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usb gadget serial: split out CDC ACM function

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Split out CDC ACM parts of "gadget serial" to a "function driver".
Some key structural differences from the previous ACM support, shared
with with the generic serial function (next patch):

 - As a function driver, it can be combined with other functions.
   One gadget configuration could offer both serial and network
   links, as an example.

 - One serial port can be exposed in multiple configurations;
   the /dev/ttyGS0 node could be exposed regardless of which
   config the host selected.

 - One configuration can expose multiple serial ports, such as
   ttyGS0, ttyGS1, ttyGS2, and ttyGS3.

This code should be a lot easier to understand than the previous
all-in-one-big-file version of the driver.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
David Brownell 2008-06-19 18:18:40 -07:00 committed by Greg Kroah-Hartman
parent 097db1d034
commit 4d5a73dc39
4 changed files with 597 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/DocBook/gadget.tmpl
View File

@ -556,6 +556,8 @@ been converted to this framework.
Near-term plans include converting all of them, except for "gadgetfs".
</para>
!Edrivers/usb/gadget/f_acm.c
</sect1>

2
drivers/usb/gadget/Makefile
View File

@ -26,7 +26,7 @@ C_UTILS = composite.o usbstring.o config.o epautoconf.o
g_zero-objs := zero.o f_sourcesink.o f_loopback.o $(C_UTILS)
g_ether-objs := ether.o usbstring.o config.o epautoconf.o
g_serial-objs := serial.o u_serial.o usbstring.o config.o epautoconf.o
g_serial-objs := serial.o u_serial.o f_acm.o $(C_UTILS)
g_midi-objs := gmidi.o usbstring.o config.o epautoconf.o
gadgetfs-objs := inode.o
g_file_storage-objs := file_storage.o usbstring.o config.o \

589
drivers/usb/gadget/f_acm.c Normal file
View File

@ -0,0 +1,589 @@
/*
* f_acm.c -- USB CDC serial (ACM) 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.
*/
/* #define VERBOSE_DEBUG */
#include <linux/kernel.h>
#include <linux/device.h>
#include "u_serial.h"
#include "gadget_chips.h"
/*
* This CDC ACM function support just wraps control functions and
* notifications around the generic serial-over-usb code.
*
* Because CDC ACM is standardized by the USB-IF, many host operating
* systems have drivers for it. Accordingly, ACM is the preferred
* interop solution for serial-port type connections. The control
* models are often not necessary, and in any case don't do much in
* this bare-bones implementation.
*
* Note that even MS-Windows has some support for ACM. However, that
* support is somewhat broken because when you use ACM in a composite
* device, having multiple interfaces confuses the poor OS. It doesn't
* seem to understand CDC Union descriptors. The new "association"
* descriptors (roughly equivalent to CDC Unions) may sometimes help.
*/
struct acm_ep_descs {
struct usb_endpoint_descriptor *in;
struct usb_endpoint_descriptor *out;
struct usb_endpoint_descriptor *notify;
};
struct f_acm {
struct gserial port;
u8 ctrl_id, data_id;
u8 port_num;
struct usb_descriptor_header **fs_function;
struct acm_ep_descs fs;
struct usb_descriptor_header **hs_function;
struct acm_ep_descs hs;
struct usb_ep *notify;
struct usb_endpoint_descriptor *notify_desc;
struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */
u16 port_handshake_bits;
#define RS232_RTS (1 << 1) /* unused with full duplex */
#define RS232_DTR (1 << 0) /* host is ready for data r/w */
};
static inline struct f_acm *func_to_acm(struct usb_function *f)
{
return container_of(f, struct f_acm, port.func);
}
/*-------------------------------------------------------------------------*/
/* notification endpoint uses smallish and infrequent fixed-size messages */
#define GS_LOG2_NOTIFY_INTERVAL 5 /* 1 << 5 == 32 msec */
#define GS_NOTIFY_MAXPACKET 8
/* interface and class descriptors: */
static struct usb_interface_descriptor acm_control_interface_desc __initdata = {
.bLength = USB_DT_INTERFACE_SIZE,
.bDescriptorType = USB_DT_INTERFACE,
/* .bInterfaceNumber = DYNAMIC */
.bNumEndpoints = 1,
.bInterfaceClass = USB_CLASS_COMM,
.bInterfaceSubClass = USB_CDC_SUBCLASS_ACM,
.bInterfaceProtocol = USB_CDC_ACM_PROTO_AT_V25TER,
/* .iInterface = DYNAMIC */
};
static struct usb_interface_descriptor acm_data_interface_desc __initdata = {
.bLength = USB_DT_INTERFACE_SIZE,
.bDescriptorType = USB_DT_INTERFACE,
/* .bInterfaceNumber = DYNAMIC */
.bNumEndpoints = 2,
.bInterfaceClass = USB_CLASS_CDC_DATA,
.bInterfaceSubClass = 0,
.bInterfaceProtocol = 0,
/* .iInterface = DYNAMIC */
};
static struct usb_cdc_header_desc acm_header_desc __initdata = {
.bLength = sizeof(acm_header_desc),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_HEADER_TYPE,
.bcdCDC = __constant_cpu_to_le16(0x0110),
};
static struct usb_cdc_call_mgmt_descriptor
acm_call_mgmt_descriptor __initdata = {
.bLength = sizeof(acm_call_mgmt_descriptor),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_CALL_MANAGEMENT_TYPE,
.bmCapabilities = 0,
/* .bDataInterface = DYNAMIC */
};
static struct usb_cdc_acm_descriptor acm_descriptor __initdata = {
.bLength = sizeof(acm_descriptor),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_ACM_TYPE,
.bmCapabilities = (1 << 1),
};
static struct usb_cdc_union_desc acm_union_desc __initdata = {
.bLength = sizeof(acm_union_desc),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_UNION_TYPE,
/* .bMasterInterface0 = DYNAMIC */
/* .bSlaveInterface0 = DYNAMIC */
};
/* full speed support: */
static struct usb_endpoint_descriptor acm_fs_notify_desc __initdata = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_INT,
.wMaxPacketSize = __constant_cpu_to_le16(GS_NOTIFY_MAXPACKET),
.bInterval = 1 << GS_LOG2_NOTIFY_INTERVAL,
};
static struct usb_endpoint_descriptor acm_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 acm_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 *acm_fs_function[] __initdata = {
(struct usb_descriptor_header *) &acm_control_interface_desc,
(struct usb_descriptor_header *) &acm_header_desc,
(struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
(struct usb_descriptor_header *) &acm_descriptor,
(struct usb_descriptor_header *) &acm_union_desc,
(struct usb_descriptor_header *) &acm_fs_notify_desc,
(struct usb_descriptor_header *) &acm_data_interface_desc,
(struct usb_descriptor_header *) &acm_fs_in_desc,
(struct usb_descriptor_header *) &acm_fs_out_desc,
NULL,
};
/* high speed support: */
static struct usb_endpoint_descriptor acm_hs_notify_desc __initdata = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_INT,
.wMaxPacketSize = __constant_cpu_to_le16(GS_NOTIFY_MAXPACKET),
.bInterval = GS_LOG2_NOTIFY_INTERVAL+4,
};
static struct usb_endpoint_descriptor acm_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 acm_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 *acm_hs_function[] __initdata = {
(struct usb_descriptor_header *) &acm_control_interface_desc,
(struct usb_descriptor_header *) &acm_header_desc,
(struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
(struct usb_descriptor_header *) &acm_descriptor,
(struct usb_descriptor_header *) &acm_union_desc,
(struct usb_descriptor_header *) &acm_hs_notify_desc,
(struct usb_descriptor_header *) &acm_data_interface_desc,
(struct usb_descriptor_header *) &acm_hs_in_desc,
(struct usb_descriptor_header *) &acm_hs_out_desc,
NULL,
};
/* string descriptors: */
#define ACM_CTRL_IDX 0
#define ACM_DATA_IDX 1
/* static strings, in UTF-8 */
static struct usb_string acm_string_defs[] = {
[ACM_CTRL_IDX].s = "CDC Abstract Control Model (ACM)",
[ACM_DATA_IDX].s = "CDC ACM Data",
{ /* ZEROES END LIST */ },
};
static struct usb_gadget_strings acm_string_table = {
.language = 0x0409, /* en-us */
.strings = acm_string_defs,
};
static struct usb_gadget_strings *acm_strings[] = {
&acm_string_table,
NULL,
};
/*-------------------------------------------------------------------------*/
/* ACM control ... data handling is delegated to tty library code.
* The main task of this function is to activate and deactivate
* that code based on device state; track parameters like line
* speed, handshake state, and so on; and issue notifications.
*/
static void acm_complete_set_line_coding(struct usb_ep *ep,
struct usb_request *req)
{
struct f_acm *acm = ep->driver_data;
struct usb_composite_dev *cdev = acm->port.func.config->cdev;
if (req->status != 0) {
DBG(cdev, "acm ttyGS%d completion, err %d\n",
acm->port_num, req->status);
return;
}
/* normal completion */
if (req->actual != sizeof(acm->port_line_coding)) {
DBG(cdev, "acm ttyGS%d short resp, len %d\n",
acm->port_num, req->actual);
usb_ep_set_halt(ep);
} else {
struct usb_cdc_line_coding *value = req->buf;
/* REVISIT: we currently just remember this data.
* If we change that, (a) validate it first, then
* (b) update whatever hardware needs updating,
* (c) worry about locking. This is information on
* the order of 9600-8-N-1 ... most of which means
* nothing unless we control a real RS232 line.
*/
acm->port_line_coding = *value;
}
}
static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
{
struct f_acm *acm = func_to_acm(f);
struct usb_composite_dev *cdev = f->config->cdev;
struct usb_request *req = cdev->req;
int value = -EOPNOTSUPP;
u16 w_index = le16_to_cpu(ctrl->wIndex);
u16 w_value = le16_to_cpu(ctrl->wValue);
u16 w_length = le16_to_cpu(ctrl->wLength);
/* composite driver infrastructure handles everything except
* CDC class messages; interface activation uses set_alt().
*/
switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
/* SET_LINE_CODING ... just read and save what the host sends */
case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
| USB_CDC_REQ_SET_LINE_CODING:
if (w_length != sizeof(struct usb_cdc_line_coding)
|| w_index != acm->ctrl_id)
goto invalid;
value = w_length;
cdev->gadget->ep0->driver_data = acm;
req->complete = acm_complete_set_line_coding;
break;
/* GET_LINE_CODING ... return what host sent, or initial value */
case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
| USB_CDC_REQ_GET_LINE_CODING:
if (w_index != acm->ctrl_id)
goto invalid;
value = min_t(unsigned, w_length,
sizeof(struct usb_cdc_line_coding));
memcpy(req->buf, &acm->port_line_coding, value);
break;
/* SET_CONTROL_LINE_STATE ... save what the host sent */
case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
| USB_CDC_REQ_SET_CONTROL_LINE_STATE:
if (w_index != acm->ctrl_id)
goto invalid;
value = 0;
/* FIXME we should not allow data to flow until the
* host sets the RS232_DTR bit; and when it clears
* that bit, we should return to that no-flow state.
*/
acm->port_handshake_bits = w_value;
break;
default:
invalid:
VDBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
ctrl->bRequestType, ctrl->bRequest,
w_value, w_index, w_length);
}
/* respond with data transfer or status phase? */
if (value >= 0) {
DBG(cdev, "acm ttyGS%d req%02x.%02x v%04x i%04x l%d\n",
acm->port_num, ctrl->bRequestType, ctrl->bRequest,
w_value, w_index, w_length);
req->zero = 0;
req->length = value;
value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
if (value < 0)
ERROR(cdev, "acm response on ttyGS%d, err %d\n",
acm->port_num, value);
}
/* device either stalls (value < 0) or reports success */
return value;
}
static int acm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
struct f_acm *acm = func_to_acm(f);
struct usb_composite_dev *cdev = f->config->cdev;
/* we know alt == 0, so this is an activation or a reset */
if (intf == acm->ctrl_id) {
/* REVISIT this may need more work when we start to
* send notifications ...
*/
if (acm->notify->driver_data) {
VDBG(cdev, "reset acm control interface %d\n", intf);
usb_ep_disable(acm->notify);
} else {
VDBG(cdev, "init acm ctrl interface %d\n", intf);
acm->notify_desc = ep_choose(cdev->gadget,
acm->hs.notify,
acm->fs.notify);
}
usb_ep_enable(acm->notify, acm->notify_desc);
acm->notify->driver_data = acm;
} else if (intf == acm->data_id) {
if (acm->port.in->driver_data) {
DBG(cdev, "reset acm ttyGS%d\n", acm->port_num);
gserial_disconnect(&acm->port);
} else {
DBG(cdev, "activate acm ttyGS%d\n", acm->port_num);
acm->port.in_desc = ep_choose(cdev->gadget,
acm->hs.in, acm->fs.in);
acm->port.out_desc = ep_choose(cdev->gadget,
acm->hs.out, acm->fs.out);
}
gserial_connect(&acm->port, acm->port_num);
} else
return -EINVAL;
return 0;
}
static void acm_disable(struct usb_function *f)
{
struct f_acm *acm = func_to_acm(f);
struct usb_composite_dev *cdev = f->config->cdev;
DBG(cdev, "acm ttyGS%d deactivated\n", acm->port_num);
gserial_disconnect(&acm->port);
usb_ep_disable(acm->notify);
acm->notify->driver_data = NULL;
}
/*-------------------------------------------------------------------------*/
/* ACM function driver setup/binding */
static int __init
acm_bind(struct usb_configuration *c, struct usb_function *f)
{
struct usb_composite_dev *cdev = c->cdev;
struct f_acm *acm = func_to_acm(f);
int status;
struct usb_ep *ep;
/* allocate instance-specific interface IDs, and patch descriptors */
status = usb_interface_id(c, f);
if (status < 0)
goto fail;
acm->ctrl_id = status;
acm_control_interface_desc.bInterfaceNumber = status;
acm_union_desc .bMasterInterface0 = status;
status = usb_interface_id(c, f);
if (status < 0)
goto fail;
acm->data_id = status;
acm_data_interface_desc.bInterfaceNumber = status;
acm_union_desc.bSlaveInterface0 = status;
acm_call_mgmt_descriptor.bDataInterface = status;
status = -ENODEV;
/* allocate instance-specific endpoints */
ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_in_desc);
if (!ep)
goto fail;
acm->port.in = ep;
ep->driver_data = cdev; /* claim */
ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_out_desc);
if (!ep)
goto fail;
acm->port.out = ep;
ep->driver_data = cdev; /* claim */
ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_notify_desc);
if (!ep)
goto fail;
acm->notify = ep;
ep->driver_data = cdev; /* claim */
/* copy descriptors, and track endpoint copies */
f->descriptors = usb_copy_descriptors(acm_fs_function);
acm->fs.in = usb_find_endpoint(acm_fs_function,
f->descriptors, &acm_fs_in_desc);
acm->fs.out = usb_find_endpoint(acm_fs_function,
f->descriptors, &acm_fs_out_desc);
acm->fs.notify = usb_find_endpoint(acm_fs_function,
f->descriptors, &acm_fs_notify_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)) {
acm_hs_in_desc.bEndpointAddress =
acm_fs_in_desc.bEndpointAddress;
acm_hs_out_desc.bEndpointAddress =
acm_fs_out_desc.bEndpointAddress;
acm_hs_notify_desc.bEndpointAddress =
acm_fs_notify_desc.bEndpointAddress;
/* copy descriptors, and track endpoint copies */
f->hs_descriptors = usb_copy_descriptors(acm_hs_function);
acm->hs.in = usb_find_endpoint(acm_hs_function,
f->hs_descriptors, &acm_hs_in_desc);
acm->hs.out = usb_find_endpoint(acm_hs_function,
f->hs_descriptors, &acm_hs_out_desc);
acm->hs.notify = usb_find_endpoint(acm_hs_function,
f->hs_descriptors, &acm_hs_notify_desc);
}
/* FIXME provide a callback for triggering notifications */
DBG(cdev, "acm ttyGS%d: %s speed IN/%s OUT/%s NOTIFY/%s\n",
acm->port_num,
gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
acm->port.in->name, acm->port.out->name,
acm->notify->name);
return 0;
fail:
/* we might as well release our claims on endpoints */
if (acm->notify)
acm->notify->driver_data = NULL;
if (acm->port.out)
acm->port.out->driver_data = NULL;
if (acm->port.in)
acm->port.in->driver_data = NULL;
ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
return status;
}
static void
acm_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_acm(f));
}
/* Some controllers can't support CDC ACM ... */
static inline bool can_support_cdc(struct usb_configuration *c)
{
/* SH3 doesn't support multiple interfaces */
if (gadget_is_sh(c->cdev->gadget))
return false;
/* sa1100 doesn't have a third interrupt endpoint */
if (gadget_is_sa1100(c->cdev->gadget))
return false;
/* everything else is *probably* fine ... */
return true;
}
/**
* acm_bind_config - add a CDC ACM function to a configuration
* @c: the configuration to support the CDC ACM 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 acm_bind_config(struct usb_configuration *c, u8 port_num)
{
struct f_acm *acm;
int status;
if (!can_support_cdc(c))
return -EINVAL;
/* REVISIT might want instance-specific strings to help
* distinguish instances ...
*/
/* maybe allocate device-global string IDs, and patch descriptors */
if (acm_string_defs[ACM_CTRL_IDX].id == 0) {
status = usb_string_id(c->cdev);
if (status < 0)
return status;
acm_string_defs[ACM_CTRL_IDX].id = status;
acm_control_interface_desc.iInterface = status;
status = usb_string_id(c->cdev);
if (status < 0)
return status;
acm_string_defs[ACM_DATA_IDX].id = status;
acm_data_interface_desc.iInterface = status;
}
/* allocate and initialize one new instance */
acm = kzalloc(sizeof *acm, GFP_KERNEL);
if (!acm)
return -ENOMEM;
acm->port_num = port_num;
acm->port.func.name = "acm";
acm->port.func.strings = acm_strings;
/* descriptors are per-instance copies */
acm->port.func.bind = acm_bind;
acm->port.func.unbind = acm_unbind;
acm->port.func.set_alt = acm_set_alt;
acm->port.func.setup = acm_setup;
acm->port.func.disable = acm_disable;
status = usb_add_function(c, &acm->port.func);
if (status)
kfree(acm);
return status;
}

10
drivers/usb/gadget/u_serial.h
View File

@ -12,10 +12,7 @@
#ifndef __U_SERIAL_H
#define __U_SERIAL_H
/* #include <linux/usb/composite.h> */
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/usb/composite.h>
#include <linux/usb/cdc.h>
/*
@ -32,7 +29,7 @@
* REVISIT someday, allow multiplexing several TTYs over these endpoints.
*/
struct gserial {
/* struct usb_function func; */
struct usb_function func;
/* port is managed by gserial_{connect,disconnect} */
struct gs_port *ioport;
@ -59,4 +56,7 @@ void gserial_cleanup(void);
int gserial_connect(struct gserial *, u8 port_num);
void gserial_disconnect(struct gserial *);
/* functions are bound to configurations by a config or gadget driver */
int acm_bind_config(struct usb_configuration *c, u8 port_num);
#endif /* __U_SERIAL_H */