IB/ipath: Support blinking LEDs with an led_override file

When we want to find an InfiniPath HCA in a rack of nodes, it is often
expeditious to blink the status LEDs via a userspace /sys file.

A write-only led_override "file" is published per device. Writes to
this file are interpreted as (string form) numbers, and the resulting
value sent to ipath_set_led_override(). The upper eight bits are
interpretted as a 4.4 fixed-point "frequency in Hertz", and the bottom
two 4-bit values are alternately (D0..3, then D4..7) used by the
board-specific LED-setting function to override the normal state.

Signed-off-by: Michael Albaugh <michael.albaugh@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/ipath/ipath_driver.c

@@ -1846,6 +1846,87 @@ void ipath_write_kreg_port(const struct ipath_devdata *dd, ipath_kreg regno,
 	ipath_write_kreg(dd, where, value);
 }
 
+/*
+ * Following deal with the "obviously simple" task of overriding the state
+ * of the LEDS, which normally indicate link physical and logical status.
+ * The complications arise in dealing with different hardware mappings
+ * and the board-dependent routine being called from interrupts.
+ * and then there's the requirement to _flash_ them.
+ */
+#define LED_OVER_FREQ_SHIFT 8
+#define LED_OVER_FREQ_MASK (0xFF<<LED_OVER_FREQ_SHIFT)
+/* Below is "non-zero" to force override, but both actual LEDs are off */
+#define LED_OVER_BOTH_OFF (8)
+
+void ipath_run_led_override(unsigned long opaque)
+{
+	struct ipath_devdata *dd = (struct ipath_devdata *)opaque;
+	int timeoff;
+	int pidx;
+	u64 lstate, ltstate, val;
+
+	if (!(dd->ipath_flags & IPATH_INITTED))
+		return;
+
+	pidx = dd->ipath_led_override_phase++ & 1;
+	dd->ipath_led_override = dd->ipath_led_override_vals[pidx];
+	timeoff = dd->ipath_led_override_timeoff;
+
+	/*
+	 * below potentially restores the LED values per current status,
+	 * should also possibly setup the traffic-blink register,
+	 * but leave that to per-chip functions.
+	 */
+	val = ipath_read_kreg64(dd, dd->ipath_kregs->kr_ibcstatus);
+	ltstate = (val >> INFINIPATH_IBCS_LINKTRAININGSTATE_SHIFT) &
+		  INFINIPATH_IBCS_LINKTRAININGSTATE_MASK;
+	lstate = (val >> INFINIPATH_IBCS_LINKSTATE_SHIFT) &
+		 INFINIPATH_IBCS_LINKSTATE_MASK;
+
+	dd->ipath_f_setextled(dd, lstate, ltstate);
+	mod_timer(&dd->ipath_led_override_timer, jiffies + timeoff);
+}
+
+void ipath_set_led_override(struct ipath_devdata *dd, unsigned int val)
+{
+	int timeoff, freq;
+
+	if (!(dd->ipath_flags & IPATH_INITTED))
+		return;
+
+	/* First check if we are blinking. If not, use 1HZ polling */
+	timeoff = HZ;
+	freq = (val & LED_OVER_FREQ_MASK) >> LED_OVER_FREQ_SHIFT;
+
+	if (freq) {
+		/* For blink, set each phase from one nybble of val */
+		dd->ipath_led_override_vals[0] = val & 0xF;
+		dd->ipath_led_override_vals[1] = (val >> 4) & 0xF;
+		timeoff = (HZ << 4)/freq;
+	} else {
+		/* Non-blink set both phases the same. */
+		dd->ipath_led_override_vals[0] = val & 0xF;
+		dd->ipath_led_override_vals[1] = val & 0xF;
+	}
+	dd->ipath_led_override_timeoff = timeoff;
+
+	/*
+	 * If the timer has not already been started, do so. Use a "quick"
+	 * timeout so the function will be called soon, to look at our request.
+	 */
+	if (atomic_inc_return(&dd->ipath_led_override_timer_active) == 1) {
+		/* Need to start timer */
+		init_timer(&dd->ipath_led_override_timer);
+		dd->ipath_led_override_timer.function =
+						 ipath_run_led_override;
+		dd->ipath_led_override_timer.data = (unsigned long) dd;
+		dd->ipath_led_override_timer.expires = jiffies + 1;
+		add_timer(&dd->ipath_led_override_timer);
+	} else {
+		atomic_dec(&dd->ipath_led_override_timer_active);
+	}
+}
+
 /**
  * ipath_shutdown_device - shut down a device
  * @dd: the infinipath device
@@ -1909,7 +1990,6 @@ void ipath_shutdown_device(struct ipath_devdata *dd)
 	 * Turn the LEDs off explictly for the same reason.
 	 */
 	dd->ipath_f_quiet_serdes(dd);
-	dd->ipath_f_setextled(dd, 0, 0);
 
 	if (dd->ipath_stats_timer_active) {
 		del_timer_sync(&dd->ipath_stats_timer);
@@ -2085,6 +2165,16 @@ int ipath_reset_device(int unit)
 		goto bail;
 	}
 
+	if (atomic_read(&dd->ipath_led_override_timer_active)) {
+		/* Need to stop LED timer, _then_ shut off LEDs */
+		del_timer_sync(&dd->ipath_led_override_timer);
+		atomic_set(&dd->ipath_led_override_timer_active, 0);
+	}
+
+	/* Shut off LEDs after we are sure timer is not running */
+	dd->ipath_led_override = LED_OVER_BOTH_OFF;
+	dd->ipath_f_setextled(dd, 0, 0);
+
 	dev_info(&dd->pcidev->dev, "Reset on unit %u requested\n", unit);
 
 	if (!dd->ipath_kregbase || !(dd->ipath_flags & IPATH_PRESENT)) {

drivers/infiniband/hw/ipath/ipath_iba6110.c

@@ -1065,6 +1065,16 @@ static void ipath_setup_ht_setextled(struct ipath_devdata *dd,
 	if (ipath_diag_inuse)
 		return;
 
+	/* Allow override of LED display for, e.g. Locating system in rack */
+	if (dd->ipath_led_override) {
+		ltst = (dd->ipath_led_override & IPATH_LED_PHYS)
+			? INFINIPATH_IBCS_LT_STATE_LINKUP
+			: INFINIPATH_IBCS_LT_STATE_DISABLED;
+		lst = (dd->ipath_led_override & IPATH_LED_LOG)
+			? INFINIPATH_IBCS_L_STATE_ACTIVE
+			: INFINIPATH_IBCS_L_STATE_DOWN;
+	}
+
 	/*
 	 * start by setting both LED control bits to off, then turn
 	 * on the appropriate bit(s).

drivers/infiniband/hw/ipath/ipath_iba6120.c

@@ -797,6 +797,16 @@ static void ipath_setup_pe_setextled(struct ipath_devdata *dd, u64 lst,
 	if (ipath_diag_inuse)
 		return;
 
+	/* Allow override of LED display for, e.g. Locating system in rack */
+	if (dd->ipath_led_override) {
+		ltst = (dd->ipath_led_override & IPATH_LED_PHYS)
+			? INFINIPATH_IBCS_LT_STATE_LINKUP
+			: INFINIPATH_IBCS_LT_STATE_DISABLED;
+		lst = (dd->ipath_led_override & IPATH_LED_LOG)
+			? INFINIPATH_IBCS_L_STATE_ACTIVE
+			: INFINIPATH_IBCS_L_STATE_DOWN;
+	}
+
 	extctl = dd->ipath_extctrl & ~(INFINIPATH_EXTC_LED1PRIPORT_ON |
 				       INFINIPATH_EXTC_LED2PRIPORT_ON);
 

drivers/infiniband/hw/ipath/ipath_kernel.h

@@ -575,6 +575,16 @@ struct ipath_devdata {
 	u16 ipath_gpio_scl_num;
 	u64 ipath_gpio_sda;
 	u64 ipath_gpio_scl;
+
+	/* used to override LED behavior */
+	u8 ipath_led_override;  /* Substituted for normal value, if non-zero */
+	u16 ipath_led_override_timeoff; /* delta to next timer event */
+	u8 ipath_led_override_vals[2]; /* Alternates per blink-frame */
+	u8 ipath_led_override_phase; /* Just counts, LSB picks from vals[] */
+	atomic_t ipath_led_override_timer_active;
+	/* Used to flash LEDs in override mode */
+	struct timer_list ipath_led_override_timer;
+
 };
 
 /* Private data for file operations */
@@ -716,6 +726,15 @@ void ipath_get_eeprom_info(struct ipath_devdata *);
 u64 ipath_snap_cntr(struct ipath_devdata *, ipath_creg);
 void ipath_disarm_senderrbufs(struct ipath_devdata *, int);
 
+/*
+ * Set LED override, only the two LSBs have "public" meaning, but
+ * any non-zero value substitutes them for the Link and LinkTrain
+ * LED states.
+ */
+#define IPATH_LED_PHYS 1 /* Physical (linktraining) GREEN LED */
+#define IPATH_LED_LOG 2  /* Logical (link) YELLOW LED */
+void ipath_set_led_override(struct ipath_devdata *dd, unsigned int val);
+
 /*
  * number of words used for protocol header if not set by ipath_userinit();
  */

drivers/infiniband/hw/ipath/ipath_sysfs.c

@@ -596,6 +596,23 @@ bail:
 	return ret;
 }
 
+static ssize_t store_led_override(struct device *dev,
+			  struct device_attribute *attr,
+			  const char *buf,
+			  size_t count)
+{
+	struct ipath_devdata *dd = dev_get_drvdata(dev);
+	int ret;
+	u16 val;
+
+	ret = ipath_parse_ushort(buf, &val);
+	if (ret > 0)
+		ipath_set_led_override(dd, val);
+	else
+		ipath_dev_err(dd, "attempt to set invalid LED override\n");
+	return ret;
+}
+
 
 static DRIVER_ATTR(num_units, S_IRUGO, show_num_units, NULL);
 static DRIVER_ATTR(version, S_IRUGO, show_version, NULL);
@@ -625,6 +642,7 @@ static DEVICE_ATTR(status_str, S_IRUGO, show_status_str, NULL);
 static DEVICE_ATTR(boardversion, S_IRUGO, show_boardversion, NULL);
 static DEVICE_ATTR(unit, S_IRUGO, show_unit, NULL);
 static DEVICE_ATTR(rx_pol_inv, S_IWUSR, NULL, store_rx_pol_inv);
+static DEVICE_ATTR(led_override, S_IWUSR, NULL, store_led_override);
 
 static struct attribute *dev_attributes[] = {
 	&dev_attr_guid.attr,
@@ -641,6 +659,7 @@ static struct attribute *dev_attributes[] = {
 	&dev_attr_unit.attr,
 	&dev_attr_enabled.attr,
 	&dev_attr_rx_pol_inv.attr,
+	&dev_attr_led_override.attr,
 	NULL
 };