static int flexrm_new_request()

in bcm-flexrm-mailbox.c [985:1082]

• 71 lines of code
• 11 McCabe index (conditional complexity)

static int flexrm_new_request(struct flexrm_ring *ring,
				struct brcm_message *batch_msg,
				struct brcm_message *msg)
{
	void *next;
	unsigned long flags;
	u32 val, count, nhcnt;
	u32 read_offset, write_offset;
	bool exit_cleanup = false;
	int ret = 0, reqid;

	/* Do sanity check on message */
	if (!flexrm_sanity_check(msg))
		return -EIO;
	msg->error = 0;

	/* If no requests possible then save data pointer and goto done. */
	spin_lock_irqsave(&ring->lock, flags);
	reqid = bitmap_find_free_region(ring->requests_bmap,
					RING_MAX_REQ_COUNT, 0);
	spin_unlock_irqrestore(&ring->lock, flags);
	if (reqid < 0)
		return -ENOSPC;
	ring->requests[reqid] = msg;

	/* Do DMA mappings for the message */
	ret = flexrm_dma_map(ring->mbox->dev, msg);
	if (ret < 0) {
		ring->requests[reqid] = NULL;
		spin_lock_irqsave(&ring->lock, flags);
		bitmap_release_region(ring->requests_bmap, reqid, 0);
		spin_unlock_irqrestore(&ring->lock, flags);
		return ret;
	}

	/* Determine current HW BD read offset */
	read_offset = readl_relaxed(ring->regs + RING_BD_READ_PTR);
	val = readl_relaxed(ring->regs + RING_BD_START_ADDR);
	read_offset *= RING_DESC_SIZE;
	read_offset += (u32)(BD_START_ADDR_DECODE(val) - ring->bd_dma_base);

	/*
	 * Number required descriptors = number of non-header descriptors +
	 *				 number of header descriptors +
	 *				 1x null descriptor
	 */
	nhcnt = flexrm_estimate_nonheader_desc_count(msg);
	count = flexrm_estimate_header_desc_count(nhcnt) + nhcnt + 1;

	/* Check for available descriptor space. */
	write_offset = ring->bd_write_offset;
	while (count) {
		if (!flexrm_is_next_table_desc(ring->bd_base + write_offset))
			count--;
		write_offset += RING_DESC_SIZE;
		if (write_offset == RING_BD_SIZE)
			write_offset = 0x0;
		if (write_offset == read_offset)
			break;
	}
	if (count) {
		ret = -ENOSPC;
		exit_cleanup = true;
		goto exit;
	}

	/* Write descriptors to ring */
	next = flexrm_write_descs(msg, nhcnt, reqid,
			ring->bd_base + ring->bd_write_offset,
			RING_BD_TOGGLE_VALID(ring->bd_write_offset),
			ring->bd_base, ring->bd_base + RING_BD_SIZE);
	if (IS_ERR(next)) {
		ret = PTR_ERR(next);
		exit_cleanup = true;
		goto exit;
	}

	/* Save ring BD write offset */
	ring->bd_write_offset = (unsigned long)(next - ring->bd_base);

	/* Increment number of messages sent */
	atomic_inc_return(&ring->msg_send_count);

exit:
	/* Update error status in message */
	msg->error = ret;

	/* Cleanup if we failed */
	if (exit_cleanup) {
		flexrm_dma_unmap(ring->mbox->dev, msg);
		ring->requests[reqid] = NULL;
		spin_lock_irqsave(&ring->lock, flags);
		bitmap_release_region(ring->requests_bmap, reqid, 0);
		spin_unlock_irqrestore(&ring->lock, flags);
	}

	return ret;
}