*/
/*
- * Revision 1.10 1998/9/2 Alan Cox
- * (alan@lxorguk.ukuu.org.uk)
- * Fixed up the timer lockups reported so far. Things still suck. Looking
- * forward to 2.3 and per device request queues. Then it'll be possible to
- * SMP thread this beast and improve life no end.
-
- * Revision 1.9 1997/7/27 Ronald van Cuijlenborg
- * (ronald.van.cuijlenborg@tip.nl or nutty@dds.nl)
- * (hopefully) fixed and enhanced USLEEP
- * added support for DTC3181E card (for Mustek scanner)
- *
-
- * Revision 1.8 Ingmar Baumgart
- * (ingmar@gonzo.schwaben.de)
- * added support for NCR53C400a card
- *
-
- * Revision 1.7 1996/3/2 Ray Van Tassle (rayvt@comm.mot.com)
- * added proc_info
- * added support needed for DTC 3180/3280
- * fixed a couple of bugs
- *
-
- * Revision 1.5 1994/01/19 09:14:57 drew
- * Fixed udelay() hack that was being used on DATAOUT phases
- * instead of a proper wait for the final handshake.
- *
- * Revision 1.4 1994/01/19 06:44:25 drew
- * *** empty log message ***
- *
- * Revision 1.3 1994/01/19 05:24:40 drew
- * Added support for TCR LAST_BYTE_SENT bit.
- *
- * Revision 1.2 1994/01/15 06:14:11 drew
- * REAL DMA support, bug fixes.
- *
- * Revision 1.1 1994/01/15 06:00:54 drew
- * Initial revision
- *
+ * With contributions from Ray Van Tassle, Ingmar Baumgart,
+ * Ronald van Cuijlenborg, Alan Cox and others.
*/
/*
* transfer - some PC's will use the I/O bus, 68K's must use
* memory mapped) and drops this file in their 'C' wrapper.
*
- * (Note from hch: unfortunately it was not enough for the different
- * m68k folks and instead of improving this driver they copied it
- * and hacked it up for their needs. As a consequence they lost
- * most updates to this driver. Maybe someone will fix all these
- * drivers to use a common core one day..)
- *
* As far as command queueing, two queues are maintained for
* each 5380 in the system - commands that haven't been issued yet,
* and commands that are currently executing. This means that an
* rely on phase mismatch and EOP interrupts to determine end
* of phase.
*
- * Defaults for these will be provided although the user may want to adjust
- * these to allocate CPU resources to the SCSI driver or "real" code.
- *
* These macros MUST be defined :
*
* NCR5380_read(register) - read from the specified register
static int do_abort(struct Scsi_Host *);
static void do_reset(struct Scsi_Host *);
-/*
+/**
* initialize_SCp - init the scsi pointer field
* @cmd: command block to set up
*
* @instance: adapter state to dump
*
* Print the SCSI bus signals for debugging purposes
- *
- * Locks: caller holds hostdata lock (not essential)
*/
static void NCR5380_print(struct Scsi_Host *instance)
}
-/*
+/**
* NCR5380_print_phase - show SCSI phase
* @instance: adapter to dump
*
* Print the current SCSI phase for debugging purposes
- *
- * Locks: none
*/
static void NCR5380_print_phase(struct Scsi_Host *instance)
*
* Autoprobe for the IRQ line used by the NCR5380 by triggering an IRQ
* and then looking to see what interrupt actually turned up.
- *
- * Locks: none, irqs must be enabled on entry
*/
static int __init __maybe_unused NCR5380_probe_irq(struct Scsi_Host *instance,
* @instance: relevant scsi host instance
*
* For use as the host template info() handler.
- *
- * Locks: none
*/
static const char *NCR5380_info(struct Scsi_Host *instance)
}
#ifdef PSEUDO_DMA
-/******************************************/
-/*
- * /proc/scsi/[dtc pas16 t128 generic]/[0-ASC_NUM_BOARD_SUPPORTED]
- *
- * *buffer: I/O buffer
- * **start: if inout == FALSE pointer into buffer where user read should start
- * offset: current offset
- * length: length of buffer
- * hostno: Scsi_Host host_no
- * inout: TRUE - user is writing; FALSE - user is reading
- *
- * Return the number of bytes read from or written
- */
-
static int __maybe_unused NCR5380_write_info(struct Scsi_Host *instance,
char *buffer, int length)
{
* set correctly. I don't care about the irq and other fields.
*
* Returns 0 for success
- *
- * Locks: interrupts must be enabled when we are called
*/
static int NCR5380_init(struct Scsi_Host *instance, int flags)
* be done on the NCR5380 host adapters in a system. Both
* NCR5380_queue_command() and NCR5380_intr() will try to start it
* in case it is not running.
- *
- * Locks: called as its own thread with no locks held. Takes the
- * host lock and called routines may take the isa dma lock.
*/
static void NCR5380_main(struct work_struct *work)
*
* If failed (no target) : cmd->scsi_done() will be called, and the
* cmd->result host byte set to DID_BAD_TARGET.
- *
- * Locks: caller holds hostdata lock in IRQ mode
*/
static struct scsi_cmnd *NCR5380_select(struct Scsi_Host *instance,
* is in same phase.
*
* Also, *phase, *count, *data are modified in place.
- *
- * Locks: io_request lock held by caller
*/
} while ((tmp & BASR_PHASE_MATCH) && !(tmp & (BASR_BUSY_ERROR | BASR_END_DMA_TRANSFER)));
/*
- At this point, either we've completed DMA, or we have a phase mismatch,
- or we've unexpectedly lost BUSY (which is a real error).
-
- For write DMAs, we want to wait until the last byte has been
- transferred out over the bus before we turn off DMA mode. Alas, there
- seems to be no terribly good way of doing this on a 5380 under all
- conditions. For non-scatter-gather operations, we can wait until REQ
- and ACK both go false, or until a phase mismatch occurs. Gather-writes
- are nastier, since the device will be expecting more data than we
- are prepared to send it, and REQ will remain asserted. On a 53C8[01] we
- could test LAST BIT SENT to assure transfer (I imagine this is precisely
- why this signal was added to the newer chips) but on the older 538[01]
- this signal does not exist. The workaround for this lack is a watchdog;
- we bail out of the wait-loop after a modest amount of wait-time if
- the usual exit conditions are not met. Not a terribly clean or
- correct solution :-%
-
- Reads are equally tricky due to a nasty characteristic of the NCR5380.
- If the chip is in DMA mode for an READ, it will respond to a target's
- REQ by latching the SCSI data into the INPUT DATA register and asserting
- ACK, even if it has _already_ been notified by the DMA controller that
- the current DMA transfer has completed! If the NCR5380 is then taken
- out of DMA mode, this already-acknowledged byte is lost.
-
- This is not a problem for "one DMA transfer per command" reads, because
- the situation will never arise... either all of the data is DMA'ed
- properly, or the target switches to MESSAGE IN phase to signal a
- disconnection (either operation bringing the DMA to a clean halt).
- However, in order to handle scatter-reads, we must work around the
- problem. The chosen fix is to DMA N-2 bytes, then check for the
- condition before taking the NCR5380 out of DMA mode. One or two extra
- bytes are transferred via PIO as necessary to fill out the original
- request.
+ * At this point, either we've completed DMA, or we have a phase mismatch,
+ * or we've unexpectedly lost BUSY (which is a real error).
+ *
+ * For DMA sends, we want to wait until the last byte has been
+ * transferred out over the bus before we turn off DMA mode. Alas, there
+ * seems to be no terribly good way of doing this on a 5380 under all
+ * conditions. For non-scatter-gather operations, we can wait until REQ
+ * and ACK both go false, or until a phase mismatch occurs. Gather-sends
+ * are nastier, since the device will be expecting more data than we
+ * are prepared to send it, and REQ will remain asserted. On a 53C8[01] we
+ * could test Last Byte Sent to assure transfer (I imagine this is precisely
+ * why this signal was added to the newer chips) but on the older 538[01]
+ * this signal does not exist. The workaround for this lack is a watchdog;
+ * we bail out of the wait-loop after a modest amount of wait-time if
+ * the usual exit conditions are not met. Not a terribly clean or
+ * correct solution :-%
+ *
+ * DMA receive is equally tricky due to a nasty characteristic of the NCR5380.
+ * If the chip is in DMA receive mode, it will respond to a target's
+ * REQ by latching the SCSI data into the INPUT DATA register and asserting
+ * ACK, even if it has _already_ been notified by the DMA controller that
+ * the current DMA transfer has completed! If the NCR5380 is then taken
+ * out of DMA mode, this already-acknowledged byte is lost. This is
+ * not a problem for "one DMA transfer per READ command", because
+ * the situation will never arise... either all of the data is DMA'ed
+ * properly, or the target switches to MESSAGE IN phase to signal a
+ * disconnection (either operation bringing the DMA to a clean halt).
+ * However, in order to handle scatter-receive, we must work around the
+ * problem. The chosen fix is to DMA N-2 bytes, then check for the
+ * condition before taking the NCR5380 out of DMA mode. One or two extra
+ * bytes are transferred via PIO as necessary to fill out the original
+ * request.
*/
if (p & SR_IO) {
*
* XXX Note : we need to watch for bus free or a reset condition here
* to recover from an unexpected bus free condition.
- *
- * Locks: io_request_lock held by caller in IRQ mode
*/
static void NCR5380_information_transfer(struct Scsi_Host *instance) {
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
break;
case EXTENDED_MESSAGE:
-/*
- * Extended messages are sent in the following format :
- * Byte
- * 0 EXTENDED_MESSAGE == 1
- * 1 length (includes one byte for code, doesn't
- * include first two bytes)
- * 2 code
- * 3..length+1 arguments
- *
- * Start the extended message buffer with the EXTENDED_MESSAGE
- * byte, since spi_print_msg() wants the whole thing.
- */
+ /*
+ * Start the message buffer with the EXTENDED_MESSAGE
+ * byte, since spi_print_msg() wants the whole thing.
+ */
extended_msg[0] = EXTENDED_MESSAGE;
/* Accept first byte by clearing ACK */
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
* nexus has been reestablished,
*
* Inputs : instance - this instance of the NCR5380.
- *
- * Locks: io_request_lock held by caller if IRQ driven
*/
static void NCR5380_reselect(struct Scsi_Host *instance) {
* 1+ (800) 334-5454
*/
-/*
- * ++roman: To port the 5380 driver to the Atari, I had to do some changes in
- * this file, too:
- *
- * - Some of the debug statements were incorrect (undefined variables and the
- * like). I fixed that.
- *
- * - In information_transfer(), I think a #ifdef was wrong. Looking at the
- * possible DMA transfer size should also happen for REAL_DMA. I added this
- * in the #if statement.
- *
- * - When using real DMA, information_transfer() should return in a DATAOUT
- * phase after starting the DMA. It has nothing more to do.
- *
- * - The interrupt service routine should run main after end of DMA, too (not
- * only after RESELECTION interrupts). Additionally, it should _not_ test
- * for more interrupts after running main, since a DMA process may have
- * been started and interrupts are turned on now. The new int could happen
- * inside the execution of NCR5380_intr(), leading to recursive
- * calls.
- *
- * - I've added a function merge_contiguous_buffers() that tries to
- * merge scatter-gather buffers that are located at contiguous
- * physical addresses and can be processed with the same DMA setup.
- * Since most scatter-gather operations work on a page (4K) of
- * 4 buffers (1K), in more than 90% of all cases three interrupts and
- * DMA setup actions are saved.
- *
- * - I've deleted all the stuff for AUTOPROBE_IRQ, REAL_DMA_POLL, PSEUDO_DMA
- * and USLEEP, because these were messing up readability and will never be
- * needed for Atari SCSI.
- *
- * - I've revised the NCR5380_main() calling scheme (relax the 'main_running'
- * stuff), and 'main' is executed in a bottom half if awoken by an
- * interrupt.
- *
- * - The code was quite cluttered up by "#if (NDEBUG & NDEBUG_*) printk..."
- * constructs. In my eyes, this made the source rather unreadable, so I
- * finally replaced that by the *_PRINTK() macros.
- *
- */
+/* Ported to Atari by Roman Hodek and others. */
/* Adapted for the sun3 by Sam Creasey. */
#endif /* SUPPORT_TAGS */
-
-/*
- * Function: void merge_contiguous_buffers( struct scsi_cmnd *cmd )
- *
- * Purpose: Try to merge several scatter-gather requests into one DMA
- * transfer. This is possible if the scatter buffers lie on
- * physical contiguous addresses.
- *
- * Parameters: struct scsi_cmnd *cmd
- * The command to work on. The first scatter buffer's data are
- * assumed to be already transferred into ptr/this_residual.
+/**
+ * merge_contiguous_buffers - coalesce scatter-gather list entries
+ * @cmd: command requesting IO
+ *
+ * Try to merge several scatter-gather buffers into one DMA transfer.
+ * This is possible if the scatter buffers lie on physically
+ * contiguous addresses. The first scatter-gather buffer's data are
+ * assumed to be already transferred into cmd->SCp.this_residual.
+ * Every buffer merged avoids an interrupt and a DMA setup operation.
*/
static void merge_contiguous_buffers(struct scsi_cmnd *cmd)
cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;
cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
cmd->SCp.this_residual = cmd->SCp.buffer->length;
- /* ++roman: Try to merge some scatter-buffers if they are at
- * contiguous physical addresses.
- */
+
merge_contiguous_buffers(cmd);
} else {
cmd->SCp.buffer = NULL;
* @instance: adapter to dump
*
* Print the current SCSI phase for debugging purposes
- *
- * Locks: none
*/
static void NCR5380_print_phase(struct Scsi_Host *instance)
* @instance: relevant scsi host instance
*
* For use as the host template info() handler.
- *
- * Locks: none
*/
static const char *NCR5380_info(struct Scsi_Host *instance)
cmd->result = 0;
/*
- * Insert the cmd into the issue queue. Note that REQUEST SENSE
- * commands are added to the head of the queue since any command will
- * clear the contingent allegiance condition that exists and the
- * sense data is only guaranteed to be valid while the condition exists.
- */
-
- /* ++guenther: now that the issue queue is being set up, we can lock ST-DMA.
- * Otherwise a running NCR5380_main may steal the lock.
- * Lock before actually inserting due to fairness reasons explained in
- * atari_scsi.c. If we insert first, then it's impossible for this driver
- * to release the lock.
- * Stop timer for this command while waiting for the lock, or timeouts
- * may happen (and they really do), and it's no good if the command doesn't
- * appear in any of the queues.
* ++roman: Just disabling the NCR interrupt isn't sufficient here,
* because also a timer int can trigger an abort or reset, which would
* alter queues and touch the lock.
* be done on the NCR5380 host adapters in a system. Both
* NCR5380_queue_command() and NCR5380_intr() will try to start it
* in case it is not running.
- *
- * Locks: called as its own thread with no locks held.
*/
static void NCR5380_main(struct work_struct *work)
* mismatch occurs (which would finish the DMA transfer).
*
* Inputs : instance - this instance of the NCR5380.
- *
*/
static void NCR5380_dma_complete(struct Scsi_Host *instance)
* is in same phase.
*
* Also, *phase, *count, *data are modified in place.
- *
*/
--cmd->SCp.buffers_residual;
cmd->SCp.this_residual = cmd->SCp.buffer->length;
cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
- /* ++roman: Try to merge some scatter-buffers if
- * they are at contiguous physical addresses.
- */
merge_contiguous_buffers(cmd);
dsprintk(NDEBUG_INFORMATION, instance, "%d bytes and %d buffers left\n",
cmd->SCp.this_residual,
/*
* If the watchdog timer fires, all future
* accesses to this device will use the
- * polled-IO. */
+ * polled-IO.
+ */
scmd_printk(KERN_INFO, cmd,
"switching to slow handshake\n");
cmd->device->borken = 1;
/* Enable reselect interrupts */
NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
- /* ++roman: For Falcon SCSI, release the lock on the
- * ST-DMA here if no other commands are waiting on the
- * disconnected queue.
- */
maybe_release_dma_irq(instance);
return;
case MESSAGE_REJECT:
break;
case EXTENDED_MESSAGE:
/*
- * Extended messages are sent in the following format :
- * Byte
- * 0 EXTENDED_MESSAGE == 1
- * 1 length (includes one byte for code, doesn't
- * include first two bytes)
- * 2 code
- * 3..length+1 arguments
- *
- * Start the extended message buffer with the EXTENDED_MESSAGE
+ * Start the message buffer with the EXTENDED_MESSAGE
* byte, since spi_print_msg() wants the whole thing.
*/
extended_msg[0] = EXTENDED_MESSAGE;
* nexus has been reestablished,
*
* Inputs : instance - this instance of the NCR5380.
- *
*/
projects / users / hch / configfs.git / commitdiff