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// SPDX-License-Identifier: GPL-2.0+
/*
* 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
*/
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include "u_serial.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 f_gser {
struct gserial port;
u8 data_id;
u8 port_num;
};
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 = {
.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 = {
.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 = {
.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[] = {
(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 = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
};
static struct usb_endpoint_descriptor gser_hs_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
};
static struct usb_descriptor_header *gser_hs_function[] = {
(struct usb_descriptor_header *) &gser_interface_desc,
(struct usb_descriptor_header *) &gser_hs_in_desc,
(struct usb_descriptor_header *) &gser_hs_out_desc,
NULL,
};
static struct usb_endpoint_descriptor gser_ss_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(1024),
};
static struct usb_endpoint_descriptor gser_ss_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(1024),
};
static struct usb_ss_ep_comp_descriptor gser_ss_bulk_comp_desc = {
.bLength = sizeof gser_ss_bulk_comp_desc,
.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
};
static struct usb_descriptor_header *gser_ss_function[] = {
(struct usb_descriptor_header *) &gser_interface_desc,
(struct usb_descriptor_header *) &gser_ss_in_desc,
(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
(struct usb_descriptor_header *) &gser_ss_out_desc,
(struct usb_descriptor_header *) &gser_ss_bulk_comp_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->enabled) {
dev_dbg(&cdev->gadget->dev,
"reset generic ttyGS%d\n", gser->port_num);
gserial_disconnect(&gser->port);
}
if (!gser->port.in->desc || !gser->port.out->desc) {
dev_dbg(&cdev->gadget->dev,
"activate generic ttyGS%d\n", gser->port_num);
if (config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
gser->port.in->desc = NULL;
gser->port.out->desc = NULL;
return -EINVAL;
}
}
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;
dev_dbg(&cdev->gadget->dev,
"generic ttyGS%d deactivated\n", gser->port_num);
gserial_disconnect(&gser->port);
}
/*-------------------------------------------------------------------------*/
/* serial function driver setup/binding */
static int 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;
/* 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 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 = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
if (!ep)
goto fail;
gser->port.out = ep;
/* support all relevant hardware speeds... we expect that when
* hardware is dual speed, all bulk-capable endpoints work at
* both speeds
*/
gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function,
gser_ss_function, NULL);
if (status)
goto fail;
dev_dbg(&cdev->gadget->dev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
gser->port_num,
gadget_is_superspeed(c->cdev->gadget) ? "super" :
gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
gser->port.in->name, gser->port.out->name);
return 0;
fail:
ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
return status;
}
static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
{
return container_of(to_config_group(item), struct f_serial_opts,
func_inst.group);
}
static void serial_attr_release(struct config_item *item)
{
struct f_serial_opts *opts = to_f_serial_opts(item);
usb_put_function_instance(&opts->func_inst);
}
static struct configfs_item_operations serial_item_ops = {
.release = serial_attr_release,
};
static ssize_t f_serial_port_num_show(struct config_item *item, char *page)
{
return sprintf(page, "%u\n", to_f_serial_opts(item)->port_num);
}
CONFIGFS_ATTR_RO(f_serial_, port_num);
static struct configfs_attribute *acm_attrs[] = {
&f_serial_attr_port_num,
NULL,
};
static const struct config_item_type serial_func_type = {
.ct_item_ops = &serial_item_ops,
.ct_attrs = acm_attrs,
.ct_owner = THIS_MODULE,
};
static void gser_free_inst(struct usb_function_instance *f)
{
struct f_serial_opts *opts;
opts = container_of(f, struct f_serial_opts, func_inst);
gserial_free_line(opts->port_num);
kfree(opts);
}
static struct usb_function_instance *gser_alloc_inst(void)
{
struct f_serial_opts *opts;
int ret;
opts = kzalloc(sizeof(*opts), GFP_KERNEL);
if (!opts)
return ERR_PTR(-ENOMEM);
opts->func_inst.free_func_inst = gser_free_inst;
ret = gserial_alloc_line(&opts->port_num);
if (ret) {
kfree(opts);
return ERR_PTR(ret);
}
config_group_init_type_name(&opts->func_inst.group, "",
&serial_func_type);
return &opts->func_inst;
}
static void gser_free(struct usb_function *f)
{
struct f_gser *serial;
serial = func_to_gser(f);
kfree(serial);
}
static void gser_unbind(struct usb_configuration *c, struct usb_function *f)
{
usb_free_all_descriptors(f);
}
static struct usb_function *gser_alloc(struct usb_function_instance *fi)
{
struct f_gser *gser;
struct f_serial_opts *opts;
/* allocate and initialize one new instance */
gser = kzalloc(sizeof(*gser), GFP_KERNEL);
if (!gser)
return ERR_PTR(-ENOMEM);
opts = container_of(fi, struct f_serial_opts, func_inst);
gser->port_num = opts->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;
gser->port.func.free_func = gser_free;
return &gser->port.func;
}
DECLARE_USB_FUNCTION_INIT(gser, gser_alloc_inst, gser_alloc);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Al Borchers");
MODULE_AUTHOR("David Brownell");