IB/ipath: Enable 4KB MTU
Enable use of 4KB MTU. Since the driver uses more pinned memory for
receive buffers when the 4KB MTU is enabled, whether or not the fabric
supports that MTU, add a "mtu4096" module parameter that can be used to
limit the MTU to 2KB when it is known that 4KB MTUs can't be used
anyway.
Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
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_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@pathscale.com>");
MODULE_DESCRIPTION("QLogic InfiniPath driver");
@@ -1800,7 +1804,7 @@
* 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 @@
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 @@
}
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 219b62d..cddf29b 100644
--- a/drivers/infiniband/hw/ipath/ipath_file_ops.c
+++ b/drivers/infiniband/hw/ipath/ipath_file_ops.c
@@ -219,7 +219,12 @@
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 @@
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 @@
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 @@
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 @@
#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 @@
/* 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 @@
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 @@
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 @@
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;
