1 files changed, 183 insertions, 11 deletions

diff --git a/drivers/usb/gadget/f_acm.c b/drivers/usb/gadget/f_acm.c
index f3bf5612af2d..5ee1590b8e9c 100644
--- a/drivers/usb/gadget/f_acm.c
+++ b/drivers/usb/gadget/f_acm.c
@@ -47,16 +47,37 @@ struct f_acm {
         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 @@ static inline struct f_acm *func_to_acm(struct usb_function *f)
         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 @@ static struct usb_cdc_acm_descriptor acm_descriptor __initdata = {
         .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 @@ static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 
         /* 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 @@ static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
                 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 @@ static int acm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
         /* 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 @@ static void acm_disable(struct usb_function *f)
 
 /*-------------------------------------------------------------------------*/
 
+/**
+ * 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_bind(struct usb_configuration *c, struct usb_function *f)
         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 @@ acm_bind(struct usb_configuration *c, struct usb_function *f)
                                 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 @@ acm_bind(struct usb_configuration *c, struct usb_function *f)
         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 @@ fail:
 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 @@ int __init acm_bind_config(struct usb_configuration *c, u8 port_num)
         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 */