usb: gadget: Fix race condition in connect/disconnect

This commit fixes race condition in fast connect/disconnect
of USB cable. This race condition can also be reproduced in
USB composition change. Thus this commit also adds support
for USB composition change for BAMtoBAM compositions.

CRs-fixed: 463705
Change-Id: I21abaff6a64bb405ce2d698605aff8e0050ef8d6
Signed-off-by: Anna Perel <aperel@codeaurora.org>
Signed-off-by: Bar Weiner <bweiner@codeaurora.org>
diff --git a/drivers/usb/gadget/f_mbim.c b/drivers/usb/gadget/f_mbim.c
index aaacd43..4db4b7a 100644
--- a/drivers/usb/gadget/f_mbim.c
+++ b/drivers/usb/gadget/f_mbim.c
@@ -1455,6 +1455,7 @@
 	mbim_union_desc.bSlaveInterface0 = status;
 
 	mbim->bam_port.cdev = cdev;
+	mbim->bam_port.func = &mbim->function;
 
 	status = -ENODEV;
 
@@ -1574,6 +1575,7 @@
 {
 	struct f_mbim	*mbim = func_to_mbim(f);
 
+	bam_data_destroy(mbim->port_num);
 	if (gadget_is_dualspeed(c->cdev->gadget))
 		usb_free_descriptors(f->hs_descriptors);
 	usb_free_descriptors(f->descriptors);
diff --git a/drivers/usb/gadget/f_qc_ecm.c b/drivers/usb/gadget/f_qc_ecm.c
index a6b443f..3db5b51 100644
--- a/drivers/usb/gadget/f_qc_ecm.c
+++ b/drivers/usb/gadget/f_qc_ecm.c
@@ -846,6 +846,7 @@
 
 	DBG(c->cdev, "ecm unbind\n");
 
+	bam_data_destroy(0);
 	if (gadget_is_dualspeed(c->cdev->gadget))
 		usb_free_descriptors(f->hs_descriptors);
 	usb_free_descriptors(f->descriptors);
diff --git a/drivers/usb/gadget/f_qc_rndis.c b/drivers/usb/gadget/f_qc_rndis.c
index 267cf53..c1ab552 100644
--- a/drivers/usb/gadget/f_qc_rndis.c
+++ b/drivers/usb/gadget/f_qc_rndis.c
@@ -725,14 +725,14 @@
 		 */
 		rndis->port.cdc_filter = 0;
 
+		if (rndis_qc_bam_connect(rndis))
+			goto fail;
+
 		DBG(cdev, "RNDIS RX/TX early activation ...\n");
 		net = gether_qc_connect_name(&rndis->port, "rndis0", false);
 		if (IS_ERR(net))
 			return PTR_ERR(net);
 
-		if (rndis_qc_bam_connect(rndis))
-			goto fail;
-
 		rndis_set_param_dev(rndis->config, net,
 				&rndis->port.cdc_filter);
 	} else
@@ -976,6 +976,8 @@
 {
 	struct f_rndis_qc		*rndis = func_to_rndis_qc(f);
 
+	pr_debug("rndis_qc_unbind: free");
+	bam_data_destroy(0);
 	rndis_deregister(rndis->config);
 	rndis_exit();
 
diff --git a/drivers/usb/gadget/u_bam.c b/drivers/usb/gadget/u_bam.c
index b71f903..9dd9978 100644
--- a/drivers/usb/gadget/u_bam.c
+++ b/drivers/usb/gadget/u_bam.c
@@ -778,6 +778,7 @@
 	unsigned long flags;
 
 	if (d->trans == USB_GADGET_XPORT_BAM2BAM) {
+		usb_bam_reset_complete();
 		ret = usb_bam_connect(d->src_connection_idx, &d->src_pipe_idx);
 		if (ret) {
 			pr_err("%s: usb_bam_connect (src) failed: err:%d\n",
@@ -916,7 +917,7 @@
 	msm_hw_bam_disable(1);
 
 	/* Reset BAM */
-	ret = usb_bam_a2_reset();
+	ret = usb_bam_a2_reset(0);
 	if (ret) {
 		pr_err("%s: BAM reset failed %d\n", __func__, ret);
 		goto reenable_eps;
diff --git a/drivers/usb/gadget/u_bam_data.c b/drivers/usb/gadget/u_bam_data.c
index c638164..5c7e52f 100644
--- a/drivers/usb/gadget/u_bam_data.c
+++ b/drivers/usb/gadget/u_bam_data.c
@@ -145,69 +145,24 @@
 	struct bam_data_port	*port = (struct bam_data_port *)param;
 	struct bam_data_ch_info *d;
 	int ret;
-	bool reenable_eps = false;
 
 	d = &port->data_ch;
 
 	pr_debug("%s: reset by peer\n", __func__);
 
-	/* Disable the relevant EPs if currently EPs are enabled */
-	if (port->port_usb && port->port_usb->in &&
-	  port->port_usb->in->driver_data) {
-		usb_ep_disable(port->port_usb->out);
-		usb_ep_disable(port->port_usb->in);
-
-		port->port_usb->in->driver_data = NULL;
-		port->port_usb->out->driver_data = NULL;
-		reenable_eps = true;
-	}
-
 	/* Disable BAM */
 	msm_hw_bam_disable(1);
 
 	/* Reset BAM */
-	ret = usb_bam_a2_reset();
+	ret = usb_bam_a2_reset(0);
 	if (ret) {
 		pr_err("%s: BAM reset failed %d\n", __func__, ret);
-		goto reenable_eps;
+		return ret;
 	}
 
 	/* Enable BAM */
 	msm_hw_bam_disable(0);
 
-reenable_eps:
-	/* Re-Enable the relevant EPs, if EPs were originally enabled */
-	if (reenable_eps) {
-		if (config_ep_by_speed(port->port_usb->cdev->gadget,
-			port->port_usb->func, port->port_usb->in) ||
-		    config_ep_by_speed(port->port_usb->cdev->gadget,
-			port->port_usb->func, port->port_usb->out)) {
-			pr_err("%s: config_ep_by_speed failed", __func__);
-				port->port_usb->in->desc = NULL;
-				port->port_usb->out->desc = NULL;
-				return -EINVAL;
-		}
-		ret = usb_ep_enable(port->port_usb->in);
-		if (ret) {
-			pr_err("%s: usb_ep_enable failed eptype:IN ep:%p",
-				__func__, port->port_usb->in);
-			return ret;
-		}
-		port->port_usb->in->driver_data = port;
-
-		ret = usb_ep_enable(port->port_usb->out);
-		if (ret) {
-			pr_err("%s: usb_ep_enable failed eptype:OUT ep:%p",
-				__func__, port->port_usb->out);
-			port->port_usb->in->driver_data = 0;
-			return ret;
-		}
-		port->port_usb->out->driver_data = port;
-
-		bam_data_start_endless_rx(port);
-		bam_data_start_endless_tx(port);
-	}
-
 	/* Unregister the peer reset callback */
 	usb_bam_register_peer_reset_cb(NULL, NULL);
 
@@ -244,6 +199,7 @@
 	int ret;
 
 	pr_debug("%s: Connect workqueue started", __func__);
+	usb_bam_reset_complete();
 
 	if (d->trans == USB_GADGET_XPORT_BAM2BAM_IPA) {
 		if (d->func_type == USB_FUNC_MBIM) {
@@ -504,6 +460,23 @@
 	return 0;
 }
 
+int bam_data_destroy(unsigned int no_bam2bam_port)
+{
+	struct bam_data_ch_info	*d;
+	struct bam_data_port	*port;
+
+	port = bam2bam_data_ports[no_bam2bam_port];
+	d = &port->data_ch;
+
+	pr_debug("bam_data_destroy: Freeing ports\n");
+	bam2bam_data_port_free(no_bam2bam_port);
+	if (bam_data_wq)
+		destroy_workqueue(bam_data_wq);
+	bam_data_wq = NULL;
+
+	return 0;
+}
+
 int bam_data_setup(unsigned int no_bam2bam_port)
 {
 	int	i;
@@ -516,6 +489,11 @@
 		return -EINVAL;
 	}
 
+	if (bam_data_wq) {
+		pr_debug("bam_data is already setup");
+		return 0;
+	}
+
 	bam_data_wq = alloc_workqueue("k_bam_data",
 				      WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
 	if (!bam_data_wq) {
diff --git a/drivers/usb/gadget/u_bam_data.h b/drivers/usb/gadget/u_bam_data.h
index 5ce678d..61f653a 100644
--- a/drivers/usb/gadget/u_bam_data.h
+++ b/drivers/usb/gadget/u_bam_data.h
@@ -36,6 +36,8 @@
 
 int bam_data_setup(unsigned int no_bam2bam_port);
 
+int bam_data_destroy(unsigned int no_bam2bam_port);
+
 void bam_data_suspend(u8 port_num);
 
 void bam_data_resume(u8 port_num);