[Xen-devel] [PATCH] pvusb: don't rely on linux kernel macros for the interface

[Juergen Gross <jgross@xxxxxxxx>]

The interface description of pvUSB lacks some access macros as using
linux kernel macros is assumed to work well. This solution is rather
unfriendly for pvusb implementations being outside the linux kernel.
Additionally things will break quite unpleasent in case the linux
kernel implementation is changed.

To avoid these problems define own macros for accessing bitfields of
the interface and for values of several structure members.

While working on the file add some more comments, especially for the
xenstore interface.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/include/public/io/usbif.h | 140 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 121 insertions(+), 19 deletions(-)

diff --git a/xen/include/public/io/usbif.h b/xen/include/public/io/usbif.h
index 0af2a38..9ef0cdc 100644
--- a/xen/include/public/io/usbif.h
+++ b/xen/include/public/io/usbif.h
@@ -31,6 +31,76 @@
 #include "ring.h"
 #include "../grant_table.h"
 
+/*
+ * Feature and Parameter Negotiation
+ * =================================
+ * The two halves of a Xen pvUSB driver utilize nodes within the XenStore to
+ * communicate capabilities and to negotiate operating parameters. This
+ * section enumerates these nodes which reside in the respective front and
+ * backend portions of the XenStore, following the XenBus convention.
+ *
+ * Any specified default value is in effect if the corresponding XenBus node
+ * is not present in the XenStore.
+ *
+ * XenStore nodes in sections marked "PRIVATE" are solely for use by the
+ * driver side whose XenBus tree contains them.
+ *
+ *****************************************************************************
+ *                            Backend XenBus Nodes
+ *****************************************************************************
+ *
+ *------------------ Backend Device Identification (PRIVATE) ------------------
+ *
+ * num-ports
+ *      Values:         unsigned [1...31]
+ *
+ *      Number of ports for this (virtual) USB host connector.
+ *
+ * usb-ver
+ *      Values:         unsigned [1...2]
+ *
+ *      USB version of this host connector: 1 = USB 1.1, 2 = USB 2.0.
+ *
+ * port/[1...31]
+ *      Values:         string
+ *
+ *      Physical USB device connected to the given port, e.g. "3-1.5".
+ *
+ *****************************************************************************
+ *                            Frontend XenBus Nodes
+ *****************************************************************************
+ *
+ *----------------------- Request Transport Parameters -----------------------
+ *
+ * event-channel
+ *      Values:         unsigned
+ *
+ *      The identifier of the Xen event channel used to signal activity
+ *      in the ring buffer.
+ *
+ * urb-ring-ref
+ *      Values:         unsigned
+ *
+ *      The Xen grant reference granting permission for the backend to map
+ *      the sole page in a single page sized ring buffer. This is the ring
+ *      buffer for urb requests.
+ *
+ * conn-ring-ref
+ *      Values:         unsigned
+ *
+ *      The Xen grant reference granting permission for the backend to map
+ *      the sole page in a single page sized ring buffer. This is the ring
+ *      buffer for connection/disconnection requests.
+ *
+ * protocol
+ *      Values:         string (XEN_IO_PROTO_ABI_*)
+ *      Default Value:  XEN_IO_PROTO_ABI_NATIVE
+ *
+ *      The machine ABI rules governing the format of all ring request and
+ *      response structures.
+ *
+ */
+
 enum usb_spec_version {
        USB_VER_UNKNOWN = 0,
        USB_VER_USB11,
@@ -41,37 +111,65 @@ enum usb_spec_version {
 /*
  *  USB pipe in usbif_request
  *
- *  bits 0-5 are specific bits for virtual USB driver.
- *  bits 7-31 are standard urb pipe.
- *
- *  - port number(NEW):        bits 0-4
- *                             (USB_MAXCHILDREN is 31)
+ *  - port number:     bits 0-4
+ *                             (USB_MAXCHILDREN is 31)
  *
- *  - operation flag(NEW):     bit 5
- *                             (0 = submit urb,
- *                              1 = unlink urb)
+ *  - operation flag:  bit 5
+ *                             (0 = submit urb,
+ *                              1 = unlink urb)
  *
  *  - direction:               bit 7
- *                             (0 = Host-to-Device [Out]
- *                           1 = Device-to-Host [In])
+ *                             (0 = Host-to-Device [Out]
+ *                              1 = Device-to-Host [In])
  *
  *  - device address:  bits 8-14
  *
  *  - endpoint:                bits 15-18
  *
- *  - pipe type:               bits 30-31
- *                             (00 = isochronous, 01 = interrupt,
- *                           10 = control, 11 = bulk)
+ *  - pipe type:       bits 30-31
+ *                             (00 = isochronous, 01 = interrupt,
+ *                              10 = control, 11 = bulk)
  */
-#define usbif_pipeportnum(pipe) ((pipe) & 0x1f)
-#define usbif_setportnum_pipe(pipe, portnum) \
-       ((pipe)|(portnum))
 
-#define usbif_pipeunlink(pipe) ((pipe) & 0x20)
-#define usbif_pipesubmit(pipe) (!usbif_pipeunlink(pipe))
-#define usbif_setunlink_pipe(pipe) ((pipe)|(0x20))
+#define USBIF_PIPE_PORT_MASK   0x0000001f
+#define USBIF_PIPE_UNLINK      0x00000020
+#define USBIF_PIPE_DIR         0x00000080
+#define USBIF_PIPE_DEV_MASK    0x0000007f
+#define USBIF_PIPE_DEV_SHIFT   8
+#define USBIF_PIPE_EP_MASK     0x0000000f
+#define USBIF_PIPE_EP_SHIFT    15
+#define USBIF_PIPE_TYPE_MASK   0x00000003
+#define USBIF_PIPE_TYPE_SHIFT  30
+#define USBIF_PIPE_TYPE_ISOC   0
+#define USBIF_PIPE_TYPE_INT    1
+#define USBIF_PIPE_TYPE_CTRL   2
+#define USBIF_PIPE_TYPE_BULK   3
+
+#define usbif_pipeportnum(pipe)                        ((pipe) & 
USBIF_PIPE_PORT_MASK)
+#define usbif_setportnum_pipe(pipe, portnum)   ((pipe) | (portnum))
+
+#define usbif_pipeunlink(pipe)                 ((pipe) & USBIF_PIPE_UNLINK)
+#define usbif_pipesubmit(pipe)                 (!usbif_pipeunlink(pipe))
+#define usbif_setunlink_pipe(pipe)             ((pipe) | USBIF_PIPE_UNLINK)
+
+#define usbif_pipein(pipe)                     ((pipe) & USBIF_PIPE_DIR)
+#define usbif_pipeout(pipe)                    (!usbif_pipein(pipe))
+
+#define usbif_pipedevice(pipe)                 \
+               (((pipe) >> USBIF_PIPE_DEV_SHIFT) & USBIF_PIPE_DEV_MASK)
+
+#define usbif_pipeendpoint(pipe)               \
+               (((pipe) >> USBIF_PIPE_EP_SHIFT) & USBIF_PIPE_EP_MASK)
+
+#define usbif_pipetype(pipe)                   \
+               (((pipe) >> USBIF_PIPE_TYPE_SHIFT) & USBIF_PIPE_TYPE_MASK)
+#define usbif_pipeisoc(pipe)   (usbif_pipetype(pipe) == USBIF_PIPE_TYPE_ISOC)
+#define usbif_pipeint(pipe)    (usbif_pipetype(pipe) == USBIF_PIPE_TYPE_INT)
+#define usbif_pipectrl(pipe)   (usbif_pipetype(pipe) == USBIF_PIPE_TYPE_CTRL)
+#define usbif_pipebulk(pipe)   (usbif_pipetype(pipe) == USBIF_PIPE_TYPE_BULK)
 
 #define USBIF_MAX_SEGMENTS_PER_REQUEST (16)
+#define USBIF_MAX_PORTNR       31
 
 /*
  * RING for transferring urbs.
@@ -141,6 +239,10 @@ struct usbif_conn_response {
        uint16_t id; /* request id */
        uint8_t portnum; /* port number */
        uint8_t speed; /* usb_device_speed */
+#define USBIF_SPEED_NONE       0
+#define USBIF_SPEED_LOW                1
+#define USBIF_SPEED_FULL       2
+#define USBIF_SPEED_HIGH       3
 };
 typedef struct usbif_conn_response usbif_conn_response_t;
 
-- 
2.1.4


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