Hi Geert,
some fixes to the Atari NCR5380 SCSI driver: if the ST-DMA lock cannot be taken
in the queue function, indicate host busy to the block layer. Fix return codes
of abort and reset functions, and add scsi_unregister to module exit.
Error handling is still messed up, most likely due to missing ST-DMA lock in
abort and reset. This is still WIP, but might benefit users with a Falcon less
prone to SCSI lockups, i.e. more stable SCSI clock signal.
Signed-off-by: Michael Schmitz <schmitz@xxxxxxxxxx>
Michael
---
drivers/scsi/atari_NCR5380.c | 78 +++++++++++++++++++++++++++--------------
drivers/scsi/atari_scsi.c | 47 +++++++++++++++++++++----
2 files changed, 91 insertions(+), 34 deletions(-)
diff --git a/drivers/scsi/atari_NCR5380.c b/drivers/scsi/atari_NCR5380.c
index 0471f88..3ba46d5 100644
--- a/drivers/scsi/atari_NCR5380.c
+++ b/drivers/scsi/atari_NCR5380.c
@@ -966,13 +966,6 @@ static int NCR5380_queue_command(Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
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.
- */
-
local_irq_save(flags);
/* ++guenther: now that the issue queue is being set up, we can lock ST-DMA.
* Otherwise a running NCR5380_main may steal the lock.
@@ -987,10 +980,32 @@ static int NCR5380_queue_command(Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
* alter queues and touch the lock.
*/
if (!IS_A_TT()) {
+ int rv;
+ /* MSch: since we may now get called from softirq context here,
+ * we cannot always sleep while waiting for the lock.
+ * Use status from falcon_get_lock() to detect if the lock was
+ * successfully taken, and return appropriate status to midlevel
+ * otherwise.
+ * We used to pause the midlevel SCSI timer here; races between
+ * command timeout and lowlevel error handling should not hurt
+ * because the command isn't in any of the queues yet.
+ */
/* perhaps stop command timer here */
- falcon_get_lock();
+ rv = falcon_get_lock();
/* perhaps restart command timer here */
+ if (rv) {
+ local_irq_restore(flags);
+ return SCSI_MLQUEUE_HOST_BUSY;
+ }
}
+
+ /*
+ * 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.
+ */
+
if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) {
LIST(cmd, hostdata->issue_queue);
SET_NEXT(cmd, hostdata->issue_queue);
@@ -1014,10 +1029,12 @@ static int NCR5380_queue_command(Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
* If we're not in an interrupt, we can call NCR5380_main()
* unconditionally, because it cannot be already running.
*/
- if (in_interrupt() || ((flags >> 8) & 7) >= 6)
+ /* As of 2.6.19, the coroutine has to be put on the task queue instead
+ * of being called directly. It might still be called directly if not
+ * in softirq, though. Need to test this.
+ */
queue_main();
- else
- NCR5380_main(NULL);
+
return 0;
}
@@ -1463,6 +1480,7 @@ static int NCR5380_select(struct Scsi_Host *instance, Scsi_Cmnd *cmd, int tag)
ARB_PRINTK("scsi%d: arbitration complete\n", HOSTNO);
if (hostdata->connected) {
+
NCR5380_write(MODE_REG, MR_BASE);
return -1;
}
@@ -2065,7 +2083,6 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance)
/*
* The preferred transfer method is going to be
* PSEUDO-DMA for systems that are strictly PIO,
- * since we can let the hardware do the handshaking.
*
* For this to work, we need to know the transfersize
* ahead of time, since the pseudo-DMA code will sit
@@ -2631,7 +2648,7 @@ static void NCR5380_reselect(struct Scsi_Host *instance)
* host byte of the result field to, if zero DID_ABORTED is
* used.
*
- * Returns : 0 - success, -1 on failure.
+ * Returns : SUCCESS - success, FAILED on failure.
*
* XXX - there is no way to abort the command that is currently
* connected, you have to wait for it to complete. If this is
@@ -2701,11 +2718,12 @@ int NCR5380_abort(Scsi_Cmnd *cmd)
local_irq_restore(flags);
cmd->scsi_done(cmd);
falcon_release_lock_if_possible(hostdata);
- return SCSI_ABORT_SUCCESS;
+ return SUCCESS;
} else {
-/* local_irq_restore(flags); */
+ /* not sure */
+ local_irq_restore(flags);
printk("scsi%d: abort of connected command failed!\n", HOSTNO);
- return SCSI_ABORT_ERROR;
+ return FAILED;
}
}
#endif
@@ -2729,7 +2747,7 @@ int NCR5380_abort(Scsi_Cmnd *cmd)
* yet... */
tmp->scsi_done(tmp);
falcon_release_lock_if_possible(hostdata);
- return SCSI_ABORT_SUCCESS;
+ return SUCCESS;
}
}
@@ -2747,7 +2765,7 @@ int NCR5380_abort(Scsi_Cmnd *cmd)
if (hostdata->connected) {
local_irq_restore(flags);
ABRT_PRINTK("scsi%d: abort failed, command connected.\n", HOSTNO);
- return SCSI_ABORT_SNOOZE;
+ return FAILED;
}
/*
@@ -2782,7 +2800,7 @@ int NCR5380_abort(Scsi_Cmnd *cmd)
ABRT_PRINTK("scsi%d: aborting disconnected command.\n", HOSTNO);
if (NCR5380_select(instance, cmd, (int)cmd->tag))
- return SCSI_ABORT_BUSY;
+ return FAILED;
ABRT_PRINTK("scsi%d: nexus reestablished.\n", HOSTNO);
@@ -2809,7 +2827,7 @@ int NCR5380_abort(Scsi_Cmnd *cmd)
local_irq_restore(flags);
tmp->scsi_done(tmp);
falcon_release_lock_if_possible(hostdata);
- return SCSI_ABORT_SUCCESS;
+ return SUCCESS;
}
}
}
@@ -2835,7 +2853,9 @@ int NCR5380_abort(Scsi_Cmnd *cmd)
*/
falcon_release_lock_if_possible(hostdata);
- return SCSI_ABORT_NOT_RUNNING;
+ /* NCR5380 has FAILED here */
+ /* return SUCCESS; */
+ return FAILED;
}
@@ -2844,16 +2864,18 @@ int NCR5380_abort(Scsi_Cmnd *cmd)
*
* Purpose : reset the SCSI bus.
*
- * Returns : SCSI_RESET_WAKEUP
+ * Returns : SUCCESS
*
*/
+#undef FALCON_RESET_KILL_QUEUES
+
static int NCR5380_bus_reset(Scsi_Cmnd *cmd)
{
SETUP_HOSTDATA(cmd->device->host);
int i;
unsigned long flags;
-#if 1
+#if defined(FALCON_RESET_KILL_QUEUES)
Scsi_Cmnd *connected, *disconnected_queue;
#endif
@@ -2878,7 +2900,8 @@ static int NCR5380_bus_reset(Scsi_Cmnd *cmd)
* through anymore ... */
(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
-#if 1 /* XXX Should now be done by midlevel code, but it's broken XXX */
+#if defined(FALCON_RESET_KILL_QUEUES)
+ /* XXX Should now be done by midlevel code, but it's broken XXX */
/* XXX see below XXX */
/* MSch: old-style reset: actually abort all command processing here */
@@ -2934,7 +2957,7 @@ static int NCR5380_bus_reset(Scsi_Cmnd *cmd)
* the midlevel code that the reset was SUCCESSFUL, and there is no
* need to 'wake up' the commands by a request_sense
*/
- return SCSI_RESET_SUCCESS | SCSI_RESET_BUS_RESET;
+ return SUCCESS;
#else /* 1 */
/* MSch: new-style reset handling: let the mid-level do what it can */
@@ -2982,6 +3005,7 @@ static int NCR5380_bus_reset(Scsi_Cmnd *cmd)
local_irq_restore(flags);
/* we did no complete reset of all commands, so a wakeup is required */
- return SCSI_RESET_WAKEUP | SCSI_RESET_BUS_RESET;
-#endif /* 1 */
+ /* The new error handler code implicitly does this for us anyway */
+ return SUCCESS;
+#endif /* defined(FALCON_RESET_KILL_QUEUES) */
}
diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c
index ad7a23a..9ebfbc6 100644
--- a/drivers/scsi/atari_scsi.c
+++ b/drivers/scsi/atari_scsi.c
@@ -196,7 +196,7 @@ static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
static irqreturn_t scsi_tt_intr(int irq, void *dummy);
static irqreturn_t scsi_falcon_intr(int irq, void *dummy);
static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata);
-static void falcon_get_lock(void);
+static int falcon_get_lock(void);
#ifdef CONFIG_ATARI_SCSI_RESET_BOOT
static void atari_scsi_reset_boot(void);
#endif
@@ -498,6 +498,16 @@ static int falcon_dont_release = 0;
* again (but others waiting longer more probably will win).
*/
+/*
+ * MSch 20061228: in 2.6.x, the fairness wait appears to open a race with
+ * concurrent use of the lock by the IDE driver. Once the lock is taken by
+ * IDE, the SCSI queuecmd function can no longer schedule because it is run
+ * from softirq context a lot.
+ * Disable the fairness wait until I have had time to sort out the lock issues.
+ */
+#undef FALCON_FAIRNESS_WAIT
+#define FALCON_NEVER_SLEEP 1
+
static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata)
{
unsigned long flags;
@@ -519,7 +529,9 @@ static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata)
}
falcon_got_lock = 0;
stdma_release();
+#if defined(FALCON_FAIRNESS_WAIT)
wake_up(&falcon_fairness_wait);
+#endif
}
local_irq_restore(flags);
@@ -540,21 +552,37 @@ static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata)
* Complicated, complicated.... Sigh...
*/
-static void falcon_get_lock(void)
+/* MSch 20061229: in order to avoid sleeping when the lock is not available,
+ * return the current lock state here. atari_queue_command() will then return
+ * with error, causing the midlevel code to pause request submission.
+ */
+static int falcon_get_lock(void)
{
unsigned long flags;
if (IS_A_TT())
- return;
+ return 0;
local_irq_save(flags);
- while (!in_irq() && falcon_got_lock && stdma_others_waiting())
+#if defined(FALCON_FAIRNESS_WAIT)
+ /* MSch: we may not sleep even while in softirq ! */
+ while (!in_interrupt() && falcon_got_lock && stdma_others_waiting())
sleep_on(&falcon_fairness_wait);
-
+#endif
while (!falcon_got_lock) {
if (in_irq())
panic("Falcon SCSI hasn't ST-DMA lock in interrupt");
+ /* we may not sleep in soft interrupts neither, so bail out */
+#if defined(FALCON_NEVER_SLEEP)
+ if (stdma_islocked()) {
+#else
+ if (in_softirq() && stdma_islocked()) {
+#endif
+ // printk(KERN_INFO "Falcon SCSI does not hold ST-DMA lock in softirq!\n" );
+ local_irq_restore(flags);
+ return 1;
+ }
if (!falcon_trying_lock) {
falcon_trying_lock = 1;
stdma_lock(scsi_falcon_intr, NULL);
@@ -569,6 +597,8 @@ static void falcon_get_lock(void)
local_irq_restore(flags);
if (!falcon_got_lock)
panic("Falcon SCSI: someone stole the lock :-(\n");
+
+ return 0;
}
@@ -589,7 +619,7 @@ int atari_queue_command(Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
#endif
-int __init atari_scsi_detect(struct scsi_host_template *host)
+int atari_scsi_detect(struct scsi_host_template *host)
{
static int called = 0;
struct Scsi_Host *instance;
@@ -652,6 +682,8 @@ int __init atari_scsi_detect(struct scsi_host_template *host)
}
atari_dma_phys_buffer = virt_to_phys(atari_dma_buffer);
atari_dma_orig_addr = 0;
+ printk(KERN_ERR "atari_scsi_detect: ST-RAM "
+ "double buffer at %p\n", atari_dma_phys_buffer);
}
#endif
instance = scsi_register(host, sizeof(struct NCR5380_hostdata));
@@ -745,6 +777,7 @@ int atari_scsi_release(struct Scsi_Host *sh)
{
if (IS_A_TT())
free_irq(IRQ_TT_MFP_SCSI, sh);
+ scsi_unregister(atari_scsi_host);
if (atari_dma_buffer)
atari_stram_free(atari_dma_buffer);
return 1;
@@ -828,7 +861,7 @@ int atari_scsi_bus_reset(Scsi_Cmnd *cmd)
} else {
atari_turnon_irq(IRQ_MFP_FSCSI);
}
- if ((rv & SCSI_RESET_ACTION) == SCSI_RESET_SUCCESS)
+ if (rv == SUCCESS)
falcon_release_lock_if_possible(hostdata);
return rv;
--
1.5.6.5
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