IB/ipath: ipath_poll fixups and enhancements

Fix ipath_poll and enhance it so we can poll for urgent packets or
regular packets and receive notifications of when a header queue
overflows.
Signed-off-by: Robert Walsh <robert.walsh@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/ipath/ipath_common.h

@@ -431,8 +431,15 @@ struct ipath_user_info {
 #define IPATH_CMD_UNUSED_1	25
 #define IPATH_CMD_UNUSED_2	26
 #define IPATH_CMD_PIOAVAILUPD	27	/* force an update of PIOAvail reg */
+#define IPATH_CMD_POLL_TYPE	28	/* set the kind of polling we want */
 
-#define IPATH_CMD_MAX		27
+#define IPATH_CMD_MAX		28
+
+/*
+ * Poll types
+ */
+#define IPATH_POLL_TYPE_URGENT	 0x01
+#define IPATH_POLL_TYPE_OVERFLOW 0x02
 
 struct ipath_port_info {
 	__u32 num_active;	/* number of active units */
@@ -473,6 +480,8 @@ struct ipath_cmd {
 		__u16 part_key;
 		/* user address of __u32 bitmask of active slaves */
 		__u64 slave_mask_addr;
+		/* type of polling we want */
+		__u16 poll_type;
 	} cmd;
 };
 

drivers/infiniband/hw/ipath/ipath_file_ops.c

@@ -1341,65 +1341,98 @@ static int ipath_mmap(struct file *fp, struct vm_area_struct *vma)
 	return ret;
 }
 
-static unsigned int ipath_poll(struct file *fp,
+static unsigned int ipath_poll_urgent(struct ipath_portdata *pd,
+				      struct file *fp,
 				      struct poll_table_struct *pt)
 {
-	struct ipath_portdata *pd;
-	u32 head, tail;
-	int bit;
 	unsigned pollflag = 0;
 	struct ipath_devdata *dd;
 
-	pd = port_fp(fp);
-	if (!pd)
-		goto bail;
 	dd = pd->port_dd;
 
-	bit = pd->port_port + INFINIPATH_R_INTRAVAIL_SHIFT;
-	set_bit(bit, &dd->ipath_rcvctrl);
-
-	/*
-	 * Before blocking, make sure that head is still == tail,
-	 * reading from the chip, so we can be sure the interrupt
-	 * enable has made it to the chip.  If not equal, disable
-	 * interrupt again and return immediately.  This avoids races,
-	 * and the overhead of the chip read doesn't matter much at
-	 * this point, since we are waiting for something anyway.
-	 */
+	if (test_bit(IPATH_PORT_WAITING_OVERFLOW, &pd->int_flag)) {
+		pollflag |= POLLERR;
+		clear_bit(IPATH_PORT_WAITING_OVERFLOW, &pd->int_flag);
+	}
 
-	ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl,
-			 dd->ipath_rcvctrl);
+	if (test_bit(IPATH_PORT_WAITING_URG, &pd->int_flag)) {
+		pollflag |= POLLIN | POLLRDNORM;
+		clear_bit(IPATH_PORT_WAITING_URG, &pd->int_flag);
+	}
 
-	head = ipath_read_ureg32(dd, ur_rcvhdrhead, pd->port_port);
-	tail = ipath_read_ureg32(dd, ur_rcvhdrtail, pd->port_port);
+	if (!pollflag) {
+		set_bit(IPATH_PORT_WAITING_URG, &pd->port_flag);
+		if (pd->poll_type & IPATH_POLL_TYPE_OVERFLOW)
+			set_bit(IPATH_PORT_WAITING_OVERFLOW,
+				&pd->port_flag);
 
-	if (tail == head) {
-		set_bit(IPATH_PORT_WAITING_RCV, &pd->port_flag);
-		if (dd->ipath_rhdrhead_intr_off) /* arm rcv interrupt */
-			(void)ipath_write_ureg(dd, ur_rcvhdrhead,
-					       dd->ipath_rhdrhead_intr_off
-					       | head, pd->port_port);
 		poll_wait(fp, &pd->port_wait, pt);
-
-		if (test_bit(IPATH_PORT_WAITING_RCV, &pd->port_flag)) {
-			/* timed out, no packets received */
-			clear_bit(IPATH_PORT_WAITING_RCV, &pd->port_flag);
-			pd->port_rcvwait_to++;
 	}
-		else
-			pollflag = POLLIN | POLLRDNORM;
+
+	return pollflag;
+}
+
+static unsigned int ipath_poll_next(struct ipath_portdata *pd,
+				    struct file *fp,
+				    struct poll_table_struct *pt)
+{
+	u32 head, tail;
+	unsigned pollflag = 0;
+	struct ipath_devdata *dd;
+
+	dd = pd->port_dd;
+
+	head = ipath_read_ureg32(dd, ur_rcvhdrhead, pd->port_port);
+	tail = *(volatile u64 *)pd->port_rcvhdrtail_kvaddr;
+
+	if (test_bit(IPATH_PORT_WAITING_OVERFLOW, &pd->int_flag)) {
+		pollflag |= POLLERR;
+		clear_bit(IPATH_PORT_WAITING_OVERFLOW, &pd->int_flag);
 	}
-	else {
-		/* it's already happened; don't do wait_event overhead */
-		pollflag = POLLIN | POLLRDNORM;
-		pd->port_rcvnowait++;
+
+	if (tail != head ||
+	    test_bit(IPATH_PORT_WAITING_RCV, &pd->int_flag)) {
+		pollflag |= POLLIN | POLLRDNORM;
+		clear_bit(IPATH_PORT_WAITING_RCV, &pd->int_flag);
 	}
 
-	clear_bit(bit, &dd->ipath_rcvctrl);
+	if (!pollflag) {
+		set_bit(IPATH_PORT_WAITING_RCV, &pd->port_flag);
+		if (pd->poll_type & IPATH_POLL_TYPE_OVERFLOW)
+			set_bit(IPATH_PORT_WAITING_OVERFLOW,
+				&pd->port_flag);
+
+		set_bit(pd->port_port + INFINIPATH_R_INTRAVAIL_SHIFT,
+			&dd->ipath_rcvctrl);
+
 		ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl,
 				 dd->ipath_rcvctrl);
 
-bail:
+		if (dd->ipath_rhdrhead_intr_off) /* arm rcv interrupt */
+			ipath_write_ureg(dd, ur_rcvhdrhead,
+					 dd->ipath_rhdrhead_intr_off | head,
+					 pd->port_port);
+
+		poll_wait(fp, &pd->port_wait, pt);
+	}
+
+	return pollflag;
+}
+
+static unsigned int ipath_poll(struct file *fp,
+			       struct poll_table_struct *pt)
+{
+	struct ipath_portdata *pd;
+	unsigned pollflag;
+
+	pd = port_fp(fp);
+	if (!pd)
+		pollflag = 0;
+	else if (pd->poll_type & IPATH_POLL_TYPE_URGENT)
+		pollflag = ipath_poll_urgent(pd, fp, pt);
+	else
+		pollflag = ipath_poll_next(pd, fp, pt);
+
 	return pollflag;
 }
 
@@ -2173,6 +2206,11 @@ static ssize_t ipath_write(struct file *fp, const char __user *data,
 		src = NULL;
 		dest = NULL;
 		break;
+	case IPATH_CMD_POLL_TYPE:
+		copy = sizeof(cmd.cmd.poll_type);
+		dest = &cmd.cmd.poll_type;
+		src = &ucmd->cmd.poll_type;
+		break;
 	default:
 		ret = -EINVAL;
 		goto bail;
@@ -2245,6 +2283,9 @@ static ssize_t ipath_write(struct file *fp, const char __user *data,
 	case IPATH_CMD_PIOAVAILUPD:
 		ret = ipath_force_pio_avail_update(pd->port_dd);
 		break;
+	case IPATH_CMD_POLL_TYPE:
+		pd->poll_type = cmd.cmd.poll_type;
+		break;
 	}
 
 	if (ret >= 0)

drivers/infiniband/hw/ipath/ipath_intr.c

@@ -680,6 +680,17 @@ static int handle_errors(struct ipath_devdata *dd, ipath_err_t errs)
 					chkerrpkts = 1;
 				dd->ipath_lastrcvhdrqtails[i] = tl;
 				pd->port_hdrqfull++;
+				if (test_bit(IPATH_PORT_WAITING_OVERFLOW,
+					     &pd->port_flag)) {
+					clear_bit(
+					  IPATH_PORT_WAITING_OVERFLOW,
+					  &pd->port_flag);
+					set_bit(
+					  IPATH_PORT_WAITING_OVERFLOW,
+					  &pd->int_flag);
+					wake_up_interruptible(
+					  &pd->port_wait);
+				}
 			}
 		}
 	}
@@ -877,14 +888,25 @@ static void handle_urcv(struct ipath_devdata *dd, u32 istat)
 		   dd->ipath_i_rcvurg_mask);
 	for (i = 1; i < dd->ipath_cfgports; i++) {
 		struct ipath_portdata *pd = dd->ipath_pd[i];
-		if (portr & (1 << i) && pd && pd->port_cnt &&
-			test_bit(IPATH_PORT_WAITING_RCV, &pd->port_flag)) {
+		if (portr & (1 << i) && pd && pd->port_cnt) {
+			if (test_bit(IPATH_PORT_WAITING_RCV,
+				     &pd->port_flag)) {
 				clear_bit(IPATH_PORT_WAITING_RCV,
 					  &pd->port_flag);
+				set_bit(IPATH_PORT_WAITING_RCV,
+					&pd->int_flag);
 				clear_bit(i + INFINIPATH_R_INTRAVAIL_SHIFT,
 					  &dd->ipath_rcvctrl);
 				wake_up_interruptible(&pd->port_wait);
 				rcvdint = 1;
+			} else if (test_bit(IPATH_PORT_WAITING_URG,
+					    &pd->port_flag)) {
+				clear_bit(IPATH_PORT_WAITING_URG,
+					  &pd->port_flag);
+				set_bit(IPATH_PORT_WAITING_URG,
+					&pd->int_flag);
+				wake_up_interruptible(&pd->port_wait);
+			}
 		}
 	}
 	if (rcvdint) {

drivers/infiniband/hw/ipath/ipath_kernel.h

@@ -127,6 +127,8 @@ struct ipath_portdata {
 	u32 port_tidcursor;
 	/* next expected TID to check */
 	unsigned long port_flag;
+	/* what happened */
+	unsigned long int_flag;
 	/* WAIT_RCV that timed out, no interrupt */
 	u32 port_rcvwait_to;
 	/* WAIT_PIO that timed out, no interrupt */
@@ -155,6 +157,8 @@ struct ipath_portdata {
 	u32 userversion;
 	/* Bitmask of active slaves */
 	u32 active_slaves;
+	/* Type of packets or conditions we want to poll for */
+	u16 poll_type;
 };
 
 struct sk_buff;
@@ -754,6 +758,10 @@ int ipath_set_rx_pol_inv(struct ipath_devdata *dd, u8 new_pol_inv);
 #define IPATH_PORT_WAITING_PIO   3
 		/* master has not finished initializing */
 #define IPATH_PORT_MASTER_UNINIT 4
+		/* waiting for an urgent packet to arrive */
+#define IPATH_PORT_WAITING_URG 5
+		/* waiting for a header overflow */
+#define IPATH_PORT_WAITING_OVERFLOW 6
 
 /* free up any allocated data at closes */
 void ipath_free_data(struct ipath_portdata *dd);