// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
//
// This file is provided under a dual BSD/GPLv2 license.  When using or
// redistributing this file, you may do so under either license.
//
// Copyright(c) 2018 Intel Corporation. All rights reserved.
//
// Author: Liam Girdwood <liam.r.girdwood@linux.intel.com>
//

#include <linux/debugfs.h>
#include <linux/sched/signal.h>
#include "sof-priv.h"
#include "ops.h"

static size_t sof_wait_trace_avail(struct snd_sof_dev *sdev,
				   loff_t pos, size_t buffer_size)
{
	wait_queue_entry_t wait;
	loff_t host_offset = READ_ONCE(sdev->host_offset);

	/*
	 * If host offset is less than local pos, it means write pointer of
	 * host DMA buffer has been wrapped. We should output the trace data
	 * at the end of host DMA buffer at first.
	 */
	if (host_offset < pos)
		return buffer_size - pos;

	/* If there is available trace data now, it is unnecessary to wait. */
	if (host_offset > pos)
		return host_offset - pos;

	/* wait for available trace data from FW */
	init_waitqueue_entry(&wait, current);
	set_current_state(TASK_INTERRUPTIBLE);
	add_wait_queue(&sdev->trace_sleep, &wait);

	if (!signal_pending(current)) {
		/* set timeout to max value, no error code */
		schedule_timeout(MAX_SCHEDULE_TIMEOUT);
	}
	remove_wait_queue(&sdev->trace_sleep, &wait);

	/* return bytes available for copy */
	host_offset = READ_ONCE(sdev->host_offset);
	if (host_offset < pos)
		return buffer_size - pos;

	return host_offset - pos;
}

static ssize_t sof_dfsentry_trace_read(struct file *file, char __user *buffer,
				       size_t count, loff_t *ppos)
{
	struct snd_sof_dfsentry *dfse = file->private_data;
	struct snd_sof_dev *sdev = dfse->sdev;
	unsigned long rem;
	loff_t lpos = *ppos;
	size_t avail, buffer_size = dfse->size;
	u64 lpos_64;

	/* make sure we know about any failures on the DSP side */
	sdev->dtrace_error = false;

	/* check pos and count */
	if (lpos < 0)
		return -EINVAL;
	if (!count)
		return 0;

	/* check for buffer wrap and count overflow */
	lpos_64 = lpos;
	lpos = do_div(lpos_64, buffer_size);

	if (count > buffer_size - lpos) /* min() not used to avoid sparse warnings */
		count = buffer_size - lpos;

	/* get available count based on current host offset */
	avail = sof_wait_trace_avail(sdev, lpos, buffer_size);
	if (sdev->dtrace_error) {
		dev_err(sdev->dev, "error: trace IO error\n");
		return -EIO;
	}

	/* make sure count is <= avail */
	count = avail > count ? count : avail;

	/* copy available trace data to debugfs */
	rem = copy_to_user(buffer, ((u8 *)(dfse->buf) + lpos), count);
	if (rem)
		return -EFAULT;

	*ppos += count;

	/* move debugfs reading position */
	return count;
}

static const struct file_operations sof_dfs_trace_fops = {
	.open = simple_open,
	.read = sof_dfsentry_trace_read,
	.llseek = default_llseek,
};

static int trace_debugfs_create(struct snd_sof_dev *sdev)
{
	struct snd_sof_dfsentry *dfse;

	if (!sdev)
		return -EINVAL;

	dfse = devm_kzalloc(sdev->dev, sizeof(*dfse), GFP_KERNEL);
	if (!dfse)
		return -ENOMEM;

	dfse->type = SOF_DFSENTRY_TYPE_BUF;
	dfse->buf = sdev->dmatb.area;
	dfse->size = sdev->dmatb.bytes;
	dfse->sdev = sdev;

	dfse->dfsentry = debugfs_create_file("trace", 0444, sdev->debugfs_root,
					     dfse, &sof_dfs_trace_fops);
	if (!dfse->dfsentry) {
		/* can't rely on debugfs, only log error and keep going */
		dev_err(sdev->dev,
			"error: cannot create debugfs entry for trace\n");
	}

	return 0;
}

int snd_sof_init_trace_ipc(struct snd_sof_dev *sdev)
{
	struct sof_ipc_dma_trace_params params;
	struct sof_ipc_reply ipc_reply;
	int ret;

	if (sdev->dtrace_is_enabled || !sdev->dma_trace_pages)
		return -EINVAL;

	/* set IPC parameters */
	params.hdr.size = sizeof(params);
	params.hdr.cmd = SOF_IPC_GLB_TRACE_MSG | SOF_IPC_TRACE_DMA_PARAMS;
	params.buffer.phy_addr = sdev->dmatp.addr;
	params.buffer.size = sdev->dmatb.bytes;
	params.buffer.pages = sdev->dma_trace_pages;
	params.stream_tag = 0;

	sdev->host_offset = 0;

	ret = snd_sof_dma_trace_init(sdev, &params.stream_tag);
	if (ret < 0) {
		dev_err(sdev->dev,
			"error: fail in snd_sof_dma_trace_init %d\n", ret);
		return ret;
	}
	dev_dbg(sdev->dev, "stream_tag: %d\n", params.stream_tag);

	/* send IPC to the DSP */
	ret = sof_ipc_tx_message(sdev->ipc,
				 params.hdr.cmd, &params, sizeof(params),
				 &ipc_reply, sizeof(ipc_reply));
	if (ret < 0) {
		dev_err(sdev->dev,
			"error: can't set params for DMA for trace %d\n", ret);
		goto trace_release;
	}

	ret = snd_sof_dma_trace_trigger(sdev, SNDRV_PCM_TRIGGER_START);
	if (ret < 0) {
		dev_err(sdev->dev,
			"error: snd_sof_dma_trace_trigger: start: %d\n", ret);
		goto trace_release;
	}

	sdev->dtrace_is_enabled = true;

	return 0;

trace_release:
	snd_sof_dma_trace_release(sdev);
	return ret;
}

int snd_sof_init_trace(struct snd_sof_dev *sdev)
{
	int ret;

	/* set false before start initialization */
	sdev->dtrace_is_enabled = false;

	/* allocate trace page table buffer */
	ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, sdev->dev,
				  PAGE_SIZE, &sdev->dmatp);
	if (ret < 0) {
		dev_err(sdev->dev,
			"error: can't alloc page table for trace %d\n", ret);
		return ret;
	}

	/* allocate trace data buffer */
	ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV_SG, sdev->dev,
				  DMA_BUF_SIZE_FOR_TRACE, &sdev->dmatb);
	if (ret < 0) {
		dev_err(sdev->dev,
			"error: can't alloc buffer for trace %d\n", ret);
		goto page_err;
	}

	/* create compressed page table for audio firmware */
	ret = snd_sof_create_page_table(sdev, &sdev->dmatb, sdev->dmatp.area,
					sdev->dmatb.bytes);
	if (ret < 0)
		goto table_err;

	sdev->dma_trace_pages = ret;
	dev_dbg(sdev->dev, "dma_trace_pages: %d\n", sdev->dma_trace_pages);

	if (sdev->first_boot) {
		ret = trace_debugfs_create(sdev);
		if (ret < 0)
			goto table_err;
	}

	init_waitqueue_head(&sdev->trace_sleep);

	ret = snd_sof_init_trace_ipc(sdev);
	if (ret < 0)
		goto table_err;

	return 0;
table_err:
	sdev->dma_trace_pages = 0;
	snd_dma_free_pages(&sdev->dmatb);
page_err:
	snd_dma_free_pages(&sdev->dmatp);
	return ret;
}
EXPORT_SYMBOL(snd_sof_init_trace);

int snd_sof_trace_update_pos(struct snd_sof_dev *sdev,
			     struct sof_ipc_dma_trace_posn *posn)
{
	if (sdev->dtrace_is_enabled && sdev->host_offset != posn->host_offset) {
		sdev->host_offset = posn->host_offset;
		wake_up(&sdev->trace_sleep);
	}

	if (posn->overflow != 0)
		dev_err(sdev->dev,
			"error: DSP trace buffer overflow %u bytes. Total messages %d\n",
			posn->overflow, posn->messages);

	return 0;
}

/* an error has occurred within the DSP that prevents further trace */
void snd_sof_trace_notify_for_error(struct snd_sof_dev *sdev)
{
	if (sdev->dtrace_is_enabled) {
		dev_err(sdev->dev, "error: waking up any trace sleepers\n");
		sdev->dtrace_error = true;
		wake_up(&sdev->trace_sleep);
	}
}
EXPORT_SYMBOL(snd_sof_trace_notify_for_error);

void snd_sof_release_trace(struct snd_sof_dev *sdev)
{
	int ret;

	if (!sdev->dtrace_is_enabled)
		return;

	ret = snd_sof_dma_trace_trigger(sdev, SNDRV_PCM_TRIGGER_STOP);
	if (ret < 0)
		dev_err(sdev->dev,
			"error: snd_sof_dma_trace_trigger: stop: %d\n", ret);

	ret = snd_sof_dma_trace_release(sdev);
	if (ret < 0)
		dev_err(sdev->dev,
			"error: fail in snd_sof_dma_trace_release %d\n", ret);

	sdev->dtrace_is_enabled = false;
}
EXPORT_SYMBOL(snd_sof_release_trace);

void snd_sof_free_trace(struct snd_sof_dev *sdev)
{
	snd_sof_release_trace(sdev);

	snd_dma_free_pages(&sdev->dmatb);
	snd_dma_free_pages(&sdev->dmatp);
}
EXPORT_SYMBOL(snd_sof_free_trace);