When using this driver on a Blizzard 1260, there were failures whenever DMA
transfers from the SCSI bus to memory of 65535 bytes were followed by a DMA
transfer of 1 byte. This caused the byte at offset 65535 to be overwritten
with 0xff. The Blizzard hardware can't handle single byte DMA transfers.
Besides this issue, limiting the DMA length to something that is not a
multiple of the page size is very inefficient on most file systems.
It seems this limit was chosen because the DMA transfer counter of the ESP
by default is 16 bits wide, thus limiting the length to 65535 bytes.
However, the value 0 means 65536 bytes, which is handled by the ESP and the
Blizzard just fine. It is also the default maximum used by esp_scsi when
drivers don't provide their own dma_length_limit() function.
The limit of 65536 bytes can be used by all boards except the Fastlane. The
old driver used a limit of 65532 bytes (0xfffc), which is reintroduced in
this patch.
Fixes: b7ded0e8b0 ("scsi: zorro_esp: Limit DMA transfers to 65535 bytes")
Link: https://lore.kernel.org/r/20191112175523.23145-1-jongk@linux-m68k.org
Signed-off-by: Kars de Jong <jongk@linux-m68k.org>
Reviewed-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
As a temporary measure, the code to implement PIO transfers was
duplicated in zorro_esp and mac_esp. Now that it has stabilized move the
common code into the core driver but don't build it unless needed.
This replaces the inline assembler with more portable writesb() calls.
Optimizing the m68k writesb() implementation is a separate patch.
[mkp: applied by hand]
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The core driver, esp_scsi, does not use the ESP_CONFIG2_FENAB bit, so the
chip's Transfer Counter register is only 16 bits wide (not 24). A larger
transfer cannot work and will theoretically result in a failed command
and a "DMA length is zero" error.
Fixes: 3109e5ae03 ("scsi: zorro_esp: New driver for Amiga Zorro NCR53C9x boards")
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Cc: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Except for the mac_esp driver, which uses PIO or pseudo DMA, all drivers
share the same dma mapping calls. Move the dma mapping into the core
code using the scsi_dma_map / scsi_dma_unmap helpers, with a special
identify mapping variant triggered off a new ESP_FLAG_NO_DMA_MAP flag
for mac_esp.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
We can simplify use esp->dev now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
New combined SCSI driver for all ESP based Zorro SCSI boards for m68k Amiga.
Code largely based on board specific parts of the old drivers (blz1230.c,
blz2060.c, cyberstorm.c, cyberstormII.c, fastlane.c which were removed after
the 2.6 kernel series for lack of maintenance) with contributions by Tuomas
Vainikka (TCQ bug tests and workaround) and Finn Thain (TCQ bugfix by use of
PIO in extended message in transfer).
New Kconfig option and Makefile entries for new Amiga Zorro ESP SCSI driver
included in this patch.
Use DMA transfers wherever possible, with board-specific DMA set-up functions
copied from the old driver code. Three byte reselection messages do appear to
cause DMA timeouts. So wire up a PIO transfer routine for these
instead. esp_reselect_with_tag explicitly sets
esp->cmd_block_dma as target address for the message bytes but PIO
requires a virtual address. Substiute kernel virtual address
esp->cmd_block in PIO transfer call if DMA address is esp->cmd_block_dma
and phase is message in.
PIO code taken from mac_esp.c where the reselection timeout issue was debugged
and fixed first, with minor macro and function rename.
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christian T. Steigies <cts@debian.org>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
