4 files changed, 53 insertions, 35 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_diag.c b/drivers/infiniband/hw/ipath/ipath_diag.c
index cf25cdab02f9..4137c7770f1b 100644
--- a/drivers/infiniband/hw/ipath/ipath_diag.c
+++ b/drivers/infiniband/hw/ipath/ipath_diag.c
@@ -446,19 +446,21 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
                            dd->ipath_unit, plen - 1, pbufn);
 
         if (dp.pbc_wd == 0)
-                /* Legacy operation, use computed pbc_wd */
                 dp.pbc_wd = plen;
-
-        /* we have to flush after the PBC for correctness on some cpus
-         * or WC buffer can be written out of order */
         writeq(dp.pbc_wd, piobuf);
-        ipath_flush_wc();
-        /* copy all by the trigger word, then flush, so it's written
+        /*
+         * Copy all by the trigger word, then flush, so it's written
          * to chip before trigger word, then write trigger word, then
-         * flush again, so packet is sent. */
-        __iowrite32_copy(piobuf + 2, tmpbuf, clen - 1);
-        ipath_flush_wc();
-        __raw_writel(tmpbuf[clen - 1], piobuf + clen + 1);
+         * flush again, so packet is sent.
+         */
+        if (dd->ipath_flags & IPATH_PIO_FLUSH_WC) {
+                ipath_flush_wc();
+                __iowrite32_copy(piobuf + 2, tmpbuf, clen - 1);
+                ipath_flush_wc();
+                __raw_writel(tmpbuf[clen - 1], piobuf + clen + 1);
+        } else
+                __iowrite32_copy(piobuf + 2, tmpbuf, clen);
+
         ipath_flush_wc();
 
         ret = sizeof(dp);
diff --git a/drivers/infiniband/hw/ipath/ipath_iba6120.c b/drivers/infiniband/hw/ipath/ipath_iba6120.c
index 5b6ac9a1a709..a324c6f7aeba 100644
--- a/drivers/infiniband/hw/ipath/ipath_iba6120.c
+++ b/drivers/infiniband/hw/ipath/ipath_iba6120.c
@@ -1273,6 +1273,8 @@ static void ipath_pe_tidtemplate(struct ipath_devdata *dd)
 static int ipath_pe_early_init(struct ipath_devdata *dd)
 {
         dd->ipath_flags |= IPATH_4BYTE_TID;
+        if (ipath_unordered_wc())
+                dd->ipath_flags |= IPATH_PIO_FLUSH_WC;
 
         /*
          * For openfabrics, we need to be able to handle an IB header of
diff --git a/drivers/infiniband/hw/ipath/ipath_kernel.h b/drivers/infiniband/hw/ipath/ipath_kernel.h
index 7a7966f7e4ff..d983f92b9bcb 100644
--- a/drivers/infiniband/hw/ipath/ipath_kernel.h
+++ b/drivers/infiniband/hw/ipath/ipath_kernel.h
@@ -724,6 +724,8 @@ int ipath_set_rx_pol_inv(struct ipath_devdata *dd, u8 new_pol_inv);
 #define IPATH_LINKACTIVE    0x200
                 /* link current state is unknown */
 #define IPATH_LINKUNK       0x400
+                /* Write combining flush needed for PIO */
+#define IPATH_PIO_FLUSH_WC  0x1000
                 /* no IB cable, or no device on IB cable */
 #define IPATH_NOCABLE       0x4000
                 /* Supports port zero per packet receive interrupts via
diff --git a/drivers/infiniband/hw/ipath/ipath_verbs.c b/drivers/infiniband/hw/ipath/ipath_verbs.c
index 16aa61fd8085..559d4a662937 100644
--- a/drivers/infiniband/hw/ipath/ipath_verbs.c
+++ b/drivers/infiniband/hw/ipath/ipath_verbs.c
@@ -631,7 +631,7 @@ static inline u32 clear_upper_bytes(u32 data, u32 n, u32 off)
 #endif
 
 static void copy_io(u32 __iomem *piobuf, struct ipath_sge_state *ss,
-                    u32 length)
+                    u32 length, unsigned flush_wc)
 {
         u32 extra = 0;
         u32 data = 0;
@@ -757,11 +757,14 @@ static void copy_io(u32 __iomem *piobuf, struct ipath_sge_state *ss,
         }
         /* Update address before sending packet. */
         update_sge(ss, length);
-        /* must flush early everything before trigger word */
-        ipath_flush_wc();
-        __raw_writel(last, piobuf);
-        /* be sure trigger word is written */
-        ipath_flush_wc();
+        if (flush_wc) {
+                /* must flush early everything before trigger word */
+                ipath_flush_wc();
+                __raw_writel(last, piobuf);
+                /* be sure trigger word is written */
+                ipath_flush_wc();
+        } else
+                __raw_writel(last, piobuf);
 }
 
 /**
@@ -776,6 +779,7 @@ int ipath_verbs_send(struct ipath_devdata *dd, u32 hdrwords,
                      u32 *hdr, u32 len, struct ipath_sge_state *ss)
 {
         u32 __iomem *piobuf;
+        unsigned flush_wc;
         u32 plen;
         int ret;
 
@@ -799,47 +803,55 @@ int ipath_verbs_send(struct ipath_devdata *dd, u32 hdrwords,
          * or WC buffer can be written out of order.
          */
         writeq(plen, piobuf);
-        ipath_flush_wc();
         piobuf += 2;
+
+        flush_wc = dd->ipath_flags & IPATH_PIO_FLUSH_WC;
         if (len == 0) {
                 /*
                  * If there is just the header portion, must flush before
                  * writing last word of header for correctness, and after
                  * the last header word (trigger word).
                  */
-                __iowrite32_copy(piobuf, hdr, hdrwords - 1);
-                ipath_flush_wc();
-                __raw_writel(hdr[hdrwords - 1], piobuf + hdrwords - 1);
-                ipath_flush_wc();
-                ret = 0;
-                goto bail;
+                if (flush_wc) {
+                        ipath_flush_wc();
+                        __iowrite32_copy(piobuf, hdr, hdrwords - 1);
+                        ipath_flush_wc();
+                        __raw_writel(hdr[hdrwords - 1], piobuf + hdrwords - 1);
+                        ipath_flush_wc();
+                } else
+                        __iowrite32_copy(piobuf, hdr, hdrwords);
+                goto done;
         }
 
+        if (flush_wc)
+                ipath_flush_wc();
         __iowrite32_copy(piobuf, hdr, hdrwords);
         piobuf += hdrwords;
 
         /* The common case is aligned and contained in one segment. */
         if (likely(ss->num_sge == 1 && len <= ss->sge.length &&
                    !((unsigned long)ss->sge.vaddr & (sizeof(u32) - 1)))) {
-                u32 w;
+                u32 dwords;
                 u32 *addr = (u32 *) ss->sge.vaddr;
 
                 /* Update address before sending packet. */
                 update_sge(ss, len);
                 /* Need to round up for the last dword in the packet. */
-                w = (len + 3) >> 2;
-                __iowrite32_copy(piobuf, addr, w - 1);
-                /* must flush early everything before trigger word */
-                ipath_flush_wc();
-                __raw_writel(addr[w - 1], piobuf + w - 1);
-                /* be sure trigger word is written */
-                ipath_flush_wc();
-                ret = 0;
-                goto bail;
+                dwords = (len + 3) >> 2;
+                if (flush_wc) {
+                        __iowrite32_copy(piobuf, addr, dwords - 1);
+                        /* must flush early everything before trigger word */
+                        ipath_flush_wc();
+                        __raw_writel(addr[dwords - 1], piobuf + dwords - 1);
+                        /* be sure trigger word is written */
+                        ipath_flush_wc();
+                } else
+                        __iowrite32_copy(piobuf, addr, dwords);
+                goto done;
         }
-        copy_io(piobuf, ss, len);
+        copy_io(piobuf, ss, len, flush_wc);
+done:
         ret = 0;
-
 bail:
         return ret;
 }