static int mhu_db_probe()

in arm_mhu_db.c [248:330]

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

static int mhu_db_probe(struct amba_device *adev, const struct amba_id *id)
{
	u32 cell_count;
	int i, err, max_chans;
	struct arm_mhu *mhu;
	struct mbox_chan *chans;
	struct device *dev = &adev->dev;
	struct device_node *np = dev->of_node;
	int mhu_reg[MHU_CHANS] = {
		MHU_LP_OFFSET, MHU_HP_OFFSET, MHU_SEC_OFFSET,
	};

	if (!of_device_is_compatible(np, "arm,mhu-doorbell"))
		return -ENODEV;

	err = of_property_read_u32(np, "#mbox-cells", &cell_count);
	if (err) {
		dev_err(dev, "failed to read #mbox-cells in '%pOF'\n", np);
		return err;
	}

	if (cell_count == 2) {
		max_chans = MHU_CHAN_MAX;
	} else {
		dev_err(dev, "incorrect value of #mbox-cells in '%pOF'\n", np);
		return -EINVAL;
	}

	mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
	if (!mhu)
		return -ENOMEM;

	mhu->base = devm_ioremap_resource(dev, &adev->res);
	if (IS_ERR(mhu->base))
		return PTR_ERR(mhu->base);

	chans = devm_kcalloc(dev, max_chans, sizeof(*chans), GFP_KERNEL);
	if (!chans)
		return -ENOMEM;

	mhu->dev = dev;
	mhu->mbox.dev = dev;
	mhu->mbox.chans = chans;
	mhu->mbox.num_chans = max_chans;
	mhu->mbox.txdone_irq = false;
	mhu->mbox.txdone_poll = true;
	mhu->mbox.txpoll_period = 1;

	mhu->mbox.of_xlate = mhu_db_mbox_xlate;
	amba_set_drvdata(adev, mhu);

	mhu->mbox.ops = &mhu_db_ops;

	err = devm_mbox_controller_register(dev, &mhu->mbox);
	if (err) {
		dev_err(dev, "Failed to register mailboxes %d\n", err);
		return err;
	}

	for (i = 0; i < MHU_CHANS; i++) {
		int irq = mhu->mlink[i].irq = adev->irq[i];

		if (irq <= 0) {
			dev_dbg(dev, "No IRQ found for Channel %d\n", i);
			continue;
		}

		mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i];
		mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;

		err = devm_request_threaded_irq(dev, irq, NULL,
						mhu_db_mbox_rx_handler,
						IRQF_ONESHOT, "mhu_db_link", mhu);
		if (err) {
			dev_err(dev, "Can't claim IRQ %d\n", irq);
			mbox_controller_unregister(&mhu->mbox);
			return err;
		}
	}

	dev_info(dev, "ARM MHU Doorbell mailbox registered\n");
	return 0;
}