acm.c

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/*
 * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );

#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <byteswap.h>
#include <ipxe/profile.h>
#include <ipxe/usb.h>
#include <ipxe/usbnet.h>
#include <ipxe/rndis.h>
#include "acm.h"

/** @file
 *
 * USB RNDIS driver
 *
 */

/** Interrupt completion profiler */
static struct profiler acm_intr_profiler __profiler =
        { .name = "acm.intr" };

/** Bulk IN completion profiler */
static struct profiler acm_in_profiler __profiler =
        { .name = "acm.in" };

/** Bulk OUT profiler */
static struct profiler acm_out_profiler __profiler =
        { .name = "acm.out" };

/******************************************************************************
 *
 * USB RNDIS communications interface
 *
 ******************************************************************************
 */

/**
 * Complete interrupt transfer
 *
 * @v ep                USB endpoint
 * @v iobuf             I/O buffer
 * @v rc                Completion status code
 */
static void acm_intr_complete ( struct usb_endpoint *ep,
                                struct io_buffer *iobuf, int rc ) {
        struct acm_device *acm = container_of ( ep, struct acm_device,
                                                usbnet.intr );
        struct rndis_device *rndis = acm->rndis;
        struct usb_setup_packet *message;

        /* Profile completions */
        profile_start ( &acm_intr_profiler );

        /* Ignore packets cancelled when the endpoint closes */
        if ( ! ep->open )
                goto ignore;

        /* Drop packets with errors */
        if ( rc != 0 ) {
                DBGC ( acm, "ACM %p interrupt failed: %s\n",
                       acm, strerror ( rc ) );
                DBGC_HDA ( acm, 0, iobuf->data, iob_len ( iobuf ) );
                goto error;
        }

        /* Extract message header */
        if ( iob_len ( iobuf ) < sizeof ( *message ) ) {
                DBGC ( acm, "ACM %p underlength interrupt:\n", acm );
                DBGC_HDA ( acm, 0, iobuf->data, iob_len ( iobuf ) );
                rc = -EINVAL;
                goto error;
        }
        message = iobuf->data;

        /* Parse message header */
        switch ( message->request ) {

        case cpu_to_le16 ( CDC_RESPONSE_AVAILABLE ) :
        case cpu_to_le16 ( 0x0001 ) : /* qemu seems to use this value */
                acm->responded = 1;
                break;

        default:
                DBGC ( acm, "ACM %p unrecognised interrupt:\n", acm );
                DBGC_HDA ( acm, 0, iobuf->data, iob_len ( iobuf ) );
                rc = -ENOTSUP;
                goto error;
        }

        /* Free I/O buffer */
        free_iob ( iobuf );
        profile_stop ( &acm_intr_profiler );

        return;

 error:
        rndis_rx_err ( rndis, iob_disown ( iobuf ), rc );
 ignore:
        free_iob ( iobuf );
        return;
}

/** Interrupt endpoint operations */
static struct usb_endpoint_driver_operations acm_intr_operations = {
        .complete = acm_intr_complete,
};

/******************************************************************************
 *
 * USB RNDIS data interface
 *
 ******************************************************************************
 */

/**
 * Complete bulk IN transfer
 *
 * @v ep                USB endpoint
 * @v iobuf             I/O buffer
 * @v rc                Completion status code
 */
static void acm_in_complete ( struct usb_endpoint *ep, struct io_buffer *iobuf,
                              int rc ) {
        struct acm_device *acm = container_of ( ep, struct acm_device,
                                                usbnet.in );
        struct rndis_device *rndis = acm->rndis;

        /* Profile receive completions */
        profile_start ( &acm_in_profiler );

        /* Ignore packets cancelled when the endpoint closes */
        if ( ! ep->open )
                goto ignore;

        /* Record USB errors against the RNDIS device */
        if ( rc != 0 ) {
                DBGC ( acm, "ACM %p bulk IN failed: %s\n",
                       acm, strerror ( rc ) );
                goto error;
        }

        /* Hand off to RNDIS */
        rndis_rx ( rndis, iob_disown ( iobuf ) );

        profile_stop ( &acm_in_profiler );
        return;

 error:
        rndis_rx_err ( rndis, iob_disown ( iobuf ), rc );
 ignore:
        free_iob ( iobuf );
}

/** Bulk IN endpoint operations */
static struct usb_endpoint_driver_operations acm_in_operations = {
        .complete = acm_in_complete,
};

/**
 * Transmit packet
 *
 * @v acm               USB RNDIS device
 * @v iobuf             I/O buffer
 * @ret rc              Return status code
 */
static int acm_out_transmit ( struct acm_device *acm,
                              struct io_buffer *iobuf ) {
        int rc;

        /* Profile transmissions */
        profile_start ( &acm_out_profiler );

        /* Enqueue I/O buffer */
        if ( ( rc = usb_stream ( &acm->usbnet.out, iobuf, 0 ) ) != 0 )
                return rc;

        profile_stop ( &acm_out_profiler );
        return 0;
}

/**
 * Complete bulk OUT transfer
 *
 * @v ep                USB endpoint
 * @v iobuf             I/O buffer
 * @v rc                Completion status code
 */
static void acm_out_complete ( struct usb_endpoint *ep, struct io_buffer *iobuf,
                               int rc ) {
        struct acm_device *acm = container_of ( ep, struct acm_device,
                                                usbnet.out );
        struct rndis_device *rndis = acm->rndis;

        /* Report TX completion */
        rndis_tx_complete_err ( rndis, iobuf, rc );
}

/** Bulk OUT endpoint operations */
static struct usb_endpoint_driver_operations acm_out_operations = {
        .complete = acm_out_complete,
};

/******************************************************************************
 *
 * USB RNDIS control interface
 *
 ******************************************************************************
 */

/**
 * Send control packet
 *
 * @v acm               USB RNDIS device
 * @v iobuf             I/O buffer
 * @ret rc              Return status code
 */
static int acm_control_transmit ( struct acm_device *acm,
                                  struct io_buffer *iobuf ) {
        struct rndis_device *rndis = acm->rndis;
        struct usb_device *usb = acm->usb;
        int rc;

        /* Send packet as an encapsulated command */
        if ( ( rc = cdc_send_encapsulated_command ( usb, acm->usbnet.comms,
                                                    iobuf->data,
                                                    iob_len ( iobuf ) ) ) != 0){
                DBGC ( acm, "ACM %p could not send encapsulated command: %s\n",
                       acm, strerror ( rc ) );
                return rc;
        }

        /* Complete packet immediately */
        rndis_tx_complete ( rndis, iobuf );

        return 0;
}

/**
 * Receive control packet
 *
 * @v acm               USB RNDIS device
 * @ret rc              Return status code
 */
static int acm_control_receive ( struct acm_device *acm ) {
        struct rndis_device *rndis = acm->rndis;
        struct usb_device *usb = acm->usb;
        struct io_buffer *iobuf;
        struct rndis_header *header;
        size_t mtu = ACM_RESPONSE_MTU;
        size_t len;
        int rc;

        /* Allocate I/O buffer */
        iobuf = alloc_iob ( mtu );
        if ( ! iobuf ) {
                rc = -ENOMEM;
                goto err_alloc;
        }

        /* Get encapsulated response */
        if ( ( rc = cdc_get_encapsulated_response ( usb, acm->usbnet.comms,
                                                    iobuf->data, mtu ) ) != 0 ){
                DBGC ( acm, "ACM %p could not get encapsulated response: %s\n",
                       acm, strerror ( rc ) );
                goto err_get_response;
        }

        /* Fix up buffer length */
        header = iobuf->data;
        len = le32_to_cpu ( header->len );
        if ( len > mtu ) {
                DBGC ( acm, "ACM %p overlength encapsulated response\n", acm );
                DBGC_HDA ( acm, 0, iobuf->data, mtu );
                rc = -EPROTO;
                goto err_len;
        }
        iob_put ( iobuf, len );

        /* Hand off to RNDIS */
        rndis_rx ( rndis, iob_disown ( iobuf ) );

        return 0;

 err_len:
 err_get_response:
        free_iob ( iobuf );
 err_alloc:
        return rc;
}

/******************************************************************************
 *
 * RNDIS interface
 *
 ******************************************************************************
 */

/**
 * Open RNDIS device
 *
 * @v rndis             RNDIS device
 * @ret rc              Return status code
 */
static int acm_open ( struct rndis_device *rndis ) {
        struct acm_device *acm = rndis->priv;
        int rc;

        /* Open USB network device */
        if ( ( rc = usbnet_open ( &acm->usbnet ) ) != 0 )
                goto err_open;

        return 0;

        usbnet_close ( &acm->usbnet );
 err_open:
        return rc;
}

/**
 * Close RNDIS device
 *
 * @v rndis             RNDIS device
 */
static void acm_close ( struct rndis_device *rndis ) {
        struct acm_device *acm = rndis->priv;

        /* Close USB network device */
        usbnet_close ( &acm->usbnet );
}

/**
 * Transmit packet
 *
 * @v rndis             RNDIS device
 * @v iobuf             I/O buffer
 * @ret rc              Return status code
 */
static int acm_transmit ( struct rndis_device *rndis,
                          struct io_buffer *iobuf ) {
        struct acm_device *acm = rndis->priv;
        struct rndis_header *header = iobuf->data;

        /* Sanity check */
        assert ( iob_len ( iobuf ) >= sizeof ( *header ) );
        assert ( iob_len ( iobuf ) == le32_to_cpu ( header->len ) );

        /* Transmit packet via appropriate mechanism */
        if ( header->type == cpu_to_le32 ( RNDIS_PACKET_MSG ) ) {
                return acm_out_transmit ( acm, iobuf );
        } else {
                return acm_control_transmit ( acm, iobuf );
        }
}

/**
 * Poll for completed and received packets
 *
 * @v rndis             RNDIS device
 */
static void acm_poll ( struct rndis_device *rndis ) {
        struct acm_device *acm = rndis->priv;
        int rc;

        /* Poll USB bus */
        usb_poll ( acm->bus );

        /* Refill rings */
        if ( ( rc = usbnet_refill ( &acm->usbnet ) ) != 0 )
                rndis_rx_err ( rndis, NULL, rc );

        /* Retrieve encapsulated response, if applicable */
        if ( acm->responded ) {

                /* Clear flag */
                acm->responded = 0;

                /* Get encapsulated response */
                if ( ( rc = acm_control_receive ( acm ) ) != 0 )
                        rndis_rx_err ( rndis, NULL, rc );
        }
}

/** USB RNDIS operations */
static struct rndis_operations acm_operations = {
        .open           = acm_open,
        .close          = acm_close,
        .transmit       = acm_transmit,
        .poll           = acm_poll,
};

/******************************************************************************
 *
 * USB interface
 *
 ******************************************************************************
 */

/**
 * Probe device
 *
 * @v func              USB function
 * @v config            Configuration descriptor
 * @ret rc              Return status code
 */
static int acm_probe ( struct usb_function *func,
                       struct usb_configuration_descriptor *config ) {
        struct usb_device *usb = func->usb;
        struct rndis_device *rndis;
        struct acm_device *acm;
        int rc;

        /* Allocate and initialise structure */
        rndis = alloc_rndis ( sizeof ( *acm ) );
        if ( ! rndis ) {
                rc = -ENOMEM;
                goto err_alloc;
        }
        rndis_init ( rndis, &acm_operations );
        rndis->netdev->dev = &func->dev;
        acm = rndis->priv;
        acm->usb = usb;
        acm->bus = usb->port->hub->bus;
        acm->rndis = rndis;
        usbnet_init ( &acm->usbnet, func, &acm_intr_operations,
                      &acm_in_operations, &acm_out_operations );
        usb_refill_init ( &acm->usbnet.intr, 0, 0, ACM_INTR_MAX_FILL );
        usb_refill_init ( &acm->usbnet.in, 0, ACM_IN_MTU, ACM_IN_MAX_FILL );

        /* Describe USB network device */
        if ( ( rc = usbnet_describe ( &acm->usbnet, config ) ) != 0 ) {
                DBGC ( acm, "ACM %p could not describe: %s\n",
                       acm, strerror ( rc ) );
                goto err_describe;
        }

        /* Register RNDIS device */
        if ( ( rc = register_rndis ( rndis ) ) != 0 )
                goto err_register;

        usb_func_set_drvdata ( func, acm );
        return 0;

        unregister_rndis ( rndis );
 err_register:
 err_describe:
        free_rndis ( rndis );
 err_alloc:
        return rc;
}

/**
 * Remove device
 *
 * @v func              USB function
 */
static void acm_remove ( struct usb_function *func ) {
        struct acm_device *acm = usb_func_get_drvdata ( func );
        struct rndis_device *rndis = acm->rndis;

        /* Unregister RNDIS device */
        unregister_rndis ( rndis );

        /* Free RNDIS device */
        free_rndis ( rndis );
}

/** USB CDC-ACM device IDs */
static struct usb_device_id cdc_acm_ids[] = {
        {
                .name = "cdc-acm",
                .vendor = USB_ANY_ID,
                .product = USB_ANY_ID,
        },
};

/** USB CDC-ACM driver */
struct usb_driver cdc_acm_driver __usb_driver = {
        .ids = cdc_acm_ids,
        .id_count = ( sizeof ( cdc_acm_ids ) / sizeof ( cdc_acm_ids[0] ) ),
        .class = USB_CLASS_ID ( USB_CLASS_CDC, USB_SUBCLASS_CDC_ACM,
                                USB_PROTOCOL_ACM_RNDIS ),
        .score = USB_SCORE_DEPRECATED,
        .probe = acm_probe,
        .remove = acm_remove,
};

/** USB RF-RNDIS device IDs */
static struct usb_device_id rf_rndis_ids[] = {
        {
                .name = "rf-rndis",
                .vendor = USB_ANY_ID,
                .product = USB_ANY_ID,
        },
};

/** USB RF-RNDIS driver */
struct usb_driver rf_rndis_driver __usb_driver = {
        .ids = rf_rndis_ids,
        .id_count = ( sizeof ( rf_rndis_ids ) / sizeof ( rf_rndis_ids[0] ) ),
        .class = USB_CLASS_ID ( USB_CLASS_WIRELESS, USB_SUBCLASS_WIRELESS_RADIO,
                                USB_PROTOCOL_RADIO_RNDIS ),
        .score = USB_SCORE_DEPRECATED,
        .probe = acm_probe,
        .remove = acm_remove,
};