/*
 * 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/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;
}

static void dmatest_callback(void *completion)
{
        complete(completion);
}

/*
 * 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)
{
        struct dmatest_thread   *thread = data;
        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;

        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];
                struct completion cmp;
                unsigned long tmo = msecs_to_jiffies(timeout);
                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;
                }

                init_completion(&cmp);
                tx->callback = dmatest_callback;
                tx->callback_param = &cmp;
                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);

                tmo = wait_for_completion_timeout(&cmp, tmo);
                status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);

                if (tmo == 0) {
                        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);

        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);
        }
        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 ?: 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");