ device_t alloc_dev(struct bus *parent, struct device_path *path)
 	} else {
 		parent->children = dev;
 	}
+
 	/* If we don't have any other information about a device enable it */
 	dev->enable = 1;
+
 	return dev;
 }
 
-/** round a number to an alignment. 
+/**
+ * @brief round a number up to an alignment. 
  * @param val the starting value
  * @param roundup Alignment as a power of two
  * @returns rounded up number
@@ -104,7 +124,7 @@ static void read_resources(struct bus *bus)
 	struct device *curdev;
 
 	/* Walk through all of the devices and find which resources they need. */
-	for(curdev = bus->children; curdev; curdev = curdev->sibling) {
+	for (curdev = bus->children; curdev; curdev = curdev->sibling) {
 		unsigned links;
 		int i;
 		if (curdev->resources > 0) {
@@ -112,20 +132,22 @@ static void read_resources(struct bus *bus)
 		}
 		if (!curdev->ops || !curdev->ops->read_resources) {
 			printk_err("%s missing read_resources\n",
-				dev_path(curdev));
+				   dev_path(curdev));
 			continue;
 		}
 		if (!curdev->enable) {
 			continue;
 		}
+
 		curdev->ops->read_resources(curdev);
+
 		/* Read in subtractive resources behind the current device */
 		links = 0;
-		for(i = 0; i < curdev->resources; i++) {
+		for (i = 0; i < curdev->resources; i++) {
 			struct resource *resource;
 			resource = &curdev->resource[i];
 			if ((resource->flags & IORESOURCE_SUBTRACTIVE) &&
-				(!(links & (1 << resource->index))))
+			    (!(links & (1 << resource->index))))
 			{
 				links |= (1 << resource->index);
 				read_resources(&curdev->link[resource->index]);
@@ -142,8 +164,8 @@ struct pick_largest_state {
 	int seen_last;
 };
 
-static void pick_largest_resource(
-	struct pick_largest_state *state, struct device *dev, struct resource *resource)
+static void pick_largest_resource(struct pick_largest_state *state,
+				  struct device *dev, struct resource *resource)
 {
 	struct resource *last;
 	last = state->last;
@@ -152,32 +174,33 @@ static void pick_largest_resource(
 		state->seen_last = 1;
 		return;
 	}
-	if (last && (
-		    (last->align < resource->align) ||
-		    ((last->align == resource->align) &&
-			    (last->size < resource->size)) ||
-		    ((last->align == resource->align) &&
-			    (last->size == resource->size) &&
-			    (!state->seen_last)))) {
+	if (last &&
+	    ((last->align < resource->align) ||
+	     ((last->align == resource->align) &&
+	      (last->size < resource->size)) ||
+	     ((last->align == resource->align) &&
+	      (last->size == resource->size) &&
+	      (!state->seen_last)))) {
 		return;
 	}
-	if (!state->result || 
-		(state->result->align < resource->align) ||
-		((state->result->align == resource->align) &&
-			(state->result->size < resource->size))) {
+	if (!state->result ||
+	    (state->result->align < resource->align) ||
+	    ((state->result->align == resource->align) &&
+	     (state->result->size < resource->size))) {
 		state->result_dev = dev;
 		state->result = resource;
-	}
-		    
+	}    
 }
 
 static void find_largest_resource(struct pick_largest_state *state, 
-	struct bus *bus, unsigned long type_mask, unsigned long type)
+				  struct bus *bus, unsigned long type_mask,
+				  unsigned long type)
 {
 	struct device *curdev;
-	for(curdev = bus->children; curdev; curdev = curdev->sibling) {
+
+	for (curdev = bus->children; curdev; curdev = curdev->sibling) {
 		int i;
-		for(i = 0; i < curdev->resources; i++) {
+		for (i = 0; i < curdev->resources; i++) {
 			struct resource *resource = &curdev->resource[i];
 			/* If it isn't the right kind of resource ignore it */
 			if ((resource->flags & type_mask) != type) {
@@ -187,7 +210,8 @@ static void find_largest_resource(struct pick_largest_state *state,
 			if (resource->flags & IORESOURCE_SUBTRACTIVE) {
 				struct bus *subbus;
 				subbus = &curdev->link[resource->index];
-				find_largest_resource(state, subbus, type_mask, type);
+				find_largest_resource(state, subbus,
+						      type_mask, type);
 				continue;
 			}
 			/* See if this is the largest resource */
@@ -196,8 +220,10 @@ static void find_largest_resource(struct pick_largest_state *state,
 	}
 }
 
-static struct device *largest_resource(struct bus *bus, struct resource **result_res,
-	unsigned long type_mask, unsigned long type)
+static struct device *largest_resource(struct bus *bus,
+				       struct resource **result_res,
+				       unsigned long type_mask,
+				       unsigned long type)
 {
 	struct pick_largest_state state;
 
@@ -254,12 +280,12 @@ void compute_allocate_resource(
 	min_align = 0;
 	base = bridge->base;
 
-	printk_spew("%s compute_allocate_%s: base: %08lx size: %08lx align: %d gran: %d\n", 
-		dev_path(bus->dev),
-		(bridge->flags & IORESOURCE_IO)? "io":
-		(bridge->flags & IORESOURCE_PREFETCH)? "prefmem" : "mem",
-		base, bridge->size, bridge->align, bridge->gran);
-
+	printk_spew("%s compute_allocate_%s: base: %08lx size: %08lx "
+		    "align: %d gran: %d\n", 
+		    dev_path(bus->dev),
+		    (bridge->flags & IORESOURCE_IO)? "io":
+		    (bridge->flags & IORESOURCE_PREFETCH)? "prefmem" : "mem",
+		    base, bridge->size, bridge->align, bridge->gran);
 
 	/* We want different minimum alignments for different kinds of
 	 * resources.  These minimums are not device type specific
@@ -278,8 +304,9 @@ void compute_allocate_resource(
 	/* Remember I haven't found anything yet. */
 	resource = 0;
 
-	/* Walk through all the devices on the current bus and compute the addresses */
-	while((dev = largest_resource(bus, &resource, type_mask, type))) {
+	/* Walk through all the devices on the current bus and compute the
+	 * addresses */
+	while ((dev = largest_resource(bus, &resource, type_mask, type))) {
 		unsigned long size;
 		/* Do NOT I repeat do not ignore resources which have zero size.
 		 * If they need to be ignored dev->read_resources should not even
@@ -357,6 +384,8 @@ void compute_allocate_resource(
 static void allocate_vga_resource(void)
 {
 #warning "FIXME modify allocate_vga_resource so it is less pci centric!"
+#warning "This function knows to much about PCI stuff, it should be just a ietrator/visitor."
+
 	/* FIXME handle the VGA pallette snooping */
 	struct device *dev, *vga;
 	struct bus *bus;
@@ -422,7 +451,7 @@ void enable_resources(struct device *dev)
 	 */
 	if (!dev->ops || !dev->ops->enable_resources) {
 		printk_err("%s missing enable_resources\n",
-			dev_path(dev));
+			   dev_path(dev));
 		return;
 	}
 	if (!dev->enable) {
@@ -431,58 +460,74 @@ void enable_resources(struct device *dev)
 	dev->ops->enable_resources(dev);
 }
 
-/** Enumerate the resources on the PCI by calling pci_init
+/**
+ * @brief Determine the existence of dynamic devices and construct dynamic
+ * device tree.
+ *
+ * Start for the root device 'dev_root', scan the buses in the system, build
+ * the dynamic device tree according to the result of the probe.
+ *
+ * This function have no idea how to scan and probe the buses and devices at
+ * all. It depends on the bus/device specific scan_bus() method to do it.
+ * The scan_bus() function also have to create the device structure and attach
+ * it to the device tree. 
  */
 void dev_enumerate(void)
 {
 	struct device *root;
 	unsigned subordinate;
-	printk_info("Enumerating buses...");
+
+	printk_info("Enumerating buses...\n");
+
 	root = &dev_root;
 	subordinate = root->ops->scan_bus(root, 0);
+
 	printk_info("done\n");
 }
 
-/** Starting at the root, compute what resources are needed and allocate them. 
+/**
+ * @brief Configure devices on the devices tree.
+ * 
+ * Starting at the root, compute what resources are needed and allocate them. 
  * I/O starts at PCI_IO_START. Since the assignment is hierarchical we
  * set the values into the dev_root struct. 
  */
 void dev_configure(void)
 {
 	struct device *root = &dev_root;
+
 	printk_info("Allocating resources...");
 	printk_debug("\n");
 
-
 	root->ops->read_resources(root);
 
-	/* Make certain the io devices are allocated somewhere
-	 * safe.
-	 */
+	/* Make certain the io devices are allocated somewhere safe. */
 	root->resource[0].base = DEVICE_IO_START;
 	root->resource[0].flags |= IORESOURCE_ASSIGNED;
 	root->resource[0].flags &= ~IORESOURCE_STORED;
-	/* Now reallocate the pci resources memory with the
-	 * highest addresses I can manage.
-	 */
+
+	/* Now reallocate the pci resources memory with the highest
+	 * addresses I can manage.*/
 	root->resource[1].base = 
 		round_down(DEVICE_MEM_HIGH - root->resource[1].size,
-			1UL << root->resource[1].align);
+			   1UL << root->resource[1].align);
 	root->resource[1].flags |= IORESOURCE_ASSIGNED;
 	root->resource[1].flags &= ~IORESOURCE_STORED;
 
-	/* Allocate the VGA I/O resource..
-	 */
+	/* Allocate the VGA I/O resource.. */
 	allocate_vga_resource(); 
 
-	// now just set things into registers ... we hope ...
+	/* now just set things into registers ... we hope ... */
 	root->ops->set_resources(root);
 
 	printk_info("done.\n");
 }
 
-/** Starting at the root, walk the tree and enable all devices/bridges. 
- * What really happens is computed COMMAND bits get set in register 4
+/**
+ * @brief Enable devices on the device tree.
+ *
+ * Starting at the root, walk the tree and enable all devices/bridges by
+ * calling the device's enable_resources() method.
  */
 void dev_enable(void)
 {
@@ -490,22 +535,28 @@ void dev_enable(void)
 
 	/* now enable everything. */
 	enable_resources(&dev_root);
+
 	printk_info("done.\n");
 }
 
-/** Starting at the root, walk the tree and call a driver to
- *  do device specific setup.
+/**
+ * @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.
  */
 void dev_initialize(void)
 {
 	struct device *dev;
 
 	printk_info("Initializing devices...\n");
+
 	for (dev = all_devices; dev; dev = dev->next) {
 		if (dev->enable && dev->ops && dev->ops->init) {
 			printk_debug("%s init\n", dev_path(dev));
 			dev->ops->init(dev);
 		}
 	}
+
 	printk_info("Devices initialized\n");
 }
diff --git a/src/devices/device_util.c b/src/devices/device_util.c
index 013501474c..29bb539e1d 100644
--- a/src/devices/device_util.c
+++ b/src/devices/device_util.c
@@ -6,15 +6,16 @@
 
 
 /**
- * See if a device structure already exists and if not allocate it
+ * @brief See if a device structure already exists and if not allocate it
+ *
  * @param bus The bus to find the device on
  * @param path The relative path from the bus to the appropriate device
- * @return pointer a device structure for the device on bus at path
+ * @return pointer to a device structure for the device on bus at path
  */
 device_t alloc_find_dev(struct bus *parent, struct device_path *path)
 {
 	device_t child;
-	for(child = parent->children; child; child = child->sibling) {
+	for (child = parent->children; child; child = child->sibling) {
 		if (path_eq(path, &child->path)) {
 			return child;
 		}
diff --git a/src/devices/pci_device.c b/src/devices/pci_device.c
index c3f1f6ac8c..4bc4e1f9f0 100644
--- a/src/devices/pci_device.c
+++ b/src/devices/pci_device.c
@@ -151,7 +151,7 @@ static void pci_read_bases(struct device *dev, unsigned int howmany)
 {
 	unsigned long index;
 
-	for(index = PCI_BASE_ADDRESS_0; (index < PCI_BASE_ADDRESS_0 + (howmany << 2)); ) {
+	for (index = PCI_BASE_ADDRESS_0; (index < PCI_BASE_ADDRESS_0 + (howmany << 2)); ) {
 		struct resource *resource;
 		resource = pci_get_resource(dev, index);
 		index += (resource->flags & IORESOURCE_PCI64)?8:4;
@@ -159,7 +159,6 @@ static void pci_read_bases(struct device *dev, unsigned int howmany)
 	compact_resources(dev);
 }
 
-
 static void pci_bridge_read_bases(struct device *dev)
 {
 	struct resource *resource;
@@ -174,7 +173,7 @@ static void pci_bridge_read_bases(struct device *dev)
 	resource->limit = 0xffffUL;
 	resource->flags |= IORESOURCE_IO | IORESOURCE_PCI_BRIDGE;
 	compute_allocate_resource(&dev->link[0], resource,
-		IORESOURCE_IO, IORESOURCE_IO);
+				  IORESOURCE_IO, IORESOURCE_IO);
 
 	/* Initiliaze the prefetchable memory constraints on the current bus */
 	resource = get_resource(dev, PCI_PREF_MEMORY_BASE);
@@ -185,8 +184,8 @@ static void pci_bridge_read_bases(struct device *dev)
 	resource->flags = IORESOURCE_MEM | IORESOURCE_PREFETCH | IORESOURCE_PCI_BRIDGE;
 	resource->index = PCI_PREF_MEMORY_BASE;
 	compute_allocate_resource(&dev->link[0], resource,
-		IORESOURCE_MEM | IORESOURCE_PREFETCH, 
-		IORESOURCE_MEM | IORESOURCE_PREFETCH);
+				  IORESOURCE_MEM | IORESOURCE_PREFETCH, 
+				  IORESOURCE_MEM | IORESOURCE_PREFETCH);
 
 	/* Initialize the memory resources on the current bus */
 	resource = get_resource(dev, PCI_MEMORY_BASE);
@@ -196,17 +195,18 @@ static void pci_bridge_read_bases(struct device *dev)
 	resource->limit = 0xffffffffUL;
 	resource->flags = IORESOURCE_MEM | IORESOURCE_PCI_BRIDGE;
 	compute_allocate_resource(&dev->link[0], resource,
-		IORESOURCE_MEM | IORESOURCE_PREFETCH,
-		IORESOURCE_MEM);
+				  IORESOURCE_MEM | IORESOURCE_PREFETCH,
+				  IORESOURCE_MEM);
 
 	compact_resources(dev);
 }
 
-
 void pci_dev_read_resources(struct device *dev)
 {
 	uint32_t addr;
+
 	pci_read_bases(dev, 6);
+
 	addr = pci_read_config32(dev, PCI_ROM_ADDRESS);
 	dev->rom_address = (addr == 0xffffffff)? 0 : addr;
 }
@@ -214,14 +214,29 @@ void pci_dev_read_resources(struct device *dev)
 void pci_bus_read_resources(struct device *dev)
 {
 	uint32_t addr;
+
 	pci_bridge_read_bases(dev);
 	pci_read_bases(dev, 2);
 	
 	addr = pci_read_config32(dev, PCI_ROM_ADDRESS1);
 	dev->rom_address = (addr == 0xffffffff)? 0 : addr;
-
 }
 
+/**
+ * @brief round a number up to an alignment. 
+ * @param val the starting value
+ * @param roundup Alignment as a power of two
+ * @returns rounded up number
+ */
+static unsigned long round(unsigned long val, unsigned long roundup)
+{
+	/* ROUNDUP MUST BE A POWER OF TWO. */
+	unsigned long inverse;
+	inverse = ~(roundup - 1);
+	val += (roundup - 1);
+	val &= inverse;
+	return val;
+}
 
 static void pci_set_resource(struct device *dev, struct resource *resource)
 {
@@ -230,11 +245,10 @@ static void pci_set_resource(struct device *dev, struct resource *resource)
 	unsigned long gran;
 
 	/* Make certain the resource has actually been set */
+
 	if (!(resource->flags & IORESOURCE_ASSIGNED)) {
-#if 1
 		printk_err("ERROR: %s %02x not allocated\n",
-			dev_path(dev), resource->index);
-#endif
+			   dev_path(dev), resource->index);
 		return;
 	}
 
@@ -256,8 +270,10 @@ static void pci_set_resource(struct device *dev, struct resource *resource)
 	if (resource->flags & IORESOURCE_PCI_BRIDGE) {
 		dev->command |= PCI_COMMAND_MASTER;
 	}
+
 	/* Get the base address */
 	base = resource->base;
+
 	/* Get the resource granularity */
 	gran = 1UL << resource->gran;
 
@@ -268,15 +284,13 @@ static void pci_set_resource(struct device *dev, struct resource *resource)
 	 */
 	
 	/* Get the limit (rounded up) */
-	limit = base + ((resource->size + gran - 1UL) & ~(gran - 1UL)) -1UL;
+	limit = base + round(resource->size, gran) - 1UL;
 	
 	/* Now store the resource */
 	resource->flags |= IORESOURCE_STORED;
 	if (!(resource->flags & IORESOURCE_PCI_BRIDGE)) {
-		/*
-		 * some chipsets allow us to set/clear the IO bit. 
-		 * (e.g. VIA 82c686a.) So set it to be safe)
-		 */
+		/* some chipsets allow us to set/clear the IO bit. 
+		 * (e.g. VIA 82c686a.) So set it to be safe) */
 		limit = base + resource->size -1;
 		if (resource->flags & IORESOURCE_IO) {
 			base |= PCI_BASE_ADDRESS_SPACE_IO;
@@ -286,58 +300,50 @@ static void pci_set_resource(struct device *dev, struct resource *resource)
 			/* FIXME handle real 64bit base addresses */
 			pci_write_config32(dev, resource->index + 4, 0);
 		}
-	}
-	else if (resource->index == PCI_IO_BASE) {
+	} else if (resource->index == PCI_IO_BASE) {
 		/* set the IO ranges
 		 * WARNING: we don't really do 32-bit addressing for IO yet! 
 		 */
 		compute_allocate_resource(&dev->link[0], resource, 
-			IORESOURCE_IO, IORESOURCE_IO);
+					  IORESOURCE_IO, IORESOURCE_IO);
 		pci_write_config8(dev, PCI_IO_BASE,  base >> 8);
 		pci_write_config8(dev, PCI_IO_LIMIT, limit >> 8);
 		pci_write_config16(dev, PCI_IO_BASE_UPPER16, 0);
 		pci_write_config16(dev, PCI_IO_LIMIT_UPPER16, 0);
-	}
-	else if (resource->index == PCI_MEMORY_BASE) {
-		/* set the memory range
-		 */
+	} else if (resource->index == PCI_MEMORY_BASE) {
+		/* set the memory range */
 		compute_allocate_resource(&dev->link[0], resource,
-			IORESOURCE_MEM | IORESOURCE_PREFETCH, 
-			IORESOURCE_MEM);
+					  IORESOURCE_MEM | IORESOURCE_PREFETCH, 
+					  IORESOURCE_MEM);
 		pci_write_config16(dev, PCI_MEMORY_BASE, base >> 16);
 		pci_write_config16(dev, PCI_MEMORY_LIMIT, limit >> 16);
-	}
-	else if (resource->index == PCI_PREF_MEMORY_BASE) {
+	} else if (resource->index == PCI_PREF_MEMORY_BASE) {
 		/* set the prefetchable memory range
-		 * WARNING: we don't really do 64-bit addressing for prefetchable memory yet!
-		 */
+		 * WARNING: we don't really do 64-bit addressing for
+		 * prefetchable memory yet! */
 		compute_allocate_resource(&dev->link[0], resource,
-			IORESOURCE_MEM | IORESOURCE_PREFETCH, 
-			IORESOURCE_MEM | IORESOURCE_PREFETCH);
+					  IORESOURCE_MEM | IORESOURCE_PREFETCH, 
+					  IORESOURCE_MEM | IORESOURCE_PREFETCH);
 		pci_write_config16(dev, PCI_PREF_MEMORY_BASE,  base >> 16);
 		pci_write_config16(dev, PCI_PREF_MEMORY_LIMIT, limit >> 16);
 		pci_write_config32(dev, PCI_PREF_BASE_UPPER32, 0);
 		pci_write_config32(dev, PCI_PREF_LIMIT_UPPER32, 0);
-	}
-	else {
+	} else {
 		/* Don't let me think I stored the resource */
 		resource->flags &= ~IORESOURCE_STORED;
 		printk_err("ERROR: invalid resource->index %x\n",
-			resource->index);
+			   resource->index);
 	}
+
 	buf[0] = '\0';
 	if (resource->flags & IORESOURCE_PCI_BRIDGE) {
 		sprintf(buf, "bus %d ", dev->link[0].secondary);
 	}
-	
-	printk_debug(
-		"%s %02x <- [0x%08lx - 0x%08lx] %s%s\n",
-		dev_path(dev),
-		resource->index, 
-		resource->base, limit,
-		buf,
-		(resource->flags & IORESOURCE_IO)? "io":
-		(resource->flags & IORESOURCE_PREFETCH)? "prefmem": "mem");
+	printk_debug("%s %02x <- [0x%08lx - 0x%08lx] %s%s\n",
+		     dev_path(dev), resource->index, resource->base,
+		     limit, buf,
+		     (resource->flags & IORESOURCE_IO)? "io":
+		     (resource->flags & IORESOURCE_PREFETCH)? "prefmem": "mem");
 	return;
 }
 
@@ -348,11 +354,11 @@ void pci_dev_set_resources(struct device *dev)
 	uint8_t line;
 
 	last = &dev->resource[dev->resources];
-
-	for(resource = &dev->resource[0]; resource < last; resource++) {
+	for (resource = &dev->resource[0]; resource < last; resource++) {
 		pci_set_resource(dev, resource);
 	}
-	for(link = 0; link < dev->links; link++) {
+
+	for (link = 0; link < dev->links; link++) {
 		struct bus *bus;
 		bus = &dev->link[link];
 		if (bus->children) {
@@ -401,43 +407,55 @@ void pci_bus_enable_resources(struct device *dev)
 	pci_dev_enable_resources(dev);
 }
 
+/** Default device operation for PCI devices */
 struct device_operations default_pci_ops_dev = {
 	.read_resources   = pci_dev_read_resources,
 	.set_resources    = pci_dev_set_resources,
 	.enable_resources = pci_dev_enable_resources,
-	.init = 0,
-	.scan_bus = 0,
+	.init		  = 0,
+	.scan_bus	  = 0,
 };
+
+/** Default device operations for PCI bridges */
 struct device_operations default_pci_ops_bus = {
 	.read_resources   = pci_bus_read_resources,
 	.set_resources    = pci_dev_set_resources,
 	.enable_resources = pci_bus_enable_resources,
-	.init = 0,
-	.scan_bus = pci_scan_bridge,
+	.init		  = 0,
+	.scan_bus	  = pci_scan_bridge,
 };
+
+/**
+ * @brief Set up PCI device operation
+ *
+ *
+ * @param dev 
+ *
+ * @see pci_drivers
+ */
 static void set_pci_ops(struct device *dev)
 {
 	struct pci_driver *driver;
+
 	if (dev->ops) {
 		return;
 	}
+
 	/* Look through the list of setup drivers and find one for
-	 * this pci device 
-	 */
-	for(driver = &pci_drivers[0]; driver != &epci_drivers[0]; driver++) {
+	 * this pci device */
+	for (driver = &pci_drivers[0]; driver != &epci_drivers[0]; driver++) {
 		if ((driver->vendor == dev->vendor) &&
-			(driver->device == dev->device)) {
+		    (driver->device == dev->device)) {
 			dev->ops = driver->ops;
-#if 1
-			printk_debug("%s [%04x/%04x] %sops\n", 
-				dev_path(dev),
-				driver->vendor, driver->device,
-				(driver->ops->scan_bus?"bus ":"")
-				);
-#endif
+
+			printk_debug("%s [%04x/%04x] %sops\n", dev_path(dev),
+				     driver->vendor, driver->device,
+				     (driver->ops->scan_bus?"bus ":""));
+
 			return;
 		}
 	}
+
 	/* If I don't have a specific driver use the default operations */
 	switch(dev->hdr_type & 0x7f) {	/* header type */
 	case PCI_HEADER_TYPE_NORMAL:	/* standard header */
@@ -454,27 +472,35 @@ static void set_pci_ops(struct device *dev)
 	bad:
 		if (dev->enable) {
 			printk_err("%s [%04x/%04x/%06x] has unknown header "
-				"type %02x, ignoring.\n",
-				dev_path(dev),
-				dev->vendor, dev->device, 
-				dev->class >> 8, dev->hdr_type);
+				   "type %02x, ignoring.\n",
+				   dev_path(dev),
+				   dev->vendor, dev->device, 
+				   dev->class >> 8, dev->hdr_type);
 		}
 	}
 	return;
 }
 
 /**
- * Given a bus and a devfn number, find the device structure
- * @param bus The bus structure
+ * @brief Find a specific device structure on a list of device structures
+ *
+ * Given a linked list of PCI device structures and a devfn number, find the
+ * device structure correspond to the devfn.
+ *
+ * @param list the device structure list
  * @param devfn a device/function number
- * @return pointer to the device structure
+ *
+ * @return pointer to the device structure found
  */
-static struct device *pci_scan_get_dev(struct device **list, unsigned int devfn)
+static struct device *pci_scan_get_dev(struct device **list,
+				       unsigned int devfn)
 {
 	struct device *dev = 0;
-	for(; *list; list = &(*list)->sibling) {
+
+	for (; *list; list = &(*list)->sibling) {
 		if ((*list)->path.type != DEVICE_PATH_PCI) {
-			printk_err("child %s not a pci device\n", dev_path(*list));
+			printk_err("child %s not a pci device\n",
+				   dev_path(*list));
 			continue;
 		}
 		if ((*list)->path.u.pci.devfn == devfn) {
@@ -485,10 +511,13 @@ static struct device *pci_scan_get_dev(struct device **list, unsigned int devfn)
 			break;
 		}
 	}
+
+	/* FIXME: why are we doing this ? Isn't there some order between the
+	 * structures before ? */
 	if (dev) {
 		device_t child;
 		/* Find the last child of our parent */
-		for(child = dev->bus->children; child && child->sibling; ) {
+		for (child = dev->bus->children; child && child->sibling; ) {
 			child = child->sibling;
 		}
 		/* Place the device on the list of children of it's parent. */
@@ -502,16 +531,24 @@ static struct device *pci_scan_get_dev(struct device **list, unsigned int devfn)
 	return dev;
 }
 
-/** Scan the pci bus devices and bridges.
+/**
+ * @brief Scan a PCI bus
+ *
+ * Determine the existence of devices and bridges on a PCI bus. If there are
+ * bridges on the bus, recursively scan the buses behind the bridges.
+ *
+ * This function is the default scan_bus() method for the root device
+ * 'dev_root'.
+ *
  * @param bus pointer to the bus structure
  * @param min_devfn minimum devfn to look at in the scan usually 0x00
  * @param max_devfn maximum devfn to look at in the scan usually 0xff
  * @param max current bus number
+ *
  * @return The maximum bus number found, after scanning all subordinate busses
  */
-unsigned int pci_scan_bus(struct bus *bus,
-	unsigned min_devfn, unsigned max_devfn,
-	unsigned int max)
+unsigned int pci_scan_bus(struct bus *bus, unsigned min_devfn,
+			  unsigned max_devfn, unsigned int max)
 {
 	unsigned int devfn;
 	device_t dev;
@@ -524,42 +561,50 @@ unsigned int pci_scan_bus(struct bus *bus,
 	bus->children = 0;
 
 	post_code(0x24);
-	
 
-	/* probe all devices on this bus with some optimization for non-existance and 
-	   single funcion devices */
+	/* probe all devices on this bus with some optimization for
+	 * non-existence and single funcion devices */
 	for (devfn = min_devfn; devfn <= max_devfn; devfn++) {
 		uint32_t id, class;
 		uint8_t hdr_type;
 
-		/* First thing setup the device structure */
+		/* device structures for PCI devices associated with static
+		 * devices are already created during the static device
+		 * enumeration, find out if it is the case for this devfn */
 		dev = pci_scan_get_dev(&old_devices, devfn);
-	
-		/* Detect if a device is present */
+
 		if (!dev) {
+			/* it's not associated with a static device, detect if
+			 * this device is present */
 			struct device dummy;
 			dummy.bus              = bus;
 			dummy.path.type        = DEVICE_PATH_PCI;
 			dummy.path.u.pci.devfn = devfn;
 			id = pci_read_config32(&dummy, PCI_VENDOR_ID);
 			/* some broken boards return 0 if a slot is empty: */
-			if (	(id == 0xffffffff) || (id == 0x00000000) || 
-				(id == 0x0000ffff) || (id == 0xffff0000))
-			{
-				printk_spew("PCI: devfn 0x%x, bad id 0x%x\n", devfn, id);
+			if ((id == 0xffffffff) || (id == 0x00000000) || 
+			    (id == 0x0000ffff) || (id == 0xffff0000)) {
+				printk_spew("PCI: devfn 0x%x, bad id 0x%x\n",
+					    devfn, id);
 				if (PCI_FUNC(devfn) == 0x00) {
-					/* if this is a function 0 device and it is not present,
-					   skip to next device */
+					/* if this is a function 0 device and
+					 * it is not present, skip to next
+					 * device */
 					devfn += 0x07;
 				}
-				/* multi function device, skip to next function */
+				/* this function in a multi function device is
+				 * not present, skip to next function */
 				continue;
 			}
 			dev = alloc_dev(bus, &dummy.path);
-		}
-		else {
-			/* Run the magic enable sequence for the device */
-			if (dev->chip && dev->chip->control && dev->chip->control->enable_dev) {
+		} else {
+			/* Run the magic enable/disable sequence for the
+			 * device */
+			/* FIXME: What happen if this PCI device listed as
+			 * static device but does not exist ? This calls
+			 * some arbitray code without any justification */
+			if (dev->chip && dev->chip->control &&
+			    dev->chip->control->enable_dev) {
 				int enable  = dev->enable;
 				dev->enable = 1;
 				dev->chip->control->enable_dev(dev);
@@ -580,14 +625,15 @@ unsigned int pci_scan_bus(struct bus *bus,
 		dev->class = class >> 8;
 
 		/* Look at the vendor and device id, or at least the 
-		 * header type and class and figure out which set of configuration
-		 * methods to use.  Unless we already have some pci ops.
+		 * header type and class and figure out which set of
+		 * configuration methods to use.  Unless we already
+		 * have some pci ops.
 		 */
 		set_pci_ops(dev);
 		/* Error if we don't have some pci operations for it */
 		if (!dev->ops) {
 			printk_err("%s No device operations\n",
-				dev_path(dev));
+				   dev_path(dev));
 			continue;
 		}
 
@@ -600,24 +646,28 @@ unsigned int pci_scan_bus(struct bus *bus,
 		}
 
 		printk_debug("%s [%04x/%04x] %s\n", 
-			dev_path(dev),
-			dev->vendor, dev->device, 
-			dev->enable?"enabled": "disabled");
+			     dev_path(dev),
+			     dev->vendor, dev->device, 
+			     dev->enable?"enabled": "disabled");
 
 		if (PCI_FUNC(devfn) == 0x00 && (hdr_type & 0x80) != 0x80) {
-			/* if this is not a multi function device, don't waste time probe
-			   another function. Skip to next device. */
+			/* if this is not a multi function device, don't
+			 * waste time probe another function.
+			 * Skip to next device. */
 			devfn += 0x07;
 		}
 	}
 	post_code(0x25);
 
-	for(child = bus->children; child; child = child->sibling) {
+	/* if the child provides scan_bus(), for example a bridge, scan the
+	 * bus behind that child */
+	for (child = bus->children; child; child = child->sibling) {
 		if (!child->ops->scan_bus) {
 			continue;
 		}
 		max = child->ops->scan_bus(child, max);
 	}
+
 	/*
 	 * We've scanned the bus and so we know all about what's on
 	 * the other side of any bridges that may be on this bus plus
@@ -630,8 +680,17 @@ unsigned int pci_scan_bus(struct bus *bus,
 	return max;
 }
 
-/** Scan the bus, first for bridges and next for devices. 
- * @param pci_bus pointer to the bus structure
+/**
+ * @brief Scan a PCI bridge and the buses behind the bridge.
+ *
+ * Determine the existence of buses behind the bridge. Set up the bridge
+ * according to the result of the scan.
+ *
+ * This function is the default scan_bus() method for PCI bridge devices.
+ *
+ * @param dev pointer to the bridge device
+ * @param max the highest bus number assgined up to now
+ *
  * @return The maximum bus number found, after scanning all subordinate busses
  */
 unsigned int pci_scan_bridge(struct device *dev, unsigned int max)
@@ -645,47 +704,44 @@ unsigned int pci_scan_bridge(struct device *dev, unsigned int max)
 
 	/* Set up the primary, secondary and subordinate bus numbers. We have
 	 * no idea how many buses are behind this bridge yet, so we set the
-	 * subordinate bus number to 0xff for the moment 
-	 */
+	 * subordinate bus number to 0xff for the moment. */
 	bus->secondary = ++max;
 	bus->subordinate = 0xff;
-	
+
 	/* Clear all status bits and turn off memory, I/O and master enables. */
 	cr = pci_read_config16(dev, PCI_COMMAND);
 	pci_write_config16(dev, PCI_COMMAND, 0x0000);
 	pci_write_config16(dev, PCI_STATUS, 0xffff);
 
-	/*
-	 * Read the existing primary/secondary/subordinate bus
-	 * number configuration.
-	 */
+	/* Read the existing primary/secondary/subordinate bus
+	 * number configuration. */
 	buses = pci_read_config32(dev, PCI_PRIMARY_BUS);
 
 	/* Configure the bus numbers for this bridge: the configuration
 	 * transactions will not be propagated by the bridge if it is not
-	 * correctly configured 
-	 */
+	 * correctly configured */
 	buses &= 0xff000000;
 	buses |= (((unsigned int) (dev->bus->secondary) << 0) |
-		((unsigned int) (bus->secondary) << 8) |
-		((unsigned int) (bus->subordinate) << 16));
+		  ((unsigned int) (bus->secondary) << 8) |
+		  ((unsigned int) (bus->subordinate) << 16));
 	pci_write_config32(dev, PCI_PRIMARY_BUS, buses);
 	
-	/* Now we can scan all subordinate buses i.e. the bus hehind the bridge */
+	/* Now we can scan all subordinate buses i.e. the buses behind the
+	 * bridge */
 	max = pci_scan_bus(bus, 0x00, 0xff, max);
 	
 	/* We know the number of buses behind this bridge. Set the subordinate
-	 *  bus number to its real value 
-	 */
+	 * bus number to its real value */
 	bus->subordinate = max;
 	buses = (buses & 0xff00ffff) |
 		((unsigned int) (bus->subordinate) << 16);
 	pci_write_config32(dev, PCI_PRIMARY_BUS, buses);
 	pci_write_config16(dev, PCI_COMMAND, cr);
-		
+
 	printk_spew("%s returns max %d\n", __FUNCTION__, max);
 	return max;
 }
+
 /*
     Tell the EISA int controller this int must be level triggered
     THIS IS A KLUDGE -- sorry, this needs to get cleaned up.
diff --git a/src/devices/root_device.c b/src/devices/root_device.c
index 4a076a1bb3..0bf5ea60a8 100644
--- a/src/devices/root_device.c
+++ b/src/devices/root_device.c
@@ -21,9 +21,9 @@ void root_dev_read_resources(device_t root)
 	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]);
+		    &root->link[0], &root->resource[res]);
 	compute_allocate_resource(&root->link[0], &root->resource[res], 
-		IORESOURCE_IO, IORESOURCE_IO);
+				  IORESOURCE_IO, IORESOURCE_IO);
 	res++;
 
 	/* Initialize the system wide memory resources constraints */
@@ -35,9 +35,9 @@ void root_dev_read_resources(device_t root)
 	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]);
+		    &root->link[0], &root->resource[res]);
 	compute_allocate_resource(&root->link[0], &root->resource[res], 
-		IORESOURCE_MEM, IORESOURCE_MEM);
+				  IORESOURCE_MEM, IORESOURCE_MEM);
 	res++;
 
 	root->resources = res;
@@ -51,12 +51,12 @@ void root_dev_read_resources(device_t root)
  */
 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);
+	struct 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);
 }
 
@@ -71,18 +71,18 @@ 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) {
+
+	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");
+			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) {
+	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));
@@ -95,9 +95,9 @@ unsigned int walk_static_devices(device_t bus, unsigned int max)
 void enable_childrens_resources(device_t dev)
 {
 	unsigned link;
-	for(link = 0; link < dev->links; link++) {
+	for (link = 0; link < dev->links; link++) {
 		device_t child;
-		for(child = dev->link[link].children; child; child = child->sibling) {
+		for (child = dev->link[link].children; child; child = child->sibling) {
 			enable_resources(child);
 		}
 	}