scsi.c

Go to the documentation of this file.

/*
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <byteswap.h>
#include <errno.h>
#include <gpxe/blockdev.h>
#include <gpxe/process.h>
#include <gpxe/scsi.h>

/** @file
 *
 * SCSI block device
 *
 */

/** Maximum number of dummy "read capacity (10)" operations
 *
 * These are issued at connection setup to draw out various useless
 * power-on messages.
 */
#define SCSI_MAX_DUMMY_READ_CAP 10

static inline __attribute__ (( always_inline )) struct scsi_device *
block_to_scsi ( struct block_device *blockdev ) {
        return container_of ( blockdev, struct scsi_device, blockdev );
}

/**
 * Handle SCSI command with no backing device
 *
 * @v scsi              SCSI device
 * @v command           SCSI command
 * @ret rc              Return status code
 */
int scsi_detached_command ( struct scsi_device *scsi __unused,
                            struct scsi_command *command __unused ) {
        return -ENODEV;
}

/**
 * Issue SCSI command
 *
 * @v scsi              SCSI device
 * @v command           SCSI command
 * @ret rc              Return status code
 */
static int scsi_command ( struct scsi_device *scsi,
                          struct scsi_command *command ) {
        int rc;

        DBGC2 ( scsi, "SCSI %p " SCSI_CDB_FORMAT "\n",
                scsi, SCSI_CDB_DATA ( command->cdb ) );

        /* Clear sense response code before issuing command */
        command->sense_response = 0;

        /* Flag command as in-progress */
        command->rc = -EINPROGRESS;

        /* Issue SCSI command */
        if ( ( rc = scsi->command ( scsi, command ) ) != 0 ) {
                /* Something went wrong with the issuing mechanism */
                DBGC ( scsi, "SCSI %p " SCSI_CDB_FORMAT " err %s\n",
                       scsi, SCSI_CDB_DATA ( command->cdb ), strerror ( rc ) );
                return rc;
        }

        /* Wait for command to complete */
        while ( command->rc == -EINPROGRESS )
                step();
        if ( ( rc = command->rc ) != 0 ) {
                /* Something went wrong with the command execution */
                DBGC ( scsi, "SCSI %p " SCSI_CDB_FORMAT " err %s\n",
                       scsi, SCSI_CDB_DATA ( command->cdb ), strerror ( rc ) );
                return rc;
        }

        /* Check for SCSI errors */
        if ( command->status != 0 ) {
                DBGC ( scsi, "SCSI %p " SCSI_CDB_FORMAT " status %02x sense "
                       "%02x\n", scsi, SCSI_CDB_DATA ( command->cdb ),
                       command->status, command->sense_response );
                return -EIO;
        }

        return 0;
}

/**
 * Read block from SCSI device using READ (10)
 *
 * @v blockdev          Block device
 * @v block             LBA block number
 * @v count             Block count
 * @v buffer            Data buffer
 * @ret rc              Return status code
 */
static int scsi_read_10 ( struct block_device *blockdev, uint64_t block,
                          unsigned long count, userptr_t buffer ) {
        struct scsi_device *scsi = block_to_scsi ( blockdev );
        struct scsi_command command;
        struct scsi_cdb_read_10 *cdb = &command.cdb.read10;

        /* Issue READ (10) */
        memset ( &command, 0, sizeof ( command ) );
        cdb->opcode = SCSI_OPCODE_READ_10;
        cdb->lba = cpu_to_be32 ( block );
        cdb->len = cpu_to_be16 ( count );
        command.data_in = buffer;
        command.data_in_len = ( count * blockdev->blksize );
        return scsi_command ( scsi, &command );
}

/**
 * Read block from SCSI device using READ (16)
 *
 * @v blockdev          Block device
 * @v block             LBA block number
 * @v count             Block count
 * @v buffer            Data buffer
 * @ret rc              Return status code
 */
static int scsi_read_16 ( struct block_device *blockdev, uint64_t block,
                          unsigned long count, userptr_t buffer ) {
        struct scsi_device *scsi = block_to_scsi ( blockdev );
        struct scsi_command command;
        struct scsi_cdb_read_16 *cdb = &command.cdb.read16;

        /* Issue READ (16) */
        memset ( &command, 0, sizeof ( command ) );
        cdb->opcode = SCSI_OPCODE_READ_16;
        cdb->lba = cpu_to_be64 ( block );
        cdb->len = cpu_to_be32 ( count );
        command.data_in = buffer;
        command.data_in_len = ( count * blockdev->blksize );
        return scsi_command ( scsi, &command );
}

/**
 * Write block to SCSI device using WRITE (10)
 *
 * @v blockdev          Block device
 * @v block             LBA block number
 * @v count             Block count
 * @v buffer            Data buffer
 * @ret rc              Return status code
 */
static int scsi_write_10 ( struct block_device *blockdev, uint64_t block,
                           unsigned long count, userptr_t buffer ) {
        struct scsi_device *scsi = block_to_scsi ( blockdev );
        struct scsi_command command;
        struct scsi_cdb_write_10 *cdb = &command.cdb.write10;

        /* Issue WRITE (10) */
        memset ( &command, 0, sizeof ( command ) );
        cdb->opcode = SCSI_OPCODE_WRITE_10;
        cdb->lba = cpu_to_be32 ( block );
        cdb->len = cpu_to_be16 ( count );
        command.data_out = buffer;
        command.data_out_len = ( count * blockdev->blksize );
        return scsi_command ( scsi, &command );
}

/**
 * Write block to SCSI device using WRITE (16)
 *
 * @v blockdev          Block device
 * @v block             LBA block number
 * @v count             Block count
 * @v buffer            Data buffer
 * @ret rc              Return status code
 */
static int scsi_write_16 ( struct block_device *blockdev, uint64_t block,
                           unsigned long count, userptr_t buffer ) {
        struct scsi_device *scsi = block_to_scsi ( blockdev );
        struct scsi_command command;
        struct scsi_cdb_write_16 *cdb = &command.cdb.write16;

        /* Issue WRITE (16) */
        memset ( &command, 0, sizeof ( command ) );
        cdb->opcode = SCSI_OPCODE_WRITE_16;
        cdb->lba = cpu_to_be64 ( block );
        cdb->len = cpu_to_be32 ( count );
        command.data_out = buffer;
        command.data_out_len = ( count * blockdev->blksize );
        return scsi_command ( scsi, &command );
}

/**
 * Read capacity of SCSI device via READ CAPACITY (10)
 *
 * @v blockdev          Block device
 * @ret rc              Return status code
 */
static int scsi_read_capacity_10 ( struct block_device *blockdev ) {
        struct scsi_device *scsi = block_to_scsi ( blockdev );
        struct scsi_command command;
        struct scsi_cdb_read_capacity_10 *cdb = &command.cdb.readcap10;
        struct scsi_capacity_10 capacity;
        int rc;

        /* Issue READ CAPACITY (10) */
        memset ( &command, 0, sizeof ( command ) );
        cdb->opcode = SCSI_OPCODE_READ_CAPACITY_10;
        command.data_in = virt_to_user ( &capacity );
        command.data_in_len = sizeof ( capacity );

        if ( ( rc = scsi_command ( scsi, &command ) ) != 0 )
                return rc;

        /* Fill in block device fields */
        blockdev->blksize = be32_to_cpu ( capacity.blksize );
        blockdev->blocks = ( be32_to_cpu ( capacity.lba ) + 1 );

        return 0;
}

/**
 * Read capacity of SCSI device via READ CAPACITY (16)
 *
 * @v blockdev          Block device
 * @ret rc              Return status code
 */
static int scsi_read_capacity_16 ( struct block_device *blockdev ) {
        struct scsi_device *scsi = block_to_scsi ( blockdev );
        struct scsi_command command;
        struct scsi_cdb_read_capacity_16 *cdb = &command.cdb.readcap16;
        struct scsi_capacity_16 capacity;
        int rc;

        /* Issue READ CAPACITY (16) */
        memset ( &command, 0, sizeof ( command ) );
        cdb->opcode = SCSI_OPCODE_SERVICE_ACTION_IN;
        cdb->service_action = SCSI_SERVICE_ACTION_READ_CAPACITY_16;
        cdb->len = cpu_to_be32 ( sizeof ( capacity ) );
        command.data_in = virt_to_user ( &capacity );
        command.data_in_len = sizeof ( capacity );

        if ( ( rc = scsi_command ( scsi, &command ) ) != 0 )
                return rc;

        /* Fill in block device fields */
        blockdev->blksize = be32_to_cpu ( capacity.blksize );
        blockdev->blocks = ( be64_to_cpu ( capacity.lba ) + 1 );
        return 0;
}

static struct block_device_operations scsi_operations_16 = {
        .read   = scsi_read_16,
        .write  = scsi_write_16,
};

static struct block_device_operations scsi_operations_10 = {
        .read   = scsi_read_10,
        .write  = scsi_write_10,
};

/**
 * Initialise SCSI device
 *
 * @v scsi              SCSI device
 * @ret rc              Return status code
 *
 * Initialises a SCSI device.  The scsi_device::command and
 * scsi_device::lun fields must already be filled in.  This function
 * will configure scsi_device::blockdev, including issuing a READ
 * CAPACITY call to determine the block size and total device size.
 */
int init_scsidev ( struct scsi_device *scsi ) {
        unsigned int i;
        int rc;

        /* Issue some theoretically extraneous READ CAPACITY (10)
         * commands, solely in order to draw out the "CHECK CONDITION
         * (power-on occurred)", "CHECK CONDITION (reported LUNs data
         * has changed)" etc. that some dumb targets insist on sending
         * as an error at start of day.  The precise command that we
         * use is unimportant; we just need to provide the target with
         * an opportunity to send its responses.
         */
        for ( i = 0 ; i < SCSI_MAX_DUMMY_READ_CAP ; i++ ) {
                if ( ( rc = scsi_read_capacity_10 ( &scsi->blockdev ) ) == 0 )
                        break;
                DBGC ( scsi, "SCSI %p ignoring start-of-day error (#%d)\n",
                       scsi, ( i + 1 ) );
        }

        /* Try READ CAPACITY (10), which is a mandatory command, first. */
        scsi->blockdev.op = &scsi_operations_10;
        if ( ( rc = scsi_read_capacity_10 ( &scsi->blockdev ) ) != 0 ) {
                DBGC ( scsi, "SCSI %p could not READ CAPACITY (10): %s\n",
                       scsi, strerror ( rc ) );
                return rc;
        }

        /* If capacity range was exceeded (i.e. capacity.lba was
         * 0xffffffff, meaning that blockdev->blocks is now zero), use
         * READ CAPACITY (16) instead.  READ CAPACITY (16) is not
         * mandatory, so we can't just use it straight off.
         */
        if ( scsi->blockdev.blocks == 0 ) {
                scsi->blockdev.op = &scsi_operations_16;
                if ( ( rc = scsi_read_capacity_16 ( &scsi->blockdev ) ) != 0 ){
                        DBGC ( scsi, "SCSI %p could not READ CAPACITY (16): "
                               "%s\n", scsi, strerror ( rc ) );
                        return rc;
                }
        }

        DBGC ( scsi, "SCSI %p using READ/WRITE (%d) commands\n", scsi,
               ( ( scsi->blockdev.op == &scsi_operations_10 ) ? 10 : 16 ) );
        DBGC ( scsi, "SCSI %p capacity is %ld MB (%#llx blocks)\n", scsi,
               ( ( unsigned long ) ( scsi->blockdev.blocks >> 11 ) ),
               scsi->blockdev.blocks );

        return 0;
}

/**
 * Parse SCSI LUN
 *
 * @v lun_string        LUN string representation
 * @v lun               LUN to fill in
 * @ret rc              Return status code
 */
int scsi_parse_lun ( const char *lun_string, struct scsi_lun *lun ) {
        char *p;
        int i;

        memset ( lun, 0, sizeof ( *lun ) );
        if ( lun_string ) {
                p = ( char * ) lun_string;
                for ( i = 0 ; i < 4 ; i++ ) {
                        lun->u16[i] = htons ( strtoul ( p, &p, 16 ) );
                        if ( *p == '\0' )
                                break;
                        if ( *p != '-' )
                                return -EINVAL;
                        p++;
                }
                if ( *p )
                        return -EINVAL;
        }

        return 0;
}