IB/ipath: prevent hardware from being accessed during reset

The reset code now turns off the PRESENT flag during a reset, so that
other code won't attempt to access a device that's in mid-reset.

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

3 files changed, 23 insertions, 6 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_intr.c b/drivers/infiniband/hw/ipath/ipath_intr.c
index 0bcb428041f3..8e3b95b2928b 100644
--- a/drivers/infiniband/hw/ipath/ipath_intr.c
+++ b/drivers/infiniband/hw/ipath/ipath_intr.c
@@ -719,11 +719,24 @@ static void handle_rcv(struct ipath_devdata *dd, u32 istat)
 irqreturn_t ipath_intr(int irq, void *data, struct pt_regs *regs)
 {
         struct ipath_devdata *dd = data;
-        u32 istat = ipath_read_kreg32(dd, dd->ipath_kregs->kr_intstatus);
+        u32 istat;
         ipath_err_t estat = 0;
         static unsigned unexpected = 0;
         irqreturn_t ret;
 
+        if(!(dd->ipath_flags & IPATH_PRESENT)) {
+                /* this is mostly so we don't try to touch the chip while
+                 * it is being reset */
+                /*
+                 * This return value is perhaps odd, but we do not want the
+                 * interrupt core code to remove our interrupt handler
+                 * because we don't appear to be handling an interrupt
+                 * during a chip reset.
+                 */
+                return IRQ_HANDLED;
+        }
+
+        istat = ipath_read_kreg32(dd, dd->ipath_kregs->kr_intstatus);
         if (unlikely(!istat)) {
                 ipath_stats.sps_nullintr++;
                 ret = IRQ_NONE; /* not our interrupt, or already handled */
diff --git a/drivers/infiniband/hw/ipath/ipath_kernel.h b/drivers/infiniband/hw/ipath/ipath_kernel.h
index 0ce5f19c9d62..e6507f8115bc 100644
--- a/drivers/infiniband/hw/ipath/ipath_kernel.h
+++ b/drivers/infiniband/hw/ipath/ipath_kernel.h
@@ -731,7 +731,7 @@ u64 ipath_read_kreg64_port(const struct ipath_devdata *, ipath_kreg,
 static inline u32 ipath_read_ureg32(const struct ipath_devdata *dd,
                                     ipath_ureg regno, int port)
 {
-        if (!dd->ipath_kregbase)
+        if (!dd->ipath_kregbase || !(dd->ipath_flags & IPATH_PRESENT))
                 return 0;
 
         return readl(regno + (u64 __iomem *)
@@ -762,7 +762,7 @@ static inline void ipath_write_ureg(const struct ipath_devdata *dd,
 static inline u32 ipath_read_kreg32(const struct ipath_devdata *dd,
                                     ipath_kreg regno)
 {
-        if (!dd->ipath_kregbase)
+        if (!dd->ipath_kregbase || !(dd->ipath_flags & IPATH_PRESENT))
                 return -1;
         return readl((u32 __iomem *) & dd->ipath_kregbase[regno]);
 }
@@ -770,7 +770,7 @@ static inline u32 ipath_read_kreg32(const struct ipath_devdata *dd,
 static inline u64 ipath_read_kreg64(const struct ipath_devdata *dd,
                                     ipath_kreg regno)
 {
-        if (!dd->ipath_kregbase)
+        if (!dd->ipath_kregbase || !(dd->ipath_flags & IPATH_PRESENT))
                 return -1;
 
         return readq(&dd->ipath_kregbase[regno]);
@@ -786,7 +786,7 @@ static inline void ipath_write_kreg(const struct ipath_devdata *dd,
 static inline u64 ipath_read_creg(const struct ipath_devdata *dd,
                                   ipath_sreg regno)
 {
-        if (!dd->ipath_kregbase)
+        if (!dd->ipath_kregbase || !(dd->ipath_flags & IPATH_PRESENT))
                 return 0;
 
         return readq(regno + (u64 __iomem *)
@@ -797,7 +797,7 @@ static inline u64 ipath_read_creg(const struct ipath_devdata *dd,
 static inline u32 ipath_read_creg32(const struct ipath_devdata *dd,
                                          ipath_sreg regno)
 {
-        if (!dd->ipath_kregbase)
+        if (!dd->ipath_kregbase || !(dd->ipath_flags & IPATH_PRESENT))
                 return 0;
         return readl(regno + (u64 __iomem *)
                      (dd->ipath_cregbase +
diff --git a/drivers/infiniband/hw/ipath/ipath_pe800.c b/drivers/infiniband/hw/ipath/ipath_pe800.c
index e1dc4f757062..6318067ab5ec 100644
--- a/drivers/infiniband/hw/ipath/ipath_pe800.c
+++ b/drivers/infiniband/hw/ipath/ipath_pe800.c
@@ -972,6 +972,8 @@ static int ipath_setup_pe_reset(struct ipath_devdata *dd)
         /* Use ERROR so it shows up in logs, etc. */
         ipath_dev_err(dd, "Resetting PE-800 unit %u\n",
                       dd->ipath_unit);
+        /* keep chip from being accessed in a few places */
+        dd->ipath_flags &= ~(IPATH_INITTED|IPATH_PRESENT);
         val = dd->ipath_control | INFINIPATH_C_RESET;
         ipath_write_kreg(dd, dd->ipath_kregs->kr_control, val);
         mb();
@@ -997,6 +999,8 @@ static int ipath_setup_pe_reset(struct ipath_devdata *dd)
                 if ((r = pci_enable_device(dd->pcidev)))
                         ipath_dev_err(dd, "pci_enable_device failed after "
                                       "reset: %d\n", r);
+                /* whether it worked or not, mark as present, again */
+                dd->ipath_flags |= IPATH_PRESENT;
                 val = ipath_read_kreg64(dd, dd->ipath_kregs->kr_revision);
                 if (val == dd->ipath_revision) {
                         ipath_cdbg(VERBOSE, "Got matching revision "