soc/qman: Add self-test for QMan driver

Add self tests for the DPAA 1.x Queue Manager driver. The tests
ensure that the driver can properly enqueue and dequeue to/from
frame queues using the QMan portal infrastructure.

Signed-off-by: Roy Pledge <roy.pledge@nxp.com>
Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: Scott Wood <oss@buserror.net>

6 files changed, 995 insertions, 0 deletions

diff --git a/drivers/soc/fsl/qbman/Kconfig b/drivers/soc/fsl/qbman/Kconfig
index e6da6a2f396d..757033c0586c 100644
--- a/drivers/soc/fsl/qbman/Kconfig
+++ b/drivers/soc/fsl/qbman/Kconfig
@@ -41,4 +41,27 @@ config FSL_BMAN_TEST_API
           high-level API testing with them (whichever portal(s) are affine
           to the cpu(s) the test executes on).
 
+config FSL_QMAN_TEST
+        tristate "QMan self-tests"
+        help
+          Compile self-test code for QMan.
+
+config FSL_QMAN_TEST_API
+        bool "QMan high-level self-test"
+        depends on FSL_QMAN_TEST
+        default y
+        help
+          This requires the presence of cpu-affine portals, and performs
+          high-level API testing with them (whichever portal(s) are affine to
+          the cpu(s) the test executes on).
+
+config FSL_QMAN_TEST_STASH
+        bool "QMan 'hot potato' data-stashing self-test"
+        depends on FSL_QMAN_TEST
+        default y
+        help
+          This performs a "hot potato" style test enqueuing/dequeuing a frame
+          across a series of FQs scheduled to different portals (and cpus), with
+          DQRR, data and context stashing always on.
+
 endif # FSL_DPAA
diff --git a/drivers/soc/fsl/qbman/Makefile b/drivers/soc/fsl/qbman/Makefile
index 714dd97484b3..7ae199f1664e 100644
--- a/drivers/soc/fsl/qbman/Makefile
+++ b/drivers/soc/fsl/qbman/Makefile
@@ -5,3 +5,8 @@ obj-$(CONFIG_FSL_DPAA)                          += bman_ccsr.o qman_ccsr.o \
 obj-$(CONFIG_FSL_BMAN_TEST)                     += bman-test.o
 bman-test-y                                      = bman_test.o
 bman-test-$(CONFIG_FSL_BMAN_TEST_API)           += bman_test_api.o
+
+obj-$(CONFIG_FSL_QMAN_TEST)                     += qman-test.o
+qman-test-y                                      = qman_test.o
+qman-test-$(CONFIG_FSL_QMAN_TEST_API)           += qman_test_api.o
+qman-test-$(CONFIG_FSL_QMAN_TEST_STASH)         += qman_test_stash.o
diff --git a/drivers/soc/fsl/qbman/qman_test.c b/drivers/soc/fsl/qbman/qman_test.c
new file mode 100644
index 000000000000..18f7f0202fa7
--- /dev/null
+++ b/drivers/soc/fsl/qbman/qman_test.c
@@ -0,0 +1,62 @@
+/* Copyright 2008 - 2016 Freescale Semiconductor, Inc.
+ *
+ * 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 Freescale Semiconductor nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") as published by the Free Software
+ * Foundation, either version 2 of that License or (at your option) any
+ * later version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Freescale Semiconductor ``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 Freescale Semiconductor 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 "qman_test.h"
+
+MODULE_AUTHOR("Geoff Thorpe");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("QMan testing");
+
+static int test_init(void)
+{
+        int loop = 1;
+        int err = 0;
+
+        while (loop--) {
+#ifdef CONFIG_FSL_QMAN_TEST_STASH
+                err = qman_test_stash();
+                if (err)
+                        break;
+#endif
+#ifdef CONFIG_FSL_QMAN_TEST_API
+                err = qman_test_api();
+                if (err)
+                        break;
+#endif
+        }
+        return err;
+}
+
+static void test_exit(void)
+{
+}
+
+module_init(test_init);
+module_exit(test_exit);
diff --git a/drivers/soc/fsl/qbman/qman_test.h b/drivers/soc/fsl/qbman/qman_test.h
new file mode 100644
index 000000000000..d5f8cb2260dc
--- /dev/null
+++ b/drivers/soc/fsl/qbman/qman_test.h
@@ -0,0 +1,36 @@
+/* Copyright 2008 - 2016 Freescale Semiconductor, Inc.
+ *
+ * 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 Freescale Semiconductor nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") as published by the Free Software
+ * Foundation, either version 2 of that License or (at your option) any
+ * later version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Freescale Semiconductor ``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 Freescale Semiconductor 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 "qman_priv.h"
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+int qman_test_stash(void);
+int qman_test_api(void);
diff --git a/drivers/soc/fsl/qbman/qman_test_api.c b/drivers/soc/fsl/qbman/qman_test_api.c
new file mode 100644
index 000000000000..6880ff17f45e
--- /dev/null
+++ b/drivers/soc/fsl/qbman/qman_test_api.c
@@ -0,0 +1,252 @@
+/* Copyright 2008 - 2016 Freescale Semiconductor, Inc.
+ *
+ * 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 Freescale Semiconductor nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") as published by the Free Software
+ * Foundation, either version 2 of that License or (at your option) any
+ * later version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Freescale Semiconductor ``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 Freescale Semiconductor 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 "qman_test.h"
+
+#define CGR_ID          27
+#define POOL_ID         2
+#define FQ_FLAGS        QMAN_FQ_FLAG_DYNAMIC_FQID
+#define NUM_ENQUEUES    10
+#define NUM_PARTIAL     4
+#define PORTAL_SDQCR    (QM_SDQCR_SOURCE_CHANNELS | \
+                        QM_SDQCR_TYPE_PRIO_QOS | \
+                        QM_SDQCR_TOKEN_SET(0x98) | \
+                        QM_SDQCR_CHANNELS_DEDICATED | \
+                        QM_SDQCR_CHANNELS_POOL(POOL_ID))
+#define PORTAL_OPAQUE   ((void *)0xf00dbeef)
+#define VDQCR_FLAGS     (QMAN_VOLATILE_FLAG_WAIT | QMAN_VOLATILE_FLAG_FINISH)
+
+static enum qman_cb_dqrr_result cb_dqrr(struct qman_portal *,
+                                        struct qman_fq *,
+                                        const struct qm_dqrr_entry *);
+static void cb_ern(struct qman_portal *, struct qman_fq *,
+                   const union qm_mr_entry *);
+static void cb_fqs(struct qman_portal *, struct qman_fq *,
+                   const union qm_mr_entry *);
+
+static struct qm_fd fd, fd_dq;
+static struct qman_fq fq_base = {
+        .cb.dqrr = cb_dqrr,
+        .cb.ern = cb_ern,
+        .cb.fqs = cb_fqs
+};
+static DECLARE_WAIT_QUEUE_HEAD(waitqueue);
+static int retire_complete, sdqcr_complete;
+
+/* Helpers for initialising and "incrementing" a frame descriptor */
+static void fd_init(struct qm_fd *fd)
+{
+        qm_fd_addr_set64(fd, 0xabdeadbeefLLU);
+        qm_fd_set_contig_big(fd, 0x0000ffff);
+        fd->cmd = 0xfeedf00d;
+}
+
+static void fd_inc(struct qm_fd *fd)
+{
+        u64 t = qm_fd_addr_get64(fd);
+        int z = t >> 40;
+        unsigned int len, off;
+        enum qm_fd_format fmt;
+
+        t <<= 1;
+        if (z)
+                t |= 1;
+        qm_fd_addr_set64(fd, t);
+
+        fmt = qm_fd_get_format(fd);
+        off = qm_fd_get_offset(fd);
+        len = qm_fd_get_length(fd);
+        len--;
+        qm_fd_set_param(fd, fmt, off, len);
+
+        fd->cmd++;
+}
+
+/* The only part of the 'fd' we can't memcmp() is the ppid */
+static int fd_cmp(const struct qm_fd *a, const struct qm_fd *b)
+{
+        int r = (qm_fd_addr_get64(a) == qm_fd_addr_get64(b)) ? 0 : -1;
+
+        if (!r) {
+                enum qm_fd_format fmt_a, fmt_b;
+
+                fmt_a = qm_fd_get_format(a);
+                fmt_b = qm_fd_get_format(b);
+                r = fmt_a - fmt_b;
+        }
+        if (!r)
+                r = a->cfg - b->cfg;
+        if (!r)
+                r = a->cmd - b->cmd;
+        return r;
+}
+
+/* test */
+static int do_enqueues(struct qman_fq *fq)
+{
+        unsigned int loop;
+        int err = 0;
+
+        for (loop = 0; loop < NUM_ENQUEUES; loop++) {
+                if (qman_enqueue(fq, &fd)) {
+                        pr_crit("qman_enqueue() failed\n");
+                        err = -EIO;
+                }
+                fd_inc(&fd);
+        }
+
+        return err;
+}
+
+int qman_test_api(void)
+{
+        unsigned int flags, frmcnt;
+        int err;
+        struct qman_fq *fq = &fq_base;
+
+        pr_info("%s(): Starting\n", __func__);
+        fd_init(&fd);
+        fd_init(&fd_dq);
+
+        /* Initialise (parked) FQ */
+        err = qman_create_fq(0, FQ_FLAGS, fq);
+        if (err) {
+                pr_crit("qman_create_fq() failed\n");
+                goto failed;
+        }
+        err = qman_init_fq(fq, QMAN_INITFQ_FLAG_LOCAL, NULL);
+        if (err) {
+                pr_crit("qman_init_fq() failed\n");
+                goto failed;
+        }
+        /* Do enqueues + VDQCR, twice. (Parked FQ) */
+        err = do_enqueues(fq);
+        if (err)
+                goto failed;
+        pr_info("VDQCR (till-empty);\n");
+        frmcnt = QM_VDQCR_NUMFRAMES_TILLEMPTY;
+        err = qman_volatile_dequeue(fq, VDQCR_FLAGS, frmcnt);
+        if (err) {
+                pr_crit("qman_volatile_dequeue() failed\n");
+                goto failed;
+        }
+        err = do_enqueues(fq);
+        if (err)
+                goto failed;
+        pr_info("VDQCR (%d of %d);\n", NUM_PARTIAL, NUM_ENQUEUES);
+        frmcnt = QM_VDQCR_NUMFRAMES_SET(NUM_PARTIAL);
+        err = qman_volatile_dequeue(fq, VDQCR_FLAGS, frmcnt);
+        if (err) {
+                pr_crit("qman_volatile_dequeue() failed\n");
+                goto failed;
+        }
+        pr_info("VDQCR (%d of %d);\n", NUM_ENQUEUES - NUM_PARTIAL,
+                NUM_ENQUEUES);
+        frmcnt = QM_VDQCR_NUMFRAMES_SET(NUM_ENQUEUES - NUM_PARTIAL);
+        err = qman_volatile_dequeue(fq, VDQCR_FLAGS, frmcnt);
+        if (err) {
+                pr_err("qman_volatile_dequeue() failed\n");
+                goto failed;
+        }
+
+        err = do_enqueues(fq);
+        if (err)
+                goto failed;
+        pr_info("scheduled dequeue (till-empty)\n");
+        err = qman_schedule_fq(fq);
+        if (err) {
+                pr_crit("qman_schedule_fq() failed\n");
+                goto failed;
+        }
+        wait_event(waitqueue, sdqcr_complete);
+
+        /* Retire and OOS the FQ */
+        err = qman_retire_fq(fq, &flags);
+        if (err < 0) {
+                pr_crit("qman_retire_fq() failed\n");
+                goto failed;
+        }
+        wait_event(waitqueue, retire_complete);
+        if (flags & QMAN_FQ_STATE_BLOCKOOS) {
+                err = -EIO;
+                pr_crit("leaking frames\n");
+                goto failed;
+        }
+        err = qman_oos_fq(fq);
+        if (err) {
+                pr_crit("qman_oos_fq() failed\n");
+                goto failed;
+        }
+        qman_destroy_fq(fq);
+        pr_info("%s(): Finished\n", __func__);
+        return 0;
+
+failed:
+        WARN_ON(1);
+        return err;
+}
+
+static enum qman_cb_dqrr_result cb_dqrr(struct qman_portal *p,
+                                        struct qman_fq *fq,
+                                        const struct qm_dqrr_entry *dq)
+{
+        if (WARN_ON(fd_cmp(&fd_dq, &dq->fd))) {
+                pr_err("BADNESS: dequeued frame doesn't match;\n");
+                return qman_cb_dqrr_consume;
+        }
+        fd_inc(&fd_dq);
+        if (!(dq->stat & QM_DQRR_STAT_UNSCHEDULED) && !fd_cmp(&fd_dq, &fd)) {
+                sdqcr_complete = 1;
+                wake_up(&waitqueue);
+        }
+        return qman_cb_dqrr_consume;
+}
+
+static void cb_ern(struct qman_portal *p, struct qman_fq *fq,
+                   const union qm_mr_entry *msg)
+{
+        pr_crit("cb_ern() unimplemented");
+        WARN_ON(1);
+}
+
+static void cb_fqs(struct qman_portal *p, struct qman_fq *fq,
+                   const union qm_mr_entry *msg)
+{
+        u8 verb = (msg->verb & QM_MR_VERB_TYPE_MASK);
+
+        if ((verb != QM_MR_VERB_FQRN) && (verb != QM_MR_VERB_FQRNI)) {
+                pr_crit("unexpected FQS message");
+                WARN_ON(1);
+                return;
+        }
+        pr_info("Retirement message received\n");
+        retire_complete = 1;
+        wake_up(&waitqueue);
+}
diff --git a/drivers/soc/fsl/qbman/qman_test_stash.c b/drivers/soc/fsl/qbman/qman_test_stash.c
new file mode 100644
index 000000000000..43cf66ba42f5
--- /dev/null
+++ b/drivers/soc/fsl/qbman/qman_test_stash.c
@@ -0,0 +1,617 @@
+/* Copyright 2009 - 2016 Freescale Semiconductor, Inc.
+ *
+ * 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 Freescale Semiconductor nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") as published by the Free Software
+ * Foundation, either version 2 of that License or (at your option) any
+ * later version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Freescale Semiconductor ``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 Freescale Semiconductor 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 "qman_test.h"
+
+#include <linux/dma-mapping.h>
+#include <linux/delay.h>
+
+/*
+ * Algorithm:
+ *
+ * Each cpu will have HP_PER_CPU "handlers" set up, each of which incorporates
+ * an rx/tx pair of FQ objects (both of which are stashed on dequeue). The
+ * organisation of FQIDs is such that the HP_PER_CPU*NUM_CPUS handlers will
+ * shuttle a "hot potato" frame around them such that every forwarding action
+ * moves it from one cpu to another. (The use of more than one handler per cpu
+ * is to allow enough handlers/FQs to truly test the significance of caching -
+ * ie. when cache-expiries are occurring.)
+ *
+ * The "hot potato" frame content will be HP_NUM_WORDS*4 bytes in size, and the
+ * first and last words of the frame data will undergo a transformation step on
+ * each forwarding action. To achieve this, each handler will be assigned a
+ * 32-bit "mixer", that is produced using a 32-bit LFSR. When a frame is
+ * received by a handler, the mixer of the expected sender is XOR'd into all
+ * words of the entire frame, which is then validated against the original
+ * values. Then, before forwarding, the entire frame is XOR'd with the mixer of
+ * the current handler. Apart from validating that the frame is taking the
+ * expected path, this also provides some quasi-realistic overheads to each
+ * forwarding action - dereferencing *all* the frame data, computation, and
+ * conditional branching. There is a "special" handler designated to act as the
+ * instigator of the test by creating an enqueuing the "hot potato" frame, and
+ * to determine when the test has completed by counting HP_LOOPS iterations.
+ *
+ * Init phases:
+ *
+ * 1. prepare each cpu's 'hp_cpu' struct using on_each_cpu(,,1) and link them
+ *    into 'hp_cpu_list'. Specifically, set processor_id, allocate HP_PER_CPU
+ *    handlers and link-list them (but do no other handler setup).
+ *
+ * 2. scan over 'hp_cpu_list' HP_PER_CPU times, the first time sets each
+ *    hp_cpu's 'iterator' to point to its first handler. With each loop,
+ *    allocate rx/tx FQIDs and mixer values to the hp_cpu's iterator handler
+ *    and advance the iterator for the next loop. This includes a final fixup,
+ *    which connects the last handler to the first (and which is why phase 2
+ *    and 3 are separate).
+ *
+ * 3. scan over 'hp_cpu_list' HP_PER_CPU times, the first time sets each
+ *    hp_cpu's 'iterator' to point to its first handler. With each loop,
+ *    initialise FQ objects and advance the iterator for the next loop.
+ *    Moreover, do this initialisation on the cpu it applies to so that Rx FQ
+ *    initialisation targets the correct cpu.
+ */
+
+/*
+ * helper to run something on all cpus (can't use on_each_cpu(), as that invokes
+ * the fn from irq context, which is too restrictive).
+ */
+struct bstrap {
+        int (*fn)(void);
+        atomic_t started;
+};
+static int bstrap_fn(void *bs)
+{
+        struct bstrap *bstrap = bs;
+        int err;
+
+        atomic_inc(&bstrap->started);
+        err = bstrap->fn();
+        if (err)
+                return err;
+        while (!kthread_should_stop())
+                msleep(20);
+        return 0;
+}
+static int on_all_cpus(int (*fn)(void))
+{
+        int cpu;
+
+        for_each_cpu(cpu, cpu_online_mask) {
+                struct bstrap bstrap = {
+                        .fn = fn,
+                        .started = ATOMIC_INIT(0)
+                };
+                struct task_struct *k = kthread_create(bstrap_fn, &bstrap,
+                        "hotpotato%d", cpu);
+                int ret;
+
+                if (IS_ERR(k))
+                        return -ENOMEM;
+                kthread_bind(k, cpu);
+                wake_up_process(k);
+                /*
+                 * If we call kthread_stop() before the "wake up" has had an
+                 * effect, then the thread may exit with -EINTR without ever
+                 * running the function. So poll until it's started before
+                 * requesting it to stop.
+                 */
+                while (!atomic_read(&bstrap.started))
+                        msleep(20);
+                ret = kthread_stop(k);
+                if (ret)
+                        return ret;
+        }
+        return 0;
+}
+
+struct hp_handler {
+
+        /* The following data is stashed when 'rx' is dequeued; */
+        /* -------------- */
+        /* The Rx FQ, dequeues of which will stash the entire hp_handler */
+        struct qman_fq rx;
+        /* The Tx FQ we should forward to */
+        struct qman_fq tx;
+        /* The value we XOR post-dequeue, prior to validating */
+        u32 rx_mixer;
+        /* The value we XOR pre-enqueue, after validating */
+        u32 tx_mixer;
+        /* what the hotpotato address should be on dequeue */
+        dma_addr_t addr;
+        u32 *frame_ptr;
+
+        /* The following data isn't (necessarily) stashed on dequeue; */
+        /* -------------- */
+        u32 fqid_rx, fqid_tx;
+        /* list node for linking us into 'hp_cpu' */
+        struct list_head node;
+        /* Just to check ... */
+        unsigned int processor_id;
+} ____cacheline_aligned;
+
+struct hp_cpu {
+        /* identify the cpu we run on; */
+        unsigned int processor_id;
+        /* root node for the per-cpu list of handlers */
+        struct list_head handlers;
+        /* list node for linking us into 'hp_cpu_list' */
+        struct list_head node;
+        /*
+         * when repeatedly scanning 'hp_list', each time linking the n'th
+         * handlers together, this is used as per-cpu iterator state
+         */
+        struct hp_handler *iterator;
+};
+
+/* Each cpu has one of these */
+static DEFINE_PER_CPU(struct hp_cpu, hp_cpus);
+
+/* links together the hp_cpu structs, in first-come first-serve order. */
+static LIST_HEAD(hp_cpu_list);
+static spinlock_t hp_lock = __SPIN_LOCK_UNLOCKED(hp_lock);
+
+static unsigned int hp_cpu_list_length;
+
+/* the "special" handler, that starts and terminates the test. */
+static struct hp_handler *special_handler;
+static int loop_counter;
+
+/* handlers are allocated out of this, so they're properly aligned. */
+static struct kmem_cache *hp_handler_slab;
+
+/* this is the frame data */
+static void *__frame_ptr;
+static u32 *frame_ptr;
+static dma_addr_t frame_dma;
+
+/* the main function waits on this */
+static DECLARE_WAIT_QUEUE_HEAD(queue);
+
+#define HP_PER_CPU      2
+#define HP_LOOPS        8
+/* 80 bytes, like a small ethernet frame, and bleeds into a second cacheline */
+#define HP_NUM_WORDS    80
+/* First word of the LFSR-based frame data */
+#define HP_FIRST_WORD   0xabbaf00d
+
+static inline u32 do_lfsr(u32 prev)
+{
+        return (prev >> 1) ^ (-(prev & 1u) & 0xd0000001u);
+}
+
+static int allocate_frame_data(void)
+{
+        u32 lfsr = HP_FIRST_WORD;
+        int loop;
+        struct platform_device *pdev = platform_device_alloc("foobar", -1);
+
+        if (!pdev) {
+                pr_crit("platform_device_alloc() failed");
+                return -EIO;
+        }
+        if (platform_device_add(pdev)) {
+                pr_crit("platform_device_add() failed");
+                return -EIO;
+        }
+        __frame_ptr = kmalloc(4 * HP_NUM_WORDS, GFP_KERNEL);
+        if (!__frame_ptr)
+                return -ENOMEM;
+
+        frame_ptr = PTR_ALIGN(__frame_ptr, 64);
+        for (loop = 0; loop < HP_NUM_WORDS; loop++) {
+                frame_ptr[loop] = lfsr;
+                lfsr = do_lfsr(lfsr);
+        }
+        frame_dma = dma_map_single(&pdev->dev, frame_ptr, 4 * HP_NUM_WORDS,
+                                   DMA_BIDIRECTIONAL);
+        platform_device_del(pdev);
+        platform_device_put(pdev);
+        return 0;
+}
+
+static void deallocate_frame_data(void)
+{
+        kfree(__frame_ptr);
+}
+
+static inline int process_frame_data(struct hp_handler *handler,
+                                     const struct qm_fd *fd)
+{
+        u32 *p = handler->frame_ptr;
+        u32 lfsr = HP_FIRST_WORD;
+        int loop;
+
+        if (qm_fd_addr_get64(fd) != handler->addr) {
+                pr_crit("bad frame address");
+                return -EIO;
+        }
+        for (loop = 0; loop < HP_NUM_WORDS; loop++, p++) {
+                *p ^= handler->rx_mixer;
+                if (*p != lfsr) {
+                        pr_crit("corrupt frame data");
+                        return -EIO;
+                }
+                *p ^= handler->tx_mixer;
+                lfsr = do_lfsr(lfsr);
+        }
+        return 0;
+}
+
+static enum qman_cb_dqrr_result normal_dqrr(struct qman_portal *portal,
+                                            struct qman_fq *fq,
+                                            const struct qm_dqrr_entry *dqrr)
+{
+        struct hp_handler *handler = (struct hp_handler *)fq;
+
+        if (process_frame_data(handler, &dqrr->fd)) {
+                WARN_ON(1);
+                goto skip;
+        }
+        if (qman_enqueue(&handler->tx, &dqrr->fd)) {
+                pr_crit("qman_enqueue() failed");
+                WARN_ON(1);
+        }
+skip:
+        return qman_cb_dqrr_consume;
+}
+
+static enum qman_cb_dqrr_result special_dqrr(struct qman_portal *portal,
+                                             struct qman_fq *fq,
+                                             const struct qm_dqrr_entry *dqrr)
+{
+        struct hp_handler *handler = (struct hp_handler *)fq;
+
+        process_frame_data(handler, &dqrr->fd);
+        if (++loop_counter < HP_LOOPS) {
+                if (qman_enqueue(&handler->tx, &dqrr->fd)) {
+                        pr_crit("qman_enqueue() failed");
+                        WARN_ON(1);
+                        goto skip;
+                }
+        } else {
+                pr_info("Received final (%dth) frame\n", loop_counter);
+                wake_up(&queue);
+        }
+skip:
+        return qman_cb_dqrr_consume;
+}
+
+static int create_per_cpu_handlers(void)
+{
+        struct hp_handler *handler;
+        int loop;
+        struct hp_cpu *hp_cpu = this_cpu_ptr(&hp_cpus);
+
+        hp_cpu->processor_id = smp_processor_id();
+        spin_lock(&hp_lock);
+        list_add_tail(&hp_cpu->node, &hp_cpu_list);
+        hp_cpu_list_length++;
+        spin_unlock(&hp_lock);
+        INIT_LIST_HEAD(&hp_cpu->handlers);
+        for (loop = 0; loop < HP_PER_CPU; loop++) {
+                handler = kmem_cache_alloc(hp_handler_slab, GFP_KERNEL);
+                if (!handler) {
+                        pr_crit("kmem_cache_alloc() failed");
+                        WARN_ON(1);
+                        return -EIO;
+                }
+                handler->processor_id = hp_cpu->processor_id;
+                handler->addr = frame_dma;
+                handler->frame_ptr = frame_ptr;
+                list_add_tail(&handler->node, &hp_cpu->handlers);
+        }
+        return 0;
+}
+
+static int destroy_per_cpu_handlers(void)
+{
+        struct list_head *loop, *tmp;
+        struct hp_cpu *hp_cpu = this_cpu_ptr(&hp_cpus);
+
+        spin_lock(&hp_lock);
+        list_del(&hp_cpu->node);
+        spin_unlock(&hp_lock);
+        list_for_each_safe(loop, tmp, &hp_cpu->handlers) {
+                u32 flags = 0;
+                struct hp_handler *handler = list_entry(loop, struct hp_handler,
+                                                        node);
+                if (qman_retire_fq(&handler->rx, &flags) ||
+                    (flags & QMAN_FQ_STATE_BLOCKOOS)) {
+                        pr_crit("qman_retire_fq(rx) failed, flags: %x", flags);
+                        WARN_ON(1);
+                        return -EIO;
+                }
+                if (qman_oos_fq(&handler->rx)) {
+                        pr_crit("qman_oos_fq(rx) failed");
+                        WARN_ON(1);
+                        return -EIO;
+                }
+                qman_destroy_fq(&handler->rx);
+                qman_destroy_fq(&handler->tx);
+                qman_release_fqid(handler->fqid_rx);
+                list_del(&handler->node);
+                kmem_cache_free(hp_handler_slab, handler);
+        }
+        return 0;
+}
+
+static inline u8 num_cachelines(u32 offset)
+{
+        u8 res = (offset + (L1_CACHE_BYTES - 1))
+                         / (L1_CACHE_BYTES);
+        if (res > 3)
+                return 3;
+        return res;
+}
+#define STASH_DATA_CL \
+        num_cachelines(HP_NUM_WORDS * 4)
+#define STASH_CTX_CL \
+        num_cachelines(offsetof(struct hp_handler, fqid_rx))
+
+static int init_handler(void *h)
+{
+        struct qm_mcc_initfq opts;
+        struct hp_handler *handler = h;
+        int err;
+
+        if (handler->processor_id != smp_processor_id()) {
+                err = -EIO;
+                goto failed;
+        }
+        /* Set up rx */
+        memset(&handler->rx, 0, sizeof(handler->rx));
+        if (handler == special_handler)
+                handler->rx.cb.dqrr = special_dqrr;
+        else
+                handler->rx.cb.dqrr = normal_dqrr;
+        err = qman_create_fq(handler->fqid_rx, 0, &handler->rx);
+        if (err) {
+                pr_crit("qman_create_fq(rx) failed");
+                goto failed;
+        }
+        memset(&opts, 0, sizeof(opts));
+        opts.we_mask = QM_INITFQ_WE_FQCTRL | QM_INITFQ_WE_CONTEXTA;
+        opts.fqd.fq_ctrl = QM_FQCTRL_CTXASTASHING;
+        qm_fqd_set_stashing(&opts.fqd, 0, STASH_DATA_CL, STASH_CTX_CL);
+        err = qman_init_fq(&handler->rx, QMAN_INITFQ_FLAG_SCHED |
+                           QMAN_INITFQ_FLAG_LOCAL, &opts);
+        if (err) {
+                pr_crit("qman_init_fq(rx) failed");
+                goto failed;
+        }
+        /* Set up tx */
+        memset(&handler->tx, 0, sizeof(handler->tx));
+        err = qman_create_fq(handler->fqid_tx, QMAN_FQ_FLAG_NO_MODIFY,
+                             &handler->tx);
+        if (err) {
+                pr_crit("qman_create_fq(tx) failed");
+                goto failed;
+        }
+
+        return 0;
+failed:
+        return err;
+}
+
+static void init_handler_cb(void *h)
+{
+        if (init_handler(h))
+                WARN_ON(1);
+}
+
+static int init_phase2(void)
+{
+        int loop;
+        u32 fqid = 0;
+        u32 lfsr = 0xdeadbeef;
+        struct hp_cpu *hp_cpu;
+        struct hp_handler *handler;
+
+        for (loop = 0; loop < HP_PER_CPU; loop++) {
+                list_for_each_entry(hp_cpu, &hp_cpu_list, node) {
+                        int err;
+
+                        if (!loop)
+                                hp_cpu->iterator = list_first_entry(
+                                                &hp_cpu->handlers,
+                                                struct hp_handler, node);
+                        else
+                                hp_cpu->iterator = list_entry(
+                                                hp_cpu->iterator->node.next,
+                                                struct hp_handler, node);
+                        /* Rx FQID is the previous handler's Tx FQID */
+                        hp_cpu->iterator->fqid_rx = fqid;
+                        /* Allocate new FQID for Tx */
+                        err = qman_alloc_fqid(&fqid);
+                        if (err) {
+                                pr_crit("qman_alloc_fqid() failed");
+                                return err;
+                        }
+                        hp_cpu->iterator->fqid_tx = fqid;
+                        /* Rx mixer is the previous handler's Tx mixer */
+                        hp_cpu->iterator->rx_mixer = lfsr;
+                        /* Get new mixer for Tx */
+                        lfsr = do_lfsr(lfsr);
+                        hp_cpu->iterator->tx_mixer = lfsr;
+                }
+        }
+        /* Fix up the first handler (fqid_rx==0, rx_mixer=0xdeadbeef) */
+        hp_cpu = list_first_entry(&hp_cpu_list, struct hp_cpu, node);
+        handler = list_first_entry(&hp_cpu->handlers, struct hp_handler, node);
+        if (handler->fqid_rx != 0 || handler->rx_mixer != 0xdeadbeef)
+                return 1;
+        handler->fqid_rx = fqid;
+        handler->rx_mixer = lfsr;
+        /* and tag it as our "special" handler */
+        special_handler = handler;
+        return 0;
+}
+
+static int init_phase3(void)
+{
+        int loop, err;
+        struct hp_cpu *hp_cpu;
+
+        for (loop = 0; loop < HP_PER_CPU; loop++) {
+                list_for_each_entry(hp_cpu, &hp_cpu_list, node) {
+                        if (!loop)
+                                hp_cpu->iterator = list_first_entry(
+                                                &hp_cpu->handlers,
+                                                struct hp_handler, node);
+                        else
+                                hp_cpu->iterator = list_entry(
+                                                hp_cpu->iterator->node.next,
+                                                struct hp_handler, node);
+                        preempt_disable();
+                        if (hp_cpu->processor_id == smp_processor_id()) {
+                                err = init_handler(hp_cpu->iterator);
+                                if (err)
+                                        return err;
+                        } else {
+                                smp_call_function_single(hp_cpu->processor_id,
+                                        init_handler_cb, hp_cpu->iterator, 1);
+                        }
+                        preempt_enable();
+                }
+        }
+        return 0;
+}
+
+static int send_first_frame(void *ignore)
+{
+        u32 *p = special_handler->frame_ptr;
+        u32 lfsr = HP_FIRST_WORD;
+        int loop, err;
+        struct qm_fd fd;
+
+        if (special_handler->processor_id != smp_processor_id()) {
+                err = -EIO;
+                goto failed;
+        }
+        memset(&fd, 0, sizeof(fd));
+        qm_fd_addr_set64(&fd, special_handler->addr);
+        qm_fd_set_contig_big(&fd, HP_NUM_WORDS * 4);
+        for (loop = 0; loop < HP_NUM_WORDS; loop++, p++) {
+                if (*p != lfsr) {
+                        err = -EIO;
+                        pr_crit("corrupt frame data");
+                        goto failed;
+                }
+                *p ^= special_handler->tx_mixer;
+                lfsr = do_lfsr(lfsr);
+        }
+        pr_info("Sending first frame\n");
+        err = qman_enqueue(&special_handler->tx, &fd);
+        if (err) {
+                pr_crit("qman_enqueue() failed");
+                goto failed;
+        }
+
+        return 0;
+failed:
+        return err;
+}
+
+static void send_first_frame_cb(void *ignore)
+{
+        if (send_first_frame(NULL))
+                WARN_ON(1);
+}
+
+int qman_test_stash(void)
+{
+        int err;
+
+        if (cpumask_weight(cpu_online_mask) < 2) {
+                pr_info("%s(): skip - only 1 CPU\n", __func__);
+                return 0;
+        }
+
+        pr_info("%s(): Starting\n", __func__);
+
+        hp_cpu_list_length = 0;
+        loop_counter = 0;
+        hp_handler_slab = kmem_cache_create("hp_handler_slab",
+                        sizeof(struct hp_handler), L1_CACHE_BYTES,
+                        SLAB_HWCACHE_ALIGN, NULL);
+        if (!hp_handler_slab) {
+                err = -EIO;
+                pr_crit("kmem_cache_create() failed");
+                goto failed;
+        }
+
+        err = allocate_frame_data();
+        if (err)
+                goto failed;
+
+        /* Init phase 1 */
+        pr_info("Creating %d handlers per cpu...\n", HP_PER_CPU);
+        if (on_all_cpus(create_per_cpu_handlers)) {
+                err = -EIO;
+                pr_crit("on_each_cpu() failed");
+                goto failed;
+        }
+        pr_info("Number of cpus: %d, total of %d handlers\n",
+                hp_cpu_list_length, hp_cpu_list_length * HP_PER_CPU);
+
+        err = init_phase2();
+        if (err)
+                goto failed;
+
+        err = init_phase3();
+        if (err)
+                goto failed;
+
+        preempt_disable();
+        if (special_handler->processor_id == smp_processor_id()) {
+                err = send_first_frame(NULL);
+                if (err)
+                        goto failed;
+        } else {
+                smp_call_function_single(special_handler->processor_id,
+                                         send_first_frame_cb, NULL, 1);
+        }
+        preempt_enable();
+
+        wait_event(queue, loop_counter == HP_LOOPS);
+        deallocate_frame_data();
+        if (on_all_cpus(destroy_per_cpu_handlers)) {
+                err = -EIO;
+                pr_crit("on_each_cpu() failed");
+                goto failed;
+        }
+        kmem_cache_destroy(hp_handler_slab);
+        pr_info("%s(): Finished\n", __func__);
+
+        return 0;
+failed:
+        WARN_ON(1);
+        return err;
+}