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>

4 files changed, 131 insertions, 51 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_common.h b/drivers/infiniband/hw/ipath/ipath_common.h
index f70788c25ea6..b4b786d0dfca 100644
--- a/drivers/infiniband/hw/ipath/ipath_common.h
+++ b/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;
 };
 
diff --git a/drivers/infiniband/hw/ipath/ipath_file_ops.c b/drivers/infiniband/hw/ipath/ipath_file_ops.c
index a47479608f48..33ab0d6b80ff 100644
--- a/drivers/infiniband/hw/ipath/ipath_file_ops.c
+++ b/drivers/infiniband/hw/ipath/ipath_file_ops.c
@@ -1341,65 +1341,98 @@ bail:
         return ret;
 }
 
-static unsigned int ipath_poll(struct file *fp,
-                               struct poll_table_struct *pt)
+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);
+        if (test_bit(IPATH_PORT_WAITING_OVERFLOW, &pd->int_flag)) {
+                pollflag |= POLLERR;
+                clear_bit(IPATH_PORT_WAITING_OVERFLOW, &pd->int_flag);
+        }
 
-        /*
-         * 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_URG, &pd->int_flag)) {
+                pollflag |= POLLIN | POLLRDNORM;
+                clear_bit(IPATH_PORT_WAITING_URG, &pd->int_flag);
+        }
 
-        ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl,
-                         dd->ipath_rcvctrl);
+        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);
+
+                poll_wait(fp, &pd->port_wait, pt);
+        }
+
+        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 = ipath_read_ureg32(dd, ur_rcvhdrtail, 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);
+        }
 
-        if (tail == head) {
+        if (tail != head ||
+            test_bit(IPATH_PORT_WAITING_RCV, &pd->int_flag)) {
+                pollflag |= POLLIN | POLLRDNORM;
+                clear_bit(IPATH_PORT_WAITING_RCV, &pd->int_flag);
+        }
+
+        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);
+
                 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);
+                        ipath_write_ureg(dd, ur_rcvhdrhead,
+                                         dd->ipath_rhdrhead_intr_off | head,
+                                         pd->port_port);
 
-                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;
-        }
-        else {
-                /* it's already happened; don't do wait_event overhead */
-                pollflag = POLLIN | POLLRDNORM;
-                pd->port_rcvnowait++;
+                poll_wait(fp, &pd->port_wait, pt);
         }
 
-        clear_bit(bit, &dd->ipath_rcvctrl);
-        ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl,
-                         dd->ipath_rcvctrl);
+        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);
 
-bail:
         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)
diff --git a/drivers/infiniband/hw/ipath/ipath_intr.c b/drivers/infiniband/hw/ipath/ipath_intr.c
index 948091f7d5ac..f8aac8e932f5 100644
--- a/drivers/infiniband/hw/ipath/ipath_intr.c
+++ b/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)) {
-                        clear_bit(IPATH_PORT_WAITING_RCV,
-                                  &pd->port_flag);
-                        clear_bit(i + INFINIPATH_R_INTRAVAIL_SHIFT,
-                                  &dd->ipath_rcvctrl);
-                        wake_up_interruptible(&pd->port_wait);
-                        rcvdint = 1;
+                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) {
diff --git a/drivers/infiniband/hw/ipath/ipath_kernel.h b/drivers/infiniband/hw/ipath/ipath_kernel.h
index 2e85aeca5eac..034c283990e8 100644
--- a/drivers/infiniband/hw/ipath/ipath_kernel.h
+++ b/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);