aoe.c

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/*
 * Copyright (C) 2006 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 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 );

#include <stddef.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <assert.h>
#include <byteswap.h>
#include <ipxe/list.h>
#include <ipxe/if_ether.h>
#include <ipxe/iobuf.h>
#include <ipxe/uaccess.h>
#include <ipxe/netdevice.h>
#include <ipxe/features.h>
#include <ipxe/interface.h>
#include <ipxe/xfer.h>
#include <ipxe/uri.h>
#include <ipxe/open.h>
#include <ipxe/ata.h>
#include <ipxe/device.h>
#include <ipxe/efi/efi_path.h>
#include <ipxe/aoe.h>

/** @file
 *
 * AoE protocol
 *
 */

FEATURE ( FEATURE_PROTOCOL, "AoE", DHCP_EB_FEATURE_AOE, 1 );

struct net_protocol aoe_protocol __net_protocol;
struct acpi_model abft_model __acpi_model;

/******************************************************************************
 *
 * AoE devices and commands
 *
 ******************************************************************************
 */

/** List of all AoE devices */
static LIST_HEAD ( aoe_devices );

/** List of active AoE commands */
static LIST_HEAD ( aoe_commands );

/** An AoE command */
struct aoe_command {
        /** Reference count */
        struct refcnt refcnt;
        /** AOE device */
        struct aoe_device *aoedev;
        /** List of active commands */
        struct list_head list;

        /** ATA command interface */
        struct interface ata;

        /** ATA command */
        struct ata_cmd command;
        /** Command type */
        struct aoe_command_type *type;
        /** Command tag */
        uint32_t tag;

        /** Retransmission timer */
        struct retry_timer timer;
};

/** An AoE command type */
struct aoe_command_type {
        /**
         * Calculate length of AoE command IU
         *
         * @v aoecmd            AoE command
         * @ret len             Length of command IU
         */
        size_t ( * cmd_len ) ( struct aoe_command *aoecmd );
        /**
         * Build AoE command IU
         *
         * @v aoecmd            AoE command
         * @v data              Command IU
         * @v len               Length of command IU
         */
        void ( * cmd ) ( struct aoe_command *aoecmd, void *data, size_t len );
        /**
         * Handle AoE response IU
         *
         * @v aoecmd            AoE command
         * @v data              Response IU
         * @v len               Length of response IU
         * @v ll_source         Link-layer source address
         * @ret rc              Return status code
         */
        int ( * rsp ) ( struct aoe_command *aoecmd, const void *data,
                        size_t len, const void *ll_source );
};

/**
 * Get reference to AoE device
 *
 * @v aoedev            AoE device
 * @ret aoedev          AoE device
 */
static inline __attribute__ (( always_inline )) struct aoe_device *
aoedev_get ( struct aoe_device *aoedev ) {
        ref_get ( &aoedev->refcnt );
        return aoedev;
}

/**
 * Drop reference to AoE device
 *
 * @v aoedev            AoE device
 */
static inline __attribute__ (( always_inline )) void
aoedev_put ( struct aoe_device *aoedev ) {
        ref_put ( &aoedev->refcnt );
}

/**
 * Get reference to AoE command
 *
 * @v aoecmd            AoE command
 * @ret aoecmd          AoE command
 */
static inline __attribute__ (( always_inline )) struct aoe_command *
aoecmd_get ( struct aoe_command *aoecmd ) {
        ref_get ( &aoecmd->refcnt );
        return aoecmd;
}

/**
 * Drop reference to AoE command
 *
 * @v aoecmd            AoE command
 */
static inline __attribute__ (( always_inline )) void
aoecmd_put ( struct aoe_command *aoecmd ) {
        ref_put ( &aoecmd->refcnt );
}

/**
 * Name AoE device
 *
 * @v aoedev            AoE device
 * @ret name            AoE device name
 */
static const char * aoedev_name ( struct aoe_device *aoedev ) {
        static char buf[16];

        snprintf ( buf, sizeof ( buf ), "%s/e%d.%d", aoedev->netdev->name,
                   aoedev->major, aoedev->minor );
        return buf;
}

/**
 * Free AoE command
 *
 * @v refcnt            Reference counter
 */
static void aoecmd_free ( struct refcnt *refcnt ) {
        struct aoe_command *aoecmd =
                container_of ( refcnt, struct aoe_command, refcnt );

        assert ( ! timer_running ( &aoecmd->timer ) );
        assert ( list_empty ( &aoecmd->list ) );

        aoedev_put ( aoecmd->aoedev );
        free ( aoecmd );
}

/**
 * Close AoE command
 *
 * @v aoecmd            AoE command
 * @v rc                Reason for close
 */
static void aoecmd_close ( struct aoe_command *aoecmd, int rc ) {
        struct aoe_device *aoedev = aoecmd->aoedev;

        /* Stop timer */
        stop_timer ( &aoecmd->timer );

        /* Preserve the timeout value for subsequent commands */
        aoedev->timeout = aoecmd->timer.timeout;

        /* Remove from list of commands */
        if ( ! list_empty ( &aoecmd->list ) ) {
                list_del ( &aoecmd->list );
                INIT_LIST_HEAD ( &aoecmd->list );
                aoecmd_put ( aoecmd );
        }

        /* Shut down interfaces */
        intf_shutdown ( &aoecmd->ata, rc );
}

/**
 * Transmit AoE command request
 *
 * @v aoecmd            AoE command
 * @ret rc              Return status code
 */
static int aoecmd_tx ( struct aoe_command *aoecmd ) {
        struct aoe_device *aoedev = aoecmd->aoedev;
        struct net_device *netdev = aoedev->netdev;
        struct io_buffer *iobuf;
        struct aoehdr *aoehdr;
        size_t cmd_len;
        int rc;

        /* Sanity check */
        assert ( netdev != NULL );

        /* If we are transmitting anything that requires a response,
         * start the retransmission timer.  Do this before attempting
         * to allocate the I/O buffer, in case allocation itself
         * fails.
         */
        start_timer ( &aoecmd->timer );

        /* Create outgoing I/O buffer */
        cmd_len = aoecmd->type->cmd_len ( aoecmd );
        iobuf = alloc_iob ( MAX_LL_HEADER_LEN + cmd_len );
        if ( ! iobuf )
                return -ENOMEM;
        iob_reserve ( iobuf, MAX_LL_HEADER_LEN );
        aoehdr = iob_put ( iobuf, cmd_len );

        /* Fill AoE header */
        memset ( aoehdr, 0, sizeof ( *aoehdr ) );
        aoehdr->ver_flags = AOE_VERSION;
        aoehdr->major = htons ( aoedev->major );
        aoehdr->minor = aoedev->minor;
        aoehdr->tag = htonl ( aoecmd->tag );
        aoecmd->type->cmd ( aoecmd, iobuf->data, iob_len ( iobuf ) );

        /* Send packet */
        if ( ( rc = net_tx ( iobuf, netdev, &aoe_protocol, aoedev->target,
                             netdev->ll_addr ) ) != 0 ) {
                DBGC ( aoedev, "AoE %s/%08x could not transmit: %s\n",
                       aoedev_name ( aoedev ), aoecmd->tag,
                       strerror ( rc ) );
                return rc;
        }

        return 0;
}

/**
 * Receive AoE command response
 *
 * @v aoecmd            AoE command
 * @v iobuf             I/O buffer
 * @v ll_source         Link-layer source address
 * @ret rc              Return status code
 */
static int aoecmd_rx ( struct aoe_command *aoecmd, struct io_buffer *iobuf,
                       const void *ll_source ) {
        struct aoe_device *aoedev = aoecmd->aoedev;
        struct aoehdr *aoehdr = iobuf->data;
        int rc;

        /* Sanity check */
        if ( iob_len ( iobuf ) < sizeof ( *aoehdr ) ) {
                DBGC ( aoedev, "AoE %s/%08x received underlength response "
                       "(%zd bytes)\n", aoedev_name ( aoedev ),
                       aoecmd->tag, iob_len ( iobuf ) );
                rc = -EINVAL;
                goto done;
        }
        if ( ( ntohs ( aoehdr->major ) != aoedev->major ) ||
             ( aoehdr->minor != aoedev->minor ) ) {
                DBGC ( aoedev, "AoE %s/%08x received response for incorrect "
                       "device e%d.%d\n", aoedev_name ( aoedev ), aoecmd->tag,
                       ntohs ( aoehdr->major ), aoehdr->minor );
                rc = -EINVAL;
                goto done;
        }

        /* Catch command failures */
        if ( aoehdr->ver_flags & AOE_FL_ERROR ) {
                DBGC ( aoedev, "AoE %s/%08x terminated in error\n",
                       aoedev_name ( aoedev ), aoecmd->tag );
                aoecmd_close ( aoecmd, -EIO );
                rc = -EIO;
                goto done;
        }

        /* Hand off to command completion handler */
        if ( ( rc = aoecmd->type->rsp ( aoecmd, iobuf->data, iob_len ( iobuf ),
                                        ll_source ) ) != 0 )
                goto done;

 done:
        /* Free I/O buffer */
        free_iob ( iobuf );

        /* Terminate command */
        aoecmd_close ( aoecmd, rc );

        return rc;
}

/**
 * Handle AoE retry timer expiry
 *
 * @v timer             AoE retry timer
 * @v fail              Failure indicator
 */
static void aoecmd_expired ( struct retry_timer *timer, int fail ) {
        struct aoe_command *aoecmd =
                container_of ( timer, struct aoe_command, timer );

        if ( fail ) {
                aoecmd_close ( aoecmd, -ETIMEDOUT );
        } else {
                aoecmd_tx ( aoecmd );
        }
}

/**
 * Calculate length of AoE ATA command IU
 *
 * @v aoecmd            AoE command
 * @ret len             Length of command IU
 */
static size_t aoecmd_ata_cmd_len ( struct aoe_command *aoecmd ) {
        struct ata_cmd *command = &aoecmd->command;

        return ( sizeof ( struct aoehdr ) + sizeof ( struct aoeata ) +
                 command->data_out_len );
}

/**
 * Build AoE ATA command IU
 *
 * @v aoecmd            AoE command
 * @v data              Command IU
 * @v len               Length of command IU
 */
static void aoecmd_ata_cmd ( struct aoe_command *aoecmd,
                             void *data, size_t len ) {
        struct aoe_device *aoedev = aoecmd->aoedev;
        struct ata_cmd *command = &aoecmd->command;
        struct aoehdr *aoehdr = data;
        struct aoeata *aoeata = &aoehdr->payload[0].ata;

        /* Sanity check */
        static_assert ( AOE_FL_DEV_HEAD == ATA_DEV_SLAVE );
        assert ( len == ( sizeof ( *aoehdr ) + sizeof ( *aoeata ) +
                          command->data_out_len ) );

        /* Build IU */
        aoehdr->command = AOE_CMD_ATA;
        memset ( aoeata, 0, sizeof ( *aoeata ) );
        aoeata->aflags = ( ( command->cb.lba48 ? AOE_FL_EXTENDED : 0 ) |
                           ( command->cb.device & ATA_DEV_SLAVE ) |
                           ( command->data_out_len ? AOE_FL_WRITE : 0 ) );
        aoeata->err_feat = command->cb.err_feat.bytes.cur;
        aoeata->count = command->cb.count.native;
        aoeata->cmd_stat = command->cb.cmd_stat;
        aoeata->lba.u64 = cpu_to_le64 ( command->cb.lba.native );
        if ( ! command->cb.lba48 )
                aoeata->lba.bytes[3] |=
                        ( command->cb.device & ATA_DEV_MASK );
        copy_from_user ( aoeata->data, command->data_out, 0,
                         command->data_out_len );

        DBGC2 ( aoedev, "AoE %s/%08x ATA cmd %02x:%02x:%02x:%02x:%08llx",
                aoedev_name ( aoedev ), aoecmd->tag, aoeata->aflags,
                aoeata->err_feat, aoeata->count, aoeata->cmd_stat,
                aoeata->lba.u64 );
        if ( command->data_out_len )
                DBGC2 ( aoedev, " out %04zx", command->data_out_len );
        if ( command->data_in_len )
                DBGC2 ( aoedev, " in %04zx", command->data_in_len );
        DBGC2 ( aoedev, "\n" );
}

/**
 * Handle AoE ATA response IU
 *
 * @v aoecmd            AoE command
 * @v data              Response IU
 * @v len               Length of response IU
 * @v ll_source         Link-layer source address
 * @ret rc              Return status code
 */
static int aoecmd_ata_rsp ( struct aoe_command *aoecmd, const void *data,
                            size_t len, const void *ll_source __unused ) {
        struct aoe_device *aoedev = aoecmd->aoedev;
        struct ata_cmd *command = &aoecmd->command;
        const struct aoehdr *aoehdr = data;
        const struct aoeata *aoeata = &aoehdr->payload[0].ata;
        size_t data_len;

        /* Sanity check */
        if ( len < ( sizeof ( *aoehdr ) + sizeof ( *aoeata ) ) ) {
                DBGC ( aoedev, "AoE %s/%08x received underlength ATA response "
                       "(%zd bytes)\n", aoedev_name ( aoedev ),
                       aoecmd->tag, len );
                return -EINVAL;
        }
        data_len = ( len - ( sizeof ( *aoehdr ) + sizeof ( *aoeata ) ) );
        DBGC2 ( aoedev, "AoE %s/%08x ATA rsp %02x in %04zx\n",
                aoedev_name ( aoedev ), aoecmd->tag, aoeata->cmd_stat,
                data_len );

        /* Check for command failure */
        if ( aoeata->cmd_stat & ATA_STAT_ERR ) {
                DBGC ( aoedev, "AoE %s/%08x status %02x\n",
                       aoedev_name ( aoedev ), aoecmd->tag, aoeata->cmd_stat );
                return -EIO;
        }

        /* Check data-in length is sufficient.  (There may be trailing
         * garbage due to Ethernet minimum-frame-size padding.)
         */
        if ( data_len < command->data_in_len ) {
                DBGC ( aoedev, "AoE %s/%08x data-in underrun (received %zd, "
                       "expected %zd)\n", aoedev_name ( aoedev ), aoecmd->tag,
                       data_len, command->data_in_len );
                return -ERANGE;
        }

        /* Copy out data payload */
        copy_to_user ( command->data_in, 0, aoeata->data,
                       command->data_in_len );

        return 0;
}

/** AoE ATA command */
static struct aoe_command_type aoecmd_ata = {
        .cmd_len = aoecmd_ata_cmd_len,
        .cmd = aoecmd_ata_cmd,
        .rsp = aoecmd_ata_rsp,
};

/**
 * Calculate length of AoE configuration command IU
 *
 * @v aoecmd            AoE command
 * @ret len             Length of command IU
 */
static size_t aoecmd_cfg_cmd_len ( struct aoe_command *aoecmd __unused ) {
        return ( sizeof ( struct aoehdr ) + sizeof ( struct aoecfg ) );
}

/**
 * Build AoE configuration command IU
 *
 * @v aoecmd            AoE command
 * @v data              Command IU
 * @v len               Length of command IU
 */
static void aoecmd_cfg_cmd ( struct aoe_command *aoecmd,
                             void *data, size_t len ) {
        struct aoe_device *aoedev = aoecmd->aoedev;
        struct aoehdr *aoehdr = data;
        struct aoecfg *aoecfg = &aoehdr->payload[0].cfg;

        /* Sanity check */
        assert ( len == ( sizeof ( *aoehdr ) + sizeof ( *aoecfg ) ) );

        /* Build IU */
        aoehdr->command = AOE_CMD_CONFIG;
        memset ( aoecfg, 0, sizeof ( *aoecfg ) );

        DBGC ( aoedev, "AoE %s/%08x CONFIG cmd\n",
               aoedev_name ( aoedev ), aoecmd->tag );
}

/**
 * Handle AoE configuration response IU
 *
 * @v aoecmd            AoE command
 * @v data              Response IU
 * @v len               Length of response IU
 * @v ll_source         Link-layer source address
 * @ret rc              Return status code
 */
static int aoecmd_cfg_rsp ( struct aoe_command *aoecmd, const void *data,
                            size_t len, const void *ll_source ) {
        struct aoe_device *aoedev = aoecmd->aoedev;
        struct ll_protocol *ll_protocol = aoedev->netdev->ll_protocol;
        const struct aoehdr *aoehdr = data;
        const struct aoecfg *aoecfg = &aoehdr->payload[0].cfg;

        /* Sanity check */
        if ( len < ( sizeof ( *aoehdr ) + sizeof ( *aoecfg ) ) ) {
                DBGC ( aoedev, "AoE %s/%08x received underlength "
                       "configuration response (%zd bytes)\n",
                       aoedev_name ( aoedev ), aoecmd->tag, len );
                return -EINVAL;
        }
        DBGC ( aoedev, "AoE %s/%08x CONFIG rsp buf %04x fw %04x scnt %02x\n",
               aoedev_name ( aoedev ), aoecmd->tag, ntohs ( aoecfg->bufcnt ),
               aoecfg->fwver, aoecfg->scnt );

        /* Record target MAC address */
        memcpy ( aoedev->target, ll_source, ll_protocol->ll_addr_len );
        DBGC ( aoedev, "AoE %s has MAC address %s\n",
               aoedev_name ( aoedev ), ll_protocol->ntoa ( aoedev->target ) );

        return 0;
}

/** AoE configuration command */
static struct aoe_command_type aoecmd_cfg = {
        .cmd_len = aoecmd_cfg_cmd_len,
        .cmd = aoecmd_cfg_cmd,
        .rsp = aoecmd_cfg_rsp,
};

/** AoE command ATA interface operations */
static struct interface_operation aoecmd_ata_op[] = {
        INTF_OP ( intf_close, struct aoe_command *, aoecmd_close ),
};

/** AoE command ATA interface descriptor */
static struct interface_descriptor aoecmd_ata_desc =
        INTF_DESC ( struct aoe_command, ata, aoecmd_ata_op );

/**
 * Identify AoE command by tag
 *
 * @v tag               Command tag
 * @ret aoecmd          AoE command, or NULL
 */
static struct aoe_command * aoecmd_find_tag ( uint32_t tag ) {
        struct aoe_command *aoecmd;

        list_for_each_entry ( aoecmd, &aoe_commands, list ) {
                if ( aoecmd->tag == tag )
                        return aoecmd;
        }
        return NULL;
}

/**
 * Choose an AoE command tag
 *
 * @ret tag             New tag, or negative error
 */
static int aoecmd_new_tag ( void ) {
        static uint16_t tag_idx;
        unsigned int i;

        for ( i = 0 ; i < 65536 ; i++ ) {
                tag_idx++;
                if ( aoecmd_find_tag ( tag_idx ) == NULL )
                        return ( AOE_TAG_MAGIC | tag_idx );
        }
        return -EADDRINUSE;
}

/**
 * Create AoE command
 *
 * @v aoedev            AoE device
 * @v type              AoE command type
 * @ret aoecmd          AoE command
 */
static struct aoe_command * aoecmd_create ( struct aoe_device *aoedev,
                                            struct aoe_command_type *type ) {
        struct aoe_command *aoecmd;
        int tag;

        /* Allocate command tag */
        tag = aoecmd_new_tag();
        if ( tag < 0 )
                return NULL;

        /* Allocate and initialise structure */
        aoecmd = zalloc ( sizeof ( *aoecmd ) );
        if ( ! aoecmd )
                return NULL;
        ref_init ( &aoecmd->refcnt, aoecmd_free );
        list_add ( &aoecmd->list, &aoe_commands );
        intf_init ( &aoecmd->ata, &aoecmd_ata_desc, &aoecmd->refcnt );
        timer_init ( &aoecmd->timer, aoecmd_expired, &aoecmd->refcnt );
        aoecmd->aoedev = aoedev_get ( aoedev );
        aoecmd->type = type;
        aoecmd->tag = tag;

        /* Preserve timeout from last completed command */
        aoecmd->timer.timeout = aoedev->timeout;

        /* Return already mortalised.  (Reference is held by command list.) */
        return aoecmd;
}

/**
 * Issue AoE ATA command
 *
 * @v aoedev            AoE device
 * @v parent            Parent interface
 * @v command           ATA command
 * @ret tag             Command tag, or negative error
 */
static int aoedev_ata_command ( struct aoe_device *aoedev,
                                struct interface *parent,
                                struct ata_cmd *command ) {
        struct net_device *netdev = aoedev->netdev;
        struct aoe_command *aoecmd;

        /* Fail immediately if net device is closed */
        if ( ! netdev_is_open ( netdev ) ) {
                DBGC ( aoedev, "AoE %s cannot issue command while net device "
                       "is closed\n", aoedev_name ( aoedev ) );
                return -EWOULDBLOCK;
        }

        /* Create command */
        aoecmd = aoecmd_create ( aoedev, &aoecmd_ata );
        if ( ! aoecmd )
                return -ENOMEM;
        memcpy ( &aoecmd->command, command, sizeof ( aoecmd->command ) );

        /* Attempt to send command.  Allow failures to be handled by
         * the retry timer.
         */
        aoecmd_tx ( aoecmd );

        /* Attach to parent interface, leave reference with command
         * list, and return.
         */
        intf_plug_plug ( &aoecmd->ata, parent );
        return aoecmd->tag;
}

/**
 * Issue AoE configuration command
 *
 * @v aoedev            AoE device
 * @v parent            Parent interface
 * @ret tag             Command tag, or negative error
 */
static int aoedev_cfg_command ( struct aoe_device *aoedev,
                                struct interface *parent ) {
        struct aoe_command *aoecmd;

        /* Create command */
        aoecmd = aoecmd_create ( aoedev, &aoecmd_cfg );
        if ( ! aoecmd )
                return -ENOMEM;

        /* Attempt to send command.  Allow failures to be handled by
         * the retry timer.
         */
        aoecmd_tx ( aoecmd );

        /* Attach to parent interface, leave reference with command
         * list, and return.
         */
        intf_plug_plug ( &aoecmd->ata, parent );
        return aoecmd->tag;
}

/**
 * Free AoE device
 *
 * @v refcnt            Reference count
 */
static void aoedev_free ( struct refcnt *refcnt ) {
        struct aoe_device *aoedev =
                container_of ( refcnt, struct aoe_device, refcnt );

        netdev_put ( aoedev->netdev );
        free ( aoedev );
}

/**
 * Close AoE device
 *
 * @v aoedev            AoE device
 * @v rc                Reason for close
 */
static void aoedev_close ( struct aoe_device *aoedev, int rc ) {
        struct aoe_command *aoecmd;
        struct aoe_command *tmp;

        /* Shut down interfaces */
        intf_shutdown ( &aoedev->ata, rc );
        intf_shutdown ( &aoedev->config, rc );

        /* Shut down any active commands */
        list_for_each_entry_safe ( aoecmd, tmp, &aoe_commands, list ) {
                if ( aoecmd->aoedev != aoedev )
                        continue;
                aoecmd_get ( aoecmd );
                aoecmd_close ( aoecmd, rc );
                aoecmd_put ( aoecmd );
        }
}

/**
 * Check AoE device flow-control window
 *
 * @v aoedev            AoE device
 * @ret len             Length of window
 */
static size_t aoedev_window ( struct aoe_device *aoedev ) {
        return ( aoedev->configured ? ~( ( size_t ) 0 ) : 0 );
}

/**
 * Handle AoE device configuration completion
 *
 * @v aoedev            AoE device
 * @v rc                Reason for completion
 */
static void aoedev_config_done ( struct aoe_device *aoedev, int rc ) {

        /* Shut down interface */
        intf_shutdown ( &aoedev->config, rc );

        /* Close device on failure */
        if ( rc != 0 ) {
                aoedev_close ( aoedev, rc );
                return;
        }

        /* Mark device as configured */
        aoedev->configured = 1;
        xfer_window_changed ( &aoedev->ata );
}

/**
 * Identify device underlying AoE device
 *
 * @v aoedev            AoE device
 * @ret device          Underlying device
 */
static struct device * aoedev_identify_device ( struct aoe_device *aoedev ) {
        return aoedev->netdev->dev;
}

/**
 * Get AoE ACPI descriptor
 *
 * @v aoedev            AoE device
 * @ret desc            ACPI descriptor
 */
static struct acpi_descriptor * aoedev_describe ( struct aoe_device *aoedev ) {
        return &aoedev->desc;
}

/** AoE device ATA interface operations */
static struct interface_operation aoedev_ata_op[] = {
        INTF_OP ( ata_command, struct aoe_device *, aoedev_ata_command ),
        INTF_OP ( xfer_window, struct aoe_device *, aoedev_window ),
        INTF_OP ( intf_close, struct aoe_device *, aoedev_close ),
        INTF_OP ( acpi_describe, struct aoe_device *, aoedev_describe ),
        INTF_OP ( identify_device, struct aoe_device *,
                  aoedev_identify_device ),
        EFI_INTF_OP ( efi_describe, struct aoe_device *, efi_aoe_path ),
};

/** AoE device ATA interface descriptor */
static struct interface_descriptor aoedev_ata_desc =
        INTF_DESC ( struct aoe_device, ata, aoedev_ata_op );

/** AoE device configuration interface operations */
static struct interface_operation aoedev_config_op[] = {
        INTF_OP ( intf_close, struct aoe_device *, aoedev_config_done ),
};

/** AoE device configuration interface descriptor */
static struct interface_descriptor aoedev_config_desc =
        INTF_DESC ( struct aoe_device, config, aoedev_config_op );

/**
 * Open AoE device
 *
 * @v parent            Parent interface
 * @v netdev            Network device
 * @v major             Device major number
 * @v minor             Device minor number
 * @ret rc              Return status code
 */
static int aoedev_open ( struct interface *parent, struct net_device *netdev,
                         unsigned int major, unsigned int minor ) {
        struct aoe_device *aoedev;
        int rc;

        /* Allocate and initialise structure */
        aoedev = zalloc ( sizeof ( *aoedev ) );
        if ( ! aoedev ) {
                rc = -ENOMEM;
                goto err_zalloc;
        }
        ref_init ( &aoedev->refcnt, aoedev_free );
        intf_init ( &aoedev->ata, &aoedev_ata_desc, &aoedev->refcnt );
        intf_init ( &aoedev->config, &aoedev_config_desc, &aoedev->refcnt );
        aoedev->netdev = netdev_get ( netdev );
        aoedev->major = major;
        aoedev->minor = minor;
        memcpy ( aoedev->target, netdev->ll_broadcast,
                 netdev->ll_protocol->ll_addr_len );
        acpi_init ( &aoedev->desc, &abft_model, &aoedev->refcnt );

        /* Initiate configuration */
        if ( ( rc = aoedev_cfg_command ( aoedev, &aoedev->config ) ) < 0 ) {
                DBGC ( aoedev, "AoE %s could not initiate configuration: %s\n",
                       aoedev_name ( aoedev ), strerror ( rc ) );
                goto err_config;
        }

        /* Attach ATA device to parent interface */
        if ( ( rc = ata_open ( parent, &aoedev->ata, ATA_DEV_MASTER,
                               AOE_MAX_COUNT ) ) != 0 ) {
                DBGC ( aoedev, "AoE %s could not create ATA device: %s\n",
                       aoedev_name ( aoedev ), strerror ( rc ) );
                goto err_ata_open;
        }

        /* Mortalise self and return */
        ref_put ( &aoedev->refcnt );
        return 0;

 err_ata_open:
 err_config:
        aoedev_close ( aoedev, rc );
        ref_put ( &aoedev->refcnt );
 err_zalloc:
        return rc;
}

/******************************************************************************
 *
 * AoE network protocol
 *
 ******************************************************************************
 */

/**
 * Process incoming AoE packets
 *
 * @v iobuf             I/O buffer
 * @v netdev            Network device
 * @v ll_dest           Link-layer destination address
 * @v ll_source         Link-layer source address
 * @v flags             Packet flags
 * @ret rc              Return status code
 */
static int aoe_rx ( struct io_buffer *iobuf,
                    struct net_device *netdev __unused,
                    const void *ll_dest __unused,
                    const void *ll_source,
                    unsigned int flags __unused ) {
        struct aoehdr *aoehdr = iobuf->data;
        struct aoe_command *aoecmd;
        int rc;

        /* Sanity check */
        if ( iob_len ( iobuf ) < sizeof ( *aoehdr ) ) {
                DBG ( "AoE received underlength packet (%zd bytes)\n",
                      iob_len ( iobuf ) );
                rc = -EINVAL;
                goto err_sanity;
        }
        if ( ( aoehdr->ver_flags & AOE_VERSION_MASK ) != AOE_VERSION ) {
                DBG ( "AoE received packet for unsupported protocol version "
                      "%02x\n", ( aoehdr->ver_flags & AOE_VERSION_MASK ) );
                rc = -EPROTONOSUPPORT;
                goto err_sanity;
        }
        if ( ! ( aoehdr->ver_flags & AOE_FL_RESPONSE ) ) {
                DBG ( "AoE received request packet\n" );
                rc = -EOPNOTSUPP;
                goto err_sanity;
        }

        /* Demultiplex amongst active AoE commands */
        aoecmd = aoecmd_find_tag ( ntohl ( aoehdr->tag ) );
        if ( ! aoecmd ) {
                DBG ( "AoE received packet for unused tag %08x\n",
                      ntohl ( aoehdr->tag ) );
                rc = -ENOENT;
                goto err_demux;
        }

        /* Pass received frame to command */
        aoecmd_get ( aoecmd );
        if ( ( rc = aoecmd_rx ( aoecmd, iob_disown ( iobuf ),
                                ll_source ) ) != 0 )
                goto err_rx;

 err_rx:
        aoecmd_put ( aoecmd );
 err_demux:
 err_sanity:
        free_iob ( iobuf );
        return rc;
}

/** AoE protocol */
struct net_protocol aoe_protocol __net_protocol = {
        .name = "AoE",
        .net_proto = htons ( ETH_P_AOE ),
        .rx = aoe_rx,
};

/******************************************************************************
 *
 * AoE URIs
 *
 ******************************************************************************
 */

/**
 * Parse AoE URI
 *
 * @v uri               URI
 * @ret major           Major device number
 * @ret minor           Minor device number
 * @ret rc              Return status code
 *
 * An AoE URI has the form "aoe:e<major>.<minor>".
 */
static int aoe_parse_uri ( struct uri *uri, unsigned int *major,
                           unsigned int *minor ) {
        const char *ptr;
        char *end;

        /* Check for URI with opaque portion */
        if ( ! uri->opaque )
                return -EINVAL;
        ptr = uri->opaque;

        /* Check for initial 'e' */
        if ( *ptr != 'e' )
                return -EINVAL;
        ptr++;

        /* Parse major device number */
        *major = strtoul ( ptr, &end, 10 );
        if ( *end != '.' )
                return -EINVAL;
        ptr = ( end + 1 );

        /* Parse minor device number */
        *minor = strtoul ( ptr, &end, 10 );
        if ( *end )
                return -EINVAL;

        return 0;
}

/**
 * Open AoE URI
 *
 * @v parent            Parent interface
 * @v uri               URI
 * @ret rc              Return status code
 */
static int aoe_open ( struct interface *parent, struct uri *uri ) {
        struct net_device *netdev;
        unsigned int major;
        unsigned int minor;
        int rc;

        /* Identify network device.  This is something of a hack, but
         * the AoE URI scheme that has been in use for some time now
         * provides no way to specify a particular device.
         */
        netdev = last_opened_netdev();
        if ( ! netdev ) {
                DBG ( "AoE cannot identify network device\n" );
                return -ENODEV;
        }

        /* Parse URI */
        if ( ( rc = aoe_parse_uri ( uri, &major, &minor ) ) != 0 ) {
                DBG ( "AoE cannot parse URI\n" );
                return rc;
        }

        /* Open AoE device */
        if ( ( rc = aoedev_open ( parent, netdev, major, minor ) ) != 0 )
                return rc;

        return 0;
}

/** AoE URI opener */
struct uri_opener aoe_uri_opener __uri_opener = {
        .scheme = "aoe",
        .open = aoe_open,
};

/******************************************************************************
 *
 * AoE boot firmware table (aBFT)
 *
 ******************************************************************************
 */

/**
 * Check if AoE boot firmware table descriptor is complete
 *
 * @v desc              ACPI descriptor
 * @ret rc              Return status code
 */
static int abft_complete ( struct acpi_descriptor *desc __unused ) {
        return 0;
}

/**
 * Install AoE boot firmware table(s)
 *
 * @v install           Installation method
 * @ret rc              Return status code
 */
static int abft_install ( int ( * install ) ( struct acpi_header *acpi ) ) {
        struct aoe_device *aoedev;
        struct abft_table abft;
        int rc;

        list_for_each_entry ( aoedev, &abft_model.descs, desc.list ) {

                /* Populate table */
                memset ( &abft, 0, sizeof ( abft ) );
                abft.acpi.signature = cpu_to_le32 ( ABFT_SIG );
                abft.acpi.length = cpu_to_le32 ( sizeof ( abft ) );
                abft.acpi.revision = 1;
                abft.shelf = cpu_to_le16 ( aoedev->major );
                abft.slot = aoedev->minor;
                memcpy ( abft.mac, aoedev->netdev->ll_addr,
                         sizeof ( abft.mac ) );

                /* Install table */
                if ( ( rc = install ( &abft.acpi ) ) != 0 ) {
                        DBGC ( aoedev, "AoE %s could not install aBFT: %s\n",
                               aoedev_name ( aoedev ), strerror ( rc ) );
                        return rc;
                }
        }

        return 0;
}

/** aBFT model */
struct acpi_model abft_model __acpi_model = {
        .descs = LIST_HEAD_INIT ( abft_model.descs ),
        .complete = abft_complete,
        .install = abft_install,
};