Re: [RFC v5 4/6] usb: gadget: configfs: Check USB configuration before adding

Peter Chen
2020-08-31T02:30:03Z

On 20-08-28 22:58:44, Wesley Cheng wrote:
> Ensure that the USB gadget is able to support the configuration being
> added based on the number of endpoints required from all interfaces. This
> is for accounting for any bandwidth or space limitations.
>
> Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
> ---
> drivers/usb/gadget/configfs.c | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
> index 56051bb97349..7c74c04b1d8c 100644
> --- a/drivers/usb/gadget/configfs.c
> +++ b/drivers/usb/gadget/configfs.c
> @@ -1361,6 +1361,7 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
> struct usb_function *f;
> struct usb_function *tmp;
> struct gadget_config_name *cn;
> + unsigned long ep_map = 0;
>
> if (gadget_is_otg(gadget))
> c->descriptors = otg_desc;
> @@ -1390,7 +1391,28 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
> list_add(&f->list, &cfg->func_list);
> goto err_purge_funcs;
> }
> + if (f->ss_descriptors) {
> + struct usb_descriptor_header **d;
> +
> + d = f->ss_descriptors;
> + for (; *d; ++d) {
> + struct usb_endpoint_descriptor *ep;
> + int addr;
> +
> + if ((*d)->bDescriptorType != USB_DT_ENDPOINT)
> + continue;
> +
> + ep = (struct usb_endpoint_descriptor *)*d;
> + addr = ((ep->bEndpointAddress & 0x80) >> 3) |
> + (ep->bEndpointAddress & 0x0f);

">> 3" or "<< 3?

> + set_bit(addr, &ep_map);

You want to record all endpoints on ep_map? Considering there are
four EP_IN (1-4), and four EP_OUT (1-4), what the value of ep_map
would like?

> + }
> + }
> }
> + ret = usb_gadget_check_config(cdev->gadget, ep_map);
> + if (ret)
> + goto err_purge_funcs;
> +

You may move this patch after your 4nd patch to avoid "git bisect"
issue.

> usb_ep_autoconfig_reset(cdev->gadget);
> }
> if (cdev->use_os_string) {
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>

--

Thanks,
Peter Chen