/*
 * Copyright © 2014-2017 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

#include <linux/debugfs.h>

#include "intel_guc_log.h"
#include "i915_drv.h"

#if 0
static void guc_log_capture_logs(struct intel_guc_log *log);

/**
 * DOC: GuC firmware log
 *
 * Firmware log is enabled by setting i915.guc_log_level to the positive level.
 * Log data is printed out via reading debugfs i915_guc_log_dump. Reading from
 * i915_guc_load_status will print out firmware loading status and scratch
 * registers value.
 */

static int guc_action_flush_log_complete(struct intel_guc *guc)
{
        u32 action[] = {
                INTEL_GUC_ACTION_LOG_BUFFER_FILE_FLUSH_COMPLETE
        };

        return intel_guc_send(guc, action, ARRAY_SIZE(action));
}

static int guc_action_flush_log(struct intel_guc *guc)
{
        u32 action[] = {
                INTEL_GUC_ACTION_FORCE_LOG_BUFFER_FLUSH,
                0
        };

        return intel_guc_send(guc, action, ARRAY_SIZE(action));
}

static int guc_action_control_log(struct intel_guc *guc, bool enable,
                                  bool default_logging, u32 verbosity)
{
        u32 action[] = {
                INTEL_GUC_ACTION_UK_LOG_ENABLE_LOGGING,
                (enable ? GUC_LOG_CONTROL_LOGGING_ENABLED : 0) |
                (verbosity << GUC_LOG_CONTROL_VERBOSITY_SHIFT) |
                (default_logging ? GUC_LOG_CONTROL_DEFAULT_LOGGING : 0)
        };

        GEM_BUG_ON(verbosity > GUC_LOG_VERBOSITY_MAX);

        return intel_guc_send(guc, action, ARRAY_SIZE(action));
}

static inline struct intel_guc *log_to_guc(struct intel_guc_log *log)
{
        return container_of(log, struct intel_guc, log);
}

static void guc_log_enable_flush_events(struct intel_guc_log *log)
{
        intel_guc_enable_msg(log_to_guc(log),
                             INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER |
                             INTEL_GUC_RECV_MSG_CRASH_DUMP_POSTED);
}

static void guc_log_disable_flush_events(struct intel_guc_log *log)
{
        intel_guc_disable_msg(log_to_guc(log),
                              INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER |
                              INTEL_GUC_RECV_MSG_CRASH_DUMP_POSTED);
}

/*
 * Sub buffer switch callback. Called whenever relay has to switch to a new
 * sub buffer, relay stays on the same sub buffer if 0 is returned.
 */
static int subbuf_start_callback(struct rchan_buf *buf,
                                 void *subbuf,
                                 void *prev_subbuf,
                                 size_t prev_padding)
{
        /*
         * Use no-overwrite mode by default, where relay will stop accepting
         * new data if there are no empty sub buffers left.
         * There is no strict synchronization enforced by relay between Consumer
         * and Producer. In overwrite mode, there is a possibility of getting
         * inconsistent/garbled data, the producer could be writing on to the
         * same sub buffer from which Consumer is reading. This can't be avoided
         * unless Consumer is fast enough and can always run in tandem with
         * Producer.
         */
        if (relay_buf_full(buf))
                return 0;

        return 1;
}

/*
 * file_create() callback. Creates relay file in debugfs.
 */
static struct dentry *create_buf_file_callback(const char *filename,
                                               struct dentry *parent,
                                               umode_t mode,
                                               struct rchan_buf *buf,
                                               int *is_global)
{
        struct dentry *buf_file;

        /*
         * This to enable the use of a single buffer for the relay channel and
         * correspondingly have a single file exposed to User, through which
         * it can collect the logs in order without any post-processing.
         * Need to set 'is_global' even if parent is NULL for early logging.
         */
        *is_global = 1;

        if (!parent)
                return NULL;

        buf_file = debugfs_create_file(filename, mode,
                                       parent, buf, &relay_file_operations);
        return buf_file;
}

/*
 * file_remove() default callback. Removes relay file in debugfs.
 */
static int remove_buf_file_callback(struct dentry *dentry)
{
        debugfs_remove(dentry);
        return 0;
}

/* relay channel callbacks */
static struct rchan_callbacks relay_callbacks = {
        .subbuf_start = subbuf_start_callback,
        .create_buf_file = create_buf_file_callback,
        .remove_buf_file = remove_buf_file_callback,
};

static void guc_move_to_next_buf(struct intel_guc_log *log)
{
        /*
         * Make sure the updates made in the sub buffer are visible when
         * Consumer sees the following update to offset inside the sub buffer.
         */
        smp_wmb();

        /* All data has been written, so now move the offset of sub buffer. */
        relay_reserve(log->relay.channel, log->vma->obj->base.size);

        /* Switch to the next sub buffer */
        relay_flush(log->relay.channel);
}

static void *guc_get_write_buffer(struct intel_guc_log *log)
{
        /*
         * Just get the base address of a new sub buffer and copy data into it
         * ourselves. NULL will be returned in no-overwrite mode, if all sub
         * buffers are full. Could have used the relay_write() to indirectly
         * copy the data, but that would have been bit convoluted, as we need to
         * write to only certain locations inside a sub buffer which cannot be
         * done without using relay_reserve() along with relay_write(). So its
         * better to use relay_reserve() alone.
         */
        return relay_reserve(log->relay.channel, 0);
}

static bool guc_check_log_buf_overflow(struct intel_guc_log *log,
                                       enum guc_log_buffer_type type,
                                       unsigned int full_cnt)
{
        unsigned int prev_full_cnt = log->stats[type].sampled_overflow;
        bool overflow = false;

        if (full_cnt != prev_full_cnt) {
                overflow = true;

                log->stats[type].overflow = full_cnt;
                log->stats[type].sampled_overflow += full_cnt - prev_full_cnt;

                if (full_cnt < prev_full_cnt) {
                        /* buffer_full_cnt is a 4 bit counter */
                        log->stats[type].sampled_overflow += 16;
                }
                DRM_ERROR_RATELIMITED("GuC log buffer overflow\n");
        }

        return overflow;
}

static unsigned int guc_get_log_buffer_size(enum guc_log_buffer_type type)
{
        switch (type) {
        case GUC_ISR_LOG_BUFFER:
                return ISR_BUFFER_SIZE;
        case GUC_DPC_LOG_BUFFER:
                return DPC_BUFFER_SIZE;
        case GUC_CRASH_DUMP_LOG_BUFFER:
                return CRASH_BUFFER_SIZE;
        default:
                MISSING_CASE(type);
        }

        return 0;
}

static void guc_read_update_log_buffer(struct intel_guc_log *log)
{
        unsigned int buffer_size, read_offset, write_offset, bytes_to_copy, full_cnt;
        struct guc_log_buffer_state *log_buf_state, *log_buf_snapshot_state;
        struct guc_log_buffer_state log_buf_state_local;
        enum guc_log_buffer_type type;
        void *src_data, *dst_data;
        bool new_overflow;

        mutex_lock(&log->relay.lock);

        if (WARN_ON(!intel_guc_log_relay_enabled(log)))
                goto out_unlock;

        /* Get the pointer to shared GuC log buffer */
        log_buf_state = src_data = log->relay.buf_addr;

        /* Get the pointer to local buffer to store the logs */
        log_buf_snapshot_state = dst_data = guc_get_write_buffer(log);

        if (unlikely(!log_buf_snapshot_state)) {
                /*
                 * Used rate limited to avoid deluge of messages, logs might be
                 * getting consumed by User at a slow rate.
                 */
                DRM_ERROR_RATELIMITED("no sub-buffer to capture logs\n");
                log->relay.full_count++;

                goto out_unlock;
        }

        /* Actual logs are present from the 2nd page */
        src_data += PAGE_SIZE;
        dst_data += PAGE_SIZE;

        for (type = GUC_ISR_LOG_BUFFER; type < GUC_MAX_LOG_BUFFER; type++) {
                /*
                 * Make a copy of the state structure, inside GuC log buffer
                 * (which is uncached mapped), on the stack to avoid reading
                 * from it multiple times.
                 */
                memcpy(&log_buf_state_local, log_buf_state,
                       sizeof(struct guc_log_buffer_state));
                buffer_size = guc_get_log_buffer_size(type);
                read_offset = log_buf_state_local.read_ptr;
                write_offset = log_buf_state_local.sampled_write_ptr;
                full_cnt = log_buf_state_local.buffer_full_cnt;

                /* Bookkeeping stuff */
                log->stats[type].flush += log_buf_state_local.flush_to_file;
                new_overflow = guc_check_log_buf_overflow(log, type, full_cnt);

                /* Update the state of shared log buffer */
                log_buf_state->read_ptr = write_offset;
                log_buf_state->flush_to_file = 0;
                log_buf_state++;

                /* First copy the state structure in snapshot buffer */
                memcpy(log_buf_snapshot_state, &log_buf_state_local,
                       sizeof(struct guc_log_buffer_state));

                /*
                 * The write pointer could have been updated by GuC firmware,
                 * after sending the flush interrupt to Host, for consistency
                 * set write pointer value to same value of sampled_write_ptr
                 * in the snapshot buffer.
                 */
                log_buf_snapshot_state->write_ptr = write_offset;
                log_buf_snapshot_state++;

                /* Now copy the actual logs. */
                if (unlikely(new_overflow)) {
                        /* copy the whole buffer in case of overflow */
                        read_offset = 0;
                        write_offset = buffer_size;
                } else if (unlikely((read_offset > buffer_size) ||
                                    (write_offset > buffer_size))) {
                        DRM_ERROR("invalid log buffer state\n");
                        /* copy whole buffer as offsets are unreliable */
                        read_offset = 0;
                        write_offset = buffer_size;
                }

                /* Just copy the newly written data */
                if (read_offset > write_offset) {
                        i915_memcpy_from_wc(dst_data, src_data, write_offset);
                        bytes_to_copy = buffer_size - read_offset;
                } else {
                        bytes_to_copy = write_offset - read_offset;
                }
                i915_memcpy_from_wc(dst_data + read_offset,
                                    src_data + read_offset, bytes_to_copy);

                src_data += buffer_size;
                dst_data += buffer_size;
        }

        guc_move_to_next_buf(log);

out_unlock:
        mutex_unlock(&log->relay.lock);
}

static void capture_logs_work(struct work_struct *work)
{
        struct intel_guc_log *log =
                container_of(work, struct intel_guc_log, relay.flush_work);

        guc_log_capture_logs(log);
}

static int guc_log_map(struct intel_guc_log *log)
{
        struct intel_guc *guc = log_to_guc(log);
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        void *vaddr;
        int ret;

        lockdep_assert_held(&log->relay.lock);

        if (!log->vma)
                return -ENODEV;

        mutex_lock(&dev_priv->drm.struct_mutex);
        ret = i915_gem_object_set_to_wc_domain(log->vma->obj, true);
        mutex_unlock(&dev_priv->drm.struct_mutex);
        if (ret)
                return ret;

        /*
         * Create a WC (Uncached for read) vmalloc mapping of log
         * buffer pages, so that we can directly get the data
         * (up-to-date) from memory.
         */
        vaddr = i915_gem_object_pin_map(log->vma->obj, I915_MAP_WC);
        if (IS_ERR(vaddr)) {
                DRM_ERROR("Couldn't map log buffer pages %d\n", ret);
                return PTR_ERR(vaddr);
        }

        log->relay.buf_addr = vaddr;

        return 0;
}

static void guc_log_unmap(struct intel_guc_log *log)
{
        lockdep_assert_held(&log->relay.lock);

        i915_gem_object_unpin_map(log->vma->obj);
        log->relay.buf_addr = NULL;
}

void intel_guc_log_init_early(struct intel_guc_log *log)
{
        mutex_init(&log->relay.lock);
        INIT_WORK(&log->relay.flush_work, capture_logs_work);
}

static int guc_log_relay_create(struct intel_guc_log *log)
{
        struct intel_guc *guc = log_to_guc(log);
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        struct rchan *guc_log_relay_chan;
        size_t n_subbufs, subbuf_size;
        int ret;

        lockdep_assert_held(&log->relay.lock);

         /* Keep the size of sub buffers same as shared log buffer */
        subbuf_size = log->vma->size;

        /*
         * Store up to 8 snapshots, which is large enough to buffer sufficient
         * boot time logs and provides enough leeway to User, in terms of
         * latency, for consuming the logs from relay. Also doesn't take
         * up too much memory.
         */
        n_subbufs = 8;

        guc_log_relay_chan = relay_open("guc_log",
                                        dev_priv->drm.primary->debugfs_root,
                                        subbuf_size, n_subbufs,
                                        &relay_callbacks, dev_priv);
        if (!guc_log_relay_chan) {
                DRM_ERROR("Couldn't create relay chan for GuC logging\n");

                ret = -ENOMEM;
                return ret;
        }

        GEM_BUG_ON(guc_log_relay_chan->subbuf_size < subbuf_size);
        log->relay.channel = guc_log_relay_chan;

        return 0;
}

static void guc_log_relay_destroy(struct intel_guc_log *log)
{
        lockdep_assert_held(&log->relay.lock);

        relay_close(log->relay.channel);
        log->relay.channel = NULL;
}

static void guc_log_capture_logs(struct intel_guc_log *log)
{
        struct intel_guc *guc = log_to_guc(log);
        struct drm_i915_private *dev_priv = guc_to_i915(guc);

        guc_read_update_log_buffer(log);

        /*
         * Generally device is expected to be active only at this
         * time, so get/put should be really quick.
         */
        intel_runtime_pm_get(dev_priv);
        guc_action_flush_log_complete(guc);
        intel_runtime_pm_put(dev_priv);
}

int intel_guc_log_create(struct intel_guc_log *log)
{
        struct intel_guc *guc = log_to_guc(log);
        struct i915_vma *vma;
        u32 guc_log_size;
        int ret;

        GEM_BUG_ON(log->vma);

        /*
         *  GuC Log buffer Layout
         *
         *  +===============================+ 00B
         *  |    Crash dump state header    |
         *  +-------------------------------+ 32B
         *  |       DPC state header        |
         *  +-------------------------------+ 64B
         *  |       ISR state header        |
         *  +-------------------------------+ 96B
         *  |                               |
         *  +===============================+ PAGE_SIZE (4KB)
         *  |        Crash Dump logs        |
         *  +===============================+ + CRASH_SIZE
         *  |           DPC logs            |
         *  +===============================+ + DPC_SIZE
         *  |           ISR logs            |
         *  +===============================+ + ISR_SIZE
         */
        guc_log_size = PAGE_SIZE + CRASH_BUFFER_SIZE + DPC_BUFFER_SIZE +
                        ISR_BUFFER_SIZE;

        vma = intel_guc_allocate_vma(guc, guc_log_size);
        if (IS_ERR(vma)) {
                ret = PTR_ERR(vma);
                goto err;
        }

        log->vma = vma;

        log->level = i915_modparams.guc_log_level;

        return 0;

err:
        DRM_ERROR("Failed to allocate GuC log buffer. %d\n", ret);
        return ret;
}

void intel_guc_log_destroy(struct intel_guc_log *log)
{
        i915_vma_unpin_and_release(&log->vma, 0);
}

int intel_guc_log_set_level(struct intel_guc_log *log, u32 level)
{
        struct intel_guc *guc = log_to_guc(log);
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        int ret;

        BUILD_BUG_ON(GUC_LOG_VERBOSITY_MIN != 0);
        GEM_BUG_ON(!log->vma);

        /*
         * GuC is recognizing log levels starting from 0 to max, we're using 0
         * as indication that logging should be disabled.
         */
        if (level < GUC_LOG_LEVEL_DISABLED || level > GUC_LOG_LEVEL_MAX)
                return -EINVAL;

        mutex_lock(&dev_priv->drm.struct_mutex);

        if (log->level == level) {
                ret = 0;
                goto out_unlock;
        }

        intel_runtime_pm_get(dev_priv);
        ret = guc_action_control_log(guc, GUC_LOG_LEVEL_IS_VERBOSE(level),
                                     GUC_LOG_LEVEL_IS_ENABLED(level),
                                     GUC_LOG_LEVEL_TO_VERBOSITY(level));
        intel_runtime_pm_put(dev_priv);
        if (ret) {
                DRM_DEBUG_DRIVER("guc_log_control action failed %d\n", ret);
                goto out_unlock;
        }

        log->level = level;

out_unlock:
        mutex_unlock(&dev_priv->drm.struct_mutex);

        return ret;
}

bool intel_guc_log_relay_enabled(const struct intel_guc_log *log)
{
        return log->relay.buf_addr;
}

int intel_guc_log_relay_open(struct intel_guc_log *log)
{
        int ret;

        mutex_lock(&log->relay.lock);

        if (intel_guc_log_relay_enabled(log)) {
                ret = -EEXIST;
                goto out_unlock;
        }

        /*
         * We require SSE 4.1 for fast reads from the GuC log buffer and
         * it should be present on the chipsets supporting GuC based
         * submisssions.
         */
        if (!i915_has_memcpy_from_wc()) {
                ret = -ENXIO;
                goto out_unlock;
        }

        ret = guc_log_relay_create(log);
        if (ret)
                goto out_unlock;

        ret = guc_log_map(log);
        if (ret)
                goto out_relay;

        mutex_unlock(&log->relay.lock);

        guc_log_enable_flush_events(log);

        /*
         * When GuC is logging without us relaying to userspace, we're ignoring
         * the flush notification. This means that we need to unconditionally
         * flush on relay enabling, since GuC only notifies us once.
         */
        queue_work(log->relay.flush_wq, &log->relay.flush_work);

        return 0;

out_relay:
        guc_log_relay_destroy(log);
out_unlock:
        mutex_unlock(&log->relay.lock);

        return ret;
}

void intel_guc_log_relay_flush(struct intel_guc_log *log)
{
        struct intel_guc *guc = log_to_guc(log);
        struct drm_i915_private *i915 = guc_to_i915(guc);

        /*
         * Before initiating the forceful flush, wait for any pending/ongoing
         * flush to complete otherwise forceful flush may not actually happen.
         */
        flush_work(&log->relay.flush_work);

        intel_runtime_pm_get(i915);
        guc_action_flush_log(guc);
        intel_runtime_pm_put(i915);

        /* GuC would have updated log buffer by now, so capture it */
        guc_log_capture_logs(log);
}

void intel_guc_log_relay_close(struct intel_guc_log *log)
{
        guc_log_disable_flush_events(log);
        flush_work(&log->relay.flush_work);

        mutex_lock(&log->relay.lock);
        GEM_BUG_ON(!intel_guc_log_relay_enabled(log));
        guc_log_unmap(log);
        guc_log_relay_destroy(log);
        mutex_unlock(&log->relay.lock);
}

void intel_guc_log_handle_flush_event(struct intel_guc_log *log)
{
        queue_work(log->relay.flush_wq, &log->relay.flush_work);
}
#endif