libpayload: Make usb_initialize more efficient and fix style problems.

The usb_initialize function would scan for USB host controllers by brute force
iterating over all possible busses, devices, and functions. This change makes
it recursively scan busses only if it finds them on the other side of a bridge,
and only scan for functions beyond function 0 if the device claims to be
multifunction.

This change also takes the opportunity to clean up some style problems
throughout the file.

Change-Id: I0f5e8b9a454a42a76d30bccca898c8e1af770b2b
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: http://review.coreboot.org/1736
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
Tested-by: build bot (Jenkins)

1 files changed, 65 insertions, 46 deletions

diff --git a/payloads/libpayload/drivers/usb/usbinit.c b/payloads/libpayload/drivers/usb/usbinit.c
index 8499b82411..f51783b2fa 100644
--- a/payloads/libpayload/drivers/usb/usbinit.c
+++ b/payloads/libpayload/drivers/usb/usbinit.c
@@ -42,8 +42,7 @@
  * @param dev PCI device id at bus
  * @param func function id of the controller
  */
-int
-usb_controller_initialize (int bus, int dev, int func)
+int usb_controller_initialize(int bus, int dev, int func)
 {
 	u32 class;
 	u32 devclass;
@@ -52,8 +51,8 @@ usb_controller_initialize (int bus, int dev, int func)
 	u32 pciid;
 
 	addr = PCI_DEV (bus, dev, func);
-	class = pci_read_config32 (addr, 8);
-	pciid = pci_read_config32 (addr, 0);
+	class = pci_read_config32(addr, 8);
+	pciid = pci_read_config32(addr, 0);
 
 	devclass = class >> 16;
 	prog_if = (class >> 8) & 0xff;
@@ -64,78 +63,98 @@ usb_controller_initialize (int bus, int dev, int func)
 	if (devclass == 0xc03) {
 		u32 pci_command;
 
-		pci_command =pci_read_config32(addr, PCI_COMMAND);
+		pci_command = pci_read_config32(addr, PCI_COMMAND);
 		pci_command |= PCI_COMMAND_MASTER;
 		pci_write_config32(addr, PCI_COMMAND, pci_command);
 
-		printf ("%02x:%02x.%x %04x:%04x.%d ", bus, dev, func,
+		printf("%02x:%02x.%x %04x:%04x.%d ", bus, dev, func,
 			pciid >> 16, pciid & 0xFFFF, func);
-		switch(prog_if) {
-			case 0x00:
+		switch (prog_if) {
+		case 0x00:
 #ifdef CONFIG_USB_UHCI
-				printf ("UHCI controller\n");
-				uhci_init (addr);
+			printf("UHCI controller\n");
+			uhci_init (addr);
 #else
-				printf ("UHCI controller (not supported)\n");
+			printf("UHCI controller (not supported)\n");
 #endif
-				break;
+			break;
 
-			case 0x10:
+		case 0x10:
 #ifdef CONFIG_USB_OHCI
-				printf ("OHCI controller\n");
-				ohci_init(addr);
+			printf("OHCI controller\n");
+			ohci_init(addr);
 #else
-				printf ("OHCI controller (not supported)\n");
+			printf("OHCI controller (not supported)\n");
 #endif
-				break;
+			break;
 
-			case 0x20:
+		case 0x20:
 #ifdef CONFIG_USB_EHCI
-				printf ("EHCI controller\n");
-				ehci_init(addr);
+			printf("EHCI controller\n");
+			ehci_init(addr);
 #else
-				printf ("EHCI controller (not supported)\n");
+			printf("EHCI controller (not supported)\n");
 #endif
-				break;
+			break;
 
-			case 0x30:
+		case 0x30:
 #ifdef CONFIG_USB_XHCI
-				printf ("xHCI controller\n");
-				xhci_init(addr);
+			printf("xHCI controller\n");
+			xhci_init(addr);
 #else
-				printf ("xHCI controller (not supported)\n");
+			printf("xHCI controller (not supported)\n");
 #endif
-				break;
+			break;
 
-			default:
-				printf ("unknown controller %x not supported\n",
-						prog_if);
-				break;
+		default:
+			printf("unknown controller %x not supported\n",
+			       prog_if);
+			break;
 		}
 	}
 
 	return 0;
 }
 
+static void usb_scan_pci_bus(int bus)
+{
+	int dev, func;
+	for (dev = 0; dev < 32; dev++) {
+		u8 header_type;
+		pcidev_t addr = PCI_DEV(bus, dev, 0);
+		/* Check if there's a device here at all. */
+		if (pci_read_config32(addr, REG_VENDOR_ID) == 0xffff)
+			continue;
+		header_type = pci_read_config8(addr, REG_HEADER_TYPE);
+		/* If this is a bridge, scan the bus on the other side. */
+		if ((header_type & ~HEADER_TYPE_MULTIFUNCTION) ==
+				HEADER_TYPE_BRIDGE) {
+			int sub_bus =
+				pci_read_config8(addr, REG_SECONDARY_BUS);
+			usb_scan_pci_bus(sub_bus);
+			continue;
+		}
+		/*
+		 * EHCI is defined by standards to be at a higher function
+		 * than the USB1 controllers. We don't want to init USB1 +
+		 * devices just to "steal" those for USB2, so make sure USB2
+		 * comes first.
+		 */
+		/* Check for a multifunction device. */
+		if (header_type & HEADER_TYPE_MULTIFUNCTION)
+			for (func = 7; func > 0; func--)
+				usb_controller_initialize(bus, dev, func);
+		/* Initialize function 0. */
+		usb_controller_initialize(bus, dev, 0);
+	}
+}
+
 /**
  * Initialize all USB controllers attached to PCI.
  */
-int
-usb_initialize (void)
+int usb_initialize(void)
 {
-	int bus, dev, func;
-	/* EHCI is defined by standards to be at a
-	 * higher function than the USB1 controllers.
-	 * We don't want to init USB1 + devices just to
-	 * "steal" those for USB2, so make sure USB2
-	 * comes first.
-	 */
-	for (bus = 0; bus < 256; bus++)
-		for (dev = 0; dev < 32; dev++)
-			if (pci_read_config32 (PCI_DEV(bus, dev, 0), 8) >> 16 != 0xffff)
-				for (func = 7; func >= 0 ; func--)
-					usb_controller_initialize (bus, dev, func);
+	usb_scan_pci_bus(0);
 	usb_poll();
 	return 0;
 }
-