On 07/25/2014 04:15 PM, Michal Nazarewicz wrote: > On Fri, Jul 25 2014, Robert Baldyga wrote: >> This patch introduces ioctl named FUNCTIONFS_ENDPOINT_DESC, which >> returns endpoint descriptor to userspace. It works only if function >> is active. > > I would argue that user space should never need to know the real > descriptor. Is this ioctl needed for anything in particular? It's needed, at least, to inform user space about maximum possible wMaxPacketSize value for the endpoint, which is returned by autoconfig through the endpoint descriptor when value set by user is zero. Descriptor returned form this ioctl is mostly the same as descriptor created by user. I guess you meant that real descriptor is this one, which contains real endpoint address, because it's probably only datum in real descriptor which should be never known by user space. This ioctl would be also useful in case, when FunctionFS daemon obtains endpoint descriptors from another daemon, and do not have access to original descriptor structures given do FunctionFS. > >> >> Signed-off-by: Robert Baldyga <r.baldyga@xxxxxxxxxxx> >> --- >> drivers/usb/gadget/f_fs.c | 17 +++++++++++++++++ >> include/uapi/linux/usb/functionfs.h | 6 ++++++ >> 2 files changed, 23 insertions(+) >> >> diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c >> index 490b30f..a2e18cc 100644 >> --- a/drivers/usb/gadget/f_fs.c >> +++ b/drivers/usb/gadget/f_fs.c >> @@ -1031,6 +1031,23 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code, >> case FUNCTIONFS_ENDPOINT_REVMAP: >> ret = epfile->ep->num; >> break; >> + case FUNCTIONFS_ENDPOINT_DESC: >> + { >> + int desc_idx; >> + struct usb_endpoint_descriptor *desc; >> + >> + if (epfile->ffs->gadget->speed == USB_SPEED_SUPER) >> + desc_idx = 2; >> + else if (epfile->ffs->gadget->speed == USB_SPEED_HIGH) >> + desc_idx = 1; >> + else >> + desc_idx = 0; >> + desc = epfile->ep->descs[desc_idx]; >> + ret = copy_to_user((void *)value, desc, sizeof(*desc)); >> + if (ret) >> + ret = -EFAULT; >> + break; >> + } >> default: >> ret = -ENOTTY; >> } >> diff --git a/include/uapi/linux/usb/functionfs.h b/include/uapi/linux/usb/functionfs.h >> index 1dc473a..1ab6f06 100644 >> --- a/include/uapi/linux/usb/functionfs.h >> +++ b/include/uapi/linux/usb/functionfs.h >> @@ -197,6 +197,12 @@ struct usb_functionfs_event { >> */ >> #define FUNCTIONFS_ENDPOINT_REVMAP _IO('g', 129) >> >> +/* >> + * Returns endpoint descriptor. In funciton is not active returns -ENODEV. >> + */ >> +#define FUNCTIONFS_ENDPOINT_DESC _IOR('g', 130, \ >> + struct usb_endpoint_descriptor) >> + >> >> >> #endif /* _UAPI__LINUX_FUNCTIONFS_H__ */ >> -- >> 1.9.1 >> > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html