[PATCH v4.1 2/4] usb: gadget: add quirk_ep_out_aligned_size field to struct usb_gadget

[David Cohen <david.a.cohen@linux.intel.com>]

Due to USB controllers may have different restrictions, usb gadget layer
needs to provide a generic way to inform gadget functions to complain
with non-standard requirements.

This patch adds 'quirk_ep_out_aligned_size' field to struct usb_gadget
to inform when controller's epout requires buffer size to be aligned to
MaxPacketSize. A helper is also provided to align buffer size when
necessary.

Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
---

Changes from v4 to v4.1:
 - Simplified usb_ep_align_maxpacketsize() macro as per Alen Stern's request

 include/linux/usb/gadget.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 23b3bfd0a842..41e8834af57d 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -441,6 +441,19 @@ static inline void usb_ep_fifo_flush(struct usb_ep *ep)
 		ep->ops->fifo_flush(ep);
 }
 
+/**
+ * usb_ep_align_maxpacketsize - returns @len aligned to ep's maxpacketsize
+ * @ep: the endpoint whose maxpacketsize is used to align @len
+ * @len: buffer size's length to align to @ep's maxpacketsize
+ *
+ * This helper is used in case it's required for any reason to align buffer's
+ * size to an ep's maxpacketsize.
+ */
+static inline size_t usb_ep_align_maxpacketsize(struct usb_ep *ep, size_t len)
+{
+	return round_up(len, (size_t)ep->desc->wMaxPacketSize);
+}
+
 
 /*-------------------------------------------------------------------------*/
 
@@ -502,6 +515,8 @@ struct usb_gadget_ops {
  *	only supports HNP on a different root port.
  * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
  *	enabled HNP support.
+ * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
+ *	MaxPacketSize.
  *
  * Gadgets have a mostly-portable "gadget driver" implementing device
  * functions, handling all usb configurations and interfaces.  Gadget
@@ -541,6 +556,7 @@ struct usb_gadget {
 	unsigned			b_hnp_enable:1;
 	unsigned			a_hnp_support:1;
 	unsigned			a_alt_hnp_support:1;
+	unsigned			quirk_ep_out_aligned_size:1;
 };
 #define work_to_gadget(w)	(container_of((w), struct usb_gadget, work))
 
-- 
1.8.4.rc3