linux.git/drivers/scsi/atari_scsi.c, branch v4.12

scsi: atari_scsi: Reset DMA during bus reset only under ST-DMA lock

2017-02-01T02:39:22+00:00

The atari_scsi driver should not access Falcon DMA chip registers unless
it has acquired exclusive access to that chip. If the driver doesn't
have exclusive access then there's no need for a DMA reset as there are
no scsi commands in progress.

Signed-off-by: Finn Thain 
Tested-by: Ondrej Zary 
Tested-by: Michael Schmitz 
Signed-off-by: Martin K. Petersen

scsi: ncr5380: Resolve various static checker warnings

2017-02-01T02:38:35+00:00

Avoid various warnings from "make C=1" by annotating a couple of
unlock-then-lock sequences, replacing a zero with NULL and correcting
some type casts.

Also avoid a warning from "make W=1" by adding braces.

Signed-off-by: Finn Thain 
Tested-by: Ondrej Zary 
Tested-by: Michael Schmitz 
Signed-off-by: Martin K. Petersen

scsi: ncr5380: Clean up dead code and redundant macro usage

2017-02-01T02:37:44+00:00

Remove dead code inside #if 0 conditionals.

Remove the #ifdef __KERNEL__ test, since NCR5380.h has no definitions
that relate to userspace code.

Remove two redundant macro definitions which were overlooked in
commit e9db3198e08b ("sun3_scsi: Adopt NCR5380.c core driver").

Signed-off-by: Finn Thain 
Tested-by: Ondrej Zary 
Tested-by: Michael Schmitz 
Signed-off-by: Martin K. Petersen

scsi: ncr5380: Use correct types for DMA routines

2016-11-08T22:29:48+00:00

Apply prototypes to get consistent function signatures for the DMA
functions implemented in the board-specific drivers. To avoid using
macros to alter actual parameters, some of those functions are reworked
slightly.

This is a step toward the goal of passing the board-specific routines
to the core driver using an ops struct (as in a platform driver or
library module).

This also helps fix some inconsistent types: where the core driver uses
ints (cmd->SCp.this_residual and hostdata->dma_len) for keeping track of
transfers, certain board-specific routines used unsigned long.

While we are fixing these function signatures, pass the hostdata pointer
to DMA routines instead of a Scsi_Host pointer, for shorter and faster
code.

Signed-off-by: Finn Thain 
Reviewed-by: Hannes Reinecke 
Tested-by: Ondrej Zary 
Tested-by: Michael Schmitz 
Acked-by: Russell King 
Signed-off-by: Martin K. Petersen

scsi: ncr5380: Expedite register polling

2016-11-08T22:29:48+00:00

Avoid the call to NCR5380_poll_politely2() when possible. The call is
easily short-circuited on the PIO fast path, using the inline wrapper.
This requires that the NCR5380_read macro be made available before
any #include "NCR5380.h" so a few declarations have to be moved too.

Signed-off-by: Finn Thain 
Reviewed-by: Hannes Reinecke 
Tested-by: Ondrej Zary 
Tested-by: Michael Schmitz 
Signed-off-by: Martin K. Petersen

scsi: ncr5380: Use correct types for device register accessors

2016-11-08T22:29:48+00:00

For timeout values adopt unsigned long, which is the type of jiffies etc.

For chip register values and bit masks pass u8, which is the return type
of readb, inb etc.

For device register offsets adopt unsigned int, as it is suitable for
adding to base addresses.

Pass the NCR5380_hostdata pointer to the board-specific routines instead
of the Scsi_Host pointer. The board-specific code is concerned with
hardware and not with SCSI protocol or the mid-layer.

Signed-off-by: Finn Thain 
Reviewed-by: Hannes Reinecke 
Tested-by: Ondrej Zary 
Tested-by: Michael Schmitz 
Acked-by: Russell King 
Signed-off-by: Martin K. Petersen

scsi: atari_scsi: Make device register accessors re-entrant

2016-11-08T22:29:47+00:00

This patch fixes an old bug: accesses to device registers from the
interrupt handler (after reselection, DMA completion etc.) could mess
up a device register access elsewhere, if the latter takes place outside
of an irq lock (during selection etc.).

Signed-off-by: Finn Thain 
Reviewed-by: Hannes Reinecke 
Tested-by: Michael Schmitz 
Signed-off-by: Martin K. Petersen

atari_scsi: Allow can_queue to be increased for Falcon

2016-04-11T20:57:09+00:00

The benefit of limiting can_queue to 1 is that atari_scsi shares the
ST DMA chip more fairly with other drivers (e.g. falcon-ide).

Unfortunately, this can limit SCSI bus utilization. On systems without
IDE, atari_scsi should issue SCSI commands whenever it can arbitrate for
the bus. Make that possible by making can_queue configurable.

Signed-off-by: Finn Thain 
Reviewed-by: Hannes Reinecke 
Tested-by: Michael Schmitz 
Signed-off-by: Martin K. Petersen

atari_scsi: Set a reasonable default for cmd_per_lun

2016-04-11T20:57:09+00:00

This setting does not need to be conditional on Atari ST or TT.

Signed-off-by: Finn Thain 
Tested-by: Michael Schmitz 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Martin K. Petersen

ncr5380: Remove disused atari_NCR5380.c core driver

2016-04-11T20:57:09+00:00

Now that atari_scsi and sun3_scsi have been converted to use the NCR5380.c
core driver, remove atari_NCR5380.c. Also remove the last vestiges of its
Tagged Command Queueing implementation from the wrapper drivers.

The TCQ support in atari_NCR5380.c is abandoned by this patch. It is not
merged into the remaining core driver because,

1) atari_scsi defines SUPPORT_TAGS but leaves FLAG_TAGGED_QUEUING disabled
by default, which indicates that it is mostly undesirable.

2) I'm told that it doesn't work correctly when enabled.

3) The algorithm does not make use of block layer tags which it will have
to do because scmd->tag is deprecated.

4) sun3_scsi doesn't define SUPPORT_TAGS at all, yet the the SUPPORT_TAGS
macro interacts with the CONFIG_SUN3 macro in 'interesting' ways.

5) Compile-time configuration with macros like SUPPORT_TAGS caused the
configuration space to explode, leading to untestable and unmaintainable
code that is too hard to reason about.

The merge_contiguous_buffers() code is also abandoned. This was unused
by sun3_scsi. Only atari_scsi used it and then only on TT, because only TT
supports scatter/gather. I suspect that the TT would work fine with
ENABLE_CLUSTERING instead. If someone can benchmark the difference then
perhaps the merge_contiguous_buffers() code can be be justified. Until
then we are better off without the extra complexity.

Signed-off-by: Finn Thain 
Reviewed-by: Hannes Reinecke 
Tested-by: Michael Schmitz 
Tested-by: Ondrej Zary 
Signed-off-by: Martin K. Petersen