usb gadget: issue notifications from ACM function
Update the CDC-ACM gadget code to support the peripheral-to-host
notifications when the tty is opened or closed, or issues a BREAK.
The serial framework code calls new generic hooks; right now only
CDC-ACM uses those hooks. This resolves several REVISIT comments
in the code. (Based on a patch from Felipe Balbi.)
Note that this doesn't expose USB_CDC_CAP_BRK to the host, since
this code still rejects USB_CDC_REQ_SEND_BREAK control requests
for host-to-peripheral BREAK signaling (received via /dev/ttyGS*).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/gadget/f_acm.c b/drivers/usb/gadget/f_acm.c
index f3bf561..5ee1590 100644
--- a/drivers/usb/gadget/f_acm.c
+++ b/drivers/usb/gadget/f_acm.c
@@ -47,16 +47,37 @@
u8 ctrl_id, data_id;
u8 port_num;
+ u8 pending;
+
+ /* lock is mostly for pending and notify_req ... they get accessed
+ * by callbacks both from tty (open/close/break) under its spinlock,
+ * and notify_req.complete() which can't use that lock.
+ */
+ spinlock_t lock;
+
struct acm_ep_descs fs;
struct acm_ep_descs hs;
struct usb_ep *notify;
struct usb_endpoint_descriptor *notify_desc;
+ struct usb_request *notify_req;
struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */
+
+ /* SetControlLineState request -- CDC 1.1 section 6.2.14 (INPUT) */
u16 port_handshake_bits;
-#define RS232_RTS (1 << 1) /* unused with full duplex */
-#define RS232_DTR (1 << 0) /* host is ready for data r/w */
+#define ACM_CTRL_RTS (1 << 1) /* unused with full duplex */
+#define ACM_CTRL_DTR (1 << 0) /* host is ready for data r/w */
+
+ /* SerialState notification -- CDC 1.1 section 6.3.5 (OUTPUT) */
+ u16 serial_state;
+#define ACM_CTRL_OVERRUN (1 << 6)
+#define ACM_CTRL_PARITY (1 << 5)
+#define ACM_CTRL_FRAMING (1 << 4)
+#define ACM_CTRL_RI (1 << 3)
+#define ACM_CTRL_BRK (1 << 2)
+#define ACM_CTRL_DSR (1 << 1)
+#define ACM_CTRL_DCD (1 << 0)
};
static inline struct f_acm *func_to_acm(struct usb_function *f)
@@ -64,12 +85,17 @@
return container_of(f, struct f_acm, port.func);
}
+static inline struct f_acm *port_to_acm(struct gserial *p)
+{
+ return container_of(p, struct f_acm, port);
+}
+
/*-------------------------------------------------------------------------*/
/* notification endpoint uses smallish and infrequent fixed-size messages */
#define GS_LOG2_NOTIFY_INTERVAL 5 /* 1 << 5 == 32 msec */
-#define GS_NOTIFY_MAXPACKET 8
+#define GS_NOTIFY_MAXPACKET 10 /* notification + 2 bytes */
/* interface and class descriptors: */
@@ -115,7 +141,7 @@
.bLength = sizeof(acm_descriptor),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_ACM_TYPE,
- .bmCapabilities = (1 << 1),
+ .bmCapabilities = USB_CDC_CAP_LINE,
};
static struct usb_cdc_union_desc acm_union_desc __initdata = {
@@ -275,6 +301,11 @@
/* composite driver infrastructure handles everything except
* CDC class messages; interface activation uses set_alt().
+ *
+ * Note CDC spec table 4 lists the ACM request profile. It requires
+ * encapsulated command support ... we don't handle any, and respond
+ * to them by stalling. Options include get/set/clear comm features
+ * (not that useful) and SEND_BREAK.
*/
switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
@@ -310,7 +341,7 @@
value = 0;
/* FIXME we should not allow data to flow until the
- * host sets the RS232_DTR bit; and when it clears
+ * host sets the ACM_CTRL_DTR bit; and when it clears
* that bit, we should return to that no-flow state.
*/
acm->port_handshake_bits = w_value;
@@ -348,9 +379,6 @@
/* we know alt == 0, so this is an activation or a reset */
if (intf == acm->ctrl_id) {
- /* REVISIT this may need more work when we start to
- * send notifications ...
- */
if (acm->notify->driver_data) {
VDBG(cdev, "reset acm control interface %d\n", intf);
usb_ep_disable(acm->notify);
@@ -395,6 +423,128 @@
/*-------------------------------------------------------------------------*/
+/**
+ * acm_cdc_notify - issue CDC notification to host
+ * @acm: wraps host to be notified
+ * @type: notification type
+ * @value: Refer to cdc specs, wValue field.
+ * @data: data to be sent
+ * @length: size of data
+ * Context: irqs blocked, acm->lock held, acm_notify_req non-null
+ *
+ * Returns zero on sucess or a negative errno.
+ *
+ * See section 6.3.5 of the CDC 1.1 specification for information
+ * about the only notification we issue: SerialState change.
+ */
+static int acm_cdc_notify(struct f_acm *acm, u8 type, u16 value,
+ void *data, unsigned length)
+{
+ struct usb_ep *ep = acm->notify;
+ struct usb_request *req;
+ struct usb_cdc_notification *notify;
+ const unsigned len = sizeof(*notify) + length;
+ void *buf;
+ int status;
+
+ req = acm->notify_req;
+ acm->notify_req = NULL;
+ acm->pending = false;
+
+ req->length = len;
+ notify = req->buf;
+ buf = notify + 1;
+
+ notify->bmRequestType = USB_DIR_IN | USB_TYPE_CLASS
+ | USB_RECIP_INTERFACE;
+ notify->bNotificationType = type;
+ notify->wValue = cpu_to_le16(value);
+ notify->wIndex = cpu_to_le16(acm->ctrl_id);
+ notify->wLength = cpu_to_le16(length);
+ memcpy(buf, data, length);
+
+ status = usb_ep_queue(ep, req, GFP_ATOMIC);
+ if (status < 0) {
+ ERROR(acm->port.func.config->cdev,
+ "acm ttyGS%d can't notify serial state, %d\n",
+ acm->port_num, status);
+ acm->notify_req = req;
+ }
+
+ return status;
+}
+
+static int acm_notify_serial_state(struct f_acm *acm)
+{
+ struct usb_composite_dev *cdev = acm->port.func.config->cdev;
+ int status;
+
+ spin_lock(&acm->lock);
+ if (acm->notify_req) {
+ DBG(cdev, "acm ttyGS%d serial state %04x\n",
+ acm->port_num, acm->serial_state);
+ status = acm_cdc_notify(acm, USB_CDC_NOTIFY_SERIAL_STATE,
+ 0, &acm->serial_state, sizeof(acm->serial_state));
+ } else {
+ acm->pending = true;
+ status = 0;
+ }
+ spin_unlock(&acm->lock);
+ return status;
+}
+
+static void acm_cdc_notify_complete(struct usb_ep *ep, struct usb_request *req)
+{
+ struct f_acm *acm = req->context;
+ u8 doit = false;
+
+ /* on this call path we do NOT hold the port spinlock,
+ * which is why ACM needs its own spinlock
+ */
+ spin_lock(&acm->lock);
+ if (req->status != -ESHUTDOWN)
+ doit = acm->pending;
+ acm->notify_req = req;
+ spin_unlock(&acm->lock);
+
+ if (doit)
+ acm_notify_serial_state(acm);
+}
+
+/* connect == the TTY link is open */
+
+static void acm_connect(struct gserial *port)
+{
+ struct f_acm *acm = port_to_acm(port);
+
+ acm->serial_state |= ACM_CTRL_DSR | ACM_CTRL_DCD;
+ acm_notify_serial_state(acm);
+}
+
+static void acm_disconnect(struct gserial *port)
+{
+ struct f_acm *acm = port_to_acm(port);
+
+ acm->serial_state &= ~(ACM_CTRL_DSR | ACM_CTRL_DCD);
+ acm_notify_serial_state(acm);
+}
+
+static int acm_send_break(struct gserial *port, int duration)
+{
+ struct f_acm *acm = port_to_acm(port);
+ u16 state;
+
+ state = acm->serial_state;
+ state &= ~ACM_CTRL_BRK;
+ if (duration)
+ state |= ACM_CTRL_BRK;
+
+ acm->serial_state = state;
+ return acm_notify_serial_state(acm);
+}
+
+/*-------------------------------------------------------------------------*/
+
/* ACM function driver setup/binding */
static int __init
acm_bind(struct usb_configuration *c, struct usb_function *f)
@@ -443,8 +593,20 @@
acm->notify = ep;
ep->driver_data = cdev; /* claim */
+ /* allocate notification */
+ acm->notify_req = gs_alloc_req(ep,
+ sizeof(struct usb_cdc_notification) + 2,
+ GFP_KERNEL);
+ if (!acm->notify_req)
+ goto fail;
+
+ acm->notify_req->complete = acm_cdc_notify_complete;
+ acm->notify_req->context = acm;
+
/* copy descriptors, and track endpoint copies */
f->descriptors = usb_copy_descriptors(acm_fs_function);
+ if (!f->descriptors)
+ goto fail;
acm->fs.in = usb_find_endpoint(acm_fs_function,
f->descriptors, &acm_fs_in_desc);
@@ -476,8 +638,6 @@
f->hs_descriptors, &acm_hs_notify_desc);
}
- /* FIXME provide a callback for triggering notifications */
-
DBG(cdev, "acm ttyGS%d: %s speed IN/%s OUT/%s NOTIFY/%s\n",
acm->port_num,
gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
@@ -486,6 +646,9 @@
return 0;
fail:
+ if (acm->notify_req)
+ gs_free_req(acm->notify, acm->notify_req);
+
/* we might as well release our claims on endpoints */
if (acm->notify)
acm->notify->driver_data = NULL;
@@ -502,10 +665,13 @@
static void
acm_unbind(struct usb_configuration *c, struct usb_function *f)
{
+ struct f_acm *acm = func_to_acm(f);
+
if (gadget_is_dualspeed(c->cdev->gadget))
usb_free_descriptors(f->hs_descriptors);
usb_free_descriptors(f->descriptors);
- kfree(func_to_acm(f));
+ gs_free_req(acm->notify, acm->notify_req);
+ kfree(acm);
}
/* Some controllers can't support CDC ACM ... */
@@ -569,8 +735,14 @@
if (!acm)
return -ENOMEM;
+ spin_lock_init(&acm->lock);
+
acm->port_num = port_num;
+ acm->port.connect = acm_connect;
+ acm->port.disconnect = acm_disconnect;
+ acm->port.send_break = acm_send_break;
+
acm->port.func.name = "acm";
acm->port.func.strings = acm_strings;
/* descriptors are per-instance copies */