ncr53c8xx.txt

linux 内核源代码

In order to display profiling information, just enter:

         cat /proc/scsi/ncr53c8xx/0

and you will get something like the following text:

-------------------------------------------------------
General information:
  Chip NCR53C810, device id 0x1, revision id 0x2
  IO port address 0x6000, IRQ number 10
  Using memory mapped IO at virtual address 0x282c000
  Synchronous transfer period 25, max commands per lun 4
Profiling information:
  num_trans    = 18014
  num_kbytes   = 671314
  num_disc     = 25763
  num_break    = 1673
  num_int      = 1685
  num_fly      = 18038
  ms_setup     = 4940
  ms_data      = 369940
  ms_disc      = 183090
  ms_post      = 1320
-------------------------------------------------------

General information is easy to understand. The device ID and the
revision ID identify the SCSI chip as follows:

Chip    Device id     Revision Id
----    ---------     -----------
810       0x1            <  0x10
810A      0x1            >= 0x10
815       0x4
825       0x3            <  0x10
860       0x6
825A      0x3            >= 0x10
875       0xf
895       0xc

The profiling information is updated upon completion of SCSI commands.
A data structure is allocated and zeroed when the host adapter is
attached. So, if the driver is a module, the profile counters are
cleared each time the driver is loaded.  The "clearprof" command
allows you to clear these counters at any time.

The following counters are available:

("num" prefix means "number of",
"ms" means milli-seconds)

num_trans
	Number of completed commands
	Example above: 18014 completed commands

num_kbytes
	Number of kbytes transferred
	Example above: 671 MB transferred

num_disc
	Number of SCSI disconnections
	Example above: 25763 SCSI disconnections

num_break
	number of script interruptions (phase mismatch)
	Example above: 1673 script interruptions

num_int
	Number of interrupts other than "on the fly"
	Example above: 1685 interruptions not "on the fly"

num_fly
	Number of interrupts "on the fly"
	Example above: 18038 interruptions "on the fly"

ms_setup
	Elapsed time for SCSI commands setups
	Example above: 4.94 seconds

ms_data
	Elapsed time for data transfers
	Example above: 369.94 seconds spent for data transfer

ms_disc
	Elapsed time for SCSI disconnections
	Example above: 183.09 seconds spent disconnected

ms_post
	Elapsed time for command post processing
	(time from SCSI status get to command completion call)
	Example above: 1.32 seconds spent for post processing

Due to the 1/100 second tick of the system clock, "ms_post" time may
be wrong.

In the example above, we got 18038 interrupts "on the fly" and only
1673 script breaks generally due to disconnections inside a segment 
of the scatter list.


8. Control commands

Control commands can be sent to the driver with write operations to
the proc SCSI file system. The generic command syntax is the
following:

      echo "<verb> <parameters>" >/proc/scsi/ncr53c8xx/0
      (assumes controller number is 0)

Using "all" for "<target>" parameter with the commands below will
apply to all targets of the SCSI chain (except the controller).

Available commands:

8.1 Set minimum synchronous period factor

    setsync <target> <period factor>

    target:    target number
    period:    minimum synchronous period.
               Maximum speed = 1000/(4*period factor) except for special
               cases below.

    Specify a period of 255, to force asynchronous transfer mode.

      10 means 25 nano-seconds synchronous period
      11 means 30 nano-seconds synchronous period
      12 means 50 nano-seconds synchronous period

8.2 Set wide size

    setwide <target> <size>

    target:    target number
    size:      0=8 bits, 1=16bits

8.3 Set maximum number of concurrent tagged commands
 
    settags <target> <tags>

    target:    target number
    tags:      number of concurrent tagged commands
               must not be greater than SCSI_NCR_MAX_TAGS (default: 8)

8.4 Set order type for tagged command

    setorder <order>

    order:     3 possible values:
               simple: use SIMPLE TAG for all operations (read and write)
               ordered: use ORDERED TAG for all operations
               default: use default tag type,
                        SIMPLE  TAG for read  operations
                        ORDERED TAG for write operations


8.5 Set debug mode

    setdebug <list of debug flags>

    Available debug flags:
        alloc:   print info about memory allocations (ccb, lcb)
        queue:   print info about insertions into the command start queue
        result:  print sense data on CHECK CONDITION status
        scatter: print info about the scatter process
        scripts: print info about the script binding process
	tiny:    print minimal debugging information
	timing:  print timing information of the NCR chip
	nego:    print information about SCSI negotiations
	phase:   print information on script interruptions

    Use "setdebug" with no argument to reset debug flags.


8.6 Clear profile counters

    clearprof

    The profile counters are automatically cleared when the amount of
    data transferred reaches 1000 GB in order to avoid overflow.
    The "clearprof" command allows you to clear these counters at any time.


8.7 Set flag (no_disc)
 
    setflag <target> <flag>

    target:    target number

    For the moment, only one flag is available:

        no_disc:   not allow target to disconnect.

    Do not specify any flag in order to reset the flag. For example:
    - setflag 4
      will reset no_disc flag for target 4, so will allow it disconnections.
    - setflag all
      will allow disconnection for all devices on the SCSI bus.


8.8 Set verbose level

    setverbose #level

    The driver default verbose level is 1. This command allows to change 
    th driver verbose level after boot-up.

8.9 Reset all logical units of a target

    resetdev <target>

    target:    target number
    The driver will try to send a BUS DEVICE RESET message to the target.
    (Only supported by the SYM53C8XX driver and provided for test purpose)

8.10 Abort all tasks of all logical units of a target

    cleardev <target>

    target:    target number
    The driver will try to send a ABORT message to all the logical units 
    of the target.
    (Only supported by the SYM53C8XX driver and provided for test purpose)


9. Configuration parameters

If the firmware of all your devices is perfect enough, all the
features supported by the driver can be enabled at start-up.  However,
if only one has a flaw for some SCSI feature, you can disable the
support by the driver of this feature at linux start-up and enable
this feature after boot-up only for devices that support it safely.

CONFIG_SCSI_NCR53C8XX_IOMAPPED       (default answer: n)
    Answer "y" if you suspect your mother board to not allow memory mapped I/O.
    May slow down performance a little.  This option is required by
    Linux/PPC and is used no matter what you select here.  Linux/PPC
    suffers no performance loss with this option since all IO is memory
    mapped anyway.

CONFIG_SCSI_NCR53C8XX_DEFAULT_TAGS    (default answer: 8)
    Default tagged command queue depth.

CONFIG_SCSI_NCR53C8XX_MAX_TAGS         (default answer: 8)
    This option allows you to specify the maximum number of tagged commands 
    that can be queued to a device. The maximum supported value is 32.

CONFIG_SCSI_NCR53C8XX_SYNC            (default answer: 5)
    This option allows you to specify the frequency in MHz the driver 
    will use at boot time for synchronous data transfer negotiations.
    This frequency can be changed later with the "setsync" control command.
    0 means "asynchronous data transfers".

CONFIG_SCSI_NCR53C8XX_FORCE_SYNC_NEGO (default answer: n)
    Force synchronous negotiation for all SCSI-2 devices.
    Some SCSI-2 devices do not report this feature in byte 7 of inquiry 
    response but do support it properly (TAMARACK scanners for example).

CONFIG_SCSI_NCR53C8XX_NO_DISCONNECT   (default and only reasonable answer: n)
    If you suspect a device of yours does not properly support disconnections,
    you can answer "y". Then, all SCSI devices will never disconnect the bus 
    even while performing long SCSI operations.

CONFIG_SCSI_NCR53C8XX_SYMBIOS_COMPAT
    Genuine SYMBIOS boards use GPIO0 in output for controller LED and GPIO3 
    bit as a flag indicating singled-ended/differential interface.
    If all the boards of your system are genuine SYMBIOS boards or use
    BIOS and drivers from SYMBIOS, you would want to enable this option.
    This option must NOT be enabled if your system has at least one 53C8XX 
    based scsi board with a vendor-specific BIOS.
    For example, Tekram DC-390/U, DC-390/W and DC-390/F scsi controllers 
    use a vendor-specific BIOS and are known to not use SYMBIOS compatible 
    GPIO wiring. So, this option must not be enabled if your system has 
    such a board installed.

CONFIG_SCSI_NCR53C8XX_NVRAM_DETECT
    Enable support for reading the serial NVRAM data on Symbios and
    some Symbios compatible cards, and Tekram DC390W/U/F cards. Useful for
    systems with more than one Symbios compatible controller where at least
    one has a serial NVRAM, or for a system with a mixture of Symbios and
    Tekram cards. Enables setting the boot order of host adaptors
    to something other than the default order or "reverse probe" order. 
    Also enables Symbios and Tekram cards to be distinguished so
    CONFIG_SCSI_NCR53C8XX_SYMBIOS_COMPAT may be set in a system with a
    mixture of Symbios and Tekram cards so the Symbios cards can make use of
    the full range of Symbios features, differential, led pin, without
    causing problems for the Tekram card(s).

10. Boot setup commands

10.1 Syntax

Setup commands can be passed to the driver either at boot time or as a 
string variable using 'insmod'.

A boot setup command for the ncr53c8xx (sym53c8xx) driver begins with the 
driver name "ncr53c8xx="(sym53c8xx). The kernel syntax parser then expects 
an optional list of integers separated with comma followed by an optional 
list of comma-separated strings. Example of boot setup command under lilo 
prompt:

lilo: linux root=/dev/hda2 ncr53c8xx=tags:4,sync:10,debug:0x200

- enable tagged commands, up to 4 tagged commands queued.
- set synchronous negotiation speed to 10 Mega-transfers / second.
- set DEBUG_NEGO flag.

Since comma seems not to be allowed when defining a string variable using  
'insmod', the driver also accepts <space> as option separator. 
The following command will install driver module with the same options as 
above.

    insmod ncr53c8xx.o ncr53c8xx="tags:4 sync:10 debug:0x200"

For the moment, the integer list of arguments is discarded by the driver. 
It will be used in the future in order to allow a per controller setup.

Each string argument must be specified as "keyword:value". Only lower-case 
characters and digits are allowed.

In a system that contains multiple 53C8xx adapters insmod will install the 
specified driver on each adapter. To exclude a chip use the 'excl' keyword.

The sequence of commands, 

    insmod sym53c8xx sym53c8xx=excl:0x1400
    insmod ncr53c8xx

installs the sym53c8xx driver on all adapters except the one at IO port 
address 0x1400 and then installs the ncr53c8xx driver to the adapter at IO 
port address 0x1400.