pnic.c

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/**************************************************************************
Etherboot -  BOOTP/TFTP Bootstrap Program
Bochs Pseudo NIC driver for Etherboot
***************************************************************************/

/*
 * 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.
 *
 * See pnic_api.h for an explanation of the Bochs Pseudo NIC.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <stdint.h>
#include <stdio.h>
#include <ipxe/io.h>
#include <errno.h>
#include <ipxe/pci.h>
#include <ipxe/if_ether.h>
#include <ipxe/ethernet.h>
#include <ipxe/iobuf.h>
#include <ipxe/netdevice.h>

#include "pnic_api.h"

struct pnic {
        unsigned short ioaddr;
};

/* 
 * Utility functions: issue a PNIC command, retrieve result.  Use
 * pnic_command_quiet if you don't want failure codes to be
 * automatically printed.  Returns the PNIC status code.
 * 
 * Set output_length to NULL only if you expect to receive exactly
 * output_max_length bytes, otherwise it'll complain that you didn't
 * get enough data (on the assumption that if you not interested in
 * discovering the output length then you're expecting a fixed amount
 * of data).
 */

static uint16_t pnic_command_quiet ( struct pnic *pnic, uint16_t command,
                                     const void *input, uint16_t input_length,
                                     void *output, uint16_t output_max_length,
                                     uint16_t *output_length ) {
        uint16_t status;
        uint16_t _output_length;

        if ( input != NULL ) {
                /* Write input length */
                outw ( input_length, pnic->ioaddr + PNIC_REG_LEN );
                /* Write input data */
                outsb ( pnic->ioaddr + PNIC_REG_DATA, input, input_length );
        }
        /* Write command */
        outw ( command, pnic->ioaddr + PNIC_REG_CMD );
        /* Retrieve status */
        status = inw ( pnic->ioaddr + PNIC_REG_STAT );
        /* Retrieve output length */
        _output_length = inw ( pnic->ioaddr + PNIC_REG_LEN );
        if ( output_length == NULL ) {
                if ( _output_length != output_max_length ) {
                        printf ( "pnic_command %#hx: wrong data length "
                                 "returned (expected %d, got %d)\n", command,
                                 output_max_length, _output_length );
                }
        } else {
                *output_length = _output_length;
        }
        if ( output != NULL ) {
                if ( _output_length > output_max_length ) {
                        printf ( "pnic_command %#hx: output buffer too small "
                                 "(have %d, need %d)\n", command,
                                 output_max_length, _output_length );
                        _output_length = output_max_length;
                }
                /* Retrieve output data */
                insb ( pnic->ioaddr + PNIC_REG_DATA, output, _output_length );
        }
        return status;
}

static uint16_t pnic_command ( struct pnic *pnic, uint16_t command,
                               const void *input, uint16_t input_length,
                               void *output, uint16_t output_max_length,
                               uint16_t *output_length ) {
        uint16_t status = pnic_command_quiet ( pnic, command,
                                               input, input_length,
                                               output, output_max_length,
                                               output_length );
        if ( status == PNIC_STATUS_OK ) return status;
        printf ( "PNIC command %#hx (len %#hx) failed with status %#hx\n",
                 command, input_length, status );
        return status;
}

/* Check API version matches that of NIC */
static int pnic_api_check ( uint16_t api_version ) {
        if ( api_version != PNIC_API_VERSION ) {
                printf ( "Warning: API version mismatch! "
                         "(NIC's is %d.%d, ours is %d.%d)\n",
                         api_version >> 8, api_version & 0xff,
                         PNIC_API_VERSION >> 8, PNIC_API_VERSION & 0xff );
        }
        if ( api_version < PNIC_API_VERSION ) {
                printf ( "** You may need to update your copy of Bochs **\n" );
        }
        return ( api_version == PNIC_API_VERSION );
}

/**************************************************************************
POLL - Wait for a frame
***************************************************************************/
static void pnic_poll ( struct net_device *netdev ) {
        struct pnic *pnic = netdev->priv;
        struct io_buffer *iobuf;
        uint16_t length;
        uint16_t qlen;

        /* Fetch all available packets */
        while ( 1 ) {
                if ( pnic_command ( pnic, PNIC_CMD_RECV_QLEN, NULL, 0,
                                    &qlen, sizeof ( qlen ), NULL )
                     != PNIC_STATUS_OK )
                        return;
                if ( qlen == 0 )
                        return;
                iobuf = alloc_iob ( ETH_FRAME_LEN );
                if ( ! iobuf ) {
                        DBG ( "could not allocate buffer\n" );
                        netdev_rx_err ( netdev, NULL, -ENOMEM );
                        return;
                }
                if ( pnic_command ( pnic, PNIC_CMD_RECV, NULL, 0,
                                    iobuf->data, ETH_FRAME_LEN, &length )
                     != PNIC_STATUS_OK ) {
                        netdev_rx_err ( netdev, iobuf, -EIO );
                        return;
                }
                iob_put ( iobuf, length );
                netdev_rx ( netdev, iobuf );
        }
}

/**************************************************************************
TRANSMIT - Transmit a frame
***************************************************************************/
static int pnic_transmit ( struct net_device *netdev, struct io_buffer *iobuf ) {
        struct pnic *pnic = netdev->priv;

        /* Pad the packet */
        iob_pad ( iobuf, ETH_ZLEN );

        /* Send packet */
        pnic_command ( pnic, PNIC_CMD_XMIT, iobuf->data, iob_len ( iobuf ),
                       NULL, 0, NULL );

        netdev_tx_complete ( netdev, iobuf );
        return 0;
}

/**************************************************************************
OPEN - Open network device
***************************************************************************/
static int pnic_open ( struct net_device *netdev __unused ) {
        /* Nothing to do */
        return 0;
}

/**************************************************************************
CLOSE - Close network device
***************************************************************************/
static void pnic_close ( struct net_device *netdev __unused ) {
        /* Nothing to do */
}

/**************************************************************************
IRQ - Enable/disable interrupts
***************************************************************************/
static void pnic_irq ( struct net_device *netdev, int enable ) {
        struct pnic *pnic = netdev->priv;
        uint8_t mask = ( enable ? 1 : 0 );
        
        pnic_command ( pnic, PNIC_CMD_MASK_IRQ, &mask, sizeof ( mask ),
                       NULL, 0, NULL );
}

/**************************************************************************
OPERATIONS TABLE
***************************************************************************/
static struct net_device_operations pnic_operations = {
        .open           = pnic_open,
        .close          = pnic_close,
        .transmit       = pnic_transmit,
        .poll           = pnic_poll,
        .irq            = pnic_irq,
};

/**************************************************************************
DISABLE - Turn off ethernet interface
***************************************************************************/
static void pnic_remove ( struct pci_device *pci ) {
        struct net_device *netdev = pci_get_drvdata ( pci );
        struct pnic *pnic = netdev->priv;

        unregister_netdev ( netdev );
        pnic_command ( pnic, PNIC_CMD_RESET, NULL, 0, NULL, 0, NULL );
        netdev_nullify ( netdev );
        netdev_put ( netdev );
}

/**************************************************************************
PROBE - Look for an adapter, this routine's visible to the outside
***************************************************************************/
static int pnic_probe ( struct pci_device *pci ) {
        struct net_device *netdev;
        struct pnic *pnic;
        uint16_t api_version;
        uint16_t status;
        int rc;

        /* Allocate net device */
        netdev = alloc_etherdev ( sizeof ( *pnic ) );
        if ( ! netdev )
                return -ENOMEM;
        netdev_init ( netdev, &pnic_operations );
        pnic = netdev->priv;
        pci_set_drvdata ( pci, netdev );
        netdev->dev = &pci->dev;
        pnic->ioaddr = pci->ioaddr;

        /* Fix up PCI device */
        adjust_pci_device ( pci );
        
        /* API version check */
        status = pnic_command_quiet ( pnic, PNIC_CMD_API_VER, NULL, 0,
                                      &api_version,
                                      sizeof ( api_version ), NULL );
        if ( status != PNIC_STATUS_OK ) {
                printf ( "PNIC failed installation check, code %#hx\n",
                         status );
                rc = -EIO;
                goto err;
        }
        pnic_api_check ( api_version );

        /* Get MAC address */
        status = pnic_command ( pnic, PNIC_CMD_READ_MAC, NULL, 0,
                                netdev->hw_addr, ETH_ALEN, NULL );

        /* Register network device */
        if ( ( rc = register_netdev ( netdev ) ) != 0 )
                goto err;

        /* Mark as link up; PNIC has no concept of link state */
        netdev_link_up ( netdev );

        return 0;

 err:
        /* Free net device */
        netdev_nullify ( netdev );
        netdev_put ( netdev );
        return rc;
}

static struct pci_device_id pnic_nics[] = {
/* genrules.pl doesn't let us use macros for PCI IDs...*/
PCI_ROM ( 0xfefe, 0xefef, "pnic", "Bochs Pseudo NIC Adaptor", 0 ),
};

struct pci_driver pnic_driver __pci_driver = {
        .ids = pnic_nics,
        .id_count = ( sizeof ( pnic_nics ) / sizeof ( pnic_nics[0] ) ),
        .probe = pnic_probe,
        .remove = pnic_remove,
};