static int flexrm_process_completions()

in bcm-flexrm-mailbox.c [1084:1160]

• 46 lines of code
• 5 McCabe index (conditional complexity)

static int flexrm_process_completions(struct flexrm_ring *ring)
{
	u64 desc;
	int err, count = 0;
	unsigned long flags;
	struct brcm_message *msg = NULL;
	u32 reqid, cmpl_read_offset, cmpl_write_offset;
	struct mbox_chan *chan = &ring->mbox->controller.chans[ring->num];

	spin_lock_irqsave(&ring->lock, flags);

	/*
	 * Get current completion read and write offset
	 *
	 * Note: We should read completion write pointer at least once
	 * after we get a MSI interrupt because HW maintains internal
	 * MSI status which will allow next MSI interrupt only after
	 * completion write pointer is read.
	 */
	cmpl_write_offset = readl_relaxed(ring->regs + RING_CMPL_WRITE_PTR);
	cmpl_write_offset *= RING_DESC_SIZE;
	cmpl_read_offset = ring->cmpl_read_offset;
	ring->cmpl_read_offset = cmpl_write_offset;

	spin_unlock_irqrestore(&ring->lock, flags);

	/* For each completed request notify mailbox clients */
	reqid = 0;
	while (cmpl_read_offset != cmpl_write_offset) {
		/* Dequeue next completion descriptor */
		desc = *((u64 *)(ring->cmpl_base + cmpl_read_offset));

		/* Next read offset */
		cmpl_read_offset += RING_DESC_SIZE;
		if (cmpl_read_offset == RING_CMPL_SIZE)
			cmpl_read_offset = 0;

		/* Decode error from completion descriptor */
		err = flexrm_cmpl_desc_to_error(desc);
		if (err < 0) {
			dev_warn(ring->mbox->dev,
			"ring%d got completion desc=0x%lx with error %d\n",
			ring->num, (unsigned long)desc, err);
		}

		/* Determine request id from completion descriptor */
		reqid = flexrm_cmpl_desc_to_reqid(desc);

		/* Determine message pointer based on reqid */
		msg = ring->requests[reqid];
		if (!msg) {
			dev_warn(ring->mbox->dev,
			"ring%d null msg pointer for completion desc=0x%lx\n",
			ring->num, (unsigned long)desc);
			continue;
		}

		/* Release reqid for recycling */
		ring->requests[reqid] = NULL;
		spin_lock_irqsave(&ring->lock, flags);
		bitmap_release_region(ring->requests_bmap, reqid, 0);
		spin_unlock_irqrestore(&ring->lock, flags);

		/* Unmap DMA mappings */
		flexrm_dma_unmap(ring->mbox->dev, msg);

		/* Give-back message to mailbox client */
		msg->error = err;
		mbox_chan_received_data(chan, msg);

		/* Increment number of completions processed */
		atomic_inc_return(&ring->msg_cmpl_count);
		count++;
	}

	return count;
}