This is a note to let you know that I've just added the patch titled
usb: add helper to extract bits 12:11 of wMaxPacketSize
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: usb-add-helper-to-extract-bits-12-11-of-wmaxpacketsize.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 541b6fe63023f3059cf85d47ff2767a3e42a8e44 Mon Sep 17 00:00:00 2001
From: Felipe Balbi felipe.balbi@linux.intel.com Date: Mon, 26 Sep 2016 10:51:18 +0300 Subject: usb: add helper to extract bits 12:11 of wMaxPacketSize
From: Felipe Balbi felipe.balbi@linux.intel.com
commit 541b6fe63023f3059cf85d47ff2767a3e42a8e44 upstream.
According to USB Specification 2.0 table 9-4, wMaxPacketSize is a bitfield. Endpoint's maxpacket is laid out in bits 10:0. For high-speed, high-bandwidth isochronous endpoints, bits 12:11 contain a multiplier to tell us how many transactions we want to try per uframe.
This means that if we want an isochronous endpoint to issue 3 transfers of 1024 bytes per uframe, wMaxPacketSize should contain the value:
1024 | (2 << 11)
or 5120 (0x1400). In order to make Host and Peripheral controller drivers' life easier, we're adding a helper which returns bits 12:11. Note that no care is made WRT to checking endpoint type and gadget's speed. That's left for drivers to handle.
Signed-off-by: Felipe Balbi felipe.balbi@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- include/uapi/linux/usb/ch9.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
--- a/include/uapi/linux/usb/ch9.h +++ b/include/uapi/linux/usb/ch9.h @@ -423,6 +423,11 @@ struct usb_endpoint_descriptor { #define USB_ENDPOINT_XFER_INT 3 #define USB_ENDPOINT_MAX_ADJUSTABLE 0x80
+#define USB_EP_MAXP_MULT_SHIFT 11 +#define USB_EP_MAXP_MULT_MASK (3 << USB_EP_MAXP_MULT_SHIFT) +#define USB_EP_MAXP_MULT(m) \ + (((m) & USB_EP_MAXP_MULT_MASK) >> USB_EP_MAXP_MULT_SHIFT) + /* The USB 3.0 spec redefines bits 5:4 of bmAttributes as interrupt ep type. */ #define USB_ENDPOINT_INTRTYPE 0x30 #define USB_ENDPOINT_INTR_PERIODIC (0 << 4) @@ -630,6 +635,20 @@ static inline int usb_endpoint_maxp(cons return __le16_to_cpu(epd->wMaxPacketSize); }
+/** + * usb_endpoint_maxp_mult - get endpoint's transactional opportunities + * @epd: endpoint to be checked + * + * Return @epd's wMaxPacketSize[12:11] + 1 + */ +static inline int +usb_endpoint_maxp_mult(const struct usb_endpoint_descriptor *epd) +{ + int maxp = __le16_to_cpu(epd->wMaxPacketSize); + + return USB_EP_MAXP_MULT(maxp) + 1; +} + static inline int usb_endpoint_interrupt_type( const struct usb_endpoint_descriptor *epd) {
Patches currently in stable-queue which might be from felipe.balbi@linux.intel.com are
queue-4.9/usb-add-helper-to-extract-bits-12-11-of-wmaxpacketsize.patch