int mhi_prepare_channel()

in mhi/core/main.c [1432:1515]

• 64 lines of code
• 12 McCabe index (conditional complexity)

int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
			struct mhi_chan *mhi_chan, unsigned int flags)
{
	int ret = 0;
	struct device *dev = &mhi_chan->mhi_dev->dev;

	if (!(BIT(mhi_cntrl->ee) & mhi_chan->ee_mask)) {
		dev_err(dev, "Current EE: %s Required EE Mask: 0x%x\n",
			TO_MHI_EXEC_STR(mhi_cntrl->ee), mhi_chan->ee_mask);
		return -ENOTCONN;
	}

	mutex_lock(&mhi_chan->mutex);

	/* Check of client manages channel context for offload channels */
	if (!mhi_chan->offload_ch) {
		ret = mhi_init_chan_ctxt(mhi_cntrl, mhi_chan);
		if (ret)
			goto error_init_chan;
	}

	ret = mhi_update_channel_state(mhi_cntrl, mhi_chan,
				       MHI_CH_STATE_TYPE_START);
	if (ret)
		goto error_pm_state;

	if (mhi_chan->dir == DMA_FROM_DEVICE)
		mhi_chan->pre_alloc = !!(flags & MHI_CH_INBOUND_ALLOC_BUFS);

	/* Pre-allocate buffer for xfer ring */
	if (mhi_chan->pre_alloc) {
		int nr_el = get_nr_avail_ring_elements(mhi_cntrl,
						       &mhi_chan->tre_ring);
		size_t len = mhi_cntrl->buffer_len;

		while (nr_el--) {
			void *buf;
			struct mhi_buf_info info = { };

			buf = kmalloc(len, GFP_KERNEL);
			if (!buf) {
				ret = -ENOMEM;
				goto error_pre_alloc;
			}

			/* Prepare transfer descriptors */
			info.v_addr = buf;
			info.cb_buf = buf;
			info.len = len;
			ret = mhi_gen_tre(mhi_cntrl, mhi_chan, &info, MHI_EOT);
			if (ret) {
				kfree(buf);
				goto error_pre_alloc;
			}
		}

		read_lock_bh(&mhi_cntrl->pm_lock);
		if (MHI_DB_ACCESS_VALID(mhi_cntrl)) {
			read_lock_irq(&mhi_chan->lock);
			mhi_ring_chan_db(mhi_cntrl, mhi_chan);
			read_unlock_irq(&mhi_chan->lock);
		}
		read_unlock_bh(&mhi_cntrl->pm_lock);
	}

	mutex_unlock(&mhi_chan->mutex);

	return 0;

error_pm_state:
	if (!mhi_chan->offload_ch)
		mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);

error_init_chan:
	mutex_unlock(&mhi_chan->mutex);

	return ret;

error_pre_alloc:
	mutex_unlock(&mhi_chan->mutex);
	mhi_unprepare_channel(mhi_cntrl, mhi_chan);

	return ret;
}