[ofa-general] [PATCH 4/6] IB/ipath - Enable use of 4KB MTU via module paramater

Ralph Campbell ralph.campbell at qlogic.com
Tue Mar 18 17:24:01 PDT 2008


From: Dave Olson <dave.olson at qlogic.com>

This patch enables use of 4KB MTUs via module paramater.

Signed-off-by: Dave Olson <dave.olson at qlogic.com>
---

 drivers/infiniband/hw/ipath/ipath_driver.c    |   31 ++++++++++++-------------
 drivers/infiniband/hw/ipath/ipath_file_ops.c  |    7 +++++-
 drivers/infiniband/hw/ipath/ipath_iba6120.c   |   10 ++------
 drivers/infiniband/hw/ipath/ipath_init_chip.c |   30 ++++++------------------
 drivers/infiniband/hw/ipath/ipath_kernel.h    |    1 +
 drivers/infiniband/hw/ipath/ipath_mad.c       |   12 ++++------
 drivers/infiniband/hw/ipath/ipath_qp.c        |   12 +++++-----
 drivers/infiniband/hw/ipath/ipath_verbs.c     |    7 +-----
 8 files changed, 45 insertions(+), 65 deletions(-)

diff --git a/drivers/infiniband/hw/ipath/ipath_driver.c b/drivers/infiniband/hw/ipath/ipath_driver.c
index 367f2a3..7121fe8 100644
--- a/drivers/infiniband/hw/ipath/ipath_driver.c
+++ b/drivers/infiniband/hw/ipath/ipath_driver.c
@@ -73,6 +73,10 @@ module_param_named(debug, ipath_debug, uint, S_IWUSR | S_IRUGO);
 MODULE_PARM_DESC(debug, "mask for debug prints");
 EXPORT_SYMBOL_GPL(ipath_debug);
 
+unsigned ipath_mtu4096 = 1; /* max 4KB IB mtu by default, if supported */
+module_param_named(mtu4096, ipath_mtu4096, uint, S_IRUGO);
+MODULE_PARM_DESC(mtu4096, "enable MTU of 4096 bytes, if supported");
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("QLogic <support at pathscale.com>");
 MODULE_DESCRIPTION("QLogic InfiniPath driver");
@@ -1800,7 +1804,7 @@ int ipath_set_mtu(struct ipath_devdata *dd, u16 arg)
 	 * piosize).  We check that it's one of the valid IB sizes.
 	 */
 	if (arg != 256 && arg != 512 && arg != 1024 && arg != 2048 &&
-	    arg != 4096) {
+	    (arg != 4096 || !ipath_mtu4096)) {
 		ipath_dbg("Trying to set invalid mtu %u, failing\n", arg);
 		ret = -EINVAL;
 		goto bail;
@@ -1816,6 +1820,8 @@ int ipath_set_mtu(struct ipath_devdata *dd, u16 arg)
 	if (arg >= (piosize - IPATH_PIO_MAXIBHDR)) {
 		/* Only if it's not the initial value (or reset to it) */
 		if (piosize != dd->ipath_init_ibmaxlen) {
+			if (arg > piosize && arg <= dd->ipath_init_ibmaxlen)
+				piosize = dd->ipath_init_ibmaxlen;
 			dd->ipath_ibmaxlen = piosize;
 			changed = 1;
 		}
@@ -1829,24 +1835,17 @@ int ipath_set_mtu(struct ipath_devdata *dd, u16 arg)
 	}
 
 	if (changed) {
+		u64 ibc = dd->ipath_ibcctrl, ibdw;
 		/*
-		 * set the IBC maxpktlength to the size of our pio
-		 * buffers in words
+		 * update our housekeeping variables, and set IBC max
+		 * size, same as init code; max IBC is max we allow in
+		 * buffer, less the qword pbc, plus 1 for ICRC, in dwords
 		 */
-		u64 ibc = dd->ipath_ibcctrl;
+		dd->ipath_ibmaxlen = piosize - 2 * sizeof(u32);
+		ibdw = (dd->ipath_ibmaxlen >> 2) + 1;
 		ibc &= ~(INFINIPATH_IBCC_MAXPKTLEN_MASK <<
-			 INFINIPATH_IBCC_MAXPKTLEN_SHIFT);
-
-		piosize = piosize - 2 * sizeof(u32);    /* ignore pbc */
-		dd->ipath_ibmaxlen = piosize;
-		piosize /= sizeof(u32); /* in words */
-		/*
-		 * for ICRC, which we only send in diag test pkt mode, and
-		 * we don't need to worry about that for mtu
-		 */
-		piosize += 1;
-
-		ibc |= piosize << INFINIPATH_IBCC_MAXPKTLEN_SHIFT;
+			 dd->ibcc_mpl_shift);
+		ibc |= ibdw << dd->ibcc_mpl_shift;
 		dd->ipath_ibcctrl = ibc;
 		ipath_write_kreg(dd, dd->ipath_kregs->kr_ibcctrl,
 				 dd->ipath_ibcctrl);
diff --git a/drivers/infiniband/hw/ipath/ipath_file_ops.c b/drivers/infiniband/hw/ipath/ipath_file_ops.c
index 7e025c8..3d95b70 100644
--- a/drivers/infiniband/hw/ipath/ipath_file_ops.c
+++ b/drivers/infiniband/hw/ipath/ipath_file_ops.c
@@ -219,7 +219,12 @@ static int ipath_get_base_info(struct file *fp,
 	kinfo->spi_pioalign = dd->ipath_palign;
 
 	kinfo->spi_qpair = IPATH_KD_QP;
-	kinfo->spi_piosize = dd->ipath_ibmaxlen;
+	/*
+	 * user mode PIO buffers are always 2KB, even when 4KB can
+	 * be received, and sent via the kernel; this is ibmaxlen
+	 * for 2K MTU.
+	 */
+	kinfo->spi_piosize = dd->ipath_piosize2k - 2 * sizeof(u32);
 	kinfo->spi_mtu = dd->ipath_ibmaxlen;	/* maxlen, not ibmtu */
 	kinfo->spi_port = pd->port_port;
 	kinfo->spi_subport = subport_fp(fp);
diff --git a/drivers/infiniband/hw/ipath/ipath_iba6120.c b/drivers/infiniband/hw/ipath/ipath_iba6120.c
index 828066e..a9fc804 100644
--- a/drivers/infiniband/hw/ipath/ipath_iba6120.c
+++ b/drivers/infiniband/hw/ipath/ipath_iba6120.c
@@ -1441,17 +1441,13 @@ static int ipath_pe_early_init(struct ipath_devdata *dd)
 	dd->ipath_egrtidbase = (u64 __iomem *)
 		((char __iomem *) dd->ipath_kregbase + dd->ipath_rcvegrbase);
 
-	/*
-	 * To truly support a 4KB MTU (for usermode), we need to
-	 * bump this to a larger value.  For now, we use them for
-	 * the kernel only.
-	 */
-	dd->ipath_rcvegrbufsize = 2048;
+	dd->ipath_rcvegrbufsize = ipath_mtu4096 ? 4096 : 2048;
 	/*
 	 * the min() check here is currently a nop, but it may not always
 	 * be, depending on just how we do ipath_rcvegrbufsize
 	 */
-	dd->ipath_ibmaxlen = min(dd->ipath_piosize2k,
+	dd->ipath_ibmaxlen = min(ipath_mtu4096 ? dd->ipath_piosize4k :
+				 dd->ipath_piosize2k,
 				 dd->ipath_rcvegrbufsize +
 				 (dd->ipath_rcvhdrentsize << 2));
 	dd->ipath_init_ibmaxlen = dd->ipath_ibmaxlen;
diff --git a/drivers/infiniband/hw/ipath/ipath_init_chip.c b/drivers/infiniband/hw/ipath/ipath_init_chip.c
index 5428aff..f0d7848 100644
--- a/drivers/infiniband/hw/ipath/ipath_init_chip.c
+++ b/drivers/infiniband/hw/ipath/ipath_init_chip.c
@@ -155,24 +155,13 @@ static int bringup_link(struct ipath_devdata *dd)
 			 dd->ipath_control);
 
 	/*
-	 * Note that prior to try 14 or 15 of IB, the credit scaling
-	 * wasn't working, because it was swapped for writes with the
-	 * 1 bit default linkstate field
+	 * set initial max size pkt IBC will send, including ICRC; it's the
+	 * PIO buffer size in dwords, less 1; also see ipath_set_mtu()
 	 */
+	val = (dd->ipath_ibmaxlen >> 2) + 1;
+	ibc = val << dd->ibcc_mpl_shift;
 
-	/* ignore pbc and align word */
-	val = dd->ipath_piosize2k - 2 * sizeof(u32);
-	/*
-	 * for ICRC, which we only send in diag test pkt mode, and we
-	 * don't need to worry about that for mtu
-	 */
-	val += 1;
-	/*
-	 * Set the IBC maxpktlength to the size of our pio buffers the
-	 * maxpktlength is in words.  This is *not* the IB data MTU.
-	 */
-	ibc = (val / sizeof(u32)) << INFINIPATH_IBCC_MAXPKTLEN_SHIFT;
-	/* in KB */
+	/* flowcontrolwatermark is in units of KBytes */
 	ibc |= 0x5ULL << INFINIPATH_IBCC_FLOWCTRLWATERMARK_SHIFT;
 	/*
 	 * How often flowctrl sent.  More or less in usecs; balance against
@@ -295,12 +284,9 @@ static int init_chip_first(struct ipath_devdata *dd,
 	val = ipath_read_kreg64(dd, dd->ipath_kregs->kr_sendpiosize);
 	dd->ipath_piosize2k = val & ~0U;
 	dd->ipath_piosize4k = val >> 32;
-	/*
-	 * Note: the chips support a maximum MTU of 4096, but the driver
-	 * hasn't implemented this feature yet, so set the initial value
-	 * to 2048.
-	 */
-	dd->ipath_ibmtu = 2048;
+	if (dd->ipath_piosize4k == 0 && ipath_mtu4096)
+		ipath_mtu4096 = 0; /* 4KB not supported by this chip */
+	dd->ipath_ibmtu = ipath_mtu4096 ? 4096 : 2048;
 	val = ipath_read_kreg64(dd, dd->ipath_kregs->kr_sendpiobufcnt);
 	dd->ipath_piobcnt2k = val & ~0U;
 	dd->ipath_piobcnt4k = val >> 32;
diff --git a/drivers/infiniband/hw/ipath/ipath_kernel.h b/drivers/infiniband/hw/ipath/ipath_kernel.h
index 59dc895..70c0a0d 100644
--- a/drivers/infiniband/hw/ipath/ipath_kernel.h
+++ b/drivers/infiniband/hw/ipath/ipath_kernel.h
@@ -1066,6 +1066,7 @@ dma_addr_t ipath_map_single(struct pci_dev *, void *, size_t, int);
 #endif
 
 extern unsigned ipath_debug; /* debugging bit mask */
+extern unsigned ipath_mtu4096;
 
 #define IPATH_MAX_PARITY_ATTEMPTS 10000 /* max times to try recovery */
 
diff --git a/drivers/infiniband/hw/ipath/ipath_mad.c b/drivers/infiniband/hw/ipath/ipath_mad.c
index b34b91d..aca876b 100644
--- a/drivers/infiniband/hw/ipath/ipath_mad.c
+++ b/drivers/infiniband/hw/ipath/ipath_mad.c
@@ -292,13 +292,9 @@ static int recv_subn_get_portinfo(struct ib_smp *smp,
 	/* pip->vl_arb_high_cap; // only one VL */
 	/* pip->vl_arb_low_cap; // only one VL */
 	/* InitTypeReply = 0 */
-	/*
-	 * Note: the chips support a maximum MTU of 4096, but the driver
-	 * hasn't implemented this feature yet, so set the maximum value
-	 * to 2048.
-	 */
-	pip->inittypereply_mtucap = IB_MTU_2048;
-	// HCAs ignore VLStallCount and HOQLife
+	/* our mtu cap depends on whether 4K MTU enabled or not */
+	pip->inittypereply_mtucap = ipath_mtu4096 ? IB_MTU_4096 : IB_MTU_2048;
+	/* HCAs ignore VLStallCount and HOQLife */
 	/* pip->vlstallcnt_hoqlife; */
 	pip->operationalvl_pei_peo_fpi_fpo = 0x10;	/* OVLs = 1 */
 	pip->mkey_violations = cpu_to_be16(dev->mkey_violations);
@@ -491,6 +487,8 @@ static int recv_subn_set_portinfo(struct ib_smp *smp,
 		mtu = 2048;
 		break;
 	case IB_MTU_4096:
+		if (!ipath_mtu4096)
+			goto err;
 		mtu = 4096;
 		break;
 	default:
diff --git a/drivers/infiniband/hw/ipath/ipath_qp.c b/drivers/infiniband/hw/ipath/ipath_qp.c
index 087ed31..5c8094a 100644
--- a/drivers/infiniband/hw/ipath/ipath_qp.c
+++ b/drivers/infiniband/hw/ipath/ipath_qp.c
@@ -516,13 +516,13 @@ int ipath_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
 			goto inval;
 
 	/*
-	 * Note: the chips support a maximum MTU of 4096, but the driver
-	 * hasn't implemented this feature yet, so don't allow Path MTU
-	 * values greater than 2048.
+	 * don't allow invalid Path MTU values or greater than 2048
+	 * unless we are configured for a 4KB MTU
 	 */
-	if (attr_mask & IB_QP_PATH_MTU)
-		if (attr->path_mtu > IB_MTU_2048)
-			goto inval;
+	if ((attr_mask & IB_QP_PATH_MTU) &&
+		(ib_mtu_enum_to_int(attr->path_mtu) == -1 ||
+		(attr->path_mtu > IB_MTU_2048 && !ipath_mtu4096)))
+		goto inval;
 
 	if (attr_mask & IB_QP_PATH_MIG_STATE)
 		if (attr->path_mig_state != IB_MIG_MIGRATED &&
diff --git a/drivers/infiniband/hw/ipath/ipath_verbs.c b/drivers/infiniband/hw/ipath/ipath_verbs.c
index 32d8f88..012ccb4 100644
--- a/drivers/infiniband/hw/ipath/ipath_verbs.c
+++ b/drivers/infiniband/hw/ipath/ipath_verbs.c
@@ -1201,12 +1201,7 @@ static int ipath_query_port(struct ib_device *ibdev,
 	props->max_vl_num = 1;		/* VLCap = VL0 */
 	props->init_type_reply = 0;
 
-	/*
-	 * Note: the chip supports a maximum MTU of 4096, but the driver
-	 * hasn't implemented this feature yet, so set the maximum value
-	 * to 2048.
-	 */
-	props->max_mtu = IB_MTU_2048;
+	props->max_mtu = ipath_mtu4096 ? IB_MTU_4096 : IB_MTU_2048;
 	switch (dd->ipath_ibmtu) {
 	case 4096:
 		mtu = IB_MTU_4096;




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