Commit bf294e83 authored by vchannaiah's avatar vchannaiah Committed by Jens Axboe
Browse files

cdrom: support read sub-channel command in LBA format 



userspace application can send READ_SUB_CHANNEL command with time bit
enabled and disabled. The time bit allows selection of address reporting
format. If the time bit is disabled the response is in logical block
address(CDROM_LBA) format, represented as a 32-bit integer with ms-byte
first. If the time bit is enabled the response is in time format i.e.,
minutes, second, frame (CDROM_MSF) format.

Signed-off-by: default avatarvchannaiah <vanitha.channaiah@in.bosch.com>
Signed-off-by: default avatarMahendran Kuppusamy <mahendran.kuppusamy@in.bosch.com>
[veeraiyan.chidambaram@in.bosch.com: updated Documentation/ioctl/cdrom.txt]
Signed-off-by: default avatarVeeraiyan Chidambaram <veeraiyan.chidambaram@in.bosch.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 54adc010

Documentation/ioctl/cdrom.txt

+2 −1
Original line number Diff line number Diff line
@@ -340,7 +340,8 @@ CDROMSUBCHNL Read subchannel data (struct cdrom_subchnl) 
	  EINVAL	format not CDROM_MSF or CDROM_LBA



	notes:

	  Format is converted to CDROM_MSF on return

	  Format is converted to CDROM_MSF or CDROM_LBA

	  as per user request on return

drivers/cdrom/cdrom.c

+19 −9
Original line number Diff line number Diff line
@@ -2032,7 +2032,7 @@ static int cdrom_read_subchannel(struct cdrom_device_info *cdi, 


	init_cdrom_command(&cgc, buffer, 16, CGC_DATA_READ);

	cgc.cmd[0] = GPCMD_READ_SUBCHANNEL;

	cgc.cmd[1] = 2;     /* MSF addressing */

	cgc.cmd[1] = subchnl->cdsc_format;/* MSF or LBA addressing */

	cgc.cmd[2] = 0x40;  /* request subQ data */

	cgc.cmd[3] = mcn ? 2 : 1;

	cgc.cmd[8] = 16;
@@ -2041,17 +2041,27 @@ static int cdrom_read_subchannel(struct cdrom_device_info *cdi, 
		return ret;



	subchnl->cdsc_audiostatus = cgc.buffer[1];

	subchnl->cdsc_format = CDROM_MSF;

	subchnl->cdsc_ctrl = cgc.buffer[5] & 0xf;

	subchnl->cdsc_trk = cgc.buffer[6];

	subchnl->cdsc_ind = cgc.buffer[7];



	if (subchnl->cdsc_format == CDROM_LBA) {

		subchnl->cdsc_absaddr.lba = ((cgc.buffer[8] << 24) |

						(cgc.buffer[9] << 16) |

						(cgc.buffer[10] << 8) |

						(cgc.buffer[11]));

		subchnl->cdsc_reladdr.lba = ((cgc.buffer[12] << 24) |

						(cgc.buffer[13] << 16) |

						(cgc.buffer[14] << 8) |

						(cgc.buffer[15]));

	} else {

		subchnl->cdsc_reladdr.msf.minute = cgc.buffer[13];

		subchnl->cdsc_reladdr.msf.second = cgc.buffer[14];

		subchnl->cdsc_reladdr.msf.frame = cgc.buffer[15];

		subchnl->cdsc_absaddr.msf.minute = cgc.buffer[9];

		subchnl->cdsc_absaddr.msf.second = cgc.buffer[10];

		subchnl->cdsc_absaddr.msf.frame = cgc.buffer[11];

	}



	return 0;

}
@@ -3022,7 +3032,7 @@ static noinline int mmc_ioctl_cdrom_subchannel(struct cdrom_device_info *cdi, 
	if (!((requested == CDROM_MSF) ||

	      (requested == CDROM_LBA)))

		return -EINVAL;

	q.cdsc_format = CDROM_MSF;



	ret = cdrom_read_subchannel(cdi, &q, 0);

	if (ret)

		return ret;

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