On Sun, Apr 26, 2009 at 09:24, Michael Schmitz
<schm...@biophys.uni-duesseldorf.de> wrote:
> 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.
Any news on this one ("still WIP")?
> Signed-off-by: Michael Schmitz <schm...@debian.org>
>
> 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
>
>
--
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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