usb gadget serial: split out generic serial function

Split out the generic serial support into a "function driver".  This
closely mimics the ACM support, but with a MUCH simpler control model.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 296 insertions, 0 deletions

diff --git a/drivers/usb/gadget/f_serial.c b/drivers/usb/gadget/f_serial.c
new file mode 100644
index 000000000000..1b6bde9aaed5
--- /dev/null
+++ b/drivers/usb/gadget/f_serial.c
@@ -0,0 +1,296 @@
+/*
+ * f_serial.c - generic USB serial function driver
+ *
+ * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
+ * Copyright (C) 2008 by David Brownell
+ * Copyright (C) 2008 by Nokia Corporation
+ *
+ * This software is distributed under the terms of the GNU General
+ * Public License ("GPL") as published by the Free Software Foundation,
+ * either version 2 of that License or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+
+#include "u_serial.h"
+#include "gadget_chips.h"
+
+
+/*
+ * This function packages a simple "generic serial" port with no real
+ * control mechanisms, just raw data transfer over two bulk endpoints.
+ *
+ * Because it's not standardized, this isn't as interoperable as the
+ * CDC ACM driver.  However, for many purposes it's just as functional
+ * if you can arrange appropriate host side drivers.
+ */
+
+struct gser_descs {
+	struct usb_endpoint_descriptor	*in;
+	struct usb_endpoint_descriptor	*out;
+};
+
+struct f_gser {
+	struct gserial			port;
+	u8				data_id;
+	u8				port_num;
+
+	struct usb_descriptor_header	**fs_function;
+	struct gser_descs		fs;
+	struct usb_descriptor_header	**hs_function;
+	struct gser_descs		hs;
+};
+
+static inline struct f_gser *func_to_gser(struct usb_function *f)
+{
+	return container_of(f, struct f_gser, port.func);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* interface descriptor: */
+
+static struct usb_interface_descriptor gser_interface_desc __initdata = {
+	.bLength =		USB_DT_INTERFACE_SIZE,
+	.bDescriptorType =	USB_DT_INTERFACE,
+	/* .bInterfaceNumber = DYNAMIC */
+	.bNumEndpoints =	2,
+	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
+	.bInterfaceSubClass =	0,
+	.bInterfaceProtocol =	0,
+	/* .iInterface = DYNAMIC */
+};
+
+/* full speed support: */
+
+static struct usb_endpoint_descriptor gser_fs_in_desc __initdata = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor gser_fs_out_desc __initdata = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *gser_fs_function[] __initdata = {
+	(struct usb_descriptor_header *) &gser_interface_desc,
+	(struct usb_descriptor_header *) &gser_fs_in_desc,
+	(struct usb_descriptor_header *) &gser_fs_out_desc,
+	NULL,
+};
+
+/* high speed support: */
+
+static struct usb_endpoint_descriptor gser_hs_in_desc __initdata = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	__constant_cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor gser_hs_out_desc __initdata = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	__constant_cpu_to_le16(512),
+};
+
+static struct usb_descriptor_header *gser_hs_function[] __initdata = {
+	(struct usb_descriptor_header *) &gser_interface_desc,
+	(struct usb_descriptor_header *) &gser_hs_in_desc,
+	(struct usb_descriptor_header *) &gser_hs_out_desc,
+	NULL,
+};
+
+/* string descriptors: */
+
+static struct usb_string gser_string_defs[] = {
+	[0].s = "Generic Serial",
+	{  } /* end of list */
+};
+
+static struct usb_gadget_strings gser_string_table = {
+	.language =		0x0409,	/* en-us */
+	.strings =		gser_string_defs,
+};
+
+static struct usb_gadget_strings *gser_strings[] = {
+	&gser_string_table,
+	NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+	struct f_gser		*gser = func_to_gser(f);
+	struct usb_composite_dev *cdev = f->config->cdev;
+
+	/* we know alt == 0, so this is an activation or a reset */
+
+	if (gser->port.in->driver_data) {
+		DBG(cdev, "reset generic ttyGS%d\n", gser->port_num);
+		gserial_disconnect(&gser->port);
+	} else {
+		DBG(cdev, "activate generic ttyGS%d\n", gser->port_num);
+		gser->port.in_desc = ep_choose(cdev->gadget,
+				gser->hs.in, gser->fs.in);
+		gser->port.out_desc = ep_choose(cdev->gadget,
+				gser->hs.out, gser->fs.out);
+	}
+	gserial_connect(&gser->port, gser->port_num);
+	return 0;
+}
+
+static void gser_disable(struct usb_function *f)
+{
+	struct f_gser	*gser = func_to_gser(f);
+	struct usb_composite_dev *cdev = f->config->cdev;
+
+	DBG(cdev, "generic ttyGS%d deactivated\n", gser->port_num);
+	gserial_disconnect(&gser->port);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* serial function driver setup/binding */
+
+static int __init
+gser_bind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct usb_composite_dev *cdev = c->cdev;
+	struct f_gser		*gser = func_to_gser(f);
+	int			status;
+	struct usb_ep		*ep;
+
+	/* allocate instance-specific interface IDs */
+	status = usb_interface_id(c, f);
+	if (status < 0)
+		goto fail;
+	gser->data_id = status;
+	gser_interface_desc.bInterfaceNumber = status;
+
+	status = -ENODEV;
+
+	/* allocate instance-specific endpoints */
+	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
+	if (!ep)
+		goto fail;
+	gser->port.in = ep;
+	ep->driver_data = cdev;	/* claim */
+
+	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
+	if (!ep)
+		goto fail;
+	gser->port.out = ep;
+	ep->driver_data = cdev;	/* claim */
+
+	/* copy descriptors, and track endpoint copies */
+	f->descriptors = usb_copy_descriptors(gser_fs_function);
+
+	gser->fs.in = usb_find_endpoint(gser_fs_function,
+			f->descriptors, &gser_fs_in_desc);
+	gser->fs.out = usb_find_endpoint(gser_fs_function,
+			f->descriptors, &gser_fs_out_desc);
+
+
+	/* support all relevant hardware speeds... we expect that when
+	 * hardware is dual speed, all bulk-capable endpoints work at
+	 * both speeds
+	 */
+	if (gadget_is_dualspeed(c->cdev->gadget)) {
+		gser_hs_in_desc.bEndpointAddress =
+				gser_fs_in_desc.bEndpointAddress;
+		gser_hs_out_desc.bEndpointAddress =
+				gser_fs_out_desc.bEndpointAddress;
+
+		/* copy descriptors, and track endpoint copies */
+		f->hs_descriptors = usb_copy_descriptors(gser_hs_function);
+
+		gser->hs.in = usb_find_endpoint(gser_hs_function,
+				f->hs_descriptors, &gser_hs_in_desc);
+		gser->hs.out = usb_find_endpoint(gser_hs_function,
+				f->hs_descriptors, &gser_hs_out_desc);
+	}
+
+	DBG(cdev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
+			gser->port_num,
+			gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
+			gser->port.in->name, gser->port.out->name);
+	return 0;
+
+fail:
+	/* we might as well release our claims on endpoints */
+	if (gser->port.out)
+		gser->port.out->driver_data = NULL;
+	if (gser->port.in)
+		gser->port.in->driver_data = NULL;
+
+	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
+
+	return status;
+}
+
+static void
+gser_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	if (gadget_is_dualspeed(c->cdev->gadget))
+		usb_free_descriptors(f->hs_descriptors);
+	usb_free_descriptors(f->descriptors);
+	kfree(func_to_gser(f));
+}
+
+/**
+ * gser_bind_config - add a generic serial function to a configuration
+ * @c: the configuration to support the serial instance
+ * @port_num: /dev/ttyGS* port this interface will use
+ * Context: single threaded during gadget setup
+ *
+ * Returns zero on success, else negative errno.
+ *
+ * Caller must have called @gserial_setup() with enough ports to
+ * handle all the ones it binds.  Caller is also responsible
+ * for calling @gserial_cleanup() before module unload.
+ */
+int __init gser_bind_config(struct usb_configuration *c, u8 port_num)
+{
+	struct f_gser	*gser;
+	int		status;
+
+	/* REVISIT might want instance-specific strings to help
+	 * distinguish instances ...
+	 */
+
+	/* maybe allocate device-global string ID */
+	if (gser_string_defs[0].id == 0) {
+		status = usb_string_id(c->cdev);
+		if (status < 0)
+			return status;
+		gser_string_defs[0].id = status;
+	}
+
+	/* allocate and initialize one new instance */
+	gser = kzalloc(sizeof *gser, GFP_KERNEL);
+	if (!gser)
+		return -ENOMEM;
+
+	gser->port_num = port_num;
+
+	gser->port.func.name = "gser";
+	gser->port.func.strings = gser_strings;
+	gser->port.func.bind = gser_bind;
+	gser->port.func.unbind = gser_unbind;
+	gser->port.func.set_alt = gser_set_alt;
+	gser->port.func.disable = gser_disable;
+
+	status = usb_add_function(c, &gser->port.func);
+	if (status)
+		kfree(gser);
+	return status;
+}