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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/scsi/dtc3x80.txt
downloadconfigs-2.6.12-rc2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+README file for the Linux DTC3180/3280 scsi driver.
+by Ray Van Tassle (rayvt@comm.mot.com) March 1996
+Based on the generic & core NCR5380 code by Drew Eckhard
+
+SCSI device driver for the DTC 3180/3280.
+Data Technology Corp---a division of Qume.
+
+The 3280 has a standard floppy interface.
+
+The 3180 does not. Otherwise, they are identical.
+
+The DTC3x80 does not support DMA but it does have Pseudo-DMA which is
+supported by the driver.
+
+It's DTC406 scsi chip is supposedly compatible with the NCR 53C400.
+It is memory mapped, uses an IRQ, but no dma or io-port. There is
+internal DMA, between SCSI bus and an on-chip 128-byte buffer. Double
+buffering is done automagically by the chip. Data is transferred
+between the on-chip buffer and CPU/RAM via memory moves.
+
+The driver detects the possible memory addresses (jumper selectable):
+ CC00, DC00, C800, and D800
+The possible IRQ's (jumper selectable) are:
+ IRQ 10, 11, 12, 15
+Parity is supported by the chip, but not by this driver.
+Information can be obtained from /proc/scsi/dtc3c80/N.
+
+Note on interrupts:
+
+The documentation says that it can be set to interrupt whenever the
+on-chip buffer needs CPU attention. I couldn't get this to work. So
+the driver polls for data-ready in the pseudo-DMA transfer routine.
+The interrupt support routines in the NCR3280.c core modules handle
+scsi disconnect/reconnect, and this (mostly) works. However..... I
+have tested it with 4 totally different hard drives (both SCSI-1 and
+SCSI-2), and one CDROM drive. Interrupts works great for all but one
+specific hard drive. For this one, the driver will eventually hang in
+the transfer state. I have tested with: "dd bs=4k count=2k
+of=/dev/null if=/dev/sdb". It reads ok for a while, then hangs.
+After beating my head against this for a couple of weeks, getting
+nowhere, I give up. So.....This driver does NOT use interrupts, even
+if you have the card jumpered to an IRQ. Probably nobody will ever
+care.