dmatest.c

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/*
 * DMA Engine test module
 *
 * Copyright (C) 2007 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/freezer.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/wait.h>

static unsigned int test_buf_size = 16384;
module_param(test_buf_size, uint, S_IRUGO);
MODULE_PARM_DESC(test_buf_size, "Size of the memcpy test buffer");

static char test_channel[20];
module_param_string(channel, test_channel, sizeof(test_channel), S_IRUGO);
MODULE_PARM_DESC(channel, "Bus ID of the channel to test (default: any)");

static char test_device[20];
module_param_string(device, test_device, sizeof(test_device), S_IRUGO);
MODULE_PARM_DESC(device, "Bus ID of the DMA Engine to test (default: any)");

static unsigned int threads_per_chan = 1;
module_param(threads_per_chan, uint, S_IRUGO);
MODULE_PARM_DESC(threads_per_chan,
        "Number of threads to start per channel (default: 1)");

static unsigned int max_channels;
module_param(max_channels, uint, S_IRUGO);
MODULE_PARM_DESC(max_channels,
        "Maximum number of channels to use (default: all)");

static unsigned int iterations;
module_param(iterations, uint, S_IRUGO);
MODULE_PARM_DESC(iterations,
        "Iterations before stopping test (default: infinite)");

static unsigned int xor_sources = 3;
module_param(xor_sources, uint, S_IRUGO);
MODULE_PARM_DESC(xor_sources,
        "Number of xor source buffers (default: 3)");

static unsigned int pq_sources = 3;
module_param(pq_sources, uint, S_IRUGO);
MODULE_PARM_DESC(pq_sources,
        "Number of p+q source buffers (default: 3)");

static int timeout = 3000;
module_param(timeout, uint, S_IRUGO);
MODULE_PARM_DESC(timeout, "Transfer Timeout in msec (default: 3000), "
         "Pass -1 for infinite timeout");

/*
 * Initialization patterns. All bytes in the source buffer has bit 7
 * set, all bytes in the destination buffer has bit 7 cleared.
 *
 * Bit 6 is set for all bytes which are to be copied by the DMA
 * engine. Bit 5 is set for all bytes which are to be overwritten by
 * the DMA engine.
 *
 * The remaining bits are the inverse of a counter which increments by
 * one for each byte address.
 */
#define PATTERN_SRC     0x80
#define PATTERN_DST     0x00
#define PATTERN_COPY        0x40
#define PATTERN_OVERWRITE   0x20
#define PATTERN_COUNT_MASK  0x1f

struct dmatest_thread {
    struct list_head    node;
    struct task_struct  *task;
    struct dma_chan     *chan;
    u8          **srcs;
    u8          **dsts;
    enum dma_transaction_type type;
};

struct dmatest_chan {
    struct list_head    node;
    struct dma_chan     *chan;
    struct list_head    threads;
};

/*
 * These are protected by dma_list_mutex since they're only used by
 * the DMA filter function callback
 */
static LIST_HEAD(dmatest_channels);
static unsigned int nr_channels;

static bool dmatest_match_channel(struct dma_chan *chan)
{
    if (test_channel[0] == '\0')
        return true;
    return strcmp(dma_chan_name(chan), test_channel) == 0;
}

static bool dmatest_match_device(struct dma_device *device)
{
    if (test_device[0] == '\0')
        return true;
    return strcmp(dev_name(device->dev), test_device) == 0;
}

static unsigned long dmatest_random(void)
{
    unsigned long buf;

    get_random_bytes(&buf, sizeof(buf));
    return buf;
}

static void dmatest_init_srcs(u8 **bufs, unsigned int start, unsigned int len)
{
    unsigned int i;
    u8 *buf;

    for (; (buf = *bufs); bufs++) {
        for (i = 0; i < start; i++)
            buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
        for ( ; i < start + len; i++)
            buf[i] = PATTERN_SRC | PATTERN_COPY
                | (~i & PATTERN_COUNT_MASK);
        for ( ; i < test_buf_size; i++)
            buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
        buf++;
    }
}

static void dmatest_init_dsts(u8 **bufs, unsigned int start, unsigned int len)
{
    unsigned int i;
    u8 *buf;

    for (; (buf = *bufs); bufs++) {
        for (i = 0; i < start; i++)
            buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
        for ( ; i < start + len; i++)
            buf[i] = PATTERN_DST | PATTERN_OVERWRITE
                | (~i & PATTERN_COUNT_MASK);
        for ( ; i < test_buf_size; i++)
            buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
    }
}

static void dmatest_mismatch(u8 actual, u8 pattern, unsigned int index,
        unsigned int counter, bool is_srcbuf)
{
    u8      diff = actual ^ pattern;
    u8      expected = pattern | (~counter & PATTERN_COUNT_MASK);
    const char  *thread_name = current->comm;

    if (is_srcbuf)
        pr_warning("%s: srcbuf[0x%x] overwritten!"
                " Expected %02x, got %02x\n",
                thread_name, index, expected, actual);
    else if ((pattern & PATTERN_COPY)
            && (diff & (PATTERN_COPY | PATTERN_OVERWRITE)))
        pr_warning("%s: dstbuf[0x%x] not copied!"
                " Expected %02x, got %02x\n",
                thread_name, index, expected, actual);
    else if (diff & PATTERN_SRC)
        pr_warning("%s: dstbuf[0x%x] was copied!"
                " Expected %02x, got %02x\n",
                thread_name, index, expected, actual);
    else
        pr_warning("%s: dstbuf[0x%x] mismatch!"
                " Expected %02x, got %02x\n",
                thread_name, index, expected, actual);
}

static unsigned int dmatest_verify(u8 **bufs, unsigned int start,
        unsigned int end, unsigned int counter, u8 pattern,
        bool is_srcbuf)
{
    unsigned int i;
    unsigned int error_count = 0;
    u8 actual;
    u8 expected;
    u8 *buf;
    unsigned int counter_orig = counter;

    for (; (buf = *bufs); bufs++) {
        counter = counter_orig;
        for (i = start; i < end; i++) {
            actual = buf[i];
            expected = pattern | (~counter & PATTERN_COUNT_MASK);
            if (actual != expected) {
                if (error_count < 32)
                    dmatest_mismatch(actual, pattern, i,
                             counter, is_srcbuf);
                error_count++;
            }
            counter++;
        }
    }

    if (error_count > 32)
        pr_warning("%s: %u errors suppressed\n",
            current->comm, error_count - 32);

    return error_count;
}

/* poor man's completion - we want to use wait_event_freezable() on it */
struct dmatest_done {
    bool            done;
    wait_queue_head_t   *wait;
};

static void dmatest_callback(void *arg)
{
    struct dmatest_done *done = arg;

    done->done = true;
    wake_up_all(done->wait);
}

/*
 * This function repeatedly tests DMA transfers of various lengths and
 * offsets for a given operation type until it is told to exit by
 * kthread_stop(). There may be multiple threads running this function
 * in parallel for a single channel, and there may be multiple channels
 * being tested in parallel.
 *
 * Before each test, the source and destination buffer is initialized
 * with a known pattern. This pattern is different depending on
 * whether it's in an area which is supposed to be copied or
 * overwritten, and different in the source and destination buffers.
 * So if the DMA engine doesn't copy exactly what we tell it to copy,
 * we'll notice.
 */
static int dmatest_func(void *data)
{
    DECLARE_WAIT_QUEUE_HEAD_ONSTACK(done_wait);
    struct dmatest_thread   *thread = data;
    struct dmatest_done done = { .wait = &done_wait };
    struct dma_chan     *chan;
    const char      *thread_name;
    unsigned int        src_off, dst_off, len;
    unsigned int        error_count;
    unsigned int        failed_tests = 0;
    unsigned int        total_tests = 0;
    dma_cookie_t        cookie;
    enum dma_status     status;
    enum dma_ctrl_flags     flags;
    u8          pq_coefs[pq_sources + 1];
    int         ret;
    int         src_cnt;
    int         dst_cnt;
    int         i;

    thread_name = current->comm;
    set_freezable();

    ret = -ENOMEM;

    smp_rmb();
    chan = thread->chan;
    if (thread->type == DMA_MEMCPY)
        src_cnt = dst_cnt = 1;
    else if (thread->type == DMA_XOR) {
        src_cnt = xor_sources | 1; /* force odd to ensure dst = src */
        dst_cnt = 1;
    } else if (thread->type == DMA_PQ) {
        src_cnt = pq_sources | 1; /* force odd to ensure dst = src */
        dst_cnt = 2;
        for (i = 0; i < src_cnt; i++)
            pq_coefs[i] = 1;
    } else
        goto err_srcs;

    thread->srcs = kcalloc(src_cnt+1, sizeof(u8 *), GFP_KERNEL);
    if (!thread->srcs)
        goto err_srcs;
    for (i = 0; i < src_cnt; i++) {
        thread->srcs[i] = kmalloc(test_buf_size, GFP_KERNEL);
        if (!thread->srcs[i])
            goto err_srcbuf;
    }
    thread->srcs[i] = NULL;

    thread->dsts = kcalloc(dst_cnt+1, sizeof(u8 *), GFP_KERNEL);
    if (!thread->dsts)
        goto err_dsts;
    for (i = 0; i < dst_cnt; i++) {
        thread->dsts[i] = kmalloc(test_buf_size, GFP_KERNEL);
        if (!thread->dsts[i])
            goto err_dstbuf;
    }
    thread->dsts[i] = NULL;

    set_user_nice(current, 10);

    /*
     * src buffers are freed by the DMAEngine code with dma_unmap_single()
     * dst buffers are freed by ourselves below
     */
    flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT
          | DMA_COMPL_SKIP_DEST_UNMAP | DMA_COMPL_SRC_UNMAP_SINGLE;

    while (!kthread_should_stop()
           && !(iterations && total_tests >= iterations)) {
        struct dma_device *dev = chan->device;
        struct dma_async_tx_descriptor *tx = NULL;
        dma_addr_t dma_srcs[src_cnt];
        dma_addr_t dma_dsts[dst_cnt];
        u8 align = 0;

        total_tests++;

        /* honor alignment restrictions */
        if (thread->type == DMA_MEMCPY)
            align = dev->copy_align;
        else if (thread->type == DMA_XOR)
            align = dev->xor_align;
        else if (thread->type == DMA_PQ)
            align = dev->pq_align;

        if (1 << align > test_buf_size) {
            pr_err("%u-byte buffer too small for %d-byte alignment\n",
                   test_buf_size, 1 << align);
            break;
        }

        len = dmatest_random() % test_buf_size + 1;
        len = (len >> align) << align;
        if (!len)
            len = 1 << align;
        src_off = dmatest_random() % (test_buf_size - len + 1);
        dst_off = dmatest_random() % (test_buf_size - len + 1);

        src_off = (src_off >> align) << align;
        dst_off = (dst_off >> align) << align;

        dmatest_init_srcs(thread->srcs, src_off, len);
        dmatest_init_dsts(thread->dsts, dst_off, len);

        for (i = 0; i < src_cnt; i++) {
            u8 *buf = thread->srcs[i] + src_off;

            dma_srcs[i] = dma_map_single(dev->dev, buf, len,
                             DMA_TO_DEVICE);
        }
        /* map with DMA_BIDIRECTIONAL to force writeback/invalidate */
        for (i = 0; i < dst_cnt; i++) {
            dma_dsts[i] = dma_map_single(dev->dev, thread->dsts[i],
                             test_buf_size,
                             DMA_BIDIRECTIONAL);
        }


        if (thread->type == DMA_MEMCPY)
            tx = dev->device_prep_dma_memcpy(chan,
                             dma_dsts[0] + dst_off,
                             dma_srcs[0], len,
                             flags);
        else if (thread->type == DMA_XOR)
            tx = dev->device_prep_dma_xor(chan,
                              dma_dsts[0] + dst_off,
                              dma_srcs, src_cnt,
                              len, flags);
        else if (thread->type == DMA_PQ) {
            dma_addr_t dma_pq[dst_cnt];

            for (i = 0; i < dst_cnt; i++)
                dma_pq[i] = dma_dsts[i] + dst_off;
            tx = dev->device_prep_dma_pq(chan, dma_pq, dma_srcs,
                             src_cnt, pq_coefs,
                             len, flags);
        }

        if (!tx) {
            for (i = 0; i < src_cnt; i++)
                dma_unmap_single(dev->dev, dma_srcs[i], len,
                         DMA_TO_DEVICE);
            for (i = 0; i < dst_cnt; i++)
                dma_unmap_single(dev->dev, dma_dsts[i],
                         test_buf_size,
                         DMA_BIDIRECTIONAL);
            pr_warning("%s: #%u: prep error with src_off=0x%x "
                    "dst_off=0x%x len=0x%x\n",
                    thread_name, total_tests - 1,
                    src_off, dst_off, len);
            msleep(100);
            failed_tests++;
            continue;
        }

        done.done = false;
        tx->callback = dmatest_callback;
        tx->callback_param = &done;
        cookie = tx->tx_submit(tx);

        if (dma_submit_error(cookie)) {
            pr_warning("%s: #%u: submit error %d with src_off=0x%x "
                    "dst_off=0x%x len=0x%x\n",
                    thread_name, total_tests - 1, cookie,
                    src_off, dst_off, len);
            msleep(100);
            failed_tests++;
            continue;
        }
        dma_async_issue_pending(chan);

        wait_event_freezable_timeout(done_wait, done.done,
                         msecs_to_jiffies(timeout));

        status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);

        if (!done.done) {
            /*
             * We're leaving the timed out dma operation with
             * dangling pointer to done_wait.  To make this
             * correct, we'll need to allocate wait_done for
             * each test iteration and perform "who's gonna
             * free it this time?" dancing.  For now, just
             * leave it dangling.
             */
            pr_warning("%s: #%u: test timed out\n",
                   thread_name, total_tests - 1);
            failed_tests++;
            continue;
        } else if (status != DMA_SUCCESS) {
            pr_warning("%s: #%u: got completion callback,"
                   " but status is \'%s\'\n",
                   thread_name, total_tests - 1,
                   status == DMA_ERROR ? "error" : "in progress");
            failed_tests++;
            continue;
        }

        /* Unmap by myself (see DMA_COMPL_SKIP_DEST_UNMAP above) */
        for (i = 0; i < dst_cnt; i++)
            dma_unmap_single(dev->dev, dma_dsts[i], test_buf_size,
                     DMA_BIDIRECTIONAL);

        error_count = 0;

        pr_debug("%s: verifying source buffer...\n", thread_name);
        error_count += dmatest_verify(thread->srcs, 0, src_off,
                0, PATTERN_SRC, true);
        error_count += dmatest_verify(thread->srcs, src_off,
                src_off + len, src_off,
                PATTERN_SRC | PATTERN_COPY, true);
        error_count += dmatest_verify(thread->srcs, src_off + len,
                test_buf_size, src_off + len,
                PATTERN_SRC, true);

        pr_debug("%s: verifying dest buffer...\n",
                thread->task->comm);
        error_count += dmatest_verify(thread->dsts, 0, dst_off,
                0, PATTERN_DST, false);
        error_count += dmatest_verify(thread->dsts, dst_off,
                dst_off + len, src_off,
                PATTERN_SRC | PATTERN_COPY, false);
        error_count += dmatest_verify(thread->dsts, dst_off + len,
                test_buf_size, dst_off + len,
                PATTERN_DST, false);

        if (error_count) {
            pr_warning("%s: #%u: %u errors with "
                "src_off=0x%x dst_off=0x%x len=0x%x\n",
                thread_name, total_tests - 1, error_count,
                src_off, dst_off, len);
            failed_tests++;
        } else {
            pr_debug("%s: #%u: No errors with "
                "src_off=0x%x dst_off=0x%x len=0x%x\n",
                thread_name, total_tests - 1,
                src_off, dst_off, len);
        }
    }

    ret = 0;
    for (i = 0; thread->dsts[i]; i++)
        kfree(thread->dsts[i]);
err_dstbuf:
    kfree(thread->dsts);
err_dsts:
    for (i = 0; thread->srcs[i]; i++)
        kfree(thread->srcs[i]);
err_srcbuf:
    kfree(thread->srcs);
err_srcs:
    pr_notice("%s: terminating after %u tests, %u failures (status %d)\n",
            thread_name, total_tests, failed_tests, ret);

    /* terminate all transfers on specified channels */
    chan->device->device_control(chan, DMA_TERMINATE_ALL, 0);
    if (iterations > 0)
        while (!kthread_should_stop()) {
            DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wait_dmatest_exit);
            interruptible_sleep_on(&wait_dmatest_exit);
        }

    return ret;
}

static void dmatest_cleanup_channel(struct dmatest_chan *dtc)
{
    struct dmatest_thread   *thread;
    struct dmatest_thread   *_thread;
    int         ret;

    list_for_each_entry_safe(thread, _thread, &dtc->threads, node) {
        ret = kthread_stop(thread->task);
        pr_debug("dmatest: thread %s exited with status %d\n",
                thread->task->comm, ret);
        list_del(&thread->node);
        kfree(thread);
    }

    /* terminate all transfers on specified channels */
    dtc->chan->device->device_control(dtc->chan, DMA_TERMINATE_ALL, 0);

    kfree(dtc);
}

static int dmatest_add_threads(struct dmatest_chan *dtc, enum dma_transaction_type type)
{
    struct dmatest_thread *thread;
    struct dma_chan *chan = dtc->chan;
    char *op;
    unsigned int i;

    if (type == DMA_MEMCPY)
        op = "copy";
    else if (type == DMA_XOR)
        op = "xor";
    else if (type == DMA_PQ)
        op = "pq";
    else
        return -EINVAL;

    for (i = 0; i < threads_per_chan; i++) {
        thread = kzalloc(sizeof(struct dmatest_thread), GFP_KERNEL);
        if (!thread) {
            pr_warning("dmatest: No memory for %s-%s%u\n",
                   dma_chan_name(chan), op, i);

            break;
        }
        thread->chan = dtc->chan;
        thread->type = type;
        smp_wmb();
        thread->task = kthread_run(dmatest_func, thread, "%s-%s%u",
                dma_chan_name(chan), op, i);
        if (IS_ERR(thread->task)) {
            pr_warning("dmatest: Failed to run thread %s-%s%u\n",
                    dma_chan_name(chan), op, i);
            kfree(thread);
            break;
        }

        /* srcbuf and dstbuf are allocated by the thread itself */

        list_add_tail(&thread->node, &dtc->threads);
    }

    return i;
}

static int dmatest_add_channel(struct dma_chan *chan)
{
    struct dmatest_chan *dtc;
    struct dma_device   *dma_dev = chan->device;
    unsigned int        thread_count = 0;
    int cnt;

    dtc = kmalloc(sizeof(struct dmatest_chan), GFP_KERNEL);
    if (!dtc) {
        pr_warning("dmatest: No memory for %s\n", dma_chan_name(chan));
        return -ENOMEM;
    }

    dtc->chan = chan;
    INIT_LIST_HEAD(&dtc->threads);

    if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) {
        cnt = dmatest_add_threads(dtc, DMA_MEMCPY);
        thread_count += cnt > 0 ? cnt : 0;
    }
    if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
        cnt = dmatest_add_threads(dtc, DMA_XOR);
        thread_count += cnt > 0 ? cnt : 0;
    }
    if (dma_has_cap(DMA_PQ, dma_dev->cap_mask)) {
        cnt = dmatest_add_threads(dtc, DMA_PQ);
        thread_count += cnt > 0 ? cnt : 0;
    }

    pr_info("dmatest: Started %u threads using %s\n",
        thread_count, dma_chan_name(chan));

    list_add_tail(&dtc->node, &dmatest_channels);
    nr_channels++;

    return 0;
}

static bool filter(struct dma_chan *chan, void *param)
{
    if (!dmatest_match_channel(chan) || !dmatest_match_device(chan->device))
        return false;
    else
        return true;
}

static int __init dmatest_init(void)
{
    dma_cap_mask_t mask;
    struct dma_chan *chan;
    int err = 0;

    dma_cap_zero(mask);
    dma_cap_set(DMA_MEMCPY, mask);
    for (;;) {
        chan = dma_request_channel(mask, filter, NULL);
        if (chan) {
            err = dmatest_add_channel(chan);
            if (err) {
                dma_release_channel(chan);
                break; /* add_channel failed, punt */
            }
        } else
            break; /* no more channels available */
        if (max_channels && nr_channels >= max_channels)
            break; /* we have all we need */
    }

    return err;
}
/* when compiled-in wait for drivers to load first */
late_initcall(dmatest_init);

static void __exit dmatest_exit(void)
{
    struct dmatest_chan *dtc, *_dtc;
    struct dma_chan *chan;

    list_for_each_entry_safe(dtc, _dtc, &dmatest_channels, node) {
        list_del(&dtc->node);
        chan = dtc->chan;
        dmatest_cleanup_channel(dtc);
        pr_debug("dmatest: dropped channel %s\n",
             dma_chan_name(chan));
        dma_release_channel(chan);
    }
}
module_exit(dmatest_exit);

MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
MODULE_LICENSE("GPL v2");