IB/ipath: Add capability to modify PBC word

During compliance testing and when debugging some interconnect issues,
it is very useful to be able to send malformed packets, without having
the device signal them as malformed (drop, or terminate with EBP). The
hardware supports this, but the driver "diagnostic packet" interface
did not.

Extend capability to send specific malformed packets for testing.

Signed-off-by: Michael Albaugh <Michael.Albaugh@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 34 insertions, 5 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_diag.c b/drivers/infiniband/hw/ipath/ipath_diag.c
index 63e8368b0e95..aab21c1b822d 100644
--- a/drivers/infiniband/hw/ipath/ipath_diag.c
+++ b/drivers/infiniband/hw/ipath/ipath_diag.c
@@ -323,13 +323,14 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
 {
 	u32 __iomem *piobuf;
 	u32 plen, clen, pbufn;
-	struct ipath_diag_pkt dp;
+	struct ipath_diag_pkt odp;
+	struct ipath_diag_xpkt dp;
 	u32 *tmpbuf = NULL;
 	struct ipath_devdata *dd;
 	ssize_t ret = 0;
 	u64 val;
 
-	if (count < sizeof(dp)) {
+	if (count != sizeof(dp)) {
 		ret = -EINVAL;
 		goto bail;
 	}
@@ -339,6 +340,29 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
 		goto bail;
 	}
 
+	/*
+	 * Due to padding/alignment issues (lessened with new struct)
+	 * the old and new structs are the same length. We need to
+	 * disambiguate them, which we can do because odp.len has never
+	 * been less than the total of LRH+BTH+DETH so far, while
+	 * dp.unit (same offset) unit is unlikely to get that high.
+	 * Similarly, dp.data, the pointer to user at the same offset
+	 * as odp.unit, is almost certainly at least one (512byte)page
+	 * "above" NULL. The if-block below can be omitted if compatibility
+	 * between a new driver and older diagnostic code is unimportant.
+	 * compatibility the other direction (new diags, old driver) is
+	 * handled in the diagnostic code, with a warning.
+	 */
+	if (dp.unit >= 20 && dp.data < 512) {
+		/* very probable version mismatch. Fix it up */
+		memcpy(&odp, &dp, sizeof(odp));
+		/* We got a legacy dp, copy elements to dp */
+		dp.unit = odp.unit;
+		dp.data = odp.data;
+		dp.len = odp.len;
+		dp.pbc_wd = 0; /* Indicate we need to compute PBC wd */
+	}
+
 	/* send count must be an exact number of dwords */
 	if (dp.len & 3) {
 		ret = -EINVAL;
@@ -371,9 +395,10 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
 		ret = -ENODEV;
 		goto bail;
 	}
+	/* Check link state, but not if we have custom PBC */
 	val = dd->ipath_lastibcstat & IPATH_IBSTATE_MASK;
-	if (val != IPATH_IBSTATE_INIT && val != IPATH_IBSTATE_ARM &&
-	    val != IPATH_IBSTATE_ACTIVE) {
+	if (!dp.pbc_wd && val != IPATH_IBSTATE_INIT &&
+		val != IPATH_IBSTATE_ARM && val != IPATH_IBSTATE_ACTIVE) {
 		ipath_cdbg(VERBOSE, "unit %u not ready (state %llx)\n",
 			   dd->ipath_unit, (unsigned long long) val);
 		ret = -EINVAL;
@@ -419,9 +444,13 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
 		ipath_cdbg(VERBOSE, "unit %u 0x%x+1w pio%d\n",
 			   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(plen, piobuf);
+	writeq(dp.pbc_wd, piobuf);
 	ipath_flush_wc();
 	/* copy all by the trigger word, then flush, so it's written
 	 * to chip before trigger word, then write trigger word, then