IB/ipath: Force PIOAvail update entry point

Due to a chip bug, the PIOAvail register is not always updated to
memory.  This patch allows userspace to force an update.

Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

2 files changed, 35 insertions, 10 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_common.h b/drivers/infiniband/hw/ipath/ipath_common.h
index 048b928bb4bf..10c008f22ba6 100644
--- a/drivers/infiniband/hw/ipath/ipath_common.h
+++ b/drivers/infiniband/hw/ipath/ipath_common.h
@@ -352,7 +352,7 @@ struct ipath_base_info {
  * may not be implemented; the user code must deal with this if it
  * cares, or it must abort after initialization reports the difference.
  */
-#define IPATH_USER_SWMINOR 4
+#define IPATH_USER_SWMINOR 5
 
 #define IPATH_USER_SWVERSION ((IPATH_USER_SWMAJOR<<16) | IPATH_USER_SWMINOR)
 
@@ -429,8 +429,11 @@ struct ipath_user_info {
 #define __IPATH_CMD_SLAVE_INFO  22      /* return info on slave processes (for old user code) */
 #define IPATH_CMD_ASSIGN_PORT   23      /* allocate HCA and port */
 #define IPATH_CMD_USER_INIT     24      /* set up userspace */
+#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_MAX           24
+#define IPATH_CMD_MAX           27
 
 struct ipath_port_info {
         __u32 num_active;       /* number of active units */
diff --git a/drivers/infiniband/hw/ipath/ipath_file_ops.c b/drivers/infiniband/hw/ipath/ipath_file_ops.c
index bb53bde80ee8..9ca582b65fe9 100644
--- a/drivers/infiniband/hw/ipath/ipath_file_ops.c
+++ b/drivers/infiniband/hw/ipath/ipath_file_ops.c
@@ -2047,6 +2047,17 @@ static int ipath_get_slave_info(struct ipath_portdata *pd,
         return ret;
 }
 
+static int ipath_force_pio_avail_update(struct ipath_devdata *dd)
+{
+        u64 reg = dd->ipath_sendctrl;
+
+        clear_bit(IPATH_S_PIOBUFAVAILUPD, &reg);
+        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, reg);
+        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, dd->ipath_sendctrl);
+
+        return 0;
+}
+
 static ssize_t ipath_write(struct file *fp, const char __user *data,
                            size_t count, loff_t *off)
 {
@@ -2106,22 +2117,30 @@ static ssize_t ipath_write(struct file *fp, const char __user *data,
                 dest = &cmd.cmd.slave_mask_addr;
                 src = &ucmd->cmd.slave_mask_addr;
                 break;
+        case IPATH_CMD_PIOAVAILUPD:     // force an update of PIOAvail reg
+                copy = 0;
+                src = NULL;
+                dest = NULL;
+                break;
         default:
                 ret = -EINVAL;
                 goto bail;
         }
 
-        if ((count - consumed) < copy) {
-                ret = -EINVAL;
-                goto bail;
-        }
+        if (copy) {
+                if ((count - consumed) < copy) {
+                        ret = -EINVAL;
+                        goto bail;
+                }
 
-        if (copy_from_user(dest, src, copy)) {
-                ret = -EFAULT;
-                goto bail;
+                if (copy_from_user(dest, src, copy)) {
+                        ret = -EFAULT;
+                        goto bail;
+                }
+
+                consumed += copy;
         }
 
-        consumed += copy;
         pd = port_fp(fp);
         if (!pd && cmd.type != __IPATH_CMD_USER_INIT &&
                 cmd.type != IPATH_CMD_ASSIGN_PORT) {
@@ -2172,6 +2191,9 @@ static ssize_t ipath_write(struct file *fp, const char __user *data,
                                            (void __user *) (unsigned long)
                                            cmd.cmd.slave_mask_addr);
                 break;
+        case IPATH_CMD_PIOAVAILUPD:
+                ret = ipath_force_pio_avail_update(pd->port_dd);
+                break;
         }
 
         if (ret >= 0)