[SLOF] [PATCH v2 4/5] usb: Build correct route string for USB3 devices behind a hub

[Nikunj A Dadhania]

Thomas Huth <thuth at redhat.com> writes:

> To support USB3 devices attached to a hub, we've got to set
> the so-called "route string" in the slot context, which is
> a concatenation of the hub port numbers that need to be
> traversed between the root hub port and the destination device.
>
> Signed-off-by: Thomas Huth <thuth at redhat.com>

Reviewed-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>

> ---
>  lib/libusb/usb-xhci.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/lib/libusb/usb-xhci.c b/lib/libusb/usb-xhci.c
> index 2d34133..0b45c26 100644
> --- a/lib/libusb/usb-xhci.c
> +++ b/lib/libusb/usb-xhci.c
> @@ -538,7 +538,7 @@ static bool xhci_alloc_dev(struct xhci_hcd *xhcd, struct usb_dev *hub,
>  	struct xhci_ep_ctx *ep0;
>  	uint32_t ctx_size, val;
>  	uint16_t max_packet;
> -	uint32_t newport;
> +	uint32_t newport, rootport;
>
>  	if (slot_id > XHCI_CONFIG_MAX_SLOT) {
>  		dprintf("USB3 slot ID %d is too high (max is %d)\n", slot_id,
> @@ -565,10 +565,16 @@ static bool xhci_alloc_dev(struct xhci_hcd *xhcd, struct usb_dev *hub,
>
>  	/* Step 3 */
>  	slot = xhci_get_slot_ctx(&xdev->in_ctx, ctx_size);
> -	newport = port + 1;
> -	val = LAST_CONTEXT(1) | SLOT_SPEED_SS | (newport << 16); /* FIXME speed, read from PS */
> +	newport = rootport = port + 1;
> +	val = newport & 0xf;
> +	for (dev = hub; dev != NULL; dev = dev->hub) {
> +		val = (val << 4) | (dev->port & 0xf);	/* Build route string */
> +		rootport = dev->port;
> +	}
> +	val >>= 4;			/* Remove root hub ID from the string */
> +	val |= LAST_CONTEXT(1) | SLOT_SPEED_SS;  /* FIXME speed, read from PS */
>  	slot->field1 = cpu_to_le32(val);
> -	slot->field2 = cpu_to_le32(ROOT_HUB_PORT(newport)); /* FIXME how to get port no */
> +	slot->field2 = cpu_to_le32(ROOT_HUB_PORT(rootport));
>
>  	/* Step 4 */
>  	if (!xhci_alloc_seg(&xdev->control, XHCI_CONTROL_TRBS_SIZE, TYPE_CTRL)) {
> -- 
> 1.8.3.1

Regards
Nikunj