xpp: restore backward compat dahdi_registration

This restores a somewhat limited functionality of the "span"
write interface in the SysFS node of the span, broken by the
pinned-spans code.

* PROBLEM: dahdi-linux pinned-spans should work with existing dahdi-tools
  specifically the dahdi_registration tool.

* As a result, we should still be able to control dahdi registration
  order. However, registration is now in complete devices and not spans

* Restored dahdi_autoreg=[0/1] xpp module parameter:
  - It now refers to complete astribanks and not individual spans

* The xpp module sysfs "span" attribute:
  - Implemented write method (for dahdi_registration tool)
  - The first write of [1/0] to this attribute, registers/unregisters
    the complete astribank
  - Further writes are ignored (with DBG messages)

* Also, implemented new xbus_is_registered() function

* Once the new dahdi-tools are merged, we should turn deprecation
  messages from DBG() to NOTICE()

Signed-off-by: Oron Peled <oron.peled@xorcom.com>
Acked-by Tzafrir Cohen <tzafrir.cohen@xorcom.com>

git-svn-id: http://svn.asterisk.org/svn/dahdi/linux/trunk@10334 a0bf4364-ded3-4de4-8d8a-66a801d63aff

drivers/dahdi/xpp/xbus-core.c

@@ -61,6 +61,8 @@ extern int debug;
 static DEF_PARM(uint, command_queue_length, 1000, 0444, "Maximal command queue length");
 static DEF_PARM(uint, poll_timeout, 1000, 0644, "Timeout (in jiffies) waiting for units to reply");
 static DEF_PARM_BOOL(rx_tasklet, 0, 0644, "Use receive tasklets");
+static DEF_PARM_BOOL(dahdi_autoreg, 0, 0644,
+		"Register devices automatically (1) or not (0)");
 
 #ifdef	CONFIG_PROC_FS
 static int xbus_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data);
@@ -870,12 +872,22 @@ err:
 	goto out;
 }
 
-static int xbus_register_dahdi_device(xbus_t *xbus)
+int	xbus_is_registered(xbus_t *xbus)
+{
+	return xbus->ddev && xbus->ddev->dev.parent;
+}
+
+int xbus_register_dahdi_device(xbus_t *xbus)
 {
 	int	i;
 	int	offset = 0;
 
 	XBUS_DBG(DEVICES, xbus, "Entering %s\n", __func__);
+	if (xbus_is_registered(xbus)) {
+		XBUS_ERR(xbus, "Already registered to DAHDI\n");
+		WARN_ON(1);
+		return -EINVAL;
+	}
 	xbus->ddev = dahdi_create_device();
 	/*
 	 * This actually describe the dahdi_spaninfo version 3
@@ -929,7 +941,7 @@ static int xbus_register_dahdi_device(xbus_t *xbus)
 	return 0;
 }
 
-static void xbus_unregister_dahdi_device(xbus_t *xbus)
+void xbus_unregister_dahdi_device(xbus_t *xbus)
 {
 	int i;
 
@@ -1017,6 +1029,7 @@ void xbus_populate(void *data)
 	 */
 	xbus_request_sync(xbus, SYNC_MODE_PLL);
 	elect_syncer("xbus_populate(end)");	/* FIXME: try to do it later */
+	if (dahdi_autoreg)
 		xbus_register_dahdi_device(xbus);
 out:
 	XBUS_DBG(DEVICES, xbus, "Leaving\n");

drivers/dahdi/xpp/xbus-core.h

@@ -343,6 +343,10 @@ int	xpd_device_register(xbus_t *xbus, xpd_t *xpd);
 void	xpd_device_unregister(xpd_t *xpd);
 int	echocancel_xpd(xpd_t *xpd, int on);
 
+int	xbus_is_registered(xbus_t *xbus);
+int	xbus_register_dahdi_device(xbus_t *xbus);
+void	xbus_unregister_dahdi_device(xbus_t *xbus);
+
 int	xpp_driver_init(void);
 void	xpp_driver_exit(void);
 int	xbus_sysfs_transport_create(xbus_t *xbus);

drivers/dahdi/xpp/xbus-sysfs.c

@@ -613,6 +613,48 @@ static DEVICE_ATTR_READER(span_show, dev, buf)
 	return len;
 }
 
+/*
+ * For backward compatibility with old dahdi-tools
+ * Remove after dahdi_registration is upgraded
+ */
+static DEVICE_ATTR_WRITER(span_store, dev, buf, count)
+{
+	xpd_t		*xpd;
+	int		dahdi_reg;
+	int		ret;
+
+	BUG_ON(!dev);
+	xpd = dev_to_xpd(dev);
+	if (!xpd)
+		return -ENODEV;
+	ret = sscanf(buf, "%d", &dahdi_reg);
+	if (ret != 1)
+		return -EINVAL;
+	if (!XBUS_IS(xpd->xbus, READY))
+		return -ENODEV;
+	XPD_DBG(DEVICES, xpd,
+		"%s -- deprecated (should use pinned-spans)\n",
+		(dahdi_reg) ? "register" : "unregister");
+	if (xbus_is_registered(xpd->xbus)) {
+		if (dahdi_reg) {
+			XPD_DBG(DEVICES, xpd,
+				"already registered %s. Ignored.\n",
+				xpd->xbus->busname);
+		} else {
+			xbus_unregister_dahdi_device(xpd->xbus);
+		}
+	} else {
+		if (!dahdi_reg) {
+			XPD_DBG(DEVICES, xpd,
+				"already unregistered %s. Ignored.\n",
+				xpd->xbus->busname);
+		} else {
+			xbus_register_dahdi_device(xpd->xbus);
+		}
+	}
+	return count;
+}
+
 static DEVICE_ATTR_READER(type_show, dev, buf)
 {
 	xpd_t		*xpd;
@@ -695,7 +737,7 @@ static int xpd_match(struct device *dev, struct device_driver *driver)
 static struct device_attribute xpd_dev_attrs[] = {
 	__ATTR(chipregs,	S_IRUGO | S_IWUSR, chipregs_show, chipregs_store),
 	__ATTR(blink,		S_IRUGO | S_IWUSR, blink_show, blink_store),
-        __ATTR_RO(span),
+	__ATTR(span,		S_IRUGO | S_IWUSR, span_show, span_store),
         __ATTR_RO(type),
         __ATTR_RO(offhook),
         __ATTR_RO(timing_priority),