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>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/atari_NCR5380.c b/drivers/scsi/atari_NCR5380.c
index db87ece..a15b655 100644
--- a/drivers/scsi/atari_NCR5380.c
+++ b/drivers/scsi/atari_NCR5380.c
@@ -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 @@
}
}
+/**
+ * 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 @@
}
/**
+ * 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 @@
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)
*