[PATCH v3 2/2] usb: gadget: Add CDC ACM function
Pali Rohár
pali at kernel.org
Thu Nov 25 19:10:12 CET 2021
On Thursday 25 November 2021 18:16:15 Loic Poulain wrote:
> Add support for CDC ACM using the new UDC and gadget API. This protocol
> can be used for serial over USB data transfer and is widely supported
> by various OS (GNU/Linux, MS-Windows, OSX...). The usual purpose of
> such link is to access device debug console and can be useful for
> products not exposing regular UART to the user.
>
> A default stdio device named 'usbacm' is created, and can be used
> to redirect console to USB link over CDC ACM:
>
> > setenv stdin usbacm; setenv stdout usbacm
>
> Signed-off-by: Loic Poulain <loic.poulain at linaro.org>
> ---
> v2: - remove possible infinite recursipe print loop
> - Remove acmconsole command, start function along the stdio device
> v3: - Use __constant_cpu_to_le16() when possible
> - Rename stdio dev to 'usbacm'
> - Rename init function to drv_usbacm_init
Hello! Just one question: is in this v3 patch fixed stdout-only
configuration, or it still has a bug which you described in email?
https://lore.kernel.org/u-boot/CAMZdPi8185pAiO4w2QYMtWGAFJiX=eJ_BJW1CusRE990Wr7b_w@mail.gmail.com/
Because neither in above change long nor in driver help description nor
in driver source code is any comment related to stdout-only device.
Note that stdout-only does not have to be too uncommon. For example
Nokia N900 has enabled UART, keyboard+lcd and usbtty by default and
sometimes I enabled input only from keyboard and looked at usbtty
terminal (as stdout-only) if everything is working fine (that every
pressed key on keyboard was echoed correctly back to usbtty).
>
> common/stdio.c | 3 +
> drivers/usb/gadget/Kconfig | 9 +
> drivers/usb/gadget/Makefile | 1 +
> drivers/usb/gadget/f_acm.c | 672 ++++++++++++++++++++++++++++++++++++++++++++
> include/stdio_dev.h | 1 +
> 5 files changed, 686 insertions(+)
> create mode 100644 drivers/usb/gadget/f_acm.c
>
> diff --git a/common/stdio.c b/common/stdio.c
> index 4083e4e..e07e4a4 100644
> --- a/common/stdio.c
> +++ b/common/stdio.c
> @@ -381,6 +381,9 @@ int stdio_add_devices(void)
> #ifdef CONFIG_USB_TTY
> drv_usbtty_init();
> #endif
> +#ifdef CONFIG_USB_FUNCTION_ACM
> + drv_usbacm_init ();
> +#endif
> if (IS_ENABLED(CONFIG_NETCONSOLE))
> drv_nc_init();
> #ifdef CONFIG_JTAG_CONSOLE
> diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
> index 327ea86..d81a9c5 100644
> --- a/drivers/usb/gadget/Kconfig
> +++ b/drivers/usb/gadget/Kconfig
> @@ -182,6 +182,15 @@ config USB_FUNCTION_THOR
> Enable Tizen's THOR download protocol support in U-Boot. It
> allows downloading images into memory and flash them to target device.
>
> +config USB_FUNCTION_ACM
> + bool "Enable CDC ACM gadget"
> + select SYS_STDIO_DEREGISTER
> + select CIRCBUF
> + help
> + ACM serial link. This function can be used to create a stdio device to
> + interoperate with MS-Windows hosts or with the Linux-USB "cdc-acm"
> + driver.
> +
> endif # USB_GADGET_DOWNLOAD
>
> config USB_ETHER
> diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
> index f560068..d5d891b 100644
> --- a/drivers/usb/gadget/Makefile
> +++ b/drivers/usb/gadget/Makefile
> @@ -30,6 +30,7 @@ obj-$(CONFIG_USB_FUNCTION_MASS_STORAGE) += f_mass_storage.o
> obj-$(CONFIG_USB_FUNCTION_FASTBOOT) += f_fastboot.o
> obj-$(CONFIG_USB_FUNCTION_SDP) += f_sdp.o
> obj-$(CONFIG_USB_FUNCTION_ROCKUSB) += f_rockusb.o
> +obj-$(CONFIG_USB_FUNCTION_ACM) += f_acm.o
> endif
> endif
> ifdef CONFIG_USB_ETHER
> diff --git a/drivers/usb/gadget/f_acm.c b/drivers/usb/gadget/f_acm.c
> new file mode 100644
> index 0000000..388f73d
> --- /dev/null
> +++ b/drivers/usb/gadget/f_acm.c
> @@ -0,0 +1,672 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * USB CDC serial (ACM) function driver
> + *
> + * Copyright (C) 2003 Al Borchers (alborchers at steinerpoint.com)
> + * Copyright (C) 2008 by David Brownell
> + * Copyright (C) 2008 by Nokia Corporation
> + * Copyright (C) 2009 by Samsung Electronics
> + * Copyright (c) 2021, Linaro Ltd <loic.poulain at linaro.org>
> + */
> +
> +#include <circbuf.h>
> +#include <common.h>
> +#include <console.h>
> +#include <errno.h>
> +#include <g_dnl.h>
> +#include <malloc.h>
> +#include <memalign.h>
> +#include <stdio_dev.h>
> +#include <version.h>
> +#include <watchdog.h>
> +
> +#include <linux/usb/ch9.h>
> +#include <linux/usb/gadget.h>
> +#include <linux/usb/composite.h>
> +#include <linux/usb/cdc.h>
> +
> +#define REQ_SIZE_MAX 512
> +
> +struct f_acm {
> + int ctrl_id;
> + int data_id;
> +
> + struct usb_ep *ep_in;
> + struct usb_ep *ep_out;
> + struct usb_ep *ep_notify;
> +
> + struct usb_request *req_in;
> + struct usb_request *req_out;
> +
> + bool connected;
> + bool tx_on;
> +
> + circbuf_t rx_buf;
> + circbuf_t tx_buf;
> +
> + struct usb_function usb_function;
> +
> + struct usb_cdc_line_coding line_coding;
> + u16 handshake_bits;
> +#define ACM_CTRL_RTS BIT(1) /* unused with full duplex */
> +#define ACM_CTRL_DTR BIT(0) /* host is ready for data r/w */
> +
> + int controller_index;
> +};
> +
> +static struct f_acm *default_acm_function;
> +
> +static inline struct f_acm *func_to_acm(struct usb_function *f)
> +{
> + return container_of(f, struct f_acm, usb_function);
> +}
> +
> +static inline struct f_acm *stdio_to_acm(struct stdio_dev *s)
> +{
> + /* stdio dev is cloned on registration, do not use container_of */
> + return s->priv;
> +}
> +
> +static struct usb_interface_assoc_descriptor
> +acm_iad_descriptor = {
> + .bLength = sizeof(acm_iad_descriptor),
> + .bDescriptorType = USB_DT_INTERFACE_ASSOCIATION,
> + .bFirstInterface = 0,
> + .bInterfaceCount = 2, // control + data
> + .bFunctionClass = USB_CLASS_COMM,
> + .bFunctionSubClass = USB_CDC_SUBCLASS_ACM,
> + .bFunctionProtocol = USB_CDC_ACM_PROTO_AT_V25TER,
> +};
> +
> +static struct usb_interface_descriptor acm_control_intf_desc = {
> + .bLength = USB_DT_INTERFACE_SIZE,
> + .bDescriptorType = USB_DT_INTERFACE,
> + .bNumEndpoints = 1,
> + .bInterfaceClass = USB_CLASS_COMM,
> + .bInterfaceSubClass = USB_CDC_SUBCLASS_ACM,
> + .bInterfaceProtocol = USB_CDC_ACM_PROTO_AT_V25TER,
> +};
> +
> +static struct usb_interface_descriptor acm_data_intf_desc = {
> + .bLength = sizeof(acm_data_intf_desc),
> + .bDescriptorType = USB_DT_INTERFACE,
> + .bNumEndpoints = 2,
> + .bInterfaceClass = USB_CLASS_CDC_DATA,
> +};
> +
> +static struct usb_cdc_header_desc acm_header_desc = {
> + .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_desc = {
> + .bLength = sizeof(acm_call_mgmt_desc),
> + .bDescriptorType = USB_DT_CS_INTERFACE,
> + .bDescriptorSubType = USB_CDC_CALL_MANAGEMENT_TYPE,
> + .bmCapabilities = 0,
> + .bDataInterface = 0x01,
> +};
> +
> +static struct usb_cdc_acm_descriptor acm_desc = {
> + .bLength = sizeof(acm_desc),
> + .bDescriptorType = USB_DT_CS_INTERFACE,
> + .bDescriptorSubType = USB_CDC_ACM_TYPE,
> + .bmCapabilities = USB_CDC_CAP_LINE,
> +};
> +
> +static struct usb_cdc_union_desc acm_union_desc = {
> + .bLength = sizeof(acm_union_desc),
> + .bDescriptorType = USB_DT_CS_INTERFACE,
> + .bDescriptorSubType = USB_CDC_UNION_TYPE,
> + .bMasterInterface0 = 0x00,
> + .bSlaveInterface0 = 0x01,
> +};
> +
> +static struct usb_endpoint_descriptor acm_fs_notify_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> + .bEndpointAddress = 3 | USB_DIR_IN,
> + .bmAttributes = USB_ENDPOINT_XFER_INT,
> + .wMaxPacketSize = __constant_cpu_to_le16(64),
> + .bInterval = 32,
> +};
> +
> +static struct usb_endpoint_descriptor acm_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 acm_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 *acm_fs_function[] = {
> + (struct usb_descriptor_header *)&acm_iad_descriptor,
> + (struct usb_descriptor_header *)&acm_control_intf_desc,
> + (struct usb_descriptor_header *)&acm_header_desc,
> + (struct usb_descriptor_header *)&acm_call_mgmt_desc,
> + (struct usb_descriptor_header *)&acm_desc,
> + (struct usb_descriptor_header *)&acm_union_desc,
> + (struct usb_descriptor_header *)&acm_fs_notify_desc,
> + (struct usb_descriptor_header *)&acm_data_intf_desc,
> + (struct usb_descriptor_header *)&acm_fs_in_desc,
> + (struct usb_descriptor_header *)&acm_fs_out_desc,
> + NULL,
> +};
> +
> +static struct usb_endpoint_descriptor acm_hs_notify_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> + .bmAttributes = USB_ENDPOINT_XFER_INT,
> + .wMaxPacketSize = __constant_cpu_to_le16(64),
> + .bInterval = 11,
> +};
> +
> +static struct usb_endpoint_descriptor acm_hs_in_desc = {
> + .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 = {
> + .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[] = {
> + (struct usb_descriptor_header *)&acm_iad_descriptor,
> + (struct usb_descriptor_header *)&acm_control_intf_desc,
> + (struct usb_descriptor_header *)&acm_header_desc,
> + (struct usb_descriptor_header *)&acm_call_mgmt_desc,
> + (struct usb_descriptor_header *)&acm_desc,
> + (struct usb_descriptor_header *)&acm_union_desc,
> + (struct usb_descriptor_header *)&acm_hs_notify_desc,
> + (struct usb_descriptor_header *)&acm_data_intf_desc,
> + (struct usb_descriptor_header *)&acm_hs_in_desc,
> + (struct usb_descriptor_header *)&acm_hs_out_desc,
> + NULL,
> +};
> +
> +static inline struct usb_endpoint_descriptor *
> +ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *hs,
> + struct usb_endpoint_descriptor *fs)
> +{
> + if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
> + return hs;
> + return fs;
> +}
> +
> +static int acm_bind(struct usb_configuration *c, struct usb_function *f)
> +{
> + struct usb_gadget *gadget = c->cdev->gadget;
> + struct f_acm *f_acm = func_to_acm(f);
> + struct usb_ep *ep;
> + int id;
> +
> + id = usb_interface_id(c, f);
> + if (id < 0)
> + return id;
> +
> + acm_iad_descriptor.bFirstInterface = id;
> + acm_control_intf_desc.bInterfaceNumber = id;
> + acm_union_desc.bMasterInterface0 = id;
> +
> + f_acm->ctrl_id = id;
> +
> + id = usb_interface_id(c, f);
> + if (id < 0)
> + return id;
> +
> + acm_data_intf_desc.bInterfaceNumber = id;
> + acm_union_desc.bSlaveInterface0 = id;
> + acm_call_mgmt_desc.bDataInterface = id;
> +
> + f_acm->data_id = id;
> +
> + /* allocate instance-specific endpoints */
> + ep = usb_ep_autoconfig(gadget, &acm_fs_in_desc);
> + if (!ep)
> + return -ENODEV;
> +
> + f_acm->ep_in = ep;
> +
> + ep = usb_ep_autoconfig(gadget, &acm_fs_out_desc);
> + if (!ep)
> + return -ENODEV;
> +
> + f_acm->ep_out = ep;
> +
> + ep = usb_ep_autoconfig(gadget, &acm_fs_notify_desc);
> + if (!ep)
> + return -ENODEV;
> +
> + f_acm->ep_notify = ep;
> +
> + if (gadget_is_dualspeed(gadget)) {
> + /* Assume endpoint addresses are the same for both speeds */
> + 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;
> + }
> +
> + return 0;
> +}
> +
> +static void acm_unbind(struct usb_configuration *c, struct usb_function *f)
> +{
> + struct f_acm *f_acm = func_to_acm(f);
> +
> + if (default_acm_function == f_acm)
> + default_acm_function = NULL;
> +
> + buf_free(&f_acm->rx_buf);
> + buf_free(&f_acm->tx_buf);
> +
> + free(f_acm);
> +}
> +
> +static void acm_notify_complete(struct usb_ep *ep, struct usb_request *req)
> +{
> + /* nothing to do */
> +}
> +
> +static void acm_tx_complete(struct usb_ep *ep, struct usb_request *req)
> +{
> + struct f_acm *f_acm = req->context;
> +
> + f_acm->tx_on = true;
> +}
> +
> +static void acm_rx_complete(struct usb_ep *ep, struct usb_request *req)
> +{
> + struct f_acm *f_acm = req->context;
> +
> + buf_push(&f_acm->rx_buf, req->buf, req->actual);
> +
> + /* Queue RX req again */
> + req->actual = 0;
> + usb_ep_queue(ep, req, 0);
> +}
> +
> +static struct usb_request *acm_start_ep(struct usb_ep *ep, void *complete_cb,
> + void *context)
> +{
> + struct usb_request *req;
> +
> + req = usb_ep_alloc_request(ep, 0);
> + if (!req)
> + return NULL;
> +
> + req->length = REQ_SIZE_MAX;
> + req->buf = memalign(CONFIG_SYS_CACHELINE_SIZE, REQ_SIZE_MAX);
> + if (!req->buf) {
> + usb_ep_free_request(ep, req);
> + return NULL;
> + }
> +
> + memset(req->buf, 0, req->length);
> + req->complete = complete_cb;
> + req->context = context;
> +
> + return req;
> +}
> +
> +static int acm_start_data(struct f_acm *f_acm, struct usb_gadget *gadget)
> +{
> + const struct usb_endpoint_descriptor *d;
> + int ret;
> +
> + /* EP IN */
> + d = ep_desc(gadget, &acm_hs_in_desc, &acm_fs_in_desc);
> + ret = usb_ep_enable(f_acm->ep_in, d);
> + if (ret)
> + return ret;
> +
> + f_acm->req_in = acm_start_ep(f_acm->ep_in, acm_tx_complete, f_acm);
> +
> + /* EP OUT */
> + d = ep_desc(gadget, &acm_hs_out_desc, &acm_fs_out_desc);
> + ret = usb_ep_enable(f_acm->ep_out, d);
> + if (ret)
> + return ret;
> +
> + f_acm->req_out = acm_start_ep(f_acm->ep_out, acm_rx_complete, f_acm);
> +
> + /* Start OUT transfer (EP OUT) */
> + ret = usb_ep_queue(f_acm->ep_out, f_acm->req_out, 0);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int acm_start_ctrl(struct f_acm *f_acm, struct usb_gadget *gadget)
> +{
> + const struct usb_endpoint_descriptor *d;
> +
> + usb_ep_disable(f_acm->ep_notify);
> +
> + d = ep_desc(gadget, &acm_hs_notify_desc, &acm_fs_notify_desc);
> + usb_ep_enable(f_acm->ep_notify, d);
> +
> + acm_start_ep(f_acm->ep_notify, acm_notify_complete, f_acm);
> +
> + return 0;
> +}
> +
> +static int acm_set_alt(struct usb_function *f, unsigned int intf, unsigned int alt)
> +{
> + struct usb_gadget *gadget = f->config->cdev->gadget;
> + struct f_acm *f_acm = func_to_acm(f);
> +
> + if (intf == f_acm->ctrl_id) {
> + return acm_start_ctrl(f_acm, gadget);
> + } else if (intf == f_acm->data_id) {
> + acm_start_data(f_acm, gadget);
> + f_acm->connected = true;
> + f_acm->tx_on = true;
> + return 0;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
> +{
> + struct usb_gadget *gadget = f->config->cdev->gadget;
> + struct usb_request *req = f->config->cdev->req;
> + u16 w_index = le16_to_cpu(ctrl->wIndex);
> + u16 w_value = le16_to_cpu(ctrl->wValue);
> + u16 w_length = le16_to_cpu(ctrl->wLength);
> + struct f_acm *f_acm = func_to_acm(f);
> + int value = -1;
> +
> + switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
> + case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
> + | USB_CDC_REQ_SET_LINE_CODING:
> + /* SET_LINE_CODING */
> +
> + if (w_length != sizeof(f_acm->line_coding) || w_index != f_acm->ctrl_id)
> + goto invalid;
> +
> + value = w_length;
> +
> + memcpy(&f_acm->line_coding, req->buf, value);
> +
> + break;
> + case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
> + | USB_CDC_REQ_GET_LINE_CODING:
> + /* GET_LINE_CODING */
> +
> + if (w_length != sizeof(f_acm->line_coding) || w_index != f_acm->ctrl_id)
> + goto invalid;
> +
> + value = w_length;
> +
> + memcpy(req->buf, &f_acm->line_coding, value);
> +
> + break;
> + case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
> + | USB_CDC_REQ_SET_CONTROL_LINE_STATE:
> + /* SET_CONTROL_LINE_STATE */
> +
> + if (w_index != f_acm->ctrl_id)
> + goto invalid;
> +
> + value = 0;
> +
> + f_acm->handshake_bits = w_value;
> +
> + break;
> + default:
> +invalid:
> + printf("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) {
> + req->zero = 0;
> + req->length = value;
> + usb_ep_queue(gadget->ep0, req, GFP_ATOMIC);
> + }
> +
> + return 0;
> +}
> +
> +static void acm_disable(struct usb_function *f)
> +{
> + struct f_acm *f_acm = func_to_acm(f);
> +
> + usb_ep_disable(f_acm->ep_out);
> + usb_ep_disable(f_acm->ep_in);
> + usb_ep_disable(f_acm->ep_notify);
> +
> + if (f_acm->req_out) {
> + free(f_acm->req_out->buf);
> + usb_ep_free_request(f_acm->ep_out, f_acm->req_out);
> + f_acm->req_out = NULL;
> + }
> +
> + if (f_acm->req_in) {
> + free(f_acm->req_in->buf);
> + usb_ep_free_request(f_acm->ep_in, f_acm->req_in);
> + f_acm->req_in = NULL;
> + }
> +}
> +
> +/* static strings, in UTF-8 */
> +static struct usb_string acm_string_defs[] = {
> + [0].s = "CDC Abstract Control Model (ACM)",
> + [1].s = "CDC ACM Data",
> + [2].s = "CDC Serial",
> + { } /* end of 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,
> +};
> +
> +static void __acm_tx(struct f_acm *f_acm)
> +{
> + int len, ret;
> +
> + do {
> + usb_gadget_handle_interrupts(f_acm->controller_index);
> +
> + if (!(f_acm->handshake_bits & ACM_CTRL_DTR))
> + break;
> +
> + if (!f_acm->tx_on)
> + continue;
> +
> + len = buf_pop(&f_acm->tx_buf, f_acm->req_in->buf, REQ_SIZE_MAX);
> + if (!len)
> + break;
> +
> + f_acm->req_in->length = len;
> +
> + ret = usb_ep_queue(f_acm->ep_in, f_acm->req_in, 0);
> + if (ret)
> + break;
> +
> + f_acm->tx_on = false;
> +
> + /* Do not reset the watchdog, if TX is stuck there is probably
> + * a real issue.
> + */
> + } while (1);
> +}
> +
> +static bool acm_connected(struct stdio_dev *dev)
> +{
> + struct f_acm *f_acm = stdio_to_acm(dev);
> +
> + /* give a chance to process udc irq */
> + usb_gadget_handle_interrupts(f_acm->controller_index);
> +
> + return f_acm->connected;
> +}
> +
> +static int acm_add(struct usb_configuration *c)
> +{
> + struct f_acm *f_acm;
> + int status;
> +
> + f_acm = calloc(1, sizeof(*f_acm));
> + if (!f_acm)
> + return -ENOMEM;
> +
> + f_acm->usb_function.name = "f_acm";
> + f_acm->usb_function.bind = acm_bind;
> + f_acm->usb_function.unbind = acm_unbind;
> + f_acm->usb_function.set_alt = acm_set_alt;
> + f_acm->usb_function.disable = acm_disable;
> + f_acm->usb_function.strings = acm_strings;
> + f_acm->usb_function.descriptors = acm_fs_function;
> + f_acm->usb_function.hs_descriptors = acm_hs_function;
> + f_acm->usb_function.setup = acm_setup;
> + f_acm->controller_index = 0;
> +
> + status = usb_add_function(c, &f_acm->usb_function);
> + if (status) {
> + free(f_acm);
> + return status;
> + }
> +
> + buf_init(&f_acm->rx_buf, 2048);
> + buf_init(&f_acm->tx_buf, 2048);
> +
> + if (!default_acm_function)
> + default_acm_function = f_acm;
> +
> + return status;
> +}
> +
> +DECLARE_GADGET_BIND_CALLBACK(usb_serial_acm, acm_add);
> +
> +/* STDIO */
> +static int acm_stdio_tstc(struct stdio_dev *dev)
> +{
> + struct f_acm *f_acm = stdio_to_acm(dev);
> +
> + usb_gadget_handle_interrupts(f_acm->controller_index);
> +
> + return (f_acm->rx_buf.size > 0);
> +}
> +
> +static int acm_stdio_getc(struct stdio_dev *dev)
> +{
> + struct f_acm *f_acm = stdio_to_acm(dev);
> + char c;
> +
> + /* Wait for a character to arrive. */
> + while (!acm_stdio_tstc(dev))
> + WATCHDOG_RESET();
> +
> + buf_pop(&f_acm->rx_buf, &c, 1);
> +
> + return c;
> +}
> +
> +static void acm_stdio_putc(struct stdio_dev *dev, const char c)
> +{
> + struct f_acm *f_acm = stdio_to_acm(dev);
> +
> + if (c == '\n')
> + buf_push(&f_acm->tx_buf, "\r", 1);
> +
> + buf_push(&f_acm->tx_buf, &c, 1);
> +
> + if (!f_acm->connected)
> + return;
> +
> + __acm_tx(f_acm);
> +}
> +
> +static void acm_stdio_puts(struct stdio_dev *dev, const char *str)
> +{
> + struct f_acm *f_acm = stdio_to_acm(dev);
> +
> + while (*str) {
> + if (*str == '\n')
> + buf_push(&f_acm->tx_buf, "\r", 1);
> +
> + buf_push(&f_acm->tx_buf, str++, 1);
> + }
> +
> + if (!f_acm->connected)
> + return;
> +
> + __acm_tx(f_acm);
> +}
> +
> +static int acm_stdio_start(struct stdio_dev *dev)
> +{
> + int ret;
> +
> + if (dev->priv) { /* function already exist */
> + return 0;
> + }
> +
> + ret = g_dnl_register("usb_serial_acm");
> + if (ret)
> + return ret;
> +
> + if (default_acm_function)
> + dev->priv = default_acm_function;
> + else
> + return -ENODEV;
> +
> + while (!acm_connected(dev)) {
> + if (ctrlc())
> + return -ECANCELED;
> +
> + WATCHDOG_RESET();
> + }
> +
> + return 0;
> +}
> +
> +static int acm_stdio_stop(struct stdio_dev *dev)
> +{
> + g_dnl_unregister();
> + g_dnl_clear_detach();
> +
> + return 0;
> +}
> +
> +int drv_usbacm_init(void)
> +{
> + struct stdio_dev stdio;
> +
> + strcpy(stdio.name, "usbacm");
> + stdio.flags = DEV_FLAGS_INPUT | DEV_FLAGS_OUTPUT;
> + stdio.tstc = acm_stdio_tstc;
> + stdio.getc = acm_stdio_getc;
> + stdio.putc = acm_stdio_putc;
> + stdio.puts = acm_stdio_puts;
> + stdio.start = acm_stdio_start;
> + stdio.stop = acm_stdio_stop;
> + stdio.priv = NULL;
> + stdio.ext = 0;
> +
> + return stdio_register(&stdio);
> +}
> diff --git a/include/stdio_dev.h b/include/stdio_dev.h
> index 8fb9a12..270fa27 100644
> --- a/include/stdio_dev.h
> +++ b/include/stdio_dev.h
> @@ -103,6 +103,7 @@ int drv_lcd_init(void);
> int drv_video_init(void);
> int drv_keyboard_init(void);
> int drv_usbtty_init(void);
> +int drv_usbacm_init(void);
> int drv_nc_init(void);
> int drv_jtag_console_init(void);
> int cbmemc_init(void);
> --
> 2.7.4
>
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