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Subject[PATCH 09/71] atari_NCR5380: Reset bus on driver initialization if required
Merge the bus reset code from NCR5380.c into atari_NCR5380.c. This allows
for removal of a lot of duplicated code conditional on the RESET_BOOT
macro (in the next patch).

The atari_NCR5380.c fork lacks the do_reset() and NCR5380_poll_politely()
routines from NCR5380.c, so introduce them. They are indispensible. Keep
the two implementations in sync.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>

---
drivers/scsi/NCR5380.c | 33 +++++++-----
drivers/scsi/atari_NCR5380.c | 113 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 134 insertions(+), 12 deletions(-)

Index: linux/drivers/scsi/NCR5380.c
===================================================================
--- linux.orig/drivers/scsi/NCR5380.c 2015-11-18 19:33:12.000000000 +1100
+++ linux/drivers/scsi/NCR5380.c 2015-11-18 19:33:13.000000000 +1100
@@ -838,19 +838,20 @@ static int NCR5380_maybe_reset_bus(struc
case 1:
case 3:
case 5:
- printk(KERN_INFO "scsi%d: SCSI bus busy, waiting up to five seconds\n", instance->host_no);
- NCR5380_poll_politely(instance, STATUS_REG, SR_BSY, 0, 5*HZ);
+ shost_printk(KERN_ERR, instance, "SCSI bus busy, waiting up to five seconds\n");
+ NCR5380_poll_politely(instance,
+ STATUS_REG, SR_BSY, 0, 5 * HZ);
break;
case 2:
- printk(KERN_WARNING "scsi%d: bus busy, attempting abort\n", instance->host_no);
+ shost_printk(KERN_ERR, instance, "bus busy, attempting abort\n");
do_abort(instance);
break;
case 4:
- printk(KERN_WARNING "scsi%d: bus busy, attempting reset\n", instance->host_no);
+ shost_printk(KERN_ERR, instance, "bus busy, attempting reset\n");
do_reset(instance);
break;
case 6:
- printk(KERN_ERR "scsi%d: bus locked solid or invalid override\n", instance->host_no);
+ shost_printk(KERN_ERR, instance, "bus locked solid\n");
return -ENXIO;
}
}
@@ -1579,21 +1580,29 @@ static int NCR5380_transfer_pio(struct S
}

/**
- * do_reset - issue a reset command
- * @host: adapter to reset
+ * do_reset - issue a reset command
+ * @instance: adapter to reset
*
- * Issue a reset sequence to the NCR5380 and try and get the bus
- * back into sane shape.
+ * Issue a reset sequence to the NCR5380 and try and get the bus
+ * back into sane shape.
*
- * Locks: caller holds queue lock
+ * This clears the reset interrupt flag because there may be no handler for
+ * it. When the driver is initialized, the NCR5380_intr() handler has not yet
+ * been installed. And when in EH we may have released the ST DMA interrupt.
*/

static void do_reset(struct Scsi_Host *instance)
{
- NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG) & PHASE_MASK));
+ unsigned long flags;
+
+ local_irq_save(flags);
+ NCR5380_write(TARGET_COMMAND_REG,
+ PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG) & PHASE_MASK));
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
- udelay(25);
+ udelay(50);
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
+ (void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
+ local_irq_restore(flags);
}

/*
Index: linux/drivers/scsi/atari_NCR5380.c
===================================================================
--- linux.orig/drivers/scsi/atari_NCR5380.c 2015-11-18 19:25:56.000000000 +1100
+++ linux/drivers/scsi/atari_NCR5380.c 2015-11-18 19:33:13.000000000 +1100
@@ -234,6 +234,9 @@
#define HOSTNO instance->host_no
#define H_NO(cmd) (cmd)->device->host->host_no

+static int do_abort(struct Scsi_Host *);
+static void do_reset(struct Scsi_Host *);
+
#ifdef SUPPORT_TAGS

/*
@@ -475,6 +478,47 @@ static inline void initialize_SCp(struct
}
}

+/**
+ * NCR5380_poll_politely - wait for NCR5380 status bits
+ * @instance: controller to poll
+ * @reg: 5380 register to poll
+ * @bit: Bitmask to check
+ * @val: Value required to exit
+ *
+ * Polls the NCR5380 in a reasonably efficient manner waiting for
+ * an event to occur, after a short quick poll we begin giving the
+ * CPU back in non IRQ contexts
+ *
+ * Returns the value of the register or a negative error code.
+ */
+
+static int NCR5380_poll_politely(struct Scsi_Host *instance,
+ int reg, int bit, int val, int t)
+{
+ int n = 500;
+ unsigned long end = jiffies + t;
+ int r;
+
+ while (n-- > 0) {
+ r = NCR5380_read(reg);
+ if ((r & bit) == val)
+ return 0;
+ cpu_relax();
+ }
+
+ /* t time yet ? */
+ while (time_before(jiffies, end)) {
+ r = NCR5380_read(reg);
+ if ((r & bit) == val)
+ return 0;
+ if (!in_interrupt())
+ cond_resched();
+ else
+ cpu_relax();
+ }
+ return -ETIMEDOUT;
+}
+
#include <linux/delay.h>

#if NDEBUG
@@ -801,6 +845,49 @@ static int __init NCR5380_init(struct Sc
}

/**
+ * NCR5380_maybe_reset_bus - Detect and correct bus wedge problems.
+ * @instance: adapter to check
+ *
+ * If the system crashed, it may have crashed with a connected target and
+ * the SCSI bus busy. Check for BUS FREE phase. If not, try to abort the
+ * currently established nexus, which we know nothing about. Failing that
+ * do a bus reset.
+ *
+ * Note that a bus reset will cause the chip to assert IRQ.
+ *
+ * Returns 0 if successful, otherwise -ENXIO.
+ */
+
+static int NCR5380_maybe_reset_bus(struct Scsi_Host *instance)
+{
+ int pass;
+
+ for (pass = 1; (NCR5380_read(STATUS_REG) & SR_BSY) && pass <= 6; ++pass) {
+ switch (pass) {
+ case 1:
+ case 3:
+ case 5:
+ shost_printk(KERN_ERR, instance, "SCSI bus busy, waiting up to five seconds\n");
+ NCR5380_poll_politely(instance,
+ STATUS_REG, SR_BSY, 0, 5 * HZ);
+ break;
+ case 2:
+ shost_printk(KERN_ERR, instance, "bus busy, attempting abort\n");
+ do_abort(instance);
+ break;
+ case 4:
+ shost_printk(KERN_ERR, instance, "bus busy, attempting reset\n");
+ do_reset(instance);
+ break;
+ case 6:
+ shost_printk(KERN_ERR, instance, "bus locked solid\n");
+ return -ENXIO;
+ }
+ }
+ return 0;
+}
+
+/**
* NCR5380_exit - remove an NCR5380
* @instance: adapter to remove
*
@@ -1741,6 +1828,32 @@ static int NCR5380_transfer_pio(struct S
return -1;
}

+/**
+ * do_reset - issue a reset command
+ * @instance: adapter to reset
+ *
+ * Issue a reset sequence to the NCR5380 and try and get the bus
+ * back into sane shape.
+ *
+ * This clears the reset interrupt flag because there may be no handler for
+ * it. When the driver is initialized, the NCR5380_intr() handler has not yet
+ * been installed. And when in EH we may have released the ST DMA interrupt.
+ */
+
+static void do_reset(struct Scsi_Host *instance)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ NCR5380_write(TARGET_COMMAND_REG,
+ PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG) & PHASE_MASK));
+ NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
+ udelay(50);
+ NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
+ (void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
+ local_irq_restore(flags);
+}
+
/*
* Function : do_abort (Scsi_Host *host)
*



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