usb serial gadget: CDC ACM fixes
Based on a patch from <Aurel.Thomi@ruag.com>, this makes the
CDC-ACM support in the serial gadget handle the SET_LINE_CODING
and SET_CONTROL_LINE_STATE requests ... which should improve
interop with at least MS-Windows "usbser.sys" if not some other
ACM host drivers.
It also adds a few REVISIT comments where this code plays a bit
loose with the CDC ACM spec. If this were used to hook up to a
real RS232 or modem link, those places would need a bit of work.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/gadget/serial.c b/drivers/usb/gadget/serial.c
index 8d158e5..54cdd6f 100644
--- a/drivers/usb/gadget/serial.c
+++ b/drivers/usb/gadget/serial.c
@@ -135,7 +135,10 @@
int port_in_use; /* open/close in progress */
wait_queue_head_t port_write_wait;/* waiting to write */
struct gs_buf *port_write_buf;
- struct usb_cdc_line_coding port_line_coding;
+ struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */
+ u16 port_handshake_bits;
+#define RS232_RTS (1 << 1)
+#define RS232_DTE (1 << 0)
};
/* the device structure holds info for the USB device */
@@ -199,6 +202,8 @@
static int gs_setup_class(struct usb_gadget *gadget,
const struct usb_ctrlrequest *ctrl);
static void gs_setup_complete(struct usb_ep *ep, struct usb_request *req);
+static void gs_setup_complete_set_line_coding(struct usb_ep *ep,
+ struct usb_request *req);
static void gs_disconnect(struct usb_gadget *gadget);
static int gs_set_config(struct gs_dev *dev, unsigned config);
static void gs_reset_config(struct gs_dev *dev);
@@ -406,7 +411,7 @@
.bLength = sizeof(gs_acm_descriptor),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_ACM_TYPE,
- .bmCapabilities = 0,
+ .bmCapabilities = (1 << 1),
};
static const struct usb_cdc_union_desc gs_union_desc = {
@@ -1502,6 +1507,8 @@
u16 wValue = le16_to_cpu(ctrl->wValue);
u16 wLength = le16_to_cpu(ctrl->wLength);
+ req->complete = gs_setup_complete;
+
switch (ctrl->bRequestType & USB_TYPE_MASK) {
case USB_TYPE_STANDARD:
ret = gs_setup_standard(gadget,ctrl);
@@ -1679,18 +1686,14 @@
switch (ctrl->bRequest) {
case USB_CDC_REQ_SET_LINE_CODING:
- /* FIXME Submit req to read the data; have its completion
- * handler copy that data to port->port_line_coding (iff
- * it's valid) and maybe pass it on. Until then, fail.
- */
- pr_warning("gs_setup: set_line_coding "
- "unuspported\n");
+ if (wLength != sizeof(struct usb_cdc_line_coding))
+ break;
+ ret = wLength;
+ req->complete = gs_setup_complete_set_line_coding;
break;
case USB_CDC_REQ_GET_LINE_CODING:
- port = dev->dev_port[0]; /* ACM only has one port */
- ret = min(wLength,
- (u16)sizeof(struct usb_cdc_line_coding));
+ ret = min_t(int, wLength, sizeof(struct usb_cdc_line_coding));
if (port) {
spin_lock(&port->port_lock);
memcpy(req->buf, &port->port_line_coding, ret);
@@ -1699,15 +1702,27 @@
break;
case USB_CDC_REQ_SET_CONTROL_LINE_STATE:
- /* FIXME Submit req to read the data; have its completion
- * handler use that to set the state (iff it's valid) and
- * maybe pass it on. Until then, fail.
- */
- pr_warning("gs_setup: set_control_line_state "
- "unuspported\n");
+ if (wLength != 0)
+ break;
+ ret = 0;
+ if (port) {
+ /* REVISIT: we currently just remember this data.
+ * If we change that, update whatever hardware needs
+ * updating.
+ */
+ spin_lock(&port->port_lock);
+ port->port_handshake_bits = wValue;
+ spin_unlock(&port->port_lock);
+ }
break;
default:
+ /* NOTE: strictly speaking, we should accept AT-commands
+ * using SEND_ENCPSULATED_COMMAND/GET_ENCAPSULATED_RESPONSE.
+ * But our call management descriptor says we don't handle
+ * call management, so we should be able to get by without
+ * handling those "required" commands (except by stalling).
+ */
pr_err("gs_setup: unknown class request, "
"type=%02x, request=%02x, value=%04x, "
"index=%04x, length=%d\n",
@@ -1719,6 +1734,42 @@
return ret;
}
+static void gs_setup_complete_set_line_coding(struct usb_ep *ep,
+ struct usb_request *req)
+{
+ struct gs_dev *dev = ep->driver_data;
+ struct gs_port *port = dev->dev_port[0]; /* ACM only has one port */
+
+ switch (req->status) {
+ case 0:
+ /* normal completion */
+ if (req->actual != sizeof(port->port_line_coding))
+ usb_ep_set_halt(ep);
+ else if (port) {
+ struct usb_cdc_line_coding *value = req->buf;
+
+ /* REVISIT: we currently just remember this data.
+ * If we change that, (a) validate it first, then
+ * (b) update whatever hardware needs updating.
+ */
+ spin_lock(&port->port_lock);
+ port->port_line_coding = *value;
+ spin_unlock(&port->port_lock);
+ }
+ break;
+
+ case -ESHUTDOWN:
+ /* disconnect */
+ gs_free_req(ep, req);
+ break;
+
+ default:
+ /* unexpected */
+ break;
+ }
+ return;
+}
+
/*
* gs_setup_complete
*/
@@ -1906,6 +1957,11 @@
}
}
+ /* REVISIT the ACM mode should be able to actually *issue* some
+ * notifications, for at least serial state change events if
+ * not also for network connection; say so in bmCapabilities.
+ */
+
pr_info("gs_set_config: %s configured, %s speed %s config\n",
GS_LONG_NAME,
gadget->speed == USB_SPEED_HIGH ? "high" : "full",