Re: [PATCH 1/6] NCR5380: Use probe_irq_*() for IRQ probing

From: Finn Thain
Date: Wed Nov 02 2016 - 03:45:03 EST



On Mon, 31 Oct 2016, Ondrej Zary wrote:

> Use standard probe_irq_on() and probe_irq_off() functions instead of own
> implementation. This prevents warning messages like this in the kernel
> log: genirq: Flags mismatch irq 1. 00000000 (NCR-probe) vs. 00000080
> (i8042)
>
> Move the IRQ trigger code to a separate function so it can be used for
> other purposes (testing if the IRQ works) and move the code from NCR5380
> to g_NCR5380.
>
> Also add missing IRQ reset before and after the probe.
>
> Signed-off-by: Ondrej Zary <linux@xxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/scsi/NCR5380.c | 77 +---------------------------------------------
> drivers/scsi/NCR5380.h | 1 -
> drivers/scsi/g_NCR5380.c | 50 +++++++++++++++++++++++++++++-
> 3 files changed, 50 insertions(+), 78 deletions(-)
>
> diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
> index d849ffa..4f5ca79 100644
> --- a/drivers/scsi/NCR5380.c
> +++ b/drivers/scsi/NCR5380.c
> @@ -97,9 +97,6 @@
> * and macros and include this file in your driver.
> *
> * These macros control options :
> - * AUTOPROBE_IRQ - if defined, the NCR5380_probe_irq() function will be
> - * defined.
> - *
> * AUTOSENSE - if defined, REQUEST SENSE will be performed automatically
> * for commands that return with a CHECK CONDITION status.
> *
> @@ -127,9 +124,7 @@
> * NCR5380_dma_residual - residual byte count
> *
> * The generic driver is initialized by calling NCR5380_init(instance),
> - * after setting the appropriate host specific fields and ID. If the
> - * driver wishes to autoprobe for an IRQ line, the NCR5380_probe_irq(instance,
> - * possible) function may be used.
> + * after setting the appropriate host specific fields and ID.
> */
>
> #ifndef NCR5380_io_delay
> @@ -351,76 +346,6 @@ static void NCR5380_print_phase(struct Scsi_Host *instance)
> }
> #endif
>
> -
> -static int probe_irq;
> -
> -/**
> - * probe_intr - helper for IRQ autoprobe
> - * @irq: interrupt number
> - * @dev_id: unused
> - * @regs: unused
> - *
> - * Set a flag to indicate the IRQ in question was received. This is
> - * used by the IRQ probe code.
> - */
> -
> -static irqreturn_t probe_intr(int irq, void *dev_id)
> -{
> - probe_irq = irq;
> - return IRQ_HANDLED;
> -}
> -
> -/**
> - * NCR5380_probe_irq - find the IRQ of an NCR5380
> - * @instance: NCR5380 controller
> - * @possible: bitmask of ISA IRQ lines
> - *
> - * Autoprobe for the IRQ line used by the NCR5380 by triggering an IRQ
> - * and then looking to see what interrupt actually turned up.
> - */
> -
> -static int __maybe_unused NCR5380_probe_irq(struct Scsi_Host *instance,
> - int possible)
> -{
> - struct NCR5380_hostdata *hostdata = shost_priv(instance);
> - unsigned long timeout;
> - int trying_irqs, i, mask;
> -
> - for (trying_irqs = 0, i = 1, mask = 2; i < 16; ++i, mask <<= 1)
> - if ((mask & possible) && (request_irq(i, &probe_intr, 0, "NCR-probe", NULL) == 0))
> - trying_irqs |= mask;
> -
> - timeout = jiffies + msecs_to_jiffies(250);
> - probe_irq = NO_IRQ;
> -
> - /*
> - * A interrupt is triggered whenever BSY = false, SEL = true
> - * and a bit set in the SELECT_ENABLE_REG is asserted on the
> - * SCSI bus.
> - *
> - * Note that the bus is only driven when the phase control signals
> - * (I/O, C/D, and MSG) match those in the TCR, so we must reset that
> - * to zero.
> - */
> -
> - NCR5380_write(TARGET_COMMAND_REG, 0);
> - NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
> - NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
> - NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA | ICR_ASSERT_SEL);
> -
> - while (probe_irq == NO_IRQ && time_before(jiffies, timeout))
> - schedule_timeout_uninterruptible(1);
> -
> - NCR5380_write(SELECT_ENABLE_REG, 0);
> - NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
> -
> - for (i = 1, mask = 2; i < 16; ++i, mask <<= 1)
> - if (trying_irqs & mask)
> - free_irq(i, NULL);
> -
> - return probe_irq;
> -}
> -
> /**
> * NCR58380_info - report driver and host information
> * @instance: relevant scsi host instance
> diff --git a/drivers/scsi/NCR5380.h b/drivers/scsi/NCR5380.h
> index 3c6ce54..4724558 100644
> --- a/drivers/scsi/NCR5380.h
> +++ b/drivers/scsi/NCR5380.h
> @@ -290,7 +290,6 @@ static inline struct scsi_cmnd *NCR5380_to_scmd(struct NCR5380_cmd *ncmd_ptr)
> #define NCR5380_dprint_phase(flg, arg) do {} while (0)
> #endif
>
> -static int NCR5380_probe_irq(struct Scsi_Host *instance, int possible);
> static int NCR5380_init(struct Scsi_Host *instance, int flags);
> static int NCR5380_maybe_reset_bus(struct Scsi_Host *);
> static void NCR5380_exit(struct Scsi_Host *instance);
> diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
> index 7299ad9..09c660b 100644
> --- a/drivers/scsi/g_NCR5380.c
> +++ b/drivers/scsi/g_NCR5380.c
> @@ -67,6 +67,54 @@
> MODULE_ALIAS("g_NCR5380_mmio");
> MODULE_LICENSE("GPL");
>
> +static void NCR5380_trigger_irq(struct Scsi_Host *instance)

That should be 'g_NCR5380_trigger_irq' (if it needs a prefix).

> +{
> + struct NCR5380_hostdata *hostdata = shost_priv(instance);
> +
> + /*
> + * An interrupt is triggered whenever BSY = false, SEL = true
> + * and a bit set in the SELECT_ENABLE_REG is asserted on the
> + * SCSI bus.
> + *
> + * Note that the bus is only driven when the phase control signals
> + * (I/O, C/D, and MSG) match those in the TCR, so we must reset that
> + * to zero.
> + */
> + NCR5380_write(TARGET_COMMAND_REG, 0);

That assumes bus free phase, which we hope is the case but
NCR5380_maybe_reset_bus() doesn't guarantee it. This is more robust:

* Note that the bus is only driven when the phase control signals
* (I/O, C/D, and MSG) match those in the TCR.
*/
NCR5380_write(TARGET_COMMAND_REG,
PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG) & PHASE_MASK));


> + NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
> + NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
> + NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA | ICR_ASSERT_SEL);
> +
> + usleep_range(1000, 20000);

Again, msleep(1) would be more appropriate here.

> +
> + NCR5380_write(SELECT_ENABLE_REG, 0);
> + NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
> +}
> +
> +/**
> + * NCR5380_probe_irq - find the IRQ of an NCR5380

This should be 'g_NCR5380_probe_irq' (if it needs a prefix).

> + * @instance: NCR5380 controller
> + *
> + * Autoprobe for the IRQ line used by the NCR5380 by triggering an IRQ
> + * and then looking to see what interrupt actually turned up.
> + */
> +
> +static int NCR5380_probe_irq(struct Scsi_Host *instance)
> +{
> + struct NCR5380_hostdata *hostdata = shost_priv(instance);
> + int irq_mask, irq;
> +
> + NCR5380_read(RESET_PARITY_INTERRUPT_REG);
> + irq_mask = probe_irq_on();
> + NCR5380_trigger_irq(instance);
> + irq = probe_irq_off(irq_mask);
> + NCR5380_read(RESET_PARITY_INTERRUPT_REG);
> + if (irq < 0)
> + irq = NO_IRQ;
> +
> + return irq;
> +}
> +
> /*
> * Configure I/O address of 53C400A or DTC436 by writing magic numbers
> * to ports 0x779 and 0x379.
> @@ -265,7 +313,7 @@ static int generic_NCR5380_init_one(struct scsi_host_template *tpnt,
> if (irq != IRQ_AUTO)
> instance->irq = irq;
> else
> - instance->irq = NCR5380_probe_irq(instance, 0xffff);
> + instance->irq = NCR5380_probe_irq(instance);
>
> /* Compatibility with documented NCR5380 kernel parameters */
> if (instance->irq == 255)
>

--