USB device not enumerated by iPXE USB stack

[eugenio]

Hi all,

The USB enumeration process failed because the device failed enumeration as a USB 2.0 device, so the iPXE EHCI USB stack handed ownership of the USB port to the iPXE UHCI USB stack, but the enumeration also failed as a USB 1.x device.

So I took a look at the UHCI source code of iPXE. I think that I have found a bug in three functions of the UHCI code. The functions are called uhci_root_enable, uhci_root_speed and uhci_root_poll.

Below you can find the three functions with the changes I have made to solve this enumeration problem.

static int uhci_root_enable ( struct usb_hub *hub, struct usb_port *port ) {
struct uhci_device *uhci = usb_hub_get_drvdata ( hub );
uint16_t portsc;
unsigned int i;

/* Reset port */
portsc = inw ( uhci->regs + UHCI_PORTSC ( port->address ) );
portsc |= UHCI_PORTSC_PR;
outw ( portsc, uhci->regs + UHCI_PORTSC ( port->address ) );
mdelay ( USB_RESET_DELAY_MS );
portsc &= ~UHCI_PORTSC_PR;
outw ( portsc, uhci->regs + UHCI_PORTSC ( port->address ) );
mdelay ( USB_RESET_RECOVER_DELAY_MS );

/* Enable port */
portsc |= UHCI_PORTSC_PED;
outw ( portsc, uhci->regs + UHCI_PORTSC ( port->address ) );
mdelay ( USB_RESET_RECOVER_DELAY_MS );

/* Wait for port to become enabled */
for ( i = 0 ; i < UHCI_PORT_ENABLE_MAX_WAIT_MS ; i++ ) {

/* Check port status */
portsc = inw ( uhci->regs + UHCI_PORTSC ( port->address ) );
if ( portsc & UHCI_PORTSC_PED && portsc & UHCI_PORTSC_CCS )
{
port->disconnected = 0;
return 0;
}

/* Delay */
mdelay ( 1 );
}

DBGC ( uhci, "UHCI %s-%d timed out waiting for port to enable "
"(status %04x)\n", uhci->name, port->address, portsc );
return -ETIMEDOUT;
}

static int uhci_root_speed ( struct usb_hub *hub, struct usb_port *port ) {
struct uhci_device *uhci = usb_hub_get_drvdata ( hub );
struct pci_device pci;
uint16_t portsc;
unsigned int speed;

/* Read port status */
portsc = inw ( uhci->regs + UHCI_PORTSC ( port->address ) );
if ( ! ( portsc & UHCI_PORTSC_CCS ) ) {
/* Port not connected */
speed = USB_SPEED_NONE;
} else if ( uhci->companion &&
! find_usb_bus_by_location ( BUS_TYPE_PCI,
uhci->companion ) ) {
/* Defer connection detection until companion
* controller has been enumerated.
*/
pci_init ( &pci, uhci->companion );
DBGC ( uhci, "UHCI %s-%d deferring for companion " PCI_FMT "\n",
uhci->name, port->address, PCI_ARGS ( &pci ) );
speed = USB_SPEED_NONE;
} else if ( portsc & UHCI_PORTSC_LS ) {
/* Low-speed device */
speed = USB_SPEED_LOW;
} else {
/* Full-speed device */
speed = USB_SPEED_FULL;
}
port->speed = speed;

/* Record disconnections and clear changes */
port->disconnected |= ( (portsc & UHCI_PORTSC_CCS) == 0 );
outw ( portsc, uhci->regs + UHCI_PORTSC ( port->address ) );

return 0;
}

static void uhci_root_poll ( struct usb_hub *hub, struct usb_port *port ) {
struct uhci_device *uhci = usb_hub_get_drvdata ( hub );
uint16_t portsc;
uint16_t change;

/* Do nothing unless something has changed */
portsc = inw ( uhci->regs + UHCI_PORTSC ( port->address ) );
change = ( portsc & UHCI_PORTSC_CHANGE );
if ( ! change )
return;

/* Record disconnections and clear changes */
port->disconnected |= ( (portsc & UHCI_PORTSC_CCS) == 0 );
outw ( portsc, uhci->regs + UHCI_PORTSC ( port->address ) );

/* Report port status change */
usb_port_changed ( port );
}

In the function uhci_root_enable I initialize with 0 the disconnected variable of the port structure when the port is enabled and the current connect status bit is set. This part was using the UHCI_PORTSC_CSC mask instead of the UHCI_PORTSC_CCS mask I have put into the code.

The only change to the other two functions is the use of the UHCI_PORTSC_CCS mask instead of the UHCI_PORTSC_CSC mask.

I am not an expert on the iPXE source code, so some with deep knowledge of the iPXE USB stack could take a look at the changes I have made and integrate them into the codebase if they are deemed worthy.

Thanks in advance and execuse my English.

Eugenio