diff options
Diffstat (limited to 'drivers/scsi/scsi.c')
-rw-r--r-- | drivers/scsi/scsi.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 62d9472e08e9..c03814ce23ca 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -570,6 +570,87 @@ int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer, } EXPORT_SYMBOL(scsi_report_opcode); +#define SCSI_CDL_CHECK_BUF_LEN 64 + +static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa, + unsigned char *buf) +{ + int ret; + u8 cdlp; + + /* Check operation code */ + ret = scsi_report_opcode(sdev, buf, SCSI_CDL_CHECK_BUF_LEN, opcode, sa); + if (ret <= 0) + return false; + + if ((buf[1] & 0x03) != 0x03) + return false; + + /* See SPC-6, one command format of REPORT SUPPORTED OPERATION CODES */ + cdlp = (buf[1] & 0x18) >> 3; + if (buf[0] & 0x01) { + /* rwcdlp == 1 */ + switch (cdlp) { + case 0x01: + /* T2A page */ + return true; + case 0x02: + /* T2B page */ + return true; + } + } else { + /* rwcdlp == 0 */ + switch (cdlp) { + case 0x01: + /* A page */ + return true; + case 0x02: + /* B page */ + return true; + } + } + + return false; +} + +/** + * scsi_cdl_check - Check if a SCSI device supports Command Duration Limits + * @sdev: The device to check + */ +void scsi_cdl_check(struct scsi_device *sdev) +{ + bool cdl_supported; + unsigned char *buf; + + buf = kmalloc(SCSI_CDL_CHECK_BUF_LEN, GFP_KERNEL); + if (!buf) { + sdev->cdl_supported = 0; + return; + } + + /* Check support for READ_16, WRITE_16, READ_32 and WRITE_32 commands */ + cdl_supported = + scsi_cdl_check_cmd(sdev, READ_16, 0, buf) || + scsi_cdl_check_cmd(sdev, WRITE_16, 0, buf) || + scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, READ_32, buf) || + scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, WRITE_32, buf); + if (cdl_supported) { + /* + * We have CDL support: force the use of READ16/WRITE16. + * READ32 and WRITE32 will be used for devices that support + * the T10_PI_TYPE2_PROTECTION protection type. + */ + sdev->use_16_for_rw = 1; + sdev->use_10_for_rw = 0; + + sdev->cdl_supported = 1; + } else { + sdev->cdl_supported = 0; + } + + kfree(buf); +} + /** * scsi_device_get - get an additional reference to a scsi_device * @sdev: device to get a reference to |