diff options
| author | Finn Thain <fthain@telegraphics.com.au> | 2016-01-03 16:05:50 +1100 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2016-01-06 21:43:04 -0500 |
| commit | be3f4121aa352d8fef77a57df4b5e106d7f9a917 (patch) | |
| tree | eedef716328818f44a6fb73dd25d8c9e4b322ed2 /drivers/scsi/atari_NCR5380.c | |
| parent | e42d01518d006c4557e202bc9e8fdc41972fb49f (diff) | |
| download | linux-be3f4121aa352d8fef77a57df4b5e106d7f9a917.tar.gz | |
ncr5380: Remove redundant ICR_ARBITRATION_LOST test and eliminate FLAG_DTC3181E
Remove FLAG_DTC3181E. It was used to suppress a final Arbitration Lost
(SEL asserted) test that isn't actually needed. The test was suppressed
because it causes problems for DTC436 and DTC536 chips. It takes place
after the host wins arbitration, so SEL has been asserted. These chips
can't seem to tell whether it was the host or another bus device that
did so.
This questionable final test appears in a flow chart in an early NCR5380
datasheet. It was removed from later documents like the DP5380 datasheet.
By the time this final test takes place, the driver has already tested
the Arbitration Lost bit several times. The first test happens 3 us after
BUS FREE (or longer due to register access delays). The protocol requires
that a device stop signalling within 1.8 us after BUS FREE unless it won
arbitration, in which case it must assert SEL, which is detected 1.2 us
later by the first Arbitration Lost test.
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/atari_NCR5380.c')
| -rw-r--r-- | drivers/scsi/atari_NCR5380.c | 9 |
1 files changed, 0 insertions, 9 deletions
diff --git a/drivers/scsi/atari_NCR5380.c b/drivers/scsi/atari_NCR5380.c index 06245c07ebd2..08e8ace2681b 100644 --- a/drivers/scsi/atari_NCR5380.c +++ b/drivers/scsi/atari_NCR5380.c @@ -1420,15 +1420,6 @@ static int NCR5380_select(struct Scsi_Host *instance, struct scsi_cmnd *cmd) NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_SEL | ICR_ASSERT_BSY); - if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) || - hostdata->connected) { - NCR5380_write(MODE_REG, MR_BASE); - NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); - dprintk(NDEBUG_ARBITRATION, "scsi%d: lost arbitration, deasserting ICR_ASSERT_SEL\n", - HOSTNO); - return -1; - } - /* * Again, bus clear + bus settle time is 1.2us, however, this is * a minimum so we'll udelay ceil(1.2) |