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READ CAPACITY (16) turns out to be an optional command (even though

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READ(16) is mandatory); we must use READ CAPACITY (10) first and then
use READ CAPACITY (16) if the READ CAPACITY (10) returns "out of range".
This commit is contained in:
Michael Brown
2006-05-19 18:54:38 +00:00
parent 444b885a7d
commit 402ba15c64
2 changed files with 84 additions and 2 deletions
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59
src/drivers/block/scsi.c
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@@ -96,12 +96,41 @@ static int scsi_write ( struct block_device *blockdev, uint64_t block,
}
/**
* Read capacity of SCSI device
* Read capacity of SCSI device via READ CAPACITY (10)
*
* @v blockdev Block device
* @ret rc Return status code
*/
static int scsi_read_capacity ( struct block_device *blockdev ) {
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;
@@ -125,6 +154,32 @@ static int scsi_read_capacity ( struct block_device *blockdev ) {
return 0;
}
/**
* Read capacity of SCSI device
*
* @v blockdev Block device
* @ret rc Return status code
*/
static int scsi_read_capacity ( struct block_device *blockdev ) {
int rc;
/* Try READ CAPACITY (10), which is a mandatory command, first. */
if ( ( rc = scsi_read_capacity_10 ( blockdev ) ) != 0 )
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 ( blockdev->blocks == 0 ) {
if ( ( rc = scsi_read_capacity_16 ( blockdev ) ) != 0 )
return rc;
}
return 0;
}
/**
* Initialise SCSI device
*