text: /* 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 DEFINE_SPINLOCK(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;
  
  /* needed for dma_map*() */
  static const struct qm_portal_config *pcfg;
  
  /* 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;
  
  	if (!qman_dma_portal) {
  		pr_crit("portal not available\n");
  		return -EIO;
  	}
  
  	pcfg = qman_get_qm_portal_config(qman_dma_portal);
  
  	__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(pcfg->dev, frame_ptr, 4 * HP_NUM_WORDS,
  				   DMA_BIDIRECTIONAL);
  	if (dma_mapping_error(pcfg->dev, frame_dma)) {
  		pr_crit("dma mapping failure\n");
  		kfree(__frame_ptr);
  		return -EIO;
  	}
  
  	return 0;
  }
  
  static void deallocate_frame_data(void)
  {
  	dma_unmap_single(pcfg->dev, frame_dma, 4 * HP_NUM_WORDS,
  			 DMA_BIDIRECTIONAL);
  	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, [%llX != %llX]\n",
  			qm_fd_addr_get64(fd), handler->addr);
  		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,
  					    bool sched_napi)
  {
  	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,
  					     bool sched_napi)
  {
  	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 = cpu_to_be16(QM_INITFQ_WE_FQCTRL |
  				   QM_INITFQ_WE_CONTEXTA);
  	opts.fqd.fq_ctrl = cpu_to_be16(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;
  }
  