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.co...@linux.intel.com>
Cc: Alan Stern <st...@rowland.harvard.edu>
Cc: Michal Nazarewicz <min...@mina86.com>
---
include/linux/usb/gadget.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 23b3bfd0a842..cae8a6216551 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -502,6 +502,8 @@ 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 +543,7 @@ 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))
@@ -559,6 +562,23 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct
device *dev)
/**
+ * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
+ * requires quirk_ep_out_aligned_size, otherwise reguens len.
+ * @g: controller to check for quirk
+ * @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 check and maybe
+ * align buffer's size to an ep's maxpacketsize.
+ */
+static inline size_t
+usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
+{
+ return !g->quirk_ep_out_aligned_size ? len :
+ round_up(len, (size_t)ep->desc->wMaxPacketSize);
+}
+
+/**
* gadget_is_dualspeed - return true iff the hardware handles high speed
* @g: controller that might support both high and full speeds
*/
--
1.8.4.2
--
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