bas_gigaset: suspend support

Add basic suspend/resume support to the bas_gigaset ISDN driver for the
Siemens Gigaset SX255 series of ISDN DECT bases.

Only the USB aspects are handled so far; the ISDN subsystem is not notified in
any way, for lack of information about how to do that.  The driver will refuse
to suspend if a connection is active.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Greg KH <gregkh@suse.de>
Cc: Hansjoerg Lipp <hjlipp@web.de>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 164 insertions, 2 deletions

diff --git a/drivers/isdn/gigaset/bas-gigaset.c b/drivers/isdn/gigaset/bas-gigaset.c
index d60a6510e92b..1c401b3f88e1 100644
--- a/drivers/isdn/gigaset/bas-gigaset.c
+++ b/drivers/isdn/gigaset/bas-gigaset.c
@@ -73,6 +73,14 @@ static int gigaset_probe(struct usb_interface *interface,
 /* Function will be called if the device is unplugged */
 static void gigaset_disconnect(struct usb_interface *interface);
 
+/* functions called before/after suspend */
+static int gigaset_suspend(struct usb_interface *intf, pm_message_t message);
+static int gigaset_resume(struct usb_interface *intf);
+
+/* functions called before/after device reset */
+static int gigaset_pre_reset(struct usb_interface *intf);
+static int gigaset_post_reset(struct usb_interface *intf);
+
 static int atread_submit(struct cardstate *, int);
 static void stopurbs(struct bas_bc_state *);
 static int req_submit(struct bc_state *, int, int, int);
@@ -107,6 +115,7 @@ struct bas_cardstate {
         spinlock_t              lock;           /* locks all following */
         atomic_t                basstate;       /* bitmap (BS_*) */
         int                     pending;        /* uncompleted base request */
+        wait_queue_head_t       waitqueue;
         int                     rcvbuf_size;    /* size of AT receive buffer */
                                                 /* 0: no receive in progress */
         int                     retry_cmd_in;   /* receive req retry count */
@@ -121,6 +130,7 @@ struct bas_cardstate {
 #define BS_ATTIMER      0x020   /* waiting for HD_READY_SEND_ATDATA */
 #define BS_ATRDPEND     0x040   /* urb_cmd_in in use */
 #define BS_ATWRPEND     0x080   /* urb_cmd_out in use */
+#define BS_SUSPEND      0x100   /* USB port suspended */
 
 
 static struct gigaset_driver *driver = NULL;
@@ -132,6 +142,11 @@ static struct usb_driver gigaset_usb_driver = {
         .probe =        gigaset_probe,
         .disconnect =   gigaset_disconnect,
         .id_table =     gigaset_table,
+        .suspend =      gigaset_suspend,
+        .resume =       gigaset_resume,
+        .reset_resume = gigaset_post_reset,
+        .pre_reset =    gigaset_pre_reset,
+        .post_reset =   gigaset_post_reset,
 };
 
 /* get message text for usb_submit_urb return code
@@ -465,6 +480,7 @@ static void read_ctrl_callback(struct urb *urb)
         int rc;
 
         update_basstate(ucs, 0, BS_ATRDPEND);
+        wake_up(&ucs->waitqueue);
 
         if (!ucs->rcvbuf_size) {
                 dev_warn(cs->dev, "%s: no receive in progress\n", __func__);
@@ -551,17 +567,28 @@ static void read_ctrl_callback(struct urb *urb)
 static int atread_submit(struct cardstate *cs, int timeout)
 {
         struct bas_cardstate *ucs = cs->hw.bas;
+        int basstate;
         int ret;
 
         gig_dbg(DEBUG_USBREQ, "-------> HD_READ_ATMESSAGE (%d)",
                 ucs->rcvbuf_size);
 
-        if (update_basstate(ucs, BS_ATRDPEND, 0) & BS_ATRDPEND) {
+        basstate = update_basstate(ucs, BS_ATRDPEND, 0);
+        if (basstate & BS_ATRDPEND) {
                 dev_err(cs->dev,
                         "could not submit HD_READ_ATMESSAGE: URB busy\n");
                 return -EBUSY;
         }
 
+        if (basstate & BS_SUSPEND) {
+                dev_notice(cs->dev,
+                           "HD_READ_ATMESSAGE not submitted, "
+                           "suspend in progress\n");
+                update_basstate(ucs, 0, BS_ATRDPEND);
+                /* treat like disconnect */
+                return -ENODEV;
+        }
+
         ucs->dr_cmd_in.bRequestType = IN_VENDOR_REQ;
         ucs->dr_cmd_in.bRequest = HD_READ_ATMESSAGE;
         ucs->dr_cmd_in.wValue = 0;
@@ -747,6 +774,7 @@ static void read_int_callback(struct urb *urb)
         }
 
         check_pending(ucs);
+        wake_up(&ucs->waitqueue);
 
 resubmit:
         rc = usb_submit_urb(urb, GFP_ATOMIC);
@@ -1416,6 +1444,8 @@ static void req_timeout(unsigned long data)
                 dev_warn(bcs->cs->dev, "request 0x%02x timed out, clearing\n",
                          pending);
         }
+
+        wake_up(&ucs->waitqueue);
 }
 
 /* write_ctrl_callback
@@ -1456,7 +1486,9 @@ static void write_ctrl_callback(struct urb *urb)
                 break;
 
         default:                                /* any failure */
-                if (++ucs->retry_ctrl > BAS_RETRY) {
+                /* don't retry if suspend requested */
+                if (++ucs->retry_ctrl > BAS_RETRY ||
+                    (atomic_read(&ucs->basstate) & BS_SUSPEND)) {
                         dev_err(&ucs->interface->dev,
                                 "control request 0x%02x failed: %s\n",
                                 ucs->dr_ctrl.bRequest,
@@ -1485,6 +1517,7 @@ static void write_ctrl_callback(struct urb *urb)
         del_timer(&ucs->timer_ctrl);
         ucs->pending = 0;
         spin_unlock_irqrestore(&ucs->lock, flags);
+        wake_up(&ucs->waitqueue);
 }
 
 /* req_submit
@@ -1570,6 +1603,14 @@ static int gigaset_init_bchannel(struct bc_state *bcs)
                 return -ENODEV;
         }
 
+        if (atomic_read(&cs->hw.bas->basstate) & BS_SUSPEND) {
+                dev_notice(cs->dev,
+                           "not starting isochronous I/O, "
+                           "suspend in progress\n");
+                spin_unlock_irqrestore(&cs->lock, flags);
+                return -EHOSTUNREACH;
+        }
+
         if ((ret = starturbs(bcs)) < 0) {
                 dev_err(cs->dev,
                         "could not start isochronous I/O for channel B%d: %s\n",
@@ -1682,6 +1723,7 @@ static void write_command_callback(struct urb *urb)
         unsigned long flags;
 
         update_basstate(ucs, 0, BS_ATWRPEND);
+        wake_up(&ucs->waitqueue);
 
         /* check status */
         switch (status) {
@@ -1705,6 +1747,13 @@ static void write_command_callback(struct urb *urb)
                                  ucs->retry_cmd_out);
                         break;
                 }
+                if (atomic_read(&ucs->basstate) & BS_SUSPEND) {
+                        dev_warn(cs->dev,
+                                 "command write: %s, "
+                                 "won't retry - suspend requested\n",
+                                 get_usb_statmsg(status));
+                        break;
+                }
                 if (cs->cmdbuf == NULL) {
                         dev_warn(cs->dev,
                                  "command write: %s, "
@@ -1813,6 +1862,12 @@ static int start_cbsend(struct cardstate *cs)
         int rc;
         int retval = 0;
 
+        /* check if suspend requested */
+        if (atomic_read(&ucs->basstate) & BS_SUSPEND) {
+                gig_dbg(DEBUG_TRANSCMD|DEBUG_LOCKCMD, "suspending");
+                return -EHOSTUNREACH;
+        }
+
         /* check if AT channel is open */
         if (!(atomic_read(&ucs->basstate) & BS_ATOPEN)) {
                 gig_dbg(DEBUG_TRANSCMD|DEBUG_LOCKCMD, "AT channel not open");
@@ -2099,6 +2154,7 @@ static int gigaset_initcshw(struct cardstate *cs)
         init_timer(&ucs->timer_ctrl);
         init_timer(&ucs->timer_atrdy);
         init_timer(&ucs->timer_cmd_in);
+        init_waitqueue_head(&ucs->waitqueue);
 
         return 1;
 }
@@ -2311,6 +2367,112 @@ static void gigaset_disconnect(struct usb_interface *interface)
         gigaset_unassign(cs);
 }
 
+/* gigaset_suspend
+ * This function is called before the USB connection is suspended.
+ */
+static int gigaset_suspend(struct usb_interface *intf, pm_message_t message)
+{
+        struct cardstate *cs = usb_get_intfdata(intf);
+        struct bas_cardstate *ucs = cs->hw.bas;
+        int basstate;
+        int rc;
+
+        /* set suspend flag; this stops AT command/response traffic */
+        if (update_basstate(ucs, BS_SUSPEND, 0) & BS_SUSPEND) {
+                gig_dbg(DEBUG_SUSPEND, "already suspended");
+                return 0;
+        }
+
+        /* wait a bit for blocking conditions to go away */
+        rc = wait_event_timeout(ucs->waitqueue,
+                        !(atomic_read(&ucs->basstate) &
+                          (BS_B1OPEN|BS_B2OPEN|BS_ATRDPEND|BS_ATWRPEND)),
+                        BAS_TIMEOUT*HZ/10);
+        gig_dbg(DEBUG_SUSPEND, "wait_event_timeout() -> %d", rc);
+
+        /* check for conditions preventing suspend */
+        basstate = atomic_read(&ucs->basstate);
+        if (basstate & (BS_B1OPEN|BS_B2OPEN|BS_ATRDPEND|BS_ATWRPEND)) {
+                dev_warn(cs->dev, "cannot suspend:\n");
+                if (basstate & BS_B1OPEN)
+                        dev_warn(cs->dev, " B channel 1 open\n");
+                if (basstate & BS_B2OPEN)
+                        dev_warn(cs->dev, " B channel 2 open\n");
+                if (basstate & BS_ATRDPEND)
+                        dev_warn(cs->dev, " receiving AT reply\n");
+                if (basstate & BS_ATWRPEND)
+                        dev_warn(cs->dev, " sending AT command\n");
+                update_basstate(ucs, 0, BS_SUSPEND);
+                return -EBUSY;
+        }
+
+        /* close AT channel if open */
+        if (basstate & BS_ATOPEN) {
+                gig_dbg(DEBUG_SUSPEND, "closing AT channel");
+                rc = req_submit(cs->bcs, HD_CLOSE_ATCHANNEL, 0, 0);
+                if (rc) {
+                        update_basstate(ucs, 0, BS_SUSPEND);
+                        return rc;
+                }
+                wait_event_timeout(ucs->waitqueue, !ucs->pending,
+                                   BAS_TIMEOUT*HZ/10);
+                /* in case of timeout, proceed anyway */
+        }
+
+        /* kill all URBs and timers that might still be pending */
+        usb_kill_urb(ucs->urb_ctrl);
+        usb_kill_urb(ucs->urb_int_in);
+        del_timer_sync(&ucs->timer_ctrl);
+
+        gig_dbg(DEBUG_SUSPEND, "suspend complete");
+        return 0;
+}
+
+/* gigaset_resume
+ * This function is called after the USB connection has been resumed.
+ */
+static int gigaset_resume(struct usb_interface *intf)
+{
+        struct cardstate *cs = usb_get_intfdata(intf);
+        struct bas_cardstate *ucs = cs->hw.bas;
+        int rc;
+
+        /* resubmit interrupt URB for spontaneous messages from base */
+        rc = usb_submit_urb(ucs->urb_int_in, GFP_KERNEL);
+        if (rc) {
+                dev_err(cs->dev, "could not resubmit interrupt URB: %s\n",
+                        get_usb_rcmsg(rc));
+                return rc;
+        }
+
+        /* clear suspend flag to reallow activity */
+        update_basstate(ucs, 0, BS_SUSPEND);
+
+        gig_dbg(DEBUG_SUSPEND, "resume complete");
+        return 0;
+}
+
+/* gigaset_pre_reset
+ * This function is called before the USB connection is reset.
+ */
+static int gigaset_pre_reset(struct usb_interface *intf)
+{
+        /* handle just like suspend */
+        return gigaset_suspend(intf, PMSG_ON);
+}
+
+/* gigaset_post_reset
+ * This function is called after the USB connection has been reset.
+ */
+static int gigaset_post_reset(struct usb_interface *intf)
+{
+        /* FIXME: send HD_DEVICE_INIT_ACK? */
+
+        /* resume operations */
+        return gigaset_resume(intf);
+}
+
+
 static const struct gigaset_ops gigops = {
         gigaset_write_cmd,
         gigaset_write_room,