Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2148 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/hfi1/pio.c b/drivers/infiniband/hw/hfi1/pio.c
new file mode 100644
index 000000000..3fcbf56f8
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/pio.c
@@ -0,0 +1,2148 @@
+/*
+ * Copyright(c) 2015-2018 Intel Corporation.
+ *
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * BSD LICENSE
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  - Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  - Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *  - Neither the name of Intel Corporation nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <linux/delay.h>
+#include "hfi.h"
+#include "qp.h"
+#include "trace.h"
+
+#define SC(name) SEND_CTXT_##name
+/*
+ * Send Context functions
+ */
+static void sc_wait_for_packet_egress(struct send_context *sc, int pause);
+
+/*
+ * Set the CM reset bit and wait for it to clear.  Use the provided
+ * sendctrl register.  This routine has no locking.
+ */
+void __cm_reset(struct hfi1_devdata *dd, u64 sendctrl)
+{
+	write_csr(dd, SEND_CTRL, sendctrl | SEND_CTRL_CM_RESET_SMASK);
+	while (1) {
+		udelay(1);
+		sendctrl = read_csr(dd, SEND_CTRL);
+		if ((sendctrl & SEND_CTRL_CM_RESET_SMASK) == 0)
+			break;
+	}
+}
+
+/* defined in header release 48 and higher */
+#ifndef SEND_CTRL_UNSUPPORTED_VL_SHIFT
+#define SEND_CTRL_UNSUPPORTED_VL_SHIFT 3
+#define SEND_CTRL_UNSUPPORTED_VL_MASK 0xffull
+#define SEND_CTRL_UNSUPPORTED_VL_SMASK (SEND_CTRL_UNSUPPORTED_VL_MASK \
+		<< SEND_CTRL_UNSUPPORTED_VL_SHIFT)
+#endif
+
+/* global control of PIO send */
+void pio_send_control(struct hfi1_devdata *dd, int op)
+{
+	u64 reg, mask;
+	unsigned long flags;
+	int write = 1;	/* write sendctrl back */
+	int flush = 0;	/* re-read sendctrl to make sure it is flushed */
+	int i;
+
+	spin_lock_irqsave(&dd->sendctrl_lock, flags);
+
+	reg = read_csr(dd, SEND_CTRL);
+	switch (op) {
+	case PSC_GLOBAL_ENABLE:
+		reg |= SEND_CTRL_SEND_ENABLE_SMASK;
+	/* Fall through */
+	case PSC_DATA_VL_ENABLE:
+		mask = 0;
+		for (i = 0; i < ARRAY_SIZE(dd->vld); i++)
+			if (!dd->vld[i].mtu)
+				mask |= BIT_ULL(i);
+		/* Disallow sending on VLs not enabled */
+		mask = (mask & SEND_CTRL_UNSUPPORTED_VL_MASK) <<
+			SEND_CTRL_UNSUPPORTED_VL_SHIFT;
+		reg = (reg & ~SEND_CTRL_UNSUPPORTED_VL_SMASK) | mask;
+		break;
+	case PSC_GLOBAL_DISABLE:
+		reg &= ~SEND_CTRL_SEND_ENABLE_SMASK;
+		break;
+	case PSC_GLOBAL_VLARB_ENABLE:
+		reg |= SEND_CTRL_VL_ARBITER_ENABLE_SMASK;
+		break;
+	case PSC_GLOBAL_VLARB_DISABLE:
+		reg &= ~SEND_CTRL_VL_ARBITER_ENABLE_SMASK;
+		break;
+	case PSC_CM_RESET:
+		__cm_reset(dd, reg);
+		write = 0; /* CSR already written (and flushed) */
+		break;
+	case PSC_DATA_VL_DISABLE:
+		reg |= SEND_CTRL_UNSUPPORTED_VL_SMASK;
+		flush = 1;
+		break;
+	default:
+		dd_dev_err(dd, "%s: invalid control %d\n", __func__, op);
+		break;
+	}
+
+	if (write) {
+		write_csr(dd, SEND_CTRL, reg);
+		if (flush)
+			(void)read_csr(dd, SEND_CTRL); /* flush write */
+	}
+
+	spin_unlock_irqrestore(&dd->sendctrl_lock, flags);
+}
+
+/* number of send context memory pools */
+#define NUM_SC_POOLS 2
+
+/* Send Context Size (SCS) wildcards */
+#define SCS_POOL_0 -1
+#define SCS_POOL_1 -2
+
+/* Send Context Count (SCC) wildcards */
+#define SCC_PER_VL -1
+#define SCC_PER_CPU  -2
+#define SCC_PER_KRCVQ  -3
+
+/* Send Context Size (SCS) constants */
+#define SCS_ACK_CREDITS  32
+#define SCS_VL15_CREDITS 102	/* 3 pkts of 2048B data + 128B header */
+
+#define PIO_THRESHOLD_CEILING 4096
+
+#define PIO_WAIT_BATCH_SIZE 5
+
+/* default send context sizes */
+static struct sc_config_sizes sc_config_sizes[SC_MAX] = {
+	[SC_KERNEL] = { .size  = SCS_POOL_0,	/* even divide, pool 0 */
+			.count = SCC_PER_VL },	/* one per NUMA */
+	[SC_ACK]    = { .size  = SCS_ACK_CREDITS,
+			.count = SCC_PER_KRCVQ },
+	[SC_USER]   = { .size  = SCS_POOL_0,	/* even divide, pool 0 */
+			.count = SCC_PER_CPU },	/* one per CPU */
+	[SC_VL15]   = { .size  = SCS_VL15_CREDITS,
+			.count = 1 },
+
+};
+
+/* send context memory pool configuration */
+struct mem_pool_config {
+	int centipercent;	/* % of memory, in 100ths of 1% */
+	int absolute_blocks;	/* absolute block count */
+};
+
+/* default memory pool configuration: 100% in pool 0 */
+static struct mem_pool_config sc_mem_pool_config[NUM_SC_POOLS] = {
+	/* centi%, abs blocks */
+	{  10000,     -1 },		/* pool 0 */
+	{      0,     -1 },		/* pool 1 */
+};
+
+/* memory pool information, used when calculating final sizes */
+struct mem_pool_info {
+	int centipercent;	/*
+				 * 100th of 1% of memory to use, -1 if blocks
+				 * already set
+				 */
+	int count;		/* count of contexts in the pool */
+	int blocks;		/* block size of the pool */
+	int size;		/* context size, in blocks */
+};
+
+/*
+ * Convert a pool wildcard to a valid pool index.  The wildcards
+ * start at -1 and increase negatively.  Map them as:
+ *	-1 => 0
+ *	-2 => 1
+ *	etc.
+ *
+ * Return -1 on non-wildcard input, otherwise convert to a pool number.
+ */
+static int wildcard_to_pool(int wc)
+{
+	if (wc >= 0)
+		return -1;	/* non-wildcard */
+	return -wc - 1;
+}
+
+static const char *sc_type_names[SC_MAX] = {
+	"kernel",
+	"ack",
+	"user",
+	"vl15"
+};
+
+static const char *sc_type_name(int index)
+{
+	if (index < 0 || index >= SC_MAX)
+		return "unknown";
+	return sc_type_names[index];
+}
+
+/*
+ * Read the send context memory pool configuration and send context
+ * size configuration.  Replace any wildcards and come up with final
+ * counts and sizes for the send context types.
+ */
+int init_sc_pools_and_sizes(struct hfi1_devdata *dd)
+{
+	struct mem_pool_info mem_pool_info[NUM_SC_POOLS] = { { 0 } };
+	int total_blocks = (chip_pio_mem_size(dd) / PIO_BLOCK_SIZE) - 1;
+	int total_contexts = 0;
+	int fixed_blocks;
+	int pool_blocks;
+	int used_blocks;
+	int cp_total;		/* centipercent total */
+	int ab_total;		/* absolute block total */
+	int extra;
+	int i;
+
+	/*
+	 * When SDMA is enabled, kernel context pio packet size is capped by
+	 * "piothreshold". Reduce pio buffer allocation for kernel context by
+	 * setting it to a fixed size. The allocation allows 3-deep buffering
+	 * of the largest pio packets plus up to 128 bytes header, sufficient
+	 * to maintain verbs performance.
+	 *
+	 * When SDMA is disabled, keep the default pooling allocation.
+	 */
+	if (HFI1_CAP_IS_KSET(SDMA)) {
+		u16 max_pkt_size = (piothreshold < PIO_THRESHOLD_CEILING) ?
+					 piothreshold : PIO_THRESHOLD_CEILING;
+		sc_config_sizes[SC_KERNEL].size =
+			3 * (max_pkt_size + 128) / PIO_BLOCK_SIZE;
+	}
+
+	/*
+	 * Step 0:
+	 *	- copy the centipercents/absolute sizes from the pool config
+	 *	- sanity check these values
+	 *	- add up centipercents, then later check for full value
+	 *	- add up absolute blocks, then later check for over-commit
+	 */
+	cp_total = 0;
+	ab_total = 0;
+	for (i = 0; i < NUM_SC_POOLS; i++) {
+		int cp = sc_mem_pool_config[i].centipercent;
+		int ab = sc_mem_pool_config[i].absolute_blocks;
+
+		/*
+		 * A negative value is "unused" or "invalid".  Both *can*
+		 * be valid, but centipercent wins, so check that first
+		 */
+		if (cp >= 0) {			/* centipercent valid */
+			cp_total += cp;
+		} else if (ab >= 0) {		/* absolute blocks valid */
+			ab_total += ab;
+		} else {			/* neither valid */
+			dd_dev_err(
+				dd,
+				"Send context memory pool %d: both the block count and centipercent are invalid\n",
+				i);
+			return -EINVAL;
+		}
+
+		mem_pool_info[i].centipercent = cp;
+		mem_pool_info[i].blocks = ab;
+	}
+
+	/* do not use both % and absolute blocks for different pools */
+	if (cp_total != 0 && ab_total != 0) {
+		dd_dev_err(
+			dd,
+			"All send context memory pools must be described as either centipercent or blocks, no mixing between pools\n");
+		return -EINVAL;
+	}
+
+	/* if any percentages are present, they must add up to 100% x 100 */
+	if (cp_total != 0 && cp_total != 10000) {
+		dd_dev_err(
+			dd,
+			"Send context memory pool centipercent is %d, expecting 10000\n",
+			cp_total);
+		return -EINVAL;
+	}
+
+	/* the absolute pool total cannot be more than the mem total */
+	if (ab_total > total_blocks) {
+		dd_dev_err(
+			dd,
+			"Send context memory pool absolute block count %d is larger than the memory size %d\n",
+			ab_total, total_blocks);
+		return -EINVAL;
+	}
+
+	/*
+	 * Step 2:
+	 *	- copy from the context size config
+	 *	- replace context type wildcard counts with real values
+	 *	- add up non-memory pool block sizes
+	 *	- add up memory pool user counts
+	 */
+	fixed_blocks = 0;
+	for (i = 0; i < SC_MAX; i++) {
+		int count = sc_config_sizes[i].count;
+		int size = sc_config_sizes[i].size;
+		int pool;
+
+		/*
+		 * Sanity check count: Either a positive value or
+		 * one of the expected wildcards is valid.  The positive
+		 * value is checked later when we compare against total
+		 * memory available.
+		 */
+		if (i == SC_ACK) {
+			count = dd->n_krcv_queues;
+		} else if (i == SC_KERNEL) {
+			count = INIT_SC_PER_VL * num_vls;
+		} else if (count == SCC_PER_CPU) {
+			count = dd->num_rcv_contexts - dd->n_krcv_queues;
+		} else if (count < 0) {
+			dd_dev_err(
+				dd,
+				"%s send context invalid count wildcard %d\n",
+				sc_type_name(i), count);
+			return -EINVAL;
+		}
+		if (total_contexts + count > chip_send_contexts(dd))
+			count = chip_send_contexts(dd) - total_contexts;
+
+		total_contexts += count;
+
+		/*
+		 * Sanity check pool: The conversion will return a pool
+		 * number or -1 if a fixed (non-negative) value.  The fixed
+		 * value is checked later when we compare against
+		 * total memory available.
+		 */
+		pool = wildcard_to_pool(size);
+		if (pool == -1) {			/* non-wildcard */
+			fixed_blocks += size * count;
+		} else if (pool < NUM_SC_POOLS) {	/* valid wildcard */
+			mem_pool_info[pool].count += count;
+		} else {				/* invalid wildcard */
+			dd_dev_err(
+				dd,
+				"%s send context invalid pool wildcard %d\n",
+				sc_type_name(i), size);
+			return -EINVAL;
+		}
+
+		dd->sc_sizes[i].count = count;
+		dd->sc_sizes[i].size = size;
+	}
+	if (fixed_blocks > total_blocks) {
+		dd_dev_err(
+			dd,
+			"Send context fixed block count, %u, larger than total block count %u\n",
+			fixed_blocks, total_blocks);
+		return -EINVAL;
+	}
+
+	/* step 3: calculate the blocks in the pools, and pool context sizes */
+	pool_blocks = total_blocks - fixed_blocks;
+	if (ab_total > pool_blocks) {
+		dd_dev_err(
+			dd,
+			"Send context fixed pool sizes, %u, larger than pool block count %u\n",
+			ab_total, pool_blocks);
+		return -EINVAL;
+	}
+	/* subtract off the fixed pool blocks */
+	pool_blocks -= ab_total;
+
+	for (i = 0; i < NUM_SC_POOLS; i++) {
+		struct mem_pool_info *pi = &mem_pool_info[i];
+
+		/* % beats absolute blocks */
+		if (pi->centipercent >= 0)
+			pi->blocks = (pool_blocks * pi->centipercent) / 10000;
+
+		if (pi->blocks == 0 && pi->count != 0) {
+			dd_dev_err(
+				dd,
+				"Send context memory pool %d has %u contexts, but no blocks\n",
+				i, pi->count);
+			return -EINVAL;
+		}
+		if (pi->count == 0) {
+			/* warn about wasted blocks */
+			if (pi->blocks != 0)
+				dd_dev_err(
+					dd,
+					"Send context memory pool %d has %u blocks, but zero contexts\n",
+					i, pi->blocks);
+			pi->size = 0;
+		} else {
+			pi->size = pi->blocks / pi->count;
+		}
+	}
+
+	/* step 4: fill in the context type sizes from the pool sizes */
+	used_blocks = 0;
+	for (i = 0; i < SC_MAX; i++) {
+		if (dd->sc_sizes[i].size < 0) {
+			unsigned pool = wildcard_to_pool(dd->sc_sizes[i].size);
+
+			WARN_ON_ONCE(pool >= NUM_SC_POOLS);
+			dd->sc_sizes[i].size = mem_pool_info[pool].size;
+		}
+		/* make sure we are not larger than what is allowed by the HW */
+#define PIO_MAX_BLOCKS 1024
+		if (dd->sc_sizes[i].size > PIO_MAX_BLOCKS)
+			dd->sc_sizes[i].size = PIO_MAX_BLOCKS;
+
+		/* calculate our total usage */
+		used_blocks += dd->sc_sizes[i].size * dd->sc_sizes[i].count;
+	}
+	extra = total_blocks - used_blocks;
+	if (extra != 0)
+		dd_dev_info(dd, "unused send context blocks: %d\n", extra);
+
+	return total_contexts;
+}
+
+int init_send_contexts(struct hfi1_devdata *dd)
+{
+	u16 base;
+	int ret, i, j, context;
+
+	ret = init_credit_return(dd);
+	if (ret)
+		return ret;
+
+	dd->hw_to_sw = kmalloc_array(TXE_NUM_CONTEXTS, sizeof(u8),
+					GFP_KERNEL);
+	dd->send_contexts = kcalloc(dd->num_send_contexts,
+				    sizeof(struct send_context_info),
+				    GFP_KERNEL);
+	if (!dd->send_contexts || !dd->hw_to_sw) {
+		kfree(dd->hw_to_sw);
+		kfree(dd->send_contexts);
+		free_credit_return(dd);
+		return -ENOMEM;
+	}
+
+	/* hardware context map starts with invalid send context indices */
+	for (i = 0; i < TXE_NUM_CONTEXTS; i++)
+		dd->hw_to_sw[i] = INVALID_SCI;
+
+	/*
+	 * All send contexts have their credit sizes.  Allocate credits
+	 * for each context one after another from the global space.
+	 */
+	context = 0;
+	base = 1;
+	for (i = 0; i < SC_MAX; i++) {
+		struct sc_config_sizes *scs = &dd->sc_sizes[i];
+
+		for (j = 0; j < scs->count; j++) {
+			struct send_context_info *sci =
+						&dd->send_contexts[context];
+			sci->type = i;
+			sci->base = base;
+			sci->credits = scs->size;
+
+			context++;
+			base += scs->size;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Allocate a software index and hardware context of the given type.
+ *
+ * Must be called with dd->sc_lock held.
+ */
+static int sc_hw_alloc(struct hfi1_devdata *dd, int type, u32 *sw_index,
+		       u32 *hw_context)
+{
+	struct send_context_info *sci;
+	u32 index;
+	u32 context;
+
+	for (index = 0, sci = &dd->send_contexts[0];
+			index < dd->num_send_contexts; index++, sci++) {
+		if (sci->type == type && sci->allocated == 0) {
+			sci->allocated = 1;
+			/* use a 1:1 mapping, but make them non-equal */
+			context = chip_send_contexts(dd) - index - 1;
+			dd->hw_to_sw[context] = index;
+			*sw_index = index;
+			*hw_context = context;
+			return 0; /* success */
+		}
+	}
+	dd_dev_err(dd, "Unable to locate a free type %d send context\n", type);
+	return -ENOSPC;
+}
+
+/*
+ * Free the send context given by its software index.
+ *
+ * Must be called with dd->sc_lock held.
+ */
+static void sc_hw_free(struct hfi1_devdata *dd, u32 sw_index, u32 hw_context)
+{
+	struct send_context_info *sci;
+
+	sci = &dd->send_contexts[sw_index];
+	if (!sci->allocated) {
+		dd_dev_err(dd, "%s: sw_index %u not allocated? hw_context %u\n",
+			   __func__, sw_index, hw_context);
+	}
+	sci->allocated = 0;
+	dd->hw_to_sw[hw_context] = INVALID_SCI;
+}
+
+/* return the base context of a context in a group */
+static inline u32 group_context(u32 context, u32 group)
+{
+	return (context >> group) << group;
+}
+
+/* return the size of a group */
+static inline u32 group_size(u32 group)
+{
+	return 1 << group;
+}
+
+/*
+ * Obtain the credit return addresses, kernel virtual and bus, for the
+ * given sc.
+ *
+ * To understand this routine:
+ * o va and dma are arrays of struct credit_return.  One for each physical
+ *   send context, per NUMA.
+ * o Each send context always looks in its relative location in a struct
+ *   credit_return for its credit return.
+ * o Each send context in a group must have its return address CSR programmed
+ *   with the same value.  Use the address of the first send context in the
+ *   group.
+ */
+static void cr_group_addresses(struct send_context *sc, dma_addr_t *dma)
+{
+	u32 gc = group_context(sc->hw_context, sc->group);
+	u32 index = sc->hw_context & 0x7;
+
+	sc->hw_free = &sc->dd->cr_base[sc->node].va[gc].cr[index];
+	*dma = (unsigned long)
+	       &((struct credit_return *)sc->dd->cr_base[sc->node].dma)[gc];
+}
+
+/*
+ * Work queue function triggered in error interrupt routine for
+ * kernel contexts.
+ */
+static void sc_halted(struct work_struct *work)
+{
+	struct send_context *sc;
+
+	sc = container_of(work, struct send_context, halt_work);
+	sc_restart(sc);
+}
+
+/*
+ * Calculate PIO block threshold for this send context using the given MTU.
+ * Trigger a return when one MTU plus optional header of credits remain.
+ *
+ * Parameter mtu is in bytes.
+ * Parameter hdrqentsize is in DWORDs.
+ *
+ * Return value is what to write into the CSR: trigger return when
+ * unreturned credits pass this count.
+ */
+u32 sc_mtu_to_threshold(struct send_context *sc, u32 mtu, u32 hdrqentsize)
+{
+	u32 release_credits;
+	u32 threshold;
+
+	/* add in the header size, then divide by the PIO block size */
+	mtu += hdrqentsize << 2;
+	release_credits = DIV_ROUND_UP(mtu, PIO_BLOCK_SIZE);
+
+	/* check against this context's credits */
+	if (sc->credits <= release_credits)
+		threshold = 1;
+	else
+		threshold = sc->credits - release_credits;
+
+	return threshold;
+}
+
+/*
+ * Calculate credit threshold in terms of percent of the allocated credits.
+ * Trigger when unreturned credits equal or exceed the percentage of the whole.
+ *
+ * Return value is what to write into the CSR: trigger return when
+ * unreturned credits pass this count.
+ */
+u32 sc_percent_to_threshold(struct send_context *sc, u32 percent)
+{
+	return (sc->credits * percent) / 100;
+}
+
+/*
+ * Set the credit return threshold.
+ */
+void sc_set_cr_threshold(struct send_context *sc, u32 new_threshold)
+{
+	unsigned long flags;
+	u32 old_threshold;
+	int force_return = 0;
+
+	spin_lock_irqsave(&sc->credit_ctrl_lock, flags);
+
+	old_threshold = (sc->credit_ctrl >>
+				SC(CREDIT_CTRL_THRESHOLD_SHIFT))
+			 & SC(CREDIT_CTRL_THRESHOLD_MASK);
+
+	if (new_threshold != old_threshold) {
+		sc->credit_ctrl =
+			(sc->credit_ctrl
+				& ~SC(CREDIT_CTRL_THRESHOLD_SMASK))
+			| ((new_threshold
+				& SC(CREDIT_CTRL_THRESHOLD_MASK))
+			   << SC(CREDIT_CTRL_THRESHOLD_SHIFT));
+		write_kctxt_csr(sc->dd, sc->hw_context,
+				SC(CREDIT_CTRL), sc->credit_ctrl);
+
+		/* force a credit return on change to avoid a possible stall */
+		force_return = 1;
+	}
+
+	spin_unlock_irqrestore(&sc->credit_ctrl_lock, flags);
+
+	if (force_return)
+		sc_return_credits(sc);
+}
+
+/*
+ * set_pio_integrity
+ *
+ * Set the CHECK_ENABLE register for the send context 'sc'.
+ */
+void set_pio_integrity(struct send_context *sc)
+{
+	struct hfi1_devdata *dd = sc->dd;
+	u32 hw_context = sc->hw_context;
+	int type = sc->type;
+
+	write_kctxt_csr(dd, hw_context,
+			SC(CHECK_ENABLE),
+			hfi1_pkt_default_send_ctxt_mask(dd, type));
+}
+
+static u32 get_buffers_allocated(struct send_context *sc)
+{
+	int cpu;
+	u32 ret = 0;
+
+	for_each_possible_cpu(cpu)
+		ret += *per_cpu_ptr(sc->buffers_allocated, cpu);
+	return ret;
+}
+
+static void reset_buffers_allocated(struct send_context *sc)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		(*per_cpu_ptr(sc->buffers_allocated, cpu)) = 0;
+}
+
+/*
+ * Allocate a NUMA relative send context structure of the given type along
+ * with a HW context.
+ */
+struct send_context *sc_alloc(struct hfi1_devdata *dd, int type,
+			      uint hdrqentsize, int numa)
+{
+	struct send_context_info *sci;
+	struct send_context *sc = NULL;
+	dma_addr_t dma;
+	unsigned long flags;
+	u64 reg;
+	u32 thresh;
+	u32 sw_index;
+	u32 hw_context;
+	int ret;
+	u8 opval, opmask;
+
+	/* do not allocate while frozen */
+	if (dd->flags & HFI1_FROZEN)
+		return NULL;
+
+	sc = kzalloc_node(sizeof(*sc), GFP_KERNEL, numa);
+	if (!sc)
+		return NULL;
+
+	sc->buffers_allocated = alloc_percpu(u32);
+	if (!sc->buffers_allocated) {
+		kfree(sc);
+		dd_dev_err(dd,
+			   "Cannot allocate buffers_allocated per cpu counters\n"
+			  );
+		return NULL;
+	}
+
+	spin_lock_irqsave(&dd->sc_lock, flags);
+	ret = sc_hw_alloc(dd, type, &sw_index, &hw_context);
+	if (ret) {
+		spin_unlock_irqrestore(&dd->sc_lock, flags);
+		free_percpu(sc->buffers_allocated);
+		kfree(sc);
+		return NULL;
+	}
+
+	sci = &dd->send_contexts[sw_index];
+	sci->sc = sc;
+
+	sc->dd = dd;
+	sc->node = numa;
+	sc->type = type;
+	spin_lock_init(&sc->alloc_lock);
+	spin_lock_init(&sc->release_lock);
+	spin_lock_init(&sc->credit_ctrl_lock);
+	INIT_LIST_HEAD(&sc->piowait);
+	INIT_WORK(&sc->halt_work, sc_halted);
+	init_waitqueue_head(&sc->halt_wait);
+
+	/* grouping is always single context for now */
+	sc->group = 0;
+
+	sc->sw_index = sw_index;
+	sc->hw_context = hw_context;
+	cr_group_addresses(sc, &dma);
+	sc->credits = sci->credits;
+	sc->size = sc->credits * PIO_BLOCK_SIZE;
+
+/* PIO Send Memory Address details */
+#define PIO_ADDR_CONTEXT_MASK 0xfful
+#define PIO_ADDR_CONTEXT_SHIFT 16
+	sc->base_addr = dd->piobase + ((hw_context & PIO_ADDR_CONTEXT_MASK)
+					<< PIO_ADDR_CONTEXT_SHIFT);
+
+	/* set base and credits */
+	reg = ((sci->credits & SC(CTRL_CTXT_DEPTH_MASK))
+					<< SC(CTRL_CTXT_DEPTH_SHIFT))
+		| ((sci->base & SC(CTRL_CTXT_BASE_MASK))
+					<< SC(CTRL_CTXT_BASE_SHIFT));
+	write_kctxt_csr(dd, hw_context, SC(CTRL), reg);
+
+	set_pio_integrity(sc);
+
+	/* unmask all errors */
+	write_kctxt_csr(dd, hw_context, SC(ERR_MASK), (u64)-1);
+
+	/* set the default partition key */
+	write_kctxt_csr(dd, hw_context, SC(CHECK_PARTITION_KEY),
+			(SC(CHECK_PARTITION_KEY_VALUE_MASK) &
+			 DEFAULT_PKEY) <<
+			SC(CHECK_PARTITION_KEY_VALUE_SHIFT));
+
+	/* per context type checks */
+	if (type == SC_USER) {
+		opval = USER_OPCODE_CHECK_VAL;
+		opmask = USER_OPCODE_CHECK_MASK;
+	} else {
+		opval = OPCODE_CHECK_VAL_DISABLED;
+		opmask = OPCODE_CHECK_MASK_DISABLED;
+	}
+
+	/* set the send context check opcode mask and value */
+	write_kctxt_csr(dd, hw_context, SC(CHECK_OPCODE),
+			((u64)opmask << SC(CHECK_OPCODE_MASK_SHIFT)) |
+			((u64)opval << SC(CHECK_OPCODE_VALUE_SHIFT)));
+
+	/* set up credit return */
+	reg = dma & SC(CREDIT_RETURN_ADDR_ADDRESS_SMASK);
+	write_kctxt_csr(dd, hw_context, SC(CREDIT_RETURN_ADDR), reg);
+
+	/*
+	 * Calculate the initial credit return threshold.
+	 *
+	 * For Ack contexts, set a threshold for half the credits.
+	 * For User contexts use the given percentage.  This has been
+	 * sanitized on driver start-up.
+	 * For Kernel contexts, use the default MTU plus a header
+	 * or half the credits, whichever is smaller. This should
+	 * work for both the 3-deep buffering allocation and the
+	 * pooling allocation.
+	 */
+	if (type == SC_ACK) {
+		thresh = sc_percent_to_threshold(sc, 50);
+	} else if (type == SC_USER) {
+		thresh = sc_percent_to_threshold(sc,
+						 user_credit_return_threshold);
+	} else { /* kernel */
+		thresh = min(sc_percent_to_threshold(sc, 50),
+			     sc_mtu_to_threshold(sc, hfi1_max_mtu,
+						 hdrqentsize));
+	}
+	reg = thresh << SC(CREDIT_CTRL_THRESHOLD_SHIFT);
+	/* add in early return */
+	if (type == SC_USER && HFI1_CAP_IS_USET(EARLY_CREDIT_RETURN))
+		reg |= SC(CREDIT_CTRL_EARLY_RETURN_SMASK);
+	else if (HFI1_CAP_IS_KSET(EARLY_CREDIT_RETURN)) /* kernel, ack */
+		reg |= SC(CREDIT_CTRL_EARLY_RETURN_SMASK);
+
+	/* set up write-through credit_ctrl */
+	sc->credit_ctrl = reg;
+	write_kctxt_csr(dd, hw_context, SC(CREDIT_CTRL), reg);
+
+	/* User send contexts should not allow sending on VL15 */
+	if (type == SC_USER) {
+		reg = 1ULL << 15;
+		write_kctxt_csr(dd, hw_context, SC(CHECK_VL), reg);
+	}
+
+	spin_unlock_irqrestore(&dd->sc_lock, flags);
+
+	/*
+	 * Allocate shadow ring to track outstanding PIO buffers _after_
+	 * unlocking.  We don't know the size until the lock is held and
+	 * we can't allocate while the lock is held.  No one is using
+	 * the context yet, so allocate it now.
+	 *
+	 * User contexts do not get a shadow ring.
+	 */
+	if (type != SC_USER) {
+		/*
+		 * Size the shadow ring 1 larger than the number of credits
+		 * so head == tail can mean empty.
+		 */
+		sc->sr_size = sci->credits + 1;
+		sc->sr = kcalloc_node(sc->sr_size,
+				      sizeof(union pio_shadow_ring),
+				      GFP_KERNEL, numa);
+		if (!sc->sr) {
+			sc_free(sc);
+			return NULL;
+		}
+	}
+
+	hfi1_cdbg(PIO,
+		  "Send context %u(%u) %s group %u credits %u credit_ctrl 0x%llx threshold %u\n",
+		  sw_index,
+		  hw_context,
+		  sc_type_name(type),
+		  sc->group,
+		  sc->credits,
+		  sc->credit_ctrl,
+		  thresh);
+
+	return sc;
+}
+
+/* free a per-NUMA send context structure */
+void sc_free(struct send_context *sc)
+{
+	struct hfi1_devdata *dd;
+	unsigned long flags;
+	u32 sw_index;
+	u32 hw_context;
+
+	if (!sc)
+		return;
+
+	sc->flags |= SCF_IN_FREE;	/* ensure no restarts */
+	dd = sc->dd;
+	if (!list_empty(&sc->piowait))
+		dd_dev_err(dd, "piowait list not empty!\n");
+	sw_index = sc->sw_index;
+	hw_context = sc->hw_context;
+	sc_disable(sc);	/* make sure the HW is disabled */
+	flush_work(&sc->halt_work);
+
+	spin_lock_irqsave(&dd->sc_lock, flags);
+	dd->send_contexts[sw_index].sc = NULL;
+
+	/* clear/disable all registers set in sc_alloc */
+	write_kctxt_csr(dd, hw_context, SC(CTRL), 0);
+	write_kctxt_csr(dd, hw_context, SC(CHECK_ENABLE), 0);
+	write_kctxt_csr(dd, hw_context, SC(ERR_MASK), 0);
+	write_kctxt_csr(dd, hw_context, SC(CHECK_PARTITION_KEY), 0);
+	write_kctxt_csr(dd, hw_context, SC(CHECK_OPCODE), 0);
+	write_kctxt_csr(dd, hw_context, SC(CREDIT_RETURN_ADDR), 0);
+	write_kctxt_csr(dd, hw_context, SC(CREDIT_CTRL), 0);
+
+	/* release the index and context for re-use */
+	sc_hw_free(dd, sw_index, hw_context);
+	spin_unlock_irqrestore(&dd->sc_lock, flags);
+
+	kfree(sc->sr);
+	free_percpu(sc->buffers_allocated);
+	kfree(sc);
+}
+
+/* disable the context */
+void sc_disable(struct send_context *sc)
+{
+	u64 reg;
+	struct pio_buf *pbuf;
+
+	if (!sc)
+		return;
+
+	/* do all steps, even if already disabled */
+	spin_lock_irq(&sc->alloc_lock);
+	reg = read_kctxt_csr(sc->dd, sc->hw_context, SC(CTRL));
+	reg &= ~SC(CTRL_CTXT_ENABLE_SMASK);
+	sc->flags &= ~SCF_ENABLED;
+	sc_wait_for_packet_egress(sc, 1);
+	write_kctxt_csr(sc->dd, sc->hw_context, SC(CTRL), reg);
+
+	/*
+	 * Flush any waiters.  Once the context is disabled,
+	 * credit return interrupts are stopped (although there
+	 * could be one in-process when the context is disabled).
+	 * Wait one microsecond for any lingering interrupts, then
+	 * proceed with the flush.
+	 */
+	udelay(1);
+	spin_lock(&sc->release_lock);
+	if (sc->sr) {	/* this context has a shadow ring */
+		while (sc->sr_tail != sc->sr_head) {
+			pbuf = &sc->sr[sc->sr_tail].pbuf;
+			if (pbuf->cb)
+				(*pbuf->cb)(pbuf->arg, PRC_SC_DISABLE);
+			sc->sr_tail++;
+			if (sc->sr_tail >= sc->sr_size)
+				sc->sr_tail = 0;
+		}
+	}
+	spin_unlock(&sc->release_lock);
+	spin_unlock_irq(&sc->alloc_lock);
+}
+
+/* return SendEgressCtxtStatus.PacketOccupancy */
+static u64 packet_occupancy(u64 reg)
+{
+	return (reg &
+		SEND_EGRESS_CTXT_STATUS_CTXT_EGRESS_PACKET_OCCUPANCY_SMASK)
+		>> SEND_EGRESS_CTXT_STATUS_CTXT_EGRESS_PACKET_OCCUPANCY_SHIFT;
+}
+
+/* is egress halted on the context? */
+static bool egress_halted(u64 reg)
+{
+	return !!(reg & SEND_EGRESS_CTXT_STATUS_CTXT_EGRESS_HALT_STATUS_SMASK);
+}
+
+/* is the send context halted? */
+static bool is_sc_halted(struct hfi1_devdata *dd, u32 hw_context)
+{
+	return !!(read_kctxt_csr(dd, hw_context, SC(STATUS)) &
+		  SC(STATUS_CTXT_HALTED_SMASK));
+}
+
+/**
+ * sc_wait_for_packet_egress
+ * @sc: valid send context
+ * @pause: wait for credit return
+ *
+ * Wait for packet egress, optionally pause for credit return
+ *
+ * Egress halt and Context halt are not necessarily the same thing, so
+ * check for both.
+ *
+ * NOTE: The context halt bit may not be set immediately.  Because of this,
+ * it is necessary to check the SW SFC_HALTED bit (set in the IRQ) and the HW
+ * context bit to determine if the context is halted.
+ */
+static void sc_wait_for_packet_egress(struct send_context *sc, int pause)
+{
+	struct hfi1_devdata *dd = sc->dd;
+	u64 reg = 0;
+	u64 reg_prev;
+	u32 loop = 0;
+
+	while (1) {
+		reg_prev = reg;
+		reg = read_csr(dd, sc->hw_context * 8 +
+			       SEND_EGRESS_CTXT_STATUS);
+		/* done if any halt bits, SW or HW are set */
+		if (sc->flags & SCF_HALTED ||
+		    is_sc_halted(dd, sc->hw_context) || egress_halted(reg))
+			break;
+		reg = packet_occupancy(reg);
+		if (reg == 0)
+			break;
+		/* counter is reset if occupancy count changes */
+		if (reg != reg_prev)
+			loop = 0;
+		if (loop > 50000) {
+			/* timed out - bounce the link */
+			dd_dev_err(dd,
+				   "%s: context %u(%u) timeout waiting for packets to egress, remaining count %u, bouncing link\n",
+				   __func__, sc->sw_index,
+				   sc->hw_context, (u32)reg);
+			queue_work(dd->pport->link_wq,
+				   &dd->pport->link_bounce_work);
+			break;
+		}
+		loop++;
+		udelay(1);
+	}
+
+	if (pause)
+		/* Add additional delay to ensure chip returns all credits */
+		pause_for_credit_return(dd);
+}
+
+void sc_wait(struct hfi1_devdata *dd)
+{
+	int i;
+
+	for (i = 0; i < dd->num_send_contexts; i++) {
+		struct send_context *sc = dd->send_contexts[i].sc;
+
+		if (!sc)
+			continue;
+		sc_wait_for_packet_egress(sc, 0);
+	}
+}
+
+/*
+ * Restart a context after it has been halted due to error.
+ *
+ * If the first step fails - wait for the halt to be asserted, return early.
+ * Otherwise complain about timeouts but keep going.
+ *
+ * It is expected that allocations (enabled flag bit) have been shut off
+ * already (only applies to kernel contexts).
+ */
+int sc_restart(struct send_context *sc)
+{
+	struct hfi1_devdata *dd = sc->dd;
+	u64 reg;
+	u32 loop;
+	int count;
+
+	/* bounce off if not halted, or being free'd */
+	if (!(sc->flags & SCF_HALTED) || (sc->flags & SCF_IN_FREE))
+		return -EINVAL;
+
+	dd_dev_info(dd, "restarting send context %u(%u)\n", sc->sw_index,
+		    sc->hw_context);
+
+	/*
+	 * Step 1: Wait for the context to actually halt.
+	 *
+	 * The error interrupt is asynchronous to actually setting halt
+	 * on the context.
+	 */
+	loop = 0;
+	while (1) {
+		reg = read_kctxt_csr(dd, sc->hw_context, SC(STATUS));
+		if (reg & SC(STATUS_CTXT_HALTED_SMASK))
+			break;
+		if (loop > 100) {
+			dd_dev_err(dd, "%s: context %u(%u) not halting, skipping\n",
+				   __func__, sc->sw_index, sc->hw_context);
+			return -ETIME;
+		}
+		loop++;
+		udelay(1);
+	}
+
+	/*
+	 * Step 2: Ensure no users are still trying to write to PIO.
+	 *
+	 * For kernel contexts, we have already turned off buffer allocation.
+	 * Now wait for the buffer count to go to zero.
+	 *
+	 * For user contexts, the user handling code has cut off write access
+	 * to the context's PIO pages before calling this routine and will
+	 * restore write access after this routine returns.
+	 */
+	if (sc->type != SC_USER) {
+		/* kernel context */
+		loop = 0;
+		while (1) {
+			count = get_buffers_allocated(sc);
+			if (count == 0)
+				break;
+			if (loop > 100) {
+				dd_dev_err(dd,
+					   "%s: context %u(%u) timeout waiting for PIO buffers to zero, remaining %d\n",
+					   __func__, sc->sw_index,
+					   sc->hw_context, count);
+			}
+			loop++;
+			udelay(1);
+		}
+	}
+
+	/*
+	 * Step 3: Wait for all packets to egress.
+	 * This is done while disabling the send context
+	 *
+	 * Step 4: Disable the context
+	 *
+	 * This is a superset of the halt.  After the disable, the
+	 * errors can be cleared.
+	 */
+	sc_disable(sc);
+
+	/*
+	 * Step 5: Enable the context
+	 *
+	 * This enable will clear the halted flag and per-send context
+	 * error flags.
+	 */
+	return sc_enable(sc);
+}
+
+/*
+ * PIO freeze processing.  To be called after the TXE block is fully frozen.
+ * Go through all frozen send contexts and disable them.  The contexts are
+ * already stopped by the freeze.
+ */
+void pio_freeze(struct hfi1_devdata *dd)
+{
+	struct send_context *sc;
+	int i;
+
+	for (i = 0; i < dd->num_send_contexts; i++) {
+		sc = dd->send_contexts[i].sc;
+		/*
+		 * Don't disable unallocated, unfrozen, or user send contexts.
+		 * User send contexts will be disabled when the process
+		 * calls into the driver to reset its context.
+		 */
+		if (!sc || !(sc->flags & SCF_FROZEN) || sc->type == SC_USER)
+			continue;
+
+		/* only need to disable, the context is already stopped */
+		sc_disable(sc);
+	}
+}
+
+/*
+ * Unfreeze PIO for kernel send contexts.  The precondition for calling this
+ * is that all PIO send contexts have been disabled and the SPC freeze has
+ * been cleared.  Now perform the last step and re-enable each kernel context.
+ * User (PSM) processing will occur when PSM calls into the kernel to
+ * acknowledge the freeze.
+ */
+void pio_kernel_unfreeze(struct hfi1_devdata *dd)
+{
+	struct send_context *sc;
+	int i;
+
+	for (i = 0; i < dd->num_send_contexts; i++) {
+		sc = dd->send_contexts[i].sc;
+		if (!sc || !(sc->flags & SCF_FROZEN) || sc->type == SC_USER)
+			continue;
+		if (sc->flags & SCF_LINK_DOWN)
+			continue;
+
+		sc_enable(sc);	/* will clear the sc frozen flag */
+	}
+}
+
+/**
+ * pio_kernel_linkup() - Re-enable send contexts after linkup event
+ * @dd: valid devive data
+ *
+ * When the link goes down, the freeze path is taken.  However, a link down
+ * event is different from a freeze because if the send context is re-enabled
+ * whowever is sending data will start sending data again, which will hang
+ * any QP that is sending data.
+ *
+ * The freeze path now looks at the type of event that occurs and takes this
+ * path for link down event.
+ */
+void pio_kernel_linkup(struct hfi1_devdata *dd)
+{
+	struct send_context *sc;
+	int i;
+
+	for (i = 0; i < dd->num_send_contexts; i++) {
+		sc = dd->send_contexts[i].sc;
+		if (!sc || !(sc->flags & SCF_LINK_DOWN) || sc->type == SC_USER)
+			continue;
+
+		sc_enable(sc);	/* will clear the sc link down flag */
+	}
+}
+
+/*
+ * Wait for the SendPioInitCtxt.PioInitInProgress bit to clear.
+ * Returns:
+ *	-ETIMEDOUT - if we wait too long
+ *	-EIO	   - if there was an error
+ */
+static int pio_init_wait_progress(struct hfi1_devdata *dd)
+{
+	u64 reg;
+	int max, count = 0;
+
+	/* max is the longest possible HW init time / delay */
+	max = (dd->icode == ICODE_FPGA_EMULATION) ? 120 : 5;
+	while (1) {
+		reg = read_csr(dd, SEND_PIO_INIT_CTXT);
+		if (!(reg & SEND_PIO_INIT_CTXT_PIO_INIT_IN_PROGRESS_SMASK))
+			break;
+		if (count >= max)
+			return -ETIMEDOUT;
+		udelay(5);
+		count++;
+	}
+
+	return reg & SEND_PIO_INIT_CTXT_PIO_INIT_ERR_SMASK ? -EIO : 0;
+}
+
+/*
+ * Reset all of the send contexts to their power-on state.  Used
+ * only during manual init - no lock against sc_enable needed.
+ */
+void pio_reset_all(struct hfi1_devdata *dd)
+{
+	int ret;
+
+	/* make sure the init engine is not busy */
+	ret = pio_init_wait_progress(dd);
+	/* ignore any timeout */
+	if (ret == -EIO) {
+		/* clear the error */
+		write_csr(dd, SEND_PIO_ERR_CLEAR,
+			  SEND_PIO_ERR_CLEAR_PIO_INIT_SM_IN_ERR_SMASK);
+	}
+
+	/* reset init all */
+	write_csr(dd, SEND_PIO_INIT_CTXT,
+		  SEND_PIO_INIT_CTXT_PIO_ALL_CTXT_INIT_SMASK);
+	udelay(2);
+	ret = pio_init_wait_progress(dd);
+	if (ret < 0) {
+		dd_dev_err(dd,
+			   "PIO send context init %s while initializing all PIO blocks\n",
+			   ret == -ETIMEDOUT ? "is stuck" : "had an error");
+	}
+}
+
+/* enable the context */
+int sc_enable(struct send_context *sc)
+{
+	u64 sc_ctrl, reg, pio;
+	struct hfi1_devdata *dd;
+	unsigned long flags;
+	int ret = 0;
+
+	if (!sc)
+		return -EINVAL;
+	dd = sc->dd;
+
+	/*
+	 * Obtain the allocator lock to guard against any allocation
+	 * attempts (which should not happen prior to context being
+	 * enabled). On the release/disable side we don't need to
+	 * worry about locking since the releaser will not do anything
+	 * if the context accounting values have not changed.
+	 */
+	spin_lock_irqsave(&sc->alloc_lock, flags);
+	sc_ctrl = read_kctxt_csr(dd, sc->hw_context, SC(CTRL));
+	if ((sc_ctrl & SC(CTRL_CTXT_ENABLE_SMASK)))
+		goto unlock; /* already enabled */
+
+	/* IMPORTANT: only clear free and fill if transitioning 0 -> 1 */
+
+	*sc->hw_free = 0;
+	sc->free = 0;
+	sc->alloc_free = 0;
+	sc->fill = 0;
+	sc->fill_wrap = 0;
+	sc->sr_head = 0;
+	sc->sr_tail = 0;
+	sc->flags = 0;
+	/* the alloc lock insures no fast path allocation */
+	reset_buffers_allocated(sc);
+
+	/*
+	 * Clear all per-context errors.  Some of these will be set when
+	 * we are re-enabling after a context halt.  Now that the context
+	 * is disabled, the halt will not clear until after the PIO init
+	 * engine runs below.
+	 */
+	reg = read_kctxt_csr(dd, sc->hw_context, SC(ERR_STATUS));
+	if (reg)
+		write_kctxt_csr(dd, sc->hw_context, SC(ERR_CLEAR), reg);
+
+	/*
+	 * The HW PIO initialization engine can handle only one init
+	 * request at a time. Serialize access to each device's engine.
+	 */
+	spin_lock(&dd->sc_init_lock);
+	/*
+	 * Since access to this code block is serialized and
+	 * each access waits for the initialization to complete
+	 * before releasing the lock, the PIO initialization engine
+	 * should not be in use, so we don't have to wait for the
+	 * InProgress bit to go down.
+	 */
+	pio = ((sc->hw_context & SEND_PIO_INIT_CTXT_PIO_CTXT_NUM_MASK) <<
+	       SEND_PIO_INIT_CTXT_PIO_CTXT_NUM_SHIFT) |
+		SEND_PIO_INIT_CTXT_PIO_SINGLE_CTXT_INIT_SMASK;
+	write_csr(dd, SEND_PIO_INIT_CTXT, pio);
+	/*
+	 * Wait until the engine is done.  Give the chip the required time
+	 * so, hopefully, we read the register just once.
+	 */
+	udelay(2);
+	ret = pio_init_wait_progress(dd);
+	spin_unlock(&dd->sc_init_lock);
+	if (ret) {
+		dd_dev_err(dd,
+			   "sctxt%u(%u): Context not enabled due to init failure %d\n",
+			   sc->sw_index, sc->hw_context, ret);
+		goto unlock;
+	}
+
+	/*
+	 * All is well. Enable the context.
+	 */
+	sc_ctrl |= SC(CTRL_CTXT_ENABLE_SMASK);
+	write_kctxt_csr(dd, sc->hw_context, SC(CTRL), sc_ctrl);
+	/*
+	 * Read SendCtxtCtrl to force the write out and prevent a timing
+	 * hazard where a PIO write may reach the context before the enable.
+	 */
+	read_kctxt_csr(dd, sc->hw_context, SC(CTRL));
+	sc->flags |= SCF_ENABLED;
+
+unlock:
+	spin_unlock_irqrestore(&sc->alloc_lock, flags);
+
+	return ret;
+}
+
+/* force a credit return on the context */
+void sc_return_credits(struct send_context *sc)
+{
+	if (!sc)
+		return;
+
+	/* a 0->1 transition schedules a credit return */
+	write_kctxt_csr(sc->dd, sc->hw_context, SC(CREDIT_FORCE),
+			SC(CREDIT_FORCE_FORCE_RETURN_SMASK));
+	/*
+	 * Ensure that the write is flushed and the credit return is
+	 * scheduled. We care more about the 0 -> 1 transition.
+	 */
+	read_kctxt_csr(sc->dd, sc->hw_context, SC(CREDIT_FORCE));
+	/* set back to 0 for next time */
+	write_kctxt_csr(sc->dd, sc->hw_context, SC(CREDIT_FORCE), 0);
+}
+
+/* allow all in-flight packets to drain on the context */
+void sc_flush(struct send_context *sc)
+{
+	if (!sc)
+		return;
+
+	sc_wait_for_packet_egress(sc, 1);
+}
+
+/* drop all packets on the context, no waiting until they are sent */
+void sc_drop(struct send_context *sc)
+{
+	if (!sc)
+		return;
+
+	dd_dev_info(sc->dd, "%s: context %u(%u) - not implemented\n",
+		    __func__, sc->sw_index, sc->hw_context);
+}
+
+/*
+ * Start the software reaction to a context halt or SPC freeze:
+ *	- mark the context as halted or frozen
+ *	- stop buffer allocations
+ *
+ * Called from the error interrupt.  Other work is deferred until
+ * out of the interrupt.
+ */
+void sc_stop(struct send_context *sc, int flag)
+{
+	unsigned long flags;
+
+	/* stop buffer allocations */
+	spin_lock_irqsave(&sc->alloc_lock, flags);
+	/* mark the context */
+	sc->flags |= flag;
+	sc->flags &= ~SCF_ENABLED;
+	spin_unlock_irqrestore(&sc->alloc_lock, flags);
+	wake_up(&sc->halt_wait);
+}
+
+#define BLOCK_DWORDS (PIO_BLOCK_SIZE / sizeof(u32))
+#define dwords_to_blocks(x) DIV_ROUND_UP(x, BLOCK_DWORDS)
+
+/*
+ * The send context buffer "allocator".
+ *
+ * @sc: the PIO send context we are allocating from
+ * @len: length of whole packet - including PBC - in dwords
+ * @cb: optional callback to call when the buffer is finished sending
+ * @arg: argument for cb
+ *
+ * Return a pointer to a PIO buffer, NULL if not enough room, -ECOMM
+ * when link is down.
+ */
+struct pio_buf *sc_buffer_alloc(struct send_context *sc, u32 dw_len,
+				pio_release_cb cb, void *arg)
+{
+	struct pio_buf *pbuf = NULL;
+	unsigned long flags;
+	unsigned long avail;
+	unsigned long blocks = dwords_to_blocks(dw_len);
+	u32 fill_wrap;
+	int trycount = 0;
+	u32 head, next;
+
+	spin_lock_irqsave(&sc->alloc_lock, flags);
+	if (!(sc->flags & SCF_ENABLED)) {
+		spin_unlock_irqrestore(&sc->alloc_lock, flags);
+		return ERR_PTR(-ECOMM);
+	}
+
+retry:
+	avail = (unsigned long)sc->credits - (sc->fill - sc->alloc_free);
+	if (blocks > avail) {
+		/* not enough room */
+		if (unlikely(trycount))	{ /* already tried to get more room */
+			spin_unlock_irqrestore(&sc->alloc_lock, flags);
+			goto done;
+		}
+		/* copy from receiver cache line and recalculate */
+		sc->alloc_free = READ_ONCE(sc->free);
+		avail =
+			(unsigned long)sc->credits -
+			(sc->fill - sc->alloc_free);
+		if (blocks > avail) {
+			/* still no room, actively update */
+			sc_release_update(sc);
+			sc->alloc_free = READ_ONCE(sc->free);
+			trycount++;
+			goto retry;
+		}
+	}
+
+	/* there is enough room */
+
+	preempt_disable();
+	this_cpu_inc(*sc->buffers_allocated);
+
+	/* read this once */
+	head = sc->sr_head;
+
+	/* "allocate" the buffer */
+	sc->fill += blocks;
+	fill_wrap = sc->fill_wrap;
+	sc->fill_wrap += blocks;
+	if (sc->fill_wrap >= sc->credits)
+		sc->fill_wrap = sc->fill_wrap - sc->credits;
+
+	/*
+	 * Fill the parts that the releaser looks at before moving the head.
+	 * The only necessary piece is the sent_at field.  The credits
+	 * we have just allocated cannot have been returned yet, so the
+	 * cb and arg will not be looked at for a "while".  Put them
+	 * on this side of the memory barrier anyway.
+	 */
+	pbuf = &sc->sr[head].pbuf;
+	pbuf->sent_at = sc->fill;
+	pbuf->cb = cb;
+	pbuf->arg = arg;
+	pbuf->sc = sc;	/* could be filled in at sc->sr init time */
+	/* make sure this is in memory before updating the head */
+
+	/* calculate next head index, do not store */
+	next = head + 1;
+	if (next >= sc->sr_size)
+		next = 0;
+	/*
+	 * update the head - must be last! - the releaser can look at fields
+	 * in pbuf once we move the head
+	 */
+	smp_wmb();
+	sc->sr_head = next;
+	spin_unlock_irqrestore(&sc->alloc_lock, flags);
+
+	/* finish filling in the buffer outside the lock */
+	pbuf->start = sc->base_addr + fill_wrap * PIO_BLOCK_SIZE;
+	pbuf->end = sc->base_addr + sc->size;
+	pbuf->qw_written = 0;
+	pbuf->carry_bytes = 0;
+	pbuf->carry.val64 = 0;
+done:
+	return pbuf;
+}
+
+/*
+ * There are at least two entities that can turn on credit return
+ * interrupts and they can overlap.  Avoid problems by implementing
+ * a count scheme that is enforced by a lock.  The lock is needed because
+ * the count and CSR write must be paired.
+ */
+
+/*
+ * Start credit return interrupts.  This is managed by a count.  If already
+ * on, just increment the count.
+ */
+void sc_add_credit_return_intr(struct send_context *sc)
+{
+	unsigned long flags;
+
+	/* lock must surround both the count change and the CSR update */
+	spin_lock_irqsave(&sc->credit_ctrl_lock, flags);
+	if (sc->credit_intr_count == 0) {
+		sc->credit_ctrl |= SC(CREDIT_CTRL_CREDIT_INTR_SMASK);
+		write_kctxt_csr(sc->dd, sc->hw_context,
+				SC(CREDIT_CTRL), sc->credit_ctrl);
+	}
+	sc->credit_intr_count++;
+	spin_unlock_irqrestore(&sc->credit_ctrl_lock, flags);
+}
+
+/*
+ * Stop credit return interrupts.  This is managed by a count.  Decrement the
+ * count, if the last user, then turn the credit interrupts off.
+ */
+void sc_del_credit_return_intr(struct send_context *sc)
+{
+	unsigned long flags;
+
+	WARN_ON(sc->credit_intr_count == 0);
+
+	/* lock must surround both the count change and the CSR update */
+	spin_lock_irqsave(&sc->credit_ctrl_lock, flags);
+	sc->credit_intr_count--;
+	if (sc->credit_intr_count == 0) {
+		sc->credit_ctrl &= ~SC(CREDIT_CTRL_CREDIT_INTR_SMASK);
+		write_kctxt_csr(sc->dd, sc->hw_context,
+				SC(CREDIT_CTRL), sc->credit_ctrl);
+	}
+	spin_unlock_irqrestore(&sc->credit_ctrl_lock, flags);
+}
+
+/*
+ * The caller must be careful when calling this.  All needint calls
+ * must be paired with !needint.
+ */
+void hfi1_sc_wantpiobuf_intr(struct send_context *sc, u32 needint)
+{
+	if (needint)
+		sc_add_credit_return_intr(sc);
+	else
+		sc_del_credit_return_intr(sc);
+	trace_hfi1_wantpiointr(sc, needint, sc->credit_ctrl);
+	if (needint) {
+		mmiowb();
+		sc_return_credits(sc);
+	}
+}
+
+/**
+ * sc_piobufavail - callback when a PIO buffer is available
+ * @sc: the send context
+ *
+ * This is called from the interrupt handler when a PIO buffer is
+ * available after hfi1_verbs_send() returned an error that no buffers were
+ * available. Disable the interrupt if there are no more QPs waiting.
+ */
+static void sc_piobufavail(struct send_context *sc)
+{
+	struct hfi1_devdata *dd = sc->dd;
+	struct hfi1_ibdev *dev = &dd->verbs_dev;
+	struct list_head *list;
+	struct rvt_qp *qps[PIO_WAIT_BATCH_SIZE];
+	struct rvt_qp *qp;
+	struct hfi1_qp_priv *priv;
+	unsigned long flags;
+	uint i, n = 0, max_idx = 0;
+	u8 max_starved_cnt = 0;
+
+	if (dd->send_contexts[sc->sw_index].type != SC_KERNEL &&
+	    dd->send_contexts[sc->sw_index].type != SC_VL15)
+		return;
+	list = &sc->piowait;
+	/*
+	 * Note: checking that the piowait list is empty and clearing
+	 * the buffer available interrupt needs to be atomic or we
+	 * could end up with QPs on the wait list with the interrupt
+	 * disabled.
+	 */
+	write_seqlock_irqsave(&dev->iowait_lock, flags);
+	while (!list_empty(list)) {
+		struct iowait *wait;
+
+		if (n == ARRAY_SIZE(qps))
+			break;
+		wait = list_first_entry(list, struct iowait, list);
+		qp = iowait_to_qp(wait);
+		priv = qp->priv;
+		list_del_init(&priv->s_iowait.list);
+		priv->s_iowait.lock = NULL;
+		iowait_starve_find_max(wait, &max_starved_cnt, n, &max_idx);
+		/* refcount held until actual wake up */
+		qps[n++] = qp;
+	}
+	/*
+	 * If there had been waiters and there are more
+	 * insure that we redo the force to avoid a potential hang.
+	 */
+	if (n) {
+		hfi1_sc_wantpiobuf_intr(sc, 0);
+		if (!list_empty(list))
+			hfi1_sc_wantpiobuf_intr(sc, 1);
+	}
+	write_sequnlock_irqrestore(&dev->iowait_lock, flags);
+
+	/* Wake up the most starved one first */
+	if (n)
+		hfi1_qp_wakeup(qps[max_idx],
+			       RVT_S_WAIT_PIO | HFI1_S_WAIT_PIO_DRAIN);
+	for (i = 0; i < n; i++)
+		if (i != max_idx)
+			hfi1_qp_wakeup(qps[i],
+				       RVT_S_WAIT_PIO | HFI1_S_WAIT_PIO_DRAIN);
+}
+
+/* translate a send credit update to a bit code of reasons */
+static inline int fill_code(u64 hw_free)
+{
+	int code = 0;
+
+	if (hw_free & CR_STATUS_SMASK)
+		code |= PRC_STATUS_ERR;
+	if (hw_free & CR_CREDIT_RETURN_DUE_TO_PBC_SMASK)
+		code |= PRC_PBC;
+	if (hw_free & CR_CREDIT_RETURN_DUE_TO_THRESHOLD_SMASK)
+		code |= PRC_THRESHOLD;
+	if (hw_free & CR_CREDIT_RETURN_DUE_TO_ERR_SMASK)
+		code |= PRC_FILL_ERR;
+	if (hw_free & CR_CREDIT_RETURN_DUE_TO_FORCE_SMASK)
+		code |= PRC_SC_DISABLE;
+	return code;
+}
+
+/* use the jiffies compare to get the wrap right */
+#define sent_before(a, b) time_before(a, b)	/* a < b */
+
+/*
+ * The send context buffer "releaser".
+ */
+void sc_release_update(struct send_context *sc)
+{
+	struct pio_buf *pbuf;
+	u64 hw_free;
+	u32 head, tail;
+	unsigned long old_free;
+	unsigned long free;
+	unsigned long extra;
+	unsigned long flags;
+	int code;
+
+	if (!sc)
+		return;
+
+	spin_lock_irqsave(&sc->release_lock, flags);
+	/* update free */
+	hw_free = le64_to_cpu(*sc->hw_free);		/* volatile read */
+	old_free = sc->free;
+	extra = (((hw_free & CR_COUNTER_SMASK) >> CR_COUNTER_SHIFT)
+			- (old_free & CR_COUNTER_MASK))
+				& CR_COUNTER_MASK;
+	free = old_free + extra;
+	trace_hfi1_piofree(sc, extra);
+
+	/* call sent buffer callbacks */
+	code = -1;				/* code not yet set */
+	head = READ_ONCE(sc->sr_head);	/* snapshot the head */
+	tail = sc->sr_tail;
+	while (head != tail) {
+		pbuf = &sc->sr[tail].pbuf;
+
+		if (sent_before(free, pbuf->sent_at)) {
+			/* not sent yet */
+			break;
+		}
+		if (pbuf->cb) {
+			if (code < 0) /* fill in code on first user */
+				code = fill_code(hw_free);
+			(*pbuf->cb)(pbuf->arg, code);
+		}
+
+		tail++;
+		if (tail >= sc->sr_size)
+			tail = 0;
+	}
+	sc->sr_tail = tail;
+	/* make sure tail is updated before free */
+	smp_wmb();
+	sc->free = free;
+	spin_unlock_irqrestore(&sc->release_lock, flags);
+	sc_piobufavail(sc);
+}
+
+/*
+ * Send context group releaser.  Argument is the send context that caused
+ * the interrupt.  Called from the send context interrupt handler.
+ *
+ * Call release on all contexts in the group.
+ *
+ * This routine takes the sc_lock without an irqsave because it is only
+ * called from an interrupt handler.  Adjust if that changes.
+ */
+void sc_group_release_update(struct hfi1_devdata *dd, u32 hw_context)
+{
+	struct send_context *sc;
+	u32 sw_index;
+	u32 gc, gc_end;
+
+	spin_lock(&dd->sc_lock);
+	sw_index = dd->hw_to_sw[hw_context];
+	if (unlikely(sw_index >= dd->num_send_contexts)) {
+		dd_dev_err(dd, "%s: invalid hw (%u) to sw (%u) mapping\n",
+			   __func__, hw_context, sw_index);
+		goto done;
+	}
+	sc = dd->send_contexts[sw_index].sc;
+	if (unlikely(!sc))
+		goto done;
+
+	gc = group_context(hw_context, sc->group);
+	gc_end = gc + group_size(sc->group);
+	for (; gc < gc_end; gc++) {
+		sw_index = dd->hw_to_sw[gc];
+		if (unlikely(sw_index >= dd->num_send_contexts)) {
+			dd_dev_err(dd,
+				   "%s: invalid hw (%u) to sw (%u) mapping\n",
+				   __func__, hw_context, sw_index);
+			continue;
+		}
+		sc_release_update(dd->send_contexts[sw_index].sc);
+	}
+done:
+	spin_unlock(&dd->sc_lock);
+}
+
+/*
+ * pio_select_send_context_vl() - select send context
+ * @dd: devdata
+ * @selector: a spreading factor
+ * @vl: this vl
+ *
+ * This function returns a send context based on the selector and a vl.
+ * The mapping fields are protected by RCU
+ */
+struct send_context *pio_select_send_context_vl(struct hfi1_devdata *dd,
+						u32 selector, u8 vl)
+{
+	struct pio_vl_map *m;
+	struct pio_map_elem *e;
+	struct send_context *rval;
+
+	/*
+	 * NOTE This should only happen if SC->VL changed after the initial
+	 * checks on the QP/AH
+	 * Default will return VL0's send context below
+	 */
+	if (unlikely(vl >= num_vls)) {
+		rval = NULL;
+		goto done;
+	}
+
+	rcu_read_lock();
+	m = rcu_dereference(dd->pio_map);
+	if (unlikely(!m)) {
+		rcu_read_unlock();
+		return dd->vld[0].sc;
+	}
+	e = m->map[vl & m->mask];
+	rval = e->ksc[selector & e->mask];
+	rcu_read_unlock();
+
+done:
+	rval = !rval ? dd->vld[0].sc : rval;
+	return rval;
+}
+
+/*
+ * pio_select_send_context_sc() - select send context
+ * @dd: devdata
+ * @selector: a spreading factor
+ * @sc5: the 5 bit sc
+ *
+ * This function returns an send context based on the selector and an sc
+ */
+struct send_context *pio_select_send_context_sc(struct hfi1_devdata *dd,
+						u32 selector, u8 sc5)
+{
+	u8 vl = sc_to_vlt(dd, sc5);
+
+	return pio_select_send_context_vl(dd, selector, vl);
+}
+
+/*
+ * Free the indicated map struct
+ */
+static void pio_map_free(struct pio_vl_map *m)
+{
+	int i;
+
+	for (i = 0; m && i < m->actual_vls; i++)
+		kfree(m->map[i]);
+	kfree(m);
+}
+
+/*
+ * Handle RCU callback
+ */
+static void pio_map_rcu_callback(struct rcu_head *list)
+{
+	struct pio_vl_map *m = container_of(list, struct pio_vl_map, list);
+
+	pio_map_free(m);
+}
+
+/*
+ * Set credit return threshold for the kernel send context
+ */
+static void set_threshold(struct hfi1_devdata *dd, int scontext, int i)
+{
+	u32 thres;
+
+	thres = min(sc_percent_to_threshold(dd->kernel_send_context[scontext],
+					    50),
+		    sc_mtu_to_threshold(dd->kernel_send_context[scontext],
+					dd->vld[i].mtu,
+					dd->rcd[0]->rcvhdrqentsize));
+	sc_set_cr_threshold(dd->kernel_send_context[scontext], thres);
+}
+
+/*
+ * pio_map_init - called when #vls change
+ * @dd: hfi1_devdata
+ * @port: port number
+ * @num_vls: number of vls
+ * @vl_scontexts: per vl send context mapping (optional)
+ *
+ * This routine changes the mapping based on the number of vls.
+ *
+ * vl_scontexts is used to specify a non-uniform vl/send context
+ * loading. NULL implies auto computing the loading and giving each
+ * VL an uniform distribution of send contexts per VL.
+ *
+ * The auto algorithm computers the sc_per_vl and the number of extra
+ * send contexts. Any extra send contexts are added from the last VL
+ * on down
+ *
+ * rcu locking is used here to control access to the mapping fields.
+ *
+ * If either the num_vls or num_send_contexts are non-power of 2, the
+ * array sizes in the struct pio_vl_map and the struct pio_map_elem are
+ * rounded up to the next highest power of 2 and the first entry is
+ * reused in a round robin fashion.
+ *
+ * If an error occurs the map change is not done and the mapping is not
+ * chaged.
+ *
+ */
+int pio_map_init(struct hfi1_devdata *dd, u8 port, u8 num_vls, u8 *vl_scontexts)
+{
+	int i, j;
+	int extra, sc_per_vl;
+	int scontext = 1;
+	int num_kernel_send_contexts = 0;
+	u8 lvl_scontexts[OPA_MAX_VLS];
+	struct pio_vl_map *oldmap, *newmap;
+
+	if (!vl_scontexts) {
+		for (i = 0; i < dd->num_send_contexts; i++)
+			if (dd->send_contexts[i].type == SC_KERNEL)
+				num_kernel_send_contexts++;
+		/* truncate divide */
+		sc_per_vl = num_kernel_send_contexts / num_vls;
+		/* extras */
+		extra = num_kernel_send_contexts % num_vls;
+		vl_scontexts = lvl_scontexts;
+		/* add extras from last vl down */
+		for (i = num_vls - 1; i >= 0; i--, extra--)
+			vl_scontexts[i] = sc_per_vl + (extra > 0 ? 1 : 0);
+	}
+	/* build new map */
+	newmap = kzalloc(sizeof(*newmap) +
+			 roundup_pow_of_two(num_vls) *
+			 sizeof(struct pio_map_elem *),
+			 GFP_KERNEL);
+	if (!newmap)
+		goto bail;
+	newmap->actual_vls = num_vls;
+	newmap->vls = roundup_pow_of_two(num_vls);
+	newmap->mask = (1 << ilog2(newmap->vls)) - 1;
+	for (i = 0; i < newmap->vls; i++) {
+		/* save for wrap around */
+		int first_scontext = scontext;
+
+		if (i < newmap->actual_vls) {
+			int sz = roundup_pow_of_two(vl_scontexts[i]);
+
+			/* only allocate once */
+			newmap->map[i] = kzalloc(sizeof(*newmap->map[i]) +
+						 sz * sizeof(struct
+							     send_context *),
+						 GFP_KERNEL);
+			if (!newmap->map[i])
+				goto bail;
+			newmap->map[i]->mask = (1 << ilog2(sz)) - 1;
+			/*
+			 * assign send contexts and
+			 * adjust credit return threshold
+			 */
+			for (j = 0; j < sz; j++) {
+				if (dd->kernel_send_context[scontext]) {
+					newmap->map[i]->ksc[j] =
+					dd->kernel_send_context[scontext];
+					set_threshold(dd, scontext, i);
+				}
+				if (++scontext >= first_scontext +
+						  vl_scontexts[i])
+					/* wrap back to first send context */
+					scontext = first_scontext;
+			}
+		} else {
+			/* just re-use entry without allocating */
+			newmap->map[i] = newmap->map[i % num_vls];
+		}
+		scontext = first_scontext + vl_scontexts[i];
+	}
+	/* newmap in hand, save old map */
+	spin_lock_irq(&dd->pio_map_lock);
+	oldmap = rcu_dereference_protected(dd->pio_map,
+					   lockdep_is_held(&dd->pio_map_lock));
+
+	/* publish newmap */
+	rcu_assign_pointer(dd->pio_map, newmap);
+
+	spin_unlock_irq(&dd->pio_map_lock);
+	/* success, free any old map after grace period */
+	if (oldmap)
+		call_rcu(&oldmap->list, pio_map_rcu_callback);
+	return 0;
+bail:
+	/* free any partial allocation */
+	pio_map_free(newmap);
+	return -ENOMEM;
+}
+
+void free_pio_map(struct hfi1_devdata *dd)
+{
+	/* Free PIO map if allocated */
+	if (rcu_access_pointer(dd->pio_map)) {
+		spin_lock_irq(&dd->pio_map_lock);
+		pio_map_free(rcu_access_pointer(dd->pio_map));
+		RCU_INIT_POINTER(dd->pio_map, NULL);
+		spin_unlock_irq(&dd->pio_map_lock);
+		synchronize_rcu();
+	}
+	kfree(dd->kernel_send_context);
+	dd->kernel_send_context = NULL;
+}
+
+int init_pervl_scs(struct hfi1_devdata *dd)
+{
+	int i;
+	u64 mask, all_vl_mask = (u64)0x80ff; /* VLs 0-7, 15 */
+	u64 data_vls_mask = (u64)0x00ff; /* VLs 0-7 */
+	u32 ctxt;
+	struct hfi1_pportdata *ppd = dd->pport;
+
+	dd->vld[15].sc = sc_alloc(dd, SC_VL15,
+				  dd->rcd[0]->rcvhdrqentsize, dd->node);
+	if (!dd->vld[15].sc)
+		return -ENOMEM;
+
+	hfi1_init_ctxt(dd->vld[15].sc);
+	dd->vld[15].mtu = enum_to_mtu(OPA_MTU_2048);
+
+	dd->kernel_send_context = kcalloc_node(dd->num_send_contexts,
+					       sizeof(struct send_context *),
+					       GFP_KERNEL, dd->node);
+	if (!dd->kernel_send_context)
+		goto freesc15;
+
+	dd->kernel_send_context[0] = dd->vld[15].sc;
+
+	for (i = 0; i < num_vls; i++) {
+		/*
+		 * Since this function does not deal with a specific
+		 * receive context but we need the RcvHdrQ entry size,
+		 * use the size from rcd[0]. It is guaranteed to be
+		 * valid at this point and will remain the same for all
+		 * receive contexts.
+		 */
+		dd->vld[i].sc = sc_alloc(dd, SC_KERNEL,
+					 dd->rcd[0]->rcvhdrqentsize, dd->node);
+		if (!dd->vld[i].sc)
+			goto nomem;
+		dd->kernel_send_context[i + 1] = dd->vld[i].sc;
+		hfi1_init_ctxt(dd->vld[i].sc);
+		/* non VL15 start with the max MTU */
+		dd->vld[i].mtu = hfi1_max_mtu;
+	}
+	for (i = num_vls; i < INIT_SC_PER_VL * num_vls; i++) {
+		dd->kernel_send_context[i + 1] =
+		sc_alloc(dd, SC_KERNEL, dd->rcd[0]->rcvhdrqentsize, dd->node);
+		if (!dd->kernel_send_context[i + 1])
+			goto nomem;
+		hfi1_init_ctxt(dd->kernel_send_context[i + 1]);
+	}
+
+	sc_enable(dd->vld[15].sc);
+	ctxt = dd->vld[15].sc->hw_context;
+	mask = all_vl_mask & ~(1LL << 15);
+	write_kctxt_csr(dd, ctxt, SC(CHECK_VL), mask);
+	dd_dev_info(dd,
+		    "Using send context %u(%u) for VL15\n",
+		    dd->vld[15].sc->sw_index, ctxt);
+
+	for (i = 0; i < num_vls; i++) {
+		sc_enable(dd->vld[i].sc);
+		ctxt = dd->vld[i].sc->hw_context;
+		mask = all_vl_mask & ~(data_vls_mask);
+		write_kctxt_csr(dd, ctxt, SC(CHECK_VL), mask);
+	}
+	for (i = num_vls; i < INIT_SC_PER_VL * num_vls; i++) {
+		sc_enable(dd->kernel_send_context[i + 1]);
+		ctxt = dd->kernel_send_context[i + 1]->hw_context;
+		mask = all_vl_mask & ~(data_vls_mask);
+		write_kctxt_csr(dd, ctxt, SC(CHECK_VL), mask);
+	}
+
+	if (pio_map_init(dd, ppd->port - 1, num_vls, NULL))
+		goto nomem;
+	return 0;
+
+nomem:
+	for (i = 0; i < num_vls; i++) {
+		sc_free(dd->vld[i].sc);
+		dd->vld[i].sc = NULL;
+	}
+
+	for (i = num_vls; i < INIT_SC_PER_VL * num_vls; i++)
+		sc_free(dd->kernel_send_context[i + 1]);
+
+	kfree(dd->kernel_send_context);
+	dd->kernel_send_context = NULL;
+
+freesc15:
+	sc_free(dd->vld[15].sc);
+	return -ENOMEM;
+}
+
+int init_credit_return(struct hfi1_devdata *dd)
+{
+	int ret;
+	int i;
+
+	dd->cr_base = kcalloc(
+		node_affinity.num_possible_nodes,
+		sizeof(struct credit_return_base),
+		GFP_KERNEL);
+	if (!dd->cr_base) {
+		ret = -ENOMEM;
+		goto done;
+	}
+	for_each_node_with_cpus(i) {
+		int bytes = TXE_NUM_CONTEXTS * sizeof(struct credit_return);
+
+		set_dev_node(&dd->pcidev->dev, i);
+		dd->cr_base[i].va = dma_zalloc_coherent(
+					&dd->pcidev->dev,
+					bytes,
+					&dd->cr_base[i].dma,
+					GFP_KERNEL);
+		if (!dd->cr_base[i].va) {
+			set_dev_node(&dd->pcidev->dev, dd->node);
+			dd_dev_err(dd,
+				   "Unable to allocate credit return DMA range for NUMA %d\n",
+				   i);
+			ret = -ENOMEM;
+			goto done;
+		}
+	}
+	set_dev_node(&dd->pcidev->dev, dd->node);
+
+	ret = 0;
+done:
+	return ret;
+}
+
+void free_credit_return(struct hfi1_devdata *dd)
+{
+	int i;
+
+	if (!dd->cr_base)
+		return;
+	for (i = 0; i < node_affinity.num_possible_nodes; i++) {
+		if (dd->cr_base[i].va) {
+			dma_free_coherent(&dd->pcidev->dev,
+					  TXE_NUM_CONTEXTS *
+					  sizeof(struct credit_return),
+					  dd->cr_base[i].va,
+					  dd->cr_base[i].dma);
+		}
+	}
+	kfree(dd->cr_base);
+	dd->cr_base = NULL;
+}