IB/ipath: change handling of PIO buffers

Different ipath hardware types have different numbers of buffers
available, so we decide on the counts ourselves unless we are specifically
overridden with a module parameter.

Signed-off-by: Bryan O'Sullivan <bos@pathscale.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 22 insertions, 14 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_init_chip.c b/drivers/infiniband/hw/ipath/ipath_init_chip.c
index 2823ff9c0c62..16f640e1c16e 100644
--- a/drivers/infiniband/hw/ipath/ipath_init_chip.c
+++ b/drivers/infiniband/hw/ipath/ipath_init_chip.c
@@ -53,13 +53,19 @@ MODULE_PARM_DESC(cfgports, "Set max number of ports to use");
 
 /*
  * Number of buffers reserved for driver (layered drivers and SMA
- * send).  Reserved at end of buffer list.
+ * send).  Reserved at end of buffer list.   Initialized based on
+ * number of PIO buffers if not set via module interface.
+ * The problem with this is that it's global, but we'll use different
+ * numbers for different chip types.  So the default value is not
+ * very useful.  I've redefined it for the 1.3 release so that it's
+ * zero unless set by the user to something else, in which case we
+ * try to respect it.
  */
-static ushort ipath_kpiobufs = 32;
+static ushort ipath_kpiobufs;
 
 static int ipath_set_kpiobufs(const char *val, struct kernel_param *kp);
 
-module_param_call(kpiobufs, ipath_set_kpiobufs, param_get_uint,
+module_param_call(kpiobufs, ipath_set_kpiobufs, param_get_ushort,
                   &ipath_kpiobufs, S_IWUSR | S_IRUGO);
 MODULE_PARM_DESC(kpiobufs, "Set number of PIO buffers for driver");
 
@@ -531,8 +537,11 @@ static int init_housekeeping(struct ipath_devdata *dd,
          * Don't clear ipath_flags as 8bit mode was set before
          * entering this func. However, we do set the linkstate to
          * unknown, so we can watch for a transition.
+         * PRESENT is set because we want register reads to work,
+         * and the kernel infrastructure saw it in config space;
+         * We clear it if we have failures.
          */
-        dd->ipath_flags |= IPATH_LINKUNK;
+        dd->ipath_flags |= IPATH_LINKUNK | IPATH_PRESENT;
         dd->ipath_flags &= ~(IPATH_LINKACTIVE | IPATH_LINKARMED |
                              IPATH_LINKDOWN | IPATH_LINKINIT);
 
@@ -560,6 +569,7 @@ static int init_housekeeping(struct ipath_devdata *dd,
             || (dd->ipath_uregbase & 0xffffffff) == 0xffffffff) {
                 ipath_dev_err(dd, "Register read failures from chip, "
                               "giving up initialization\n");
+                dd->ipath_flags &= ~IPATH_PRESENT;
                 ret = -ENODEV;
                 goto done;
         }
@@ -682,16 +692,14 @@ int ipath_init_chip(struct ipath_devdata *dd, int reinit)
          */
         dd->ipath_pioavregs = ALIGN(val, sizeof(u64) * BITS_PER_BYTE / 2)
                 / (sizeof(u64) * BITS_PER_BYTE / 2);
-        if (!ipath_kpiobufs)    /* have to have at least 1, for SMA */
-                kpiobufs = ipath_kpiobufs = 1;
-        else if ((dd->ipath_piobcnt2k + dd->ipath_piobcnt4k) <
-                 (dd->ipath_cfgports * IPATH_MIN_USER_PORT_BUFCNT)) {
-                dev_info(&dd->pcidev->dev, "Too few PIO buffers (%u) "
-                         "for %u ports to have %u each!\n",
-                         dd->ipath_piobcnt2k + dd->ipath_piobcnt4k,
-                         dd->ipath_cfgports, IPATH_MIN_USER_PORT_BUFCNT);
-                kpiobufs = 1;   /* reserve just the minimum for SMA/ether */
-        } else
+        if (ipath_kpiobufs == 0) {
+                /* not set by user, or set explictly to default  */
+                if ((dd->ipath_piobcnt2k + dd->ipath_piobcnt4k) > 128)
+                        kpiobufs = 32;
+                else
+                        kpiobufs = 16;
+        }
+        else
                 kpiobufs = ipath_kpiobufs;
 
         if (kpiobufs >