usb: gadget: zero: Add support for interrupt EP

Interrupt endpoints behave quite similar to the bulk endpoints with the
difference that the endpoints expect data sending/reception request at
particular intervals till the whole data has not been transmitted.

The interrupt EP support is added to gadget zero. A new alternate setting (=2)
has been added. It has 2 interrupt endpoints. The default parameters are set as:
	bInterval: 1 ms for FS and 8 uFrames (implying 1 ms) for HS/SS
	wMaxPacketSize: 64 bytes for FS and 1024 bytes for HS/SS
However, the same can be overridden through the module parameter interface.

The code is tested for HS and SS on a platform having DWC3 controller.
Signed-off-by: Amit Virdi <amit.virdi@st.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/f_loopback.c

@@ -298,7 +298,8 @@ static void disable_loopback(struct f_loopback *loop)
 	struct usb_composite_dev	*cdev;
 
 	cdev = loop->function.config->cdev;
-	disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL);
+	disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL, NULL,
+			NULL);
 	VDBG(cdev, "%s disabled\n", loop->function.name);
 }
 

drivers/usb/gadget/function/g_zero.h

@@ -10,6 +10,8 @@
 #define GZERO_QLEN		32
 #define GZERO_ISOC_INTERVAL	4
 #define GZERO_ISOC_MAXPACKET	1024
+#define GZERO_INT_INTERVAL	1 /* Default interrupt interval = 1 ms */
+#define GZERO_INT_MAXPACKET	1024
 
 struct usb_zero_options {
 	unsigned pattern;
@@ -17,6 +19,10 @@ struct usb_zero_options {
 	unsigned isoc_maxpacket;
 	unsigned isoc_mult;
 	unsigned isoc_maxburst;
+	unsigned int_interval; /* In ms */
+	unsigned int_maxpacket;
+	unsigned int_mult;
+	unsigned int_maxburst;
 	unsigned bulk_buflen;
 	unsigned qlen;
 };
@@ -28,6 +34,10 @@ struct f_ss_opts {
 	unsigned isoc_maxpacket;
 	unsigned isoc_mult;
 	unsigned isoc_maxburst;
+	unsigned int_interval; /* In ms */
+	unsigned int_maxpacket;
+	unsigned int_mult;
+	unsigned int_maxburst;
 	unsigned bulk_buflen;
 
 	/*
@@ -62,6 +72,7 @@ int lb_modinit(void);
 void free_ep_req(struct usb_ep *ep, struct usb_request *req);
 void disable_endpoints(struct usb_composite_dev *cdev,
 		struct usb_ep *in, struct usb_ep *out,
-		struct usb_ep *iso_in, struct usb_ep *iso_out);
+		struct usb_ep *iso_in, struct usb_ep *iso_out,
+		struct usb_ep *int_in, struct usb_ep *int_out);
 
 #endif /* __G_ZERO_H */

drivers/usb/gadget/legacy/zero.c

@@ -68,6 +68,8 @@ static struct usb_zero_options gzero_options = {
 	.isoc_maxpacket = GZERO_ISOC_MAXPACKET,
 	.bulk_buflen = GZERO_BULK_BUFLEN,
 	.qlen = GZERO_QLEN,
+	.int_interval = GZERO_INT_INTERVAL,
+	.int_maxpacket = GZERO_INT_MAXPACKET,
 };
 
 /*-------------------------------------------------------------------------*/
@@ -266,6 +268,21 @@ module_param_named(isoc_maxburst, gzero_options.isoc_maxburst, uint,
 		S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(isoc_maxburst, "0 - 15 (ss only)");
 
+module_param_named(int_interval, gzero_options.int_interval, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(int_interval, "1 - 16");
+
+module_param_named(int_maxpacket, gzero_options.int_maxpacket, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(int_maxpacket, "0 - 1023 (fs), 0 - 1024 (hs/ss)");
+
+module_param_named(int_mult, gzero_options.int_mult, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(int_mult, "0 - 2 (hs/ss only)");
+
+module_param_named(int_maxburst, gzero_options.int_maxburst, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(int_maxburst, "0 - 15 (ss only)");
+
 static struct usb_function *func_lb;
 static struct usb_function_instance *func_inst_lb;
 
@@ -301,6 +318,10 @@ static int __init zero_bind(struct usb_composite_dev *cdev)
 	ss_opts->isoc_maxpacket = gzero_options.isoc_maxpacket;
 	ss_opts->isoc_mult = gzero_options.isoc_mult;
 	ss_opts->isoc_maxburst = gzero_options.isoc_maxburst;
+	ss_opts->int_interval = gzero_options.int_interval;
+	ss_opts->int_maxpacket = gzero_options.int_maxpacket;
+	ss_opts->int_mult = gzero_options.int_mult;
+	ss_opts->int_maxburst = gzero_options.int_maxburst;
 	ss_opts->bulk_buflen = gzero_options.bulk_buflen;
 
 	func_ss = usb_get_function(func_inst_ss);